aboutsummaryrefslogtreecommitdiff
path: root/gzip.c
blob: 98ce259caf892ae45932b2695734153c56a3e7fe (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
/* vi: set sw=4 ts=4: */
/*
 * Gzip implementation for busybox
 *
 * Based on GNU gzip Copyright (C) 1992-1993 Jean-loup Gailly.
 *
 * Originally adjusted for busybox by Charles P. Wright <cpw@unix.asb.com>
 *		"this is a stripped down version of gzip I put into busybox, it does
 *		only standard in to standard out with -9 compression.  It also requires
 *		the zcat module for some important functions."
 *
 * Adjusted further by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
 * to support files as well as stdin/stdout, and to generally behave itself wrt
 * command line handling.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include "internal.h"
#define BB_DECLARE_EXTERN
#define bb_need_memory_exhausted
#include "messages.c"

/* These defines are very important for BusyBox.  Without these,
 * huge chunks of ram are pre-allocated making the BusyBox bss 
 * size Freaking Huge(tm), which is a bad thing.*/
#define SMALL_MEM
#define DYN_ALLOC

/* I don't like nested includes, but the string and io functions are used
 * too often
 */
#include <stdio.h>
#include <string.h>
#define memzero(s, n)     memset ((void *)(s), 0, (n))

#ifndef RETSIGTYPE
#  define RETSIGTYPE void
#endif

#define local static

typedef unsigned char uch;
typedef unsigned short ush;
typedef unsigned long ulg;

/* Return codes from gzip */
#define OK      0
#define ERROR   1
#define WARNING 2

/* Compression methods (see algorithm.doc) */
#define STORED      0
#define COMPRESSED  1
#define PACKED      2
#define LZHED       3
/* methods 4 to 7 reserved */
#define DEFLATED    8
#define MAX_METHODS 9
extern int method;				/* compression method */

/* To save memory for 16 bit systems, some arrays are overlaid between
 * the various modules:
 * deflate:  prev+head   window      d_buf  l_buf  outbuf
 * unlzw:    tab_prefix  tab_suffix  stack  inbuf  outbuf
 * inflate:              window             inbuf
 * unpack:               window             inbuf  prefix_len
 * unlzh:    left+right  window      c_table inbuf c_len
 * For compression, input is done in window[]. For decompression, output
 * is done in window except for unlzw.
 */

#ifndef	INBUFSIZ
#  ifdef SMALL_MEM
#    define INBUFSIZ  0x2000	/* input buffer size */
#  else
#    define INBUFSIZ  0x8000	/* input buffer size */
#  endif
#endif
#define INBUF_EXTRA  64			/* required by unlzw() */

#ifndef	OUTBUFSIZ
#  ifdef SMALL_MEM
#    define OUTBUFSIZ   8192	/* output buffer size */
#  else
#    define OUTBUFSIZ  16384	/* output buffer size */
#  endif
#endif
#define OUTBUF_EXTRA 2048		/* required by unlzw() */

#ifndef DIST_BUFSIZE
#  ifdef SMALL_MEM
#    define DIST_BUFSIZE 0x2000	/* buffer for distances, see trees.c */
#  else
#    define DIST_BUFSIZE 0x8000	/* buffer for distances, see trees.c */
#  endif
#endif

#ifdef DYN_ALLOC
#  define EXTERN(type, array)  extern type * array
#  define DECLARE(type, array, size)  type * array
#  define ALLOC(type, array, size) { \
      array = (type*)calloc((size_t)(((size)+1L)/2), 2*sizeof(type)); \
      if (array == NULL) errorMsg(memory_exhausted); \
   }
#  define FREE(array) {if (array != NULL) free(array), array=NULL;}
#else
#  define EXTERN(type, array)  extern type array[]
#  define DECLARE(type, array, size)  type array[size]
#  define ALLOC(type, array, size)
#  define FREE(array)
#endif

EXTERN(uch, inbuf);				/* input buffer */
EXTERN(uch, outbuf);			/* output buffer */
EXTERN(ush, d_buf);				/* buffer for distances, see trees.c */
EXTERN(uch, window);			/* Sliding window and suffix table (unlzw) */
#define tab_suffix window
#ifndef MAXSEG_64K
#  define tab_prefix prev		/* hash link (see deflate.c) */
#  define head (prev+WSIZE)		/* hash head (see deflate.c) */
EXTERN(ush, tab_prefix);		/* prefix code (see unlzw.c) */
#else
#  define tab_prefix0 prev
#  define head tab_prefix1
EXTERN(ush, tab_prefix0);		/* prefix for even codes */
EXTERN(ush, tab_prefix1);		/* prefix for odd  codes */
#endif

extern unsigned insize;			/* valid bytes in inbuf */
extern unsigned inptr;			/* index of next byte to be processed in inbuf */
extern unsigned outcnt;			/* bytes in output buffer */

extern long bytes_in;			/* number of input bytes */
extern long bytes_out;			/* number of output bytes */
extern long header_bytes;		/* number of bytes in gzip header */

#define isize bytes_in
/* for compatibility with old zip sources (to be cleaned) */

extern int ifd;					/* input file descriptor */
extern int ofd;					/* output file descriptor */
extern char ifname[];			/* input file name or "stdin" */
extern char ofname[];			/* output file name or "stdout" */
extern char *progname;			/* program name */

extern long time_stamp;			/* original time stamp (modification time) */
extern long ifile_size;			/* input file size, -1 for devices (debug only) */

typedef int file_t;				/* Do not use stdio */

#define NO_FILE  (-1)			/* in memory compression */


#define	PACK_MAGIC     "\037\036"	/* Magic header for packed files */
#define	GZIP_MAGIC     "\037\213"	/* Magic header for gzip files, 1F 8B */
#define	OLD_GZIP_MAGIC "\037\236"	/* Magic header for gzip 0.5 = freeze 1.x */
#define	LZH_MAGIC      "\037\240"	/* Magic header for SCO LZH Compress files */
#define PKZIP_MAGIC    "\120\113\003\004"	/* Magic header for pkzip files */

/* gzip flag byte */
#define ASCII_FLAG   0x01		/* bit 0 set: file probably ascii text */
#define CONTINUATION 0x02		/* bit 1 set: continuation of multi-part gzip file */
#define EXTRA_FIELD  0x04		/* bit 2 set: extra field present */
#define ORIG_NAME    0x08		/* bit 3 set: original file name present */
#define COMMENT      0x10		/* bit 4 set: file comment present */
#define ENCRYPTED    0x20		/* bit 5 set: file is encrypted */
#define RESERVED     0xC0		/* bit 6,7:   reserved */

/* internal file attribute */
#define UNKNOWN 0xffff
#define BINARY  0
#define ASCII   1

#ifndef WSIZE
#  define WSIZE 0x8000			/* window size--must be a power of two, and */
#endif							/*  at least 32K for zip's deflate method */

#define MIN_MATCH  3
#define MAX_MATCH  258
/* The minimum and maximum match lengths */

#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
/* Minimum amount of lookahead, except at the end of the input file.
 * See deflate.c for comments about the MIN_MATCH+1.
 */

#define MAX_DIST  (WSIZE-MIN_LOOKAHEAD)
/* In order to simplify the code, particularly on 16 bit machines, match
 * distances are limited to MAX_DIST instead of WSIZE.
 */

extern int decrypt;				/* flag to turn on decryption */
extern int exit_code;			/* program exit code */
extern int verbose;				/* be verbose (-v) */
extern int quiet;				/* be quiet (-q) */
extern int test;				/* check .z file integrity */
extern int save_orig_name;		/* set if original name must be saved */

#define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf(0))
#define try_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf(1))

/* put_byte is used for the compressed output, put_ubyte for the
 * uncompressed output. However unlzw() uses window for its
 * suffix table instead of its output buffer, so it does not use put_ubyte
 * (to be cleaned up).
 */
#define put_byte(c) {outbuf[outcnt++]=(uch)(c); if (outcnt==OUTBUFSIZ)\
   flush_outbuf();}
#define put_ubyte(c) {window[outcnt++]=(uch)(c); if (outcnt==WSIZE)\
   flush_window();}

/* Output a 16 bit value, lsb first */
#define put_short(w) \
{ if (outcnt < OUTBUFSIZ-2) { \
    outbuf[outcnt++] = (uch) ((w) & 0xff); \
    outbuf[outcnt++] = (uch) ((ush)(w) >> 8); \
  } else { \
    put_byte((uch)((w) & 0xff)); \
    put_byte((uch)((ush)(w) >> 8)); \
  } \
}

/* Output a 32 bit value to the bit stream, lsb first */
#define put_long(n) { \
    put_short((n) & 0xffff); \
    put_short(((ulg)(n)) >> 16); \
}

#define seekable()    0			/* force sequential output */
#define translate_eol 0			/* no option -a yet */

#define tolow(c)  (isupper(c) ? (c)-'A'+'a' : (c))	/* force to lower case */

/* Macros for getting two-byte and four-byte header values */
#define SH(p) ((ush)(uch)((p)[0]) | ((ush)(uch)((p)[1]) << 8))
#define LG(p) ((ulg)(SH(p)) | ((ulg)(SH((p)+2)) << 16))

/* Diagnostic functions */
#ifdef DEBUG
#  define Assert(cond,msg) {if(!(cond)) errorMsg(msg);}
#  define Trace(x) fprintf x
#  define Tracev(x) {if (verbose) fprintf x ;}
#  define Tracevv(x) {if (verbose>1) fprintf x ;}
#  define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
#  define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
#else
#  define Assert(cond,msg)
#  define Trace(x)
#  define Tracev(x)
#  define Tracevv(x)
#  define Tracec(c,x)
#  define Tracecv(c,x)
#endif

#define WARN(msg) {if (!quiet) fprintf msg ; \
		   if (exit_code == OK) exit_code = WARNING;}


	/* in zip.c: */
extern int zip (int in, int out);
extern int file_read (char *buf, unsigned size);

	/* in unzip.c */
extern int unzip (int in, int out);
extern int check_zipfile (int in);

	/* in unpack.c */
extern int unpack (int in, int out);

	/* in unlzh.c */
extern int unlzh (int in, int out);

	/* in gzip.c */
RETSIGTYPE abort_gzip (void);

		/* in deflate.c */
void lm_init (ush * flags);
ulg deflate (void);

		/* in trees.c */
void ct_init (ush * attr, int *method);
int ct_tally (int dist, int lc);
ulg flush_block (char *buf, ulg stored_len, int eof);

		/* in bits.c */
void bi_init (file_t zipfile);
void send_bits (int value, int length);
unsigned bi_reverse (unsigned value, int length);
void bi_windup (void);
void copy_block (char *buf, unsigned len, int header);
extern int (*read_buf) (char *buf, unsigned size);

	/* in util.c: */
extern int copy (int in, int out);
extern ulg updcrc (uch * s, unsigned n);
extern void clear_bufs (void);
extern int fill_inbuf (int eof_ok);
extern void flush_outbuf (void);
extern void flush_window (void);
extern void write_buf (int fd, void * buf, unsigned cnt);
extern char *strlwr (char *s);
extern char *add_envopt (int *argcp, char ***argvp, char *env);
extern void read_error_msg (void);
extern void write_error_msg (void);
extern void display_ratio (long num, long den, FILE * file);

	/* in inflate.c */
extern int inflate (void);

/* lzw.h -- define the lzw functions.
 * Copyright (C) 1992-1993 Jean-loup Gailly.
 * This is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License, see the file COPYING.
 */

#if !defined(OF) && defined(lint)
#  include "gzip.h"
#endif

#ifndef BITS
#  define BITS 16
#endif
#define INIT_BITS 9				/* Initial number of bits per code */

#define BIT_MASK    0x1f		/* Mask for 'number of compression bits' */
/* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free.
 * It's a pity that old uncompress does not check bit 0x20. That makes
 * extension of the format actually undesirable because old compress
 * would just crash on the new format instead of giving a meaningful
 * error message. It does check the number of bits, but it's more
 * helpful to say "unsupported format, get a new version" than
 * "can only handle 16 bits".
 */

#define BLOCK_MODE  0x80
/* Block compression: if table is full and compression rate is dropping,
 * clear the dictionary.
 */

#define LZW_RESERVED 0x60		/* reserved bits */

#define	CLEAR  256				/* flush the dictionary */
#define FIRST  (CLEAR+1)		/* first free entry */

extern int maxbits;				/* max bits per code for LZW */
extern int block_mode;			/* block compress mode -C compatible with 2.0 */

/* revision.h -- define the version number
 * Copyright (C) 1992-1993 Jean-loup Gailly.
 * This is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License, see the file COPYING.
 */

#define VERSION "1.2.4"
#define PATCHLEVEL 0
#define REVDATE "18 Aug 93"

/* This version does not support compression into old compress format: */
#ifdef LZW
#  undef LZW
#endif

/* tailor.h -- target dependent definitions
 * Copyright (C) 1992-1993 Jean-loup Gailly.
 * This is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License, see the file COPYING.
 */

/* The target dependent definitions should be defined here only.
 * The target dependent functions should be defined in tailor.c.
 */


#if defined(__MSDOS__) && !defined(MSDOS)
#  define MSDOS
#endif

#if defined(__OS2__) && !defined(OS2)
#  define OS2
#endif

#if defined(OS2) && defined(MSDOS)	/* MS C under OS/2 */
#  undef MSDOS
#endif

#ifdef MSDOS
#  ifdef __GNUC__
	 /* DJGPP version 1.09+ on MS-DOS.
	  * The DJGPP 1.09 stat() function must be upgraded before gzip will
	  * fully work.
	  * No need for DIRENT, since <unistd.h> defines POSIX_SOURCE which
	  * implies DIRENT.
	  */
#    define near
#  else
#    define MAXSEG_64K
#    ifdef __TURBOC__
#      define NO_OFF_T
#      ifdef __BORLANDC__
#        define DIRENT
#      else
#        define NO_UTIME
#      endif
#    else						/* MSC */
#      define HAVE_SYS_UTIME_H
#      define NO_UTIME_H
#    endif
#  endif
#  define PATH_SEP2 '\\'
#  define PATH_SEP3 ':'
#  define MAX_PATH_LEN  128
#  define NO_MULTIPLE_DOTS
#  define MAX_EXT_CHARS 3
#  define Z_SUFFIX "z"
#  define NO_CHOWN
#  define PROTO
#  define STDC_HEADERS
#  define NO_SIZE_CHECK
#  define casemap(c) tolow(c)	/* Force file names to lower case */
#  include <io.h>
#  define OS_CODE  0x00
#  define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
#  if !defined(NO_ASM) && !defined(ASMV)
#    define ASMV
#  endif
#else
#  define near
#endif

#ifdef OS2
#  define PATH_SEP2 '\\'
#  define PATH_SEP3 ':'
#  define MAX_PATH_LEN  260
#  ifdef OS2FAT
#    define NO_MULTIPLE_DOTS
#    define MAX_EXT_CHARS 3
#    define Z_SUFFIX "z"
#    define casemap(c) tolow(c)
#  endif
#  define NO_CHOWN
#  define PROTO
#  define STDC_HEADERS
#  include <io.h>
#  define OS_CODE  0x06
#  define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
#  ifdef _MSC_VER
#    define HAVE_SYS_UTIME_H
#    define NO_UTIME_H
#    define MAXSEG_64K
#    undef near
#    define near _near
#  endif
#  ifdef __EMX__
#    define HAVE_SYS_UTIME_H
#    define NO_UTIME_H
#    define DIRENT
#    define EXPAND(argc,argv) \
       {_response(&argc, &argv); _wildcard(&argc, &argv);}
#  endif
#  ifdef __BORLANDC__
#    define DIRENT
#  endif
#  ifdef __ZTC__
#    define NO_DIR
#    define NO_UTIME_H
#    include <dos.h>
#    define EXPAND(argc,argv) \
       {response_expand(&argc, &argv);}
#  endif
#endif

#ifdef WIN32					/* Windows NT */
#  define HAVE_SYS_UTIME_H
#  define NO_UTIME_H
#  define PATH_SEP2 '\\'
#  define PATH_SEP3 ':'
#  define MAX_PATH_LEN  260
#  define NO_CHOWN
#  define PROTO
#  define STDC_HEADERS
#  define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
#  include <io.h>
#  include <malloc.h>
#  ifdef NTFAT
#    define NO_MULTIPLE_DOTS
#    define MAX_EXT_CHARS 3
#    define Z_SUFFIX "z"
#    define casemap(c) tolow(c)	/* Force file names to lower case */
#  endif
#  define OS_CODE  0x0b
#endif

#ifdef MSDOS
#  ifdef __TURBOC__
#    include <alloc.h>
#    define DYN_ALLOC
	 /* Turbo C 2.0 does not accept static allocations of large arrays */
void *fcalloc(unsigned items, unsigned size);
void fcfree(void *ptr);
#  else							/* MSC */
#    include <malloc.h>
#    define fcalloc(nitems,itemsize) halloc((long)(nitems),(itemsize))
#    define fcfree(ptr) hfree(ptr)
#  endif
#else
#  ifdef MAXSEG_64K
#    define fcalloc(items,size) calloc((items),(size))
#  else
#    define fcalloc(items,size) malloc((size_t)(items)*(size_t)(size))
#  endif
#  define fcfree(ptr) free(ptr)
#endif

#if defined(VAXC) || defined(VMS)
#  define PATH_SEP ']'
#  define PATH_SEP2 ':'
#  define SUFFIX_SEP ';'
#  define NO_MULTIPLE_DOTS
#  define Z_SUFFIX "-gz"
#  define RECORD_IO 1
#  define casemap(c) tolow(c)
#  define OS_CODE  0x02
#  define OPTIONS_VAR "GZIP_OPT"
#  define STDC_HEADERS
#  define NO_UTIME
#  define EXPAND(argc,argv) vms_expand_args(&argc,&argv);
#  include <file.h>
#  define unlink delete
#  ifdef VAXC
#    define NO_FCNTL_H
#    include <unixio.h>
#  endif
#endif

#ifdef AMIGA
#  define PATH_SEP2 ':'
#  define STDC_HEADERS
#  define OS_CODE  0x01
#  define ASMV
#  ifdef __GNUC__
#    define DIRENT
#    define HAVE_UNISTD_H
#  else							/* SASC */
#    define NO_STDIN_FSTAT
#    define SYSDIR
#    define NO_SYMLINK
#    define NO_CHOWN
#    define NO_FCNTL_H
#    include <fcntl.h>			/* for read() and write() */
#    define direct dirent
extern void _expand_args(int *argc, char ***argv);

#    define EXPAND(argc,argv) _expand_args(&argc,&argv);
#    undef  O_BINARY			/* disable useless --ascii option */
#  endif
#endif

#if defined(ATARI) || defined(atarist)
#  ifndef STDC_HEADERS
#    define STDC_HEADERS
#    define HAVE_UNISTD_H
#    define DIRENT
#  endif
#  define ASMV
#  define OS_CODE  0x05
#  ifdef TOSFS
#    define PATH_SEP2 '\\'
#    define PATH_SEP3 ':'
#    define MAX_PATH_LEN  128
#    define NO_MULTIPLE_DOTS
#    define MAX_EXT_CHARS 3
#    define Z_SUFFIX "z"
#    define NO_CHOWN
#    define casemap(c) tolow(c)	/* Force file names to lower case */
#    define NO_SYMLINK
#  endif
#endif

#ifdef MACOS
#  define PATH_SEP ':'
#  define DYN_ALLOC
#  define PROTO
#  define NO_STDIN_FSTAT
#  define NO_CHOWN
#  define NO_UTIME
#  define chmod(file, mode) (0)
#  define OPEN(name, flags, mode) open(name, flags)
#  define OS_CODE  0x07
#  ifdef MPW
#    define isatty(fd) ((fd) <= 2)
#  endif
#endif

#ifdef __50SERIES				/* Prime/PRIMOS */
#  define PATH_SEP '>'
#  define STDC_HEADERS
#  define NO_MEMORY_H
#  define NO_UTIME_H
#  define NO_UTIME
#  define NO_CHOWN
#  define NO_STDIN_FSTAT
#  define NO_SIZE_CHECK
#  define NO_SYMLINK
#  define RECORD_IO  1
#  define casemap(c)  tolow(c)	/* Force file names to lower case */
#  define put_char(c) put_byte((c) & 0x7F)
#  define get_char(c) ascii2pascii(get_byte())
#  define OS_CODE  0x0F			/* temporary, subject to change */
#  ifdef SIGTERM
#    undef SIGTERM				/* We don't want a signal handler for SIGTERM */
#  endif
#endif

#if defined(pyr) && !defined(NOMEMCPY)	/* Pyramid */
#  define NOMEMCPY				/* problem with overlapping copies */
#endif

#ifdef TOPS20
#  define OS_CODE  0x0a
#endif

#ifndef unix
#  define NO_ST_INO				/* don't rely on inode numbers */
#endif


	/* Common defaults */

#ifndef OS_CODE
#  define OS_CODE  0x03			/* assume Unix */
#endif

#ifndef PATH_SEP
#  define PATH_SEP '/'
#endif

#ifndef casemap
#  define casemap(c) (c)
#endif

#ifndef OPTIONS_VAR
#  define OPTIONS_VAR "GZIP"
#endif

#ifndef Z_SUFFIX
#  define Z_SUFFIX ".gz"
#endif

#ifdef MAX_EXT_CHARS
#  define MAX_SUFFIX  MAX_EXT_CHARS
#else
#  define MAX_SUFFIX  30
#endif

#ifndef MAKE_LEGAL_NAME
#  ifdef NO_MULTIPLE_DOTS
#    define MAKE_LEGAL_NAME(name)   make_simple_name(name)
#  else
#    define MAKE_LEGAL_NAME(name)
#  endif
#endif

#ifndef MIN_PART
#  define MIN_PART 3
   /* keep at least MIN_PART chars between dots in a file name. */
#endif

#ifndef EXPAND
#  define EXPAND(argc,argv)
#endif

#ifndef RECORD_IO
#  define RECORD_IO 0
#endif

#ifndef SET_BINARY_MODE
#  define SET_BINARY_MODE(fd)
#endif

#ifndef OPEN
#  define OPEN(name, flags, mode) open(name, flags, mode)
#endif

#ifndef get_char
#  define get_char() get_byte()
#endif

#ifndef put_char
#  define put_char(c) put_byte(c)
#endif
/* bits.c -- output variable-length bit strings
 * Copyright (C) 1992-1993 Jean-loup Gailly
 * This is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License, see the file COPYING.
 */


/*
 *  PURPOSE
 *
 *      Output variable-length bit strings. Compression can be done
 *      to a file or to memory. (The latter is not supported in this version.)
 *
 *  DISCUSSION
 *
 *      The PKZIP "deflate" file format interprets compressed file data
 *      as a sequence of bits.  Multi-bit strings in the file may cross
 *      byte boundaries without restriction.
 *
 *      The first bit of each byte is the low-order bit.
 *
 *      The routines in this file allow a variable-length bit value to
 *      be output right-to-left (useful for literal values). For
 *      left-to-right output (useful for code strings from the tree routines),
 *      the bits must have been reversed first with bi_reverse().
 *
 *      For in-memory compression, the compressed bit stream goes directly
 *      into the requested output buffer. The input data is read in blocks
 *      by the mem_read() function. The buffer is limited to 64K on 16 bit
 *      machines.
 *
 *  INTERFACE
 *
 *      void bi_init (FILE *zipfile)
 *          Initialize the bit string routines.
 *
 *      void send_bits (int value, int length)
 *          Write out a bit string, taking the source bits right to
 *          left.
 *
 *      int bi_reverse (int value, int length)
 *          Reverse the bits of a bit string, taking the source bits left to
 *          right and emitting them right to left.
 *
 *      void bi_windup (void)
 *          Write out any remaining bits in an incomplete byte.
 *
 *      void copy_block(char *buf, unsigned len, int header)
 *          Copy a stored block to the zip file, storing first the length and
 *          its one's complement if requested.
 *
 */

#ifdef DEBUG
#  include <stdio.h>
#endif

/* ===========================================================================
 * Local data used by the "bit string" routines.
 */

local file_t zfile;				/* output gzip file */

local unsigned short bi_buf;

/* Output buffer. bits are inserted starting at the bottom (least significant
 * bits).
 */

#define Buf_size (8 * 2*sizeof(char))
/* Number of bits used within bi_buf. (bi_buf might be implemented on
 * more than 16 bits on some systems.)
 */

local int bi_valid;

/* Number of valid bits in bi_buf.  All bits above the last valid bit
 * are always zero.
 */

int (*read_buf) (char *buf, unsigned size);

/* Current input function. Set to mem_read for in-memory compression */

#ifdef DEBUG
ulg bits_sent;					/* bit length of the compressed data */
#endif

/* ===========================================================================
 * Initialize the bit string routines.
 */
void bi_init(zipfile)
file_t zipfile;					/* output zip file, NO_FILE for in-memory compression */
{
	zfile = zipfile;
	bi_buf = 0;
	bi_valid = 0;
#ifdef DEBUG
	bits_sent = 0L;
#endif

	/* Set the defaults for file compression. They are set by memcompress
	 * for in-memory compression.
	 */
	if (zfile != NO_FILE) {
		read_buf = file_read;
	}
}

/* ===========================================================================
 * Send a value on a given number of bits.
 * IN assertion: length <= 16 and value fits in length bits.
 */
void send_bits(value, length)
int value;						/* value to send */
int length;						/* number of bits */
{
#ifdef DEBUG
	Tracev((stderr, " l %2d v %4x ", length, value));
	Assert(length > 0 && length <= 15, "invalid length");
	bits_sent += (ulg) length;
#endif
	/* If not enough room in bi_buf, use (valid) bits from bi_buf and
	 * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
	 * unused bits in value.
	 */
	if (bi_valid > (int) Buf_size - length) {
		bi_buf |= (value << bi_valid);
		put_short(bi_buf);
		bi_buf = (ush) value >> (Buf_size - bi_valid);
		bi_valid += length - Buf_size;
	} else {
		bi_buf |= value << bi_valid;
		bi_valid += length;
	}
}

/* ===========================================================================
 * Reverse the first len bits of a code, using straightforward code (a faster
 * method would use a table)
 * IN assertion: 1 <= len <= 15
 */
unsigned bi_reverse(code, len)
unsigned code;					/* the value to invert */
int len;						/* its bit length */
{
	register unsigned res = 0;

	do {
		res |= code & 1;
		code >>= 1, res <<= 1;
	} while (--len > 0);
	return res >> 1;
}

/* ===========================================================================
 * Write out any remaining bits in an incomplete byte.
 */
void bi_windup()
{
	if (bi_valid > 8) {
		put_short(bi_buf);
	} else if (bi_valid > 0) {
		put_byte(bi_buf);
	}
	bi_buf = 0;
	bi_valid = 0;
#ifdef DEBUG
	bits_sent = (bits_sent + 7) & ~7;
#endif
}

/* ===========================================================================
 * Copy a stored block to the zip file, storing first the length and its
 * one's complement if requested.
 */
void copy_block(buf, len, header)
char *buf;						/* the input data */
unsigned len;					/* its length */
int header;						/* true if block header must be written */
{
	bi_windup();				/* align on byte boundary */

	if (header) {
		put_short((ush) len);
		put_short((ush) ~ len);
#ifdef DEBUG
		bits_sent += 2 * 16;
#endif
	}
#ifdef DEBUG
	bits_sent += (ulg) len << 3;
#endif
	while (len--) {
#ifdef CRYPT
		int t;

		if (key)
			zencode(*buf, t);
#endif
		put_byte(*buf++);
	}
}

/* deflate.c -- compress data using the deflation algorithm
 * Copyright (C) 1992-1993 Jean-loup Gailly
 * This is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License, see the file COPYING.
 */

/*
 *  PURPOSE
 *
 *      Identify new text as repetitions of old text within a fixed-
 *      length sliding window trailing behind the new text.
 *
 *  DISCUSSION
 *
 *      The "deflation" process depends on being able to identify portions
 *      of the input text which are identical to earlier input (within a
 *      sliding window trailing behind the input currently being processed).
 *
 *      The most straightforward technique turns out to be the fastest for
 *      most input files: try all possible matches and select the longest.
 *      The key feature of this algorithm is that insertions into the string
 *      dictionary are very simple and thus fast, and deletions are avoided
 *      completely. Insertions are performed at each input character, whereas
 *      string matches are performed only when the previous match ends. So it
 *      is preferable to spend more time in matches to allow very fast string
 *      insertions and avoid deletions. The matching algorithm for small
 *      strings is inspired from that of Rabin & Karp. A brute force approach
 *      is used to find longer strings when a small match has been found.
 *      A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
 *      (by Leonid Broukhis).
 *         A previous version of this file used a more sophisticated algorithm
 *      (by Fiala and Greene) which is guaranteed to run in linear amortized
 *      time, but has a larger average cost, uses more memory and is patented.
 *      However the F&G algorithm may be faster for some highly redundant
 *      files if the parameter max_chain_length (described below) is too large.
 *
 *  ACKNOWLEDGEMENTS
 *
 *      The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
 *      I found it in 'freeze' written by Leonid Broukhis.
 *      Thanks to many info-zippers for bug reports and testing.
 *
 *  REFERENCES
 *
 *      APPNOTE.TXT documentation file in PKZIP 1.93a distribution.
 *
 *      A description of the Rabin and Karp algorithm is given in the book
 *         "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
 *
 *      Fiala,E.R., and Greene,D.H.
 *         Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
 *
 *  INTERFACE
 *
 *      void lm_init (int pack_level, ush *flags)
 *          Initialize the "longest match" routines for a new file
 *
 *      ulg deflate (void)
 *          Processes a new input file and return its compressed length. Sets
 *          the compressed length, crc, deflate flags and internal file
 *          attributes.
 */

#include <stdio.h>

/* ===========================================================================
 * Configuration parameters
 */

/* Compile with MEDIUM_MEM to reduce the memory requirements or
 * with SMALL_MEM to use as little memory as possible. Use BIG_MEM if the
 * entire input file can be held in memory (not possible on 16 bit systems).
 * Warning: defining these symbols affects HASH_BITS (see below) and thus
 * affects the compression ratio. The compressed output
 * is still correct, and might even be smaller in some cases.
 */

#ifdef SMALL_MEM
#   define HASH_BITS  13		/* Number of bits used to hash strings */
#endif
#ifdef MEDIUM_MEM
#   define HASH_BITS  14
#endif
#ifndef HASH_BITS
#   define HASH_BITS  15
   /* For portability to 16 bit machines, do not use values above 15. */
#endif

/* To save space (see unlzw.c), we overlay prev+head with tab_prefix and
 * window with tab_suffix. Check that we can do this:
 */
#if (WSIZE<<1) > (1<<BITS)
error:cannot overlay window with tab_suffix and prev with tab_prefix0
#endif
#if HASH_BITS > BITS-1
error:cannot overlay head with tab_prefix1
#endif
#define HASH_SIZE (unsigned)(1<<HASH_BITS)
#define HASH_MASK (HASH_SIZE-1)
#define WMASK     (WSIZE-1)
/* HASH_SIZE and WSIZE must be powers of two */
#define NIL 0
/* Tail of hash chains */
#define FAST 4
#define SLOW 2
/* speed options for the general purpose bit flag */
#ifndef TOO_FAR
#  define TOO_FAR 4096
#endif
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
/* ===========================================================================
 * Local data used by the "longest match" routines.
 */
typedef ush Pos;
typedef unsigned IPos;

/* A Pos is an index in the character window. We use short instead of int to
 * save space in the various tables. IPos is used only for parameter passing.
 */

/* DECLARE(uch, window, 2L*WSIZE); */
/* Sliding window. Input bytes are read into the second half of the window,
 * and move to the first half later to keep a dictionary of at least WSIZE
 * bytes. With this organization, matches are limited to a distance of
 * WSIZE-MAX_MATCH bytes, but this ensures that IO is always
 * performed with a length multiple of the block size. Also, it limits
 * the window size to 64K, which is quite useful on MSDOS.
 * To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would
 * be less efficient).
 */

/* DECLARE(Pos, prev, WSIZE); */
/* Link to older string with same hash index. To limit the size of this
 * array to 64K, this link is maintained only for the last 32K strings.
 * An index in this array is thus a window index modulo 32K.
 */

/* DECLARE(Pos, head, 1<<HASH_BITS); */
/* Heads of the hash chains or NIL. */

ulg window_size = (ulg) 2 * WSIZE;

/* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the
 * input file length plus MIN_LOOKAHEAD.
 */

long block_start;

/* window position at the beginning of the current output block. Gets
 * negative when the window is moved backwards.
 */

local unsigned ins_h;			/* hash index of string to be inserted */

#define H_SHIFT  ((HASH_BITS+MIN_MATCH-1)/MIN_MATCH)
/* Number of bits by which ins_h and del_h must be shifted at each
 * input step. It must be such that after MIN_MATCH steps, the oldest
 * byte no longer takes part in the hash key, that is:
 *   H_SHIFT * MIN_MATCH >= HASH_BITS
 */

unsigned int near prev_length;

/* Length of the best match at previous step. Matches not greater than this
 * are discarded. This is used in the lazy match evaluation.
 */

unsigned near strstart;			/* start of string to insert */
unsigned near match_start;		/* start of matching string */
local int eofile;				/* flag set at end of input file */
local unsigned lookahead;		/* number of valid bytes ahead in window */

unsigned near max_chain_length;

/* To speed up deflation, hash chains are never searched beyond this length.
 * A higher limit improves compression ratio but degrades the speed.
 */

local unsigned int max_lazy_match;

/* Attempt to find a better match only when the current match is strictly
 * smaller than this value. This mechanism is used only for compression
 * levels >= 4.
 */
#define max_insert_length  max_lazy_match
/* Insert new strings in the hash table only if the match length
 * is not greater than this length. This saves time but degrades compression.
 * max_insert_length is used only for compression levels <= 3.
 */

unsigned near good_match;

/* Use a faster search when the previous match is longer than this */


/* Values for max_lazy_match, good_match and max_chain_length, depending on
 * the desired pack level (0..9). The values given below have been tuned to
 * exclude worst case performance for pathological files. Better values may be
 * found for specific files.
 */

typedef struct config {
	ush good_length;			/* reduce lazy search above this match length */
	ush max_lazy;				/* do not perform lazy search above this match length */
	ush nice_length;			/* quit search above this match length */
	ush max_chain;
} config;

#ifdef  FULL_SEARCH
# define nice_match MAX_MATCH
#else
int near nice_match;			/* Stop searching when current match exceeds this */
#endif

local config configuration_table =
								/* 9 */ { 32, 258, 258, 4096 };
								/* maximum compression */

/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
 * meaning.
 */

#define EQUAL 0
/* result of memcmp for equal strings */

/* ===========================================================================
 *  Prototypes for local functions.
 */
local void fill_window (void);

int longest_match (IPos cur_match);

#ifdef ASMV
void match_init (void);		/* asm code initialization */
#endif

#ifdef DEBUG
local void check_match (IPos start, IPos match, int length);
#endif

/* ===========================================================================
 * Update a hash value with the given input byte
 * IN  assertion: all calls to to UPDATE_HASH are made with consecutive
 *    input characters, so that a running hash key can be computed from the
 *    previous key instead of complete recalculation each time.
 */
#define UPDATE_HASH(h,c) (h = (((h)<<H_SHIFT) ^ (c)) & HASH_MASK)

/* ===========================================================================
 * Insert string s in the dictionary and set match_head to the previous head
 * of the hash chain (the most recent string with same hash key). Return
 * the previous length of the hash chain.
 * IN  assertion: all calls to to INSERT_STRING are made with consecutive
 *    input characters and the first MIN_MATCH bytes of s are valid
 *    (except for the last MIN_MATCH-1 bytes of the input file).
 */
#define INSERT_STRING(s, match_head) \
   (UPDATE_HASH(ins_h, window[(s) + MIN_MATCH-1]), \
    prev[(s) & WMASK] = match_head = head[ins_h], \
    head[ins_h] = (s))

/* ===========================================================================
 * Initialize the "longest match" routines for a new file
 */
void lm_init(flags)
ush *flags;						/* general purpose bit flag */
{
	register unsigned j;

	/* Initialize the hash table. */
#if defined(MAXSEG_64K) && HASH_BITS == 15
	for (j = 0; j < HASH_SIZE; j++)
		head[j] = NIL;
#else
	memzero((char *) head, HASH_SIZE * sizeof(*head));
#endif
	/* prev will be initialized on the fly */

	/* Set the default configuration parameters:
	 */
	max_lazy_match = configuration_table.max_lazy;
	good_match = configuration_table.good_length;
#ifndef FULL_SEARCH
	nice_match = configuration_table.nice_length;
#endif
	max_chain_length = configuration_table.max_chain;
	*flags |= SLOW;
	/* ??? reduce max_chain_length for binary files */

	strstart = 0;
	block_start = 0L;
#ifdef ASMV
	match_init();				/* initialize the asm code */
#endif

	lookahead = read_buf((char *) window,
						 sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE);

	if (lookahead == 0 || lookahead == (unsigned) EOF) {
		eofile = 1, lookahead = 0;
		return;
	}
	eofile = 0;
	/* Make sure that we always have enough lookahead. This is important
	 * if input comes from a device such as a tty.
	 */
	while (lookahead < MIN_LOOKAHEAD && !eofile)
		fill_window();

	ins_h = 0;
	for (j = 0; j < MIN_MATCH - 1; j++)
		UPDATE_HASH(ins_h, window[j]);
	/* If lookahead < MIN_MATCH, ins_h is garbage, but this is
	 * not important since only literal bytes will be emitted.
	 */
}

/* ===========================================================================
 * Set match_start to the longest match starting at the given string and
 * return its length. Matches shorter or equal to prev_length are discarded,
 * in which case the result is equal to prev_length and match_start is
 * garbage.
 * IN assertions: cur_match is the head of the hash chain for the current
 *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
 */
#ifndef ASMV
/* For MSDOS, OS/2 and 386 Unix, an optimized version is in match.asm or
 * match.s. The code is functionally equivalent, so you can use the C version
 * if desired.
 */
int longest_match(cur_match)
IPos cur_match;					/* current match */
{
	unsigned chain_length = max_chain_length;	/* max hash chain length */
	register uch *scan = window + strstart;	/* current string */
	register uch *match;		/* matched string */
	register int len;			/* length of current match */
	int best_len = prev_length;	/* best match length so far */
	IPos limit =

		strstart > (IPos) MAX_DIST ? strstart - (IPos) MAX_DIST : NIL;
	/* Stop when cur_match becomes <= limit. To simplify the code,
	 * we prevent matches with the string of window index 0.
	 */

/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
 * It is easy to get rid of this optimization if necessary.
 */
#if HASH_BITS < 8 || MAX_MATCH != 258
  error:Code too clever
#endif
#ifdef UNALIGNED_OK
		/* Compare two bytes at a time. Note: this is not always beneficial.
		 * Try with and without -DUNALIGNED_OK to check.
		 */
	register uch *strend = window + strstart + MAX_MATCH - 1;
	register ush scan_start = *(ush *) scan;
	register ush scan_end = *(ush *) (scan + best_len - 1);
#else
	register uch *strend = window + strstart + MAX_MATCH;
	register uch scan_end1 = scan[best_len - 1];
	register uch scan_end = scan[best_len];
#endif

	/* Do not waste too much time if we already have a good match: */
	if (prev_length >= good_match) {
		chain_length >>= 2;
	}
	Assert(strstart <= window_size - MIN_LOOKAHEAD,
		   "insufficient lookahead");

	do {
		Assert(cur_match < strstart, "no future");
		match = window + cur_match;

		/* Skip to next match if the match length cannot increase
		 * or if the match length is less than 2:
		 */
#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
		/* This code assumes sizeof(unsigned short) == 2. Do not use
		 * UNALIGNED_OK if your compiler uses a different size.
		 */
		if (*(ush *) (match + best_len - 1) != scan_end ||
			*(ush *) match != scan_start)
			continue;

		/* It is not necessary to compare scan[2] and match[2] since they are
		 * always equal when the other bytes match, given that the hash keys
		 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
		 * strstart+3, +5, ... up to strstart+257. We check for insufficient
		 * lookahead only every 4th comparison; the 128th check will be made
		 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
		 * necessary to put more guard bytes at the end of the window, or
		 * to check more often for insufficient lookahead.
		 */
		scan++, match++;
		do {
		} while (*(ush *) (scan += 2) == *(ush *) (match += 2) &&
				 *(ush *) (scan += 2) == *(ush *) (match += 2) &&
				 *(ush *) (scan += 2) == *(ush *) (match += 2) &&
				 *(ush *) (scan += 2) == *(ush *) (match += 2) &&
				 scan < strend);
		/* The funny "do {}" generates better code on most compilers */

		/* Here, scan <= window+strstart+257 */
		Assert(scan <= window + (unsigned) (window_size - 1), "wild scan");
		if (*scan == *match)
			scan++;

		len = (MAX_MATCH - 1) - (int) (strend - scan);
		scan = strend - (MAX_MATCH - 1);

#else							/* UNALIGNED_OK */

		if (match[best_len] != scan_end ||
			match[best_len - 1] != scan_end1 ||
			*match != *scan || *++match != scan[1])
			continue;

		/* The check at best_len-1 can be removed because it will be made
		 * again later. (This heuristic is not always a win.)
		 * It is not necessary to compare scan[2] and match[2] since they
		 * are always equal when the other bytes match, given that
		 * the hash keys are equal and that HASH_BITS >= 8.
		 */
		scan += 2, match++;

		/* We check for insufficient lookahead only every 8th comparison;
		 * the 256th check will be made at strstart+258.
		 */
		do {
		} while (*++scan == *++match && *++scan == *++match &&
				 *++scan == *++match && *++scan == *++match &&
				 *++scan == *++match && *++scan == *++match &&
				 *++scan == *++match && *++scan == *++match &&
				 scan < strend);

		len = MAX_MATCH - (int) (strend - scan);
		scan = strend - MAX_MATCH;

#endif							/* UNALIGNED_OK */

		if (len > best_len) {
			match_start = cur_match;
			best_len = len;
			if (len >= nice_match)
				break;
#ifdef UNALIGNED_OK
			scan_end = *(ush *) (scan + best_len - 1);
#else
			scan_end1 = scan[best_len - 1];
			scan_end = scan[best_len];
#endif
		}
	} while ((cur_match = prev[cur_match & WMASK]) > limit
			 && --chain_length != 0);

	return best_len;
}
#endif							/* ASMV */

#ifdef DEBUG
/* ===========================================================================
 * Check that the match at match_start is indeed a match.
 */
local void check_match(start, match, length)
IPos start, match;
int length;
{
	/* check that the match is indeed a match */
	if (memcmp((char *) window + match,
			   (char *) window + start, length) != EQUAL) {
		fprintf(stderr,
				" start %d, match %d, length %d\n", start, match, length);
		errorMsg("invalid match");
	}
	if (verbose > 1) {
		fprintf(stderr, "\\[%d,%d]", start - match, length);
		do {
			putc(window[start++], stderr);
		} while (--length != 0);
	}
}
#else
#  define check_match(start, match, length)
#endif

/* ===========================================================================
 * Fill the window when the lookahead becomes insufficient.
 * Updates strstart and lookahead, and sets eofile if end of input file.
 * IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0
 * OUT assertions: at least one byte has been read, or eofile is set;
 *    file reads are performed for at least two bytes (required for the
 *    translate_eol option).
 */
local void fill_window()
{
	register unsigned n, m;
	unsigned more =

		(unsigned) (window_size - (ulg) lookahead - (ulg) strstart);
	/* Amount of free space at the end of the window. */

	/* If the window is almost full and there is insufficient lookahead,
	 * move the upper half to the lower one to make room in the upper half.
	 */
	if (more == (unsigned) EOF) {
		/* Very unlikely, but possible on 16 bit machine if strstart == 0
		 * and lookahead == 1 (input done one byte at time)
		 */
		more--;
	} else if (strstart >= WSIZE + MAX_DIST) {
		/* By the IN assertion, the window is not empty so we can't confuse
		 * more == 0 with more == 64K on a 16 bit machine.
		 */
		Assert(window_size == (ulg) 2 * WSIZE, "no sliding with BIG_MEM");

		memcpy((char *) window, (char *) window + WSIZE, (unsigned) WSIZE);
		match_start -= WSIZE;
		strstart -= WSIZE;		/* we now have strstart >= MAX_DIST: */

		block_start -= (long) WSIZE;

		for (n = 0; n < HASH_SIZE; n++) {
			m = head[n];
			head[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL);
		}
		for (n = 0; n < WSIZE; n++) {
			m = prev[n];
			prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL);
			/* If n is not on any hash chain, prev[n] is garbage but
			 * its value will never be used.
			 */
		}
		more += WSIZE;
	}
	/* At this point, more >= 2 */
	if (!eofile) {
		n = read_buf((char *) window + strstart + lookahead, more);
		if (n == 0 || n == (unsigned) EOF) {
			eofile = 1;
		} else {
			lookahead += n;
		}
	}
}

/* ===========================================================================
 * Flush the current block, with given end-of-file flag.
 * IN assertion: strstart is set to the end of the current match.
 */
#define FLUSH_BLOCK(eof) \
   flush_block(block_start >= 0L ? (char*)&window[(unsigned)block_start] : \
                (char*)NULL, (long)strstart - block_start, (eof))

/* ===========================================================================
 * Same as above, but achieves better compression. We use a lazy
 * evaluation for matches: a match is finally adopted only if there is
 * no better match at the next window position.
 */
ulg deflate()
{
	IPos hash_head;				/* head of hash chain */
	IPos prev_match;			/* previous match */
	int flush;					/* set if current block must be flushed */
	int match_available = 0;	/* set if previous match exists */
	register unsigned match_length = MIN_MATCH - 1;	/* length of best match */

#ifdef DEBUG
	extern long isize;			/* byte length of input file, for debug only */
#endif

	/* Process the input block. */
	while (lookahead != 0) {
		/* Insert the string window[strstart .. strstart+2] in the
		 * dictionary, and set hash_head to the head of the hash chain:
		 */
		INSERT_STRING(strstart, hash_head);

		/* Find the longest match, discarding those <= prev_length.
		 */
		prev_length = match_length, prev_match = match_start;
		match_length = MIN_MATCH - 1;

		if (hash_head != NIL && prev_length < max_lazy_match &&
			strstart - hash_head <= MAX_DIST) {
			/* To simplify the code, we prevent matches with the string
			 * of window index 0 (in particular we have to avoid a match
			 * of the string with itself at the start of the input file).
			 */
			match_length = longest_match(hash_head);
			/* longest_match() sets match_start */
			if (match_length > lookahead)
				match_length = lookahead;

			/* Ignore a length 3 match if it is too distant: */
			if (match_length == MIN_MATCH
				&& strstart - match_start > TOO_FAR) {
				/* If prev_match is also MIN_MATCH, match_start is garbage
				 * but we will ignore the current match anyway.
				 */
				match_length--;
			}
		}
		/* If there was a match at the previous step and the current
		 * match is not better, output the previous match:
		 */
		if (prev_length >= MIN_MATCH && match_length <= prev_length) {

			check_match(strstart - 1, prev_match, prev_length);

			flush =
				ct_tally(strstart - 1 - prev_match,
						 prev_length - MIN_MATCH);

			/* Insert in hash table all strings up to the end of the match.
			 * strstart-1 and strstart are already inserted.
			 */
			lookahead -= prev_length - 1;
			prev_length -= 2;
			do {
				strstart++;
				INSERT_STRING(strstart, hash_head);
				/* strstart never exceeds WSIZE-MAX_MATCH, so there are
				 * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
				 * these bytes are garbage, but it does not matter since the
				 * next lookahead bytes will always be emitted as literals.
				 */
			} while (--prev_length != 0);
			match_available = 0;
			match_length = MIN_MATCH - 1;
			strstart++;
			if (flush)
				FLUSH_BLOCK(0), block_start = strstart;

		} else if (match_available) {
			/* If there was no match at the previous position, output a
			 * single literal. If there was a match but the current match
			 * is longer, truncate the previous match to a single literal.
			 */
			Tracevv((stderr, "%c", window[strstart - 1]));
			if (ct_tally(0, window[strstart - 1])) {
				FLUSH_BLOCK(0), block_start = strstart;
			}
			strstart++;
			lookahead--;
		} else {
			/* There is no previous match to compare with, wait for
			 * the next step to decide.
			 */
			match_available = 1;
			strstart++;
			lookahead--;
		}
		Assert(strstart <= isize && lookahead <= isize, "a bit too far");

		/* Make sure that we always have enough lookahead, except
		 * at the end of the input file. We need MAX_MATCH bytes
		 * for the next match, plus MIN_MATCH bytes to insert the
		 * string following the next match.
		 */
		while (lookahead < MIN_LOOKAHEAD && !eofile)
			fill_window();
	}
	if (match_available)
		ct_tally(0, window[strstart - 1]);

	return FLUSH_BLOCK(1);		/* eof */
}

/* gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
 * Copyright (C) 1992-1993 Jean-loup Gailly
 * The unzip code was written and put in the public domain by Mark Adler.
 * Portions of the lzw code are derived from the public domain 'compress'
 * written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
 * Ken Turkowski, Dave Mack and Peter Jannesen.
 *
 * See the license_msg below and the file COPYING for the software license.
 * See the file algorithm.doc for the compression algorithms and file formats.
 */

/* Compress files with zip algorithm and 'compress' interface.
 * See usage() and help() functions below for all options.
 * Outputs:
 *        file.gz:   compressed file with same mode, owner, and utimes
 *     or stdout with -c option or if stdin used as input.
 * If the output file name had to be truncated, the original name is kept
 * in the compressed file.
 * On MSDOS, file.tmp -> file.tmz. On VMS, file.tmp -> file.tmp-gz.
 *
 * Using gz on MSDOS would create too many file name conflicts. For
 * example, foo.txt -> foo.tgz (.tgz must be reserved as shorthand for
 * tar.gz). Similarly, foo.dir and foo.doc would both be mapped to foo.dgz.
 * I also considered 12345678.txt -> 12345txt.gz but this truncates the name
 * too heavily. There is no ideal solution given the MSDOS 8+3 limitation. 
 *
 * For the meaning of all compilation flags, see comments in Makefile.in.
 */

#include <ctype.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/stat.h>
#include <errno.h>

		/* configuration */

#ifdef NO_TIME_H
#  include <sys/time.h>
#else
#  include <time.h>
#endif

#ifndef NO_FCNTL_H
#  include <fcntl.h>
#endif

#ifdef HAVE_UNISTD_H
#  include <unistd.h>
#endif

#if defined(STDC_HEADERS) || !defined(NO_STDLIB_H)
#  include <stdlib.h>
#else
extern int errno;
#endif

#if defined(DIRENT)
#  include <dirent.h>
typedef struct dirent dir_type;

#  define NLENGTH(dirent) ((int)strlen((dirent)->d_name))
#  define DIR_OPT "DIRENT"
#else
#  define NLENGTH(dirent) ((dirent)->d_namlen)
#  ifdef SYSDIR
#    include <sys/dir.h>
typedef struct direct dir_type;

#    define DIR_OPT "SYSDIR"
#  else
#    ifdef SYSNDIR
#      include <sys/ndir.h>
typedef struct direct dir_type;

#      define DIR_OPT "SYSNDIR"
#    else
#      ifdef NDIR
#        include <ndir.h>
typedef struct direct dir_type;

#        define DIR_OPT "NDIR"
#      else
#        define NO_DIR
#        define DIR_OPT "NO_DIR"
#      endif
#    endif
#  endif
#endif

#ifndef NO_UTIME
#  ifndef NO_UTIME_H
#    include <utime.h>
#    define TIME_OPT "UTIME"
#  else
#    ifdef HAVE_SYS_UTIME_H
#      include <sys/utime.h>
#      define TIME_OPT "SYS_UTIME"
#    else
struct utimbuf {
	time_t actime;
	time_t modtime;
};

#      define TIME_OPT ""
#    endif
#  endif
#else
#  define TIME_OPT "NO_UTIME"
#endif

#if !defined(S_ISDIR) && defined(S_IFDIR)
#  define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#endif
#if !defined(S_ISREG) && defined(S_IFREG)
#  define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
#endif

typedef RETSIGTYPE(*sig_type) (int);

#ifndef	O_BINARY
#  define  O_BINARY  0			/* creation mode for open() */
#endif

#ifndef O_CREAT
   /* Pure BSD system? */
#  include <sys/file.h>
#  ifndef O_CREAT
#    define O_CREAT FCREAT
#  endif
#  ifndef O_EXCL
#    define O_EXCL FEXCL
#  endif
#endif

#ifndef S_IRUSR
#  define S_IRUSR 0400
#endif
#ifndef S_IWUSR
#  define S_IWUSR 0200
#endif
#define RW_USER (S_IRUSR | S_IWUSR)	/* creation mode for open() */

#ifndef MAX_PATH_LEN
#  define MAX_PATH_LEN   1024	/* max pathname length */
#endif

#ifndef SEEK_END
#  define SEEK_END 2
#endif

#ifdef NO_OFF_T
typedef long off_t;
off_t lseek (int fd, off_t offset, int whence);
#endif

/* Separator for file name parts (see shorten_name()) */
#ifdef NO_MULTIPLE_DOTS
#  define PART_SEP "-"
#else
#  define PART_SEP "."
#endif

		/* global buffers */

DECLARE(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
DECLARE(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
DECLARE(ush, d_buf, DIST_BUFSIZE);
DECLARE(uch, window, 2L * WSIZE);
#ifndef MAXSEG_64K
DECLARE(ush, tab_prefix, 1L << BITS);
#else
DECLARE(ush, tab_prefix0, 1L << (BITS - 1));
DECLARE(ush, tab_prefix1, 1L << (BITS - 1));
#endif

		/* local variables */

int ascii = 0;					/* convert end-of-lines to local OS conventions */
int decompress = 0;				/* decompress (-d) */
int no_name = -1;				/* don't save or restore the original file name */
int no_time = -1;				/* don't save or restore the original file time */
int foreground;					/* set if program run in foreground */
char *progname;					/* program name */
static int method = DEFLATED;	/* compression method */
static int exit_code = OK;		/* program exit code */
int save_orig_name;				/* set if original name must be saved */
int last_member;				/* set for .zip and .Z files */
int part_nb;					/* number of parts in .gz file */
long time_stamp;				/* original time stamp (modification time) */
long ifile_size;				/* input file size, -1 for devices (debug only) */
char *env;						/* contents of GZIP env variable */
char z_suffix[MAX_SUFFIX + 1];	/* default suffix (can be set with --suffix) */
int z_len;						/* strlen(z_suffix) */

long bytes_in;					/* number of input bytes */
long bytes_out;					/* number of output bytes */
char ifname[MAX_PATH_LEN];		/* input file name */
char ofname[MAX_PATH_LEN];		/* output file name */
int remove_ofname = 0;			/* remove output file on error */
struct stat istat;				/* status for input file */
int ifd;						/* input file descriptor */
int ofd;						/* output file descriptor */
unsigned insize;				/* valid bytes in inbuf */
unsigned inptr;					/* index of next byte to be processed in inbuf */
unsigned outcnt;				/* bytes in output buffer */

/* local functions */

#define strequ(s1, s2) (strcmp((s1),(s2)) == 0)

/* ======================================================================== */
// int main (argc, argv)
//    int argc;
//    char **argv;
int gzip_main(int argc, char **argv)
{
	int result;
	int inFileNum;
	int outFileNum;
	struct stat statBuf;
	char *delFileName;
	int tostdout = 0;
	int fromstdin = 0;

	if (argc == 1)
		usage(gzip_usage);

	/* Parse any options */
	while (--argc > 0 && **(++argv) == '-') {
		if (*((*argv) + 1) == '\0') {
			fromstdin = 1;
			tostdout = 1;
		}
		while (*(++(*argv))) {
			switch (**argv) {
			case 'c':
				tostdout = 1;
				break;
			default:
				usage(gzip_usage);
			}
		}
	}

	foreground = signal(SIGINT, SIG_IGN) != SIG_IGN;
	if (foreground) {
		(void) signal(SIGINT, (sig_type) abort_gzip);
	}
#ifdef SIGTERM
	if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
		(void) signal(SIGTERM, (sig_type) abort_gzip);
	}
#endif
#ifdef SIGHUP
	if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
		(void) signal(SIGHUP, (sig_type) abort_gzip);
	}
#endif

	strncpy(z_suffix, Z_SUFFIX, sizeof(z_suffix) - 1);
	z_len = strlen(z_suffix);

	/* Allocate all global buffers (for DYN_ALLOC option) */
	ALLOC(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
	ALLOC(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
	ALLOC(ush, d_buf, DIST_BUFSIZE);
	ALLOC(uch, window, 2L * WSIZE);
#ifndef MAXSEG_64K
	ALLOC(ush, tab_prefix, 1L << BITS);
#else
	ALLOC(ush, tab_prefix0, 1L << (BITS - 1));
	ALLOC(ush, tab_prefix1, 1L << (BITS - 1));
#endif

	if (fromstdin == 1) {
		strcpy(ofname, "stdin");

		inFileNum = fileno(stdin);
		time_stamp = 0;			/* time unknown by default */
		ifile_size = -1L;		/* convention for unknown size */
	} else {
		/* Open up the input file */
		if (*argv == '\0')
			usage(gzip_usage);
		strncpy(ifname, *argv, MAX_PATH_LEN);

		/* Open input fille */
		inFileNum = open(ifname, O_RDONLY);
		if (inFileNum < 0) {
			perror(ifname);
			exit(WARNING);
		}
		/* Get the time stamp on the input file. */
		result = stat(ifname, &statBuf);
		if (result < 0) {
			perror(ifname);
			exit(WARNING);
		}
		time_stamp = statBuf.st_ctime;
		ifile_size = statBuf.st_size;
	}


	if (tostdout == 1) {
		/* And get to work */
		strcpy(ofname, "stdout");
		outFileNum = fileno(stdout);
		SET_BINARY_MODE(fileno(stdout));

		clear_bufs();			/* clear input and output buffers */
		part_nb = 0;

		/* Actually do the compression/decompression. */
		zip(inFileNum, outFileNum);

	} else {

		/* And get to work */
		strncpy(ofname, ifname, MAX_PATH_LEN - 4);
		strcat(ofname, ".gz");


		/* Open output fille */
#if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1)
		outFileNum = open(ofname, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW);
#else
		outFileNum = open(ofname, O_RDWR | O_CREAT | O_EXCL);
#endif
		if (outFileNum < 0) {
			perror(ofname);
			exit(WARNING);
		}
		SET_BINARY_MODE(outFileNum);
		/* Set permissions on the file */
		fchmod(outFileNum, statBuf.st_mode);

		clear_bufs();			/* clear input and output buffers */
		part_nb = 0;

		/* Actually do the compression/decompression. */
		result = zip(inFileNum, outFileNum);
		close(outFileNum);
		close(inFileNum);
		/* Delete the original file */
		if (result == OK)
			delFileName = ifname;
		else
			delFileName = ofname;

		if (unlink(delFileName) < 0) {
			perror(delFileName);
			exit(FALSE);
		}
	}

	return(exit_code);
}

/* trees.c -- output deflated data using Huffman coding
 * Copyright (C) 1992-1993 Jean-loup Gailly
 * This is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License, see the file COPYING.
 */

/*
 *  PURPOSE
 *
 *      Encode various sets of source values using variable-length
 *      binary code trees.
 *
 *  DISCUSSION
 *
 *      The PKZIP "deflation" process uses several Huffman trees. The more
 *      common source values are represented by shorter bit sequences.
 *
 *      Each code tree is stored in the ZIP file in a compressed form
 *      which is itself a Huffman encoding of the lengths of
 *      all the code strings (in ascending order by source values).
 *      The actual code strings are reconstructed from the lengths in
 *      the UNZIP process, as described in the "application note"
 *      (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program.
 *
 *  REFERENCES
 *
 *      Lynch, Thomas J.
 *          Data Compression:  Techniques and Applications, pp. 53-55.
 *          Lifetime Learning Publications, 1985.  ISBN 0-534-03418-7.
 *
 *      Storer, James A.
 *          Data Compression:  Methods and Theory, pp. 49-50.
 *          Computer Science Press, 1988.  ISBN 0-7167-8156-5.
 *
 *      Sedgewick, R.
 *          Algorithms, p290.
 *          Addison-Wesley, 1983. ISBN 0-201-06672-6.
 *
 *  INTERFACE
 *
 *      void ct_init (ush *attr, int *methodp)
 *          Allocate the match buffer, initialize the various tables and save
 *          the location of the internal file attribute (ascii/binary) and
 *          method (DEFLATE/STORE)
 *
 *      void ct_tally (int dist, int lc);
 *          Save the match info and tally the frequency counts.
 *
 *      long flush_block (char *buf, ulg stored_len, int eof)
 *          Determine the best encoding for the current block: dynamic trees,
 *          static trees or store, and output the encoded block to the zip
 *          file. Returns the total compressed length for the file so far.
 *
 */

#include <ctype.h>

/* ===========================================================================
 * Constants
 */

#define MAX_BITS 15
/* All codes must not exceed MAX_BITS bits */

#define MAX_BL_BITS 7
/* Bit length codes must not exceed MAX_BL_BITS bits */

#define LENGTH_CODES 29
/* number of length codes, not counting the special END_BLOCK code */

#define LITERALS  256
/* number of literal bytes 0..255 */

#define END_BLOCK 256
/* end of block literal code */

#define L_CODES (LITERALS+1+LENGTH_CODES)
/* number of Literal or Length codes, including the END_BLOCK code */

#define D_CODES   30
/* number of distance codes */

#define BL_CODES  19
/* number of codes used to transfer the bit lengths */


local int near extra_lbits[LENGTH_CODES]	/* extra bits for each length code */
	= { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4,
		4, 4, 5, 5, 5, 5, 0 };

local int near extra_dbits[D_CODES]	/* extra bits for each distance code */
	= { 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9,
		10, 10, 11, 11, 12, 12, 13, 13 };

local int near extra_blbits[BL_CODES]	/* extra bits for each bit length code */
= { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 };

#define STORED_BLOCK 0
#define STATIC_TREES 1
#define DYN_TREES    2
/* The three kinds of block type */

#ifndef LIT_BUFSIZE
#  ifdef SMALL_MEM
#    define LIT_BUFSIZE  0x2000
#  else
#  ifdef MEDIUM_MEM
#    define LIT_BUFSIZE  0x4000
#  else
#    define LIT_BUFSIZE  0x8000
#  endif
#  endif
#endif
#ifndef DIST_BUFSIZE
#  define DIST_BUFSIZE  LIT_BUFSIZE
#endif
/* Sizes of match buffers for literals/lengths and distances.  There are
 * 4 reasons for limiting LIT_BUFSIZE to 64K:
 *   - frequencies can be kept in 16 bit counters
 *   - if compression is not successful for the first block, all input data is
 *     still in the window so we can still emit a stored block even when input
 *     comes from standard input.  (This can also be done for all blocks if
 *     LIT_BUFSIZE is not greater than 32K.)
 *   - if compression is not successful for a file smaller than 64K, we can
 *     even emit a stored file instead of a stored block (saving 5 bytes).
 *   - creating new Huffman trees less frequently may not provide fast
 *     adaptation to changes in the input data statistics. (Take for
 *     example a binary file with poorly compressible code followed by
 *     a highly compressible string table.) Smaller buffer sizes give
 *     fast adaptation but have of course the overhead of transmitting trees
 *     more frequently.
 *   - I can't count above 4
 * The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save
 * memory at the expense of compression). Some optimizations would be possible
 * if we rely on DIST_BUFSIZE == LIT_BUFSIZE.
 */
#if LIT_BUFSIZE > INBUFSIZ
error cannot overlay l_buf and inbuf
#endif
#define REP_3_6      16
/* repeat previous bit length 3-6 times (2 bits of repeat count) */
#define REPZ_3_10    17
/* repeat a zero length 3-10 times  (3 bits of repeat count) */
#define REPZ_11_138  18
/* repeat a zero length 11-138 times  (7 bits of repeat count) *//* ===========================================================================
 * Local data
 *//* Data structure describing a single value and its code string. */ typedef struct ct_data {
	union {
		ush freq;				/* frequency count */
		ush code;				/* bit string */
	} fc;
	union {
		ush dad;				/* father node in Huffman tree */
		ush len;				/* length of bit string */
	} dl;
} ct_data;

#define Freq fc.freq
#define Code fc.code
#define Dad  dl.dad
#define Len  dl.len

#define HEAP_SIZE (2*L_CODES+1)
/* maximum heap size */

local ct_data near dyn_ltree[HEAP_SIZE];	/* literal and length tree */
local ct_data near dyn_dtree[2 * D_CODES + 1];	/* distance tree */

local ct_data near static_ltree[L_CODES + 2];

/* The static literal tree. Since the bit lengths are imposed, there is no
 * need for the L_CODES extra codes used during heap construction. However
 * The codes 286 and 287 are needed to build a canonical tree (see ct_init
 * below).
 */

local ct_data near static_dtree[D_CODES];

/* The static distance tree. (Actually a trivial tree since all codes use
 * 5 bits.)
 */

local ct_data near bl_tree[2 * BL_CODES + 1];

/* Huffman tree for the bit lengths */

typedef struct tree_desc {
	ct_data near *dyn_tree;		/* the dynamic tree */
	ct_data near *static_tree;	/* corresponding static tree or NULL */
	int near *extra_bits;		/* extra bits for each code or NULL */
	int extra_base;				/* base index for extra_bits */
	int elems;					/* max number of elements in the tree */
	int max_length;				/* max bit length for the codes */
	int max_code;				/* largest code with non zero frequency */
} tree_desc;

local tree_desc near l_desc =
	{ dyn_ltree, static_ltree, extra_lbits, LITERALS + 1, L_CODES,
		MAX_BITS, 0 };

local tree_desc near d_desc =
	{ dyn_dtree, static_dtree, extra_dbits, 0, D_CODES, MAX_BITS, 0 };

local tree_desc near bl_desc =
	{ bl_tree, (ct_data near *) 0, extra_blbits, 0, BL_CODES, MAX_BL_BITS,
		0 };


local ush near bl_count[MAX_BITS + 1];

/* number of codes at each bit length for an optimal tree */

local uch near bl_order[BL_CODES]
= { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };

/* The lengths of the bit length codes are sent in order of decreasing
 * probability, to avoid transmitting the lengths for unused bit length codes.
 */

local int near heap[2 * L_CODES + 1];	/* heap used to build the Huffman trees */
local int heap_len;				/* number of elements in the heap */
local int heap_max;				/* element of largest frequency */

/* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
 * The same heap array is used to build all trees.
 */

local uch near depth[2 * L_CODES + 1];

/* Depth of each subtree used as tie breaker for trees of equal frequency */

local uch length_code[MAX_MATCH - MIN_MATCH + 1];

/* length code for each normalized match length (0 == MIN_MATCH) */

local uch dist_code[512];

/* distance codes. The first 256 values correspond to the distances
 * 3 .. 258, the last 256 values correspond to the top 8 bits of
 * the 15 bit distances.
 */

local int near base_length[LENGTH_CODES];

/* First normalized length for each code (0 = MIN_MATCH) */

local int near base_dist[D_CODES];

/* First normalized distance for each code (0 = distance of 1) */

#define l_buf inbuf
/* DECLARE(uch, l_buf, LIT_BUFSIZE);  buffer for literals or lengths */

/* DECLARE(ush, d_buf, DIST_BUFSIZE); buffer for distances */

local uch near flag_buf[(LIT_BUFSIZE / 8)];

/* flag_buf is a bit array distinguishing literals from lengths in
 * l_buf, thus indicating the presence or absence of a distance.
 */

local unsigned last_lit;		/* running index in l_buf */
local unsigned last_dist;		/* running index in d_buf */
local unsigned last_flags;		/* running index in flag_buf */
local uch flags;				/* current flags not yet saved in flag_buf */
local uch flag_bit;				/* current bit used in flags */

/* bits are filled in flags starting at bit 0 (least significant).
 * Note: these flags are overkill in the current code since we don't
 * take advantage of DIST_BUFSIZE == LIT_BUFSIZE.
 */

local ulg opt_len;				/* bit length of current block with optimal trees */
local ulg static_len;			/* bit length of current block with static trees */

local ulg compressed_len;		/* total bit length of compressed file */

local ulg input_len;			/* total byte length of input file */

/* input_len is for debugging only since we can get it by other means. */

ush *file_type;					/* pointer to UNKNOWN, BINARY or ASCII */
int *file_method;				/* pointer to DEFLATE or STORE */

#ifdef DEBUG
extern ulg bits_sent;			/* bit length of the compressed data */
extern long isize;				/* byte length of input file */
#endif

extern long block_start;		/* window offset of current block */
extern unsigned near strstart;	/* window offset of current string */

/* ===========================================================================
 * Local (static) routines in this file.
 */

local void init_block (void);
local void pqdownheap (ct_data near * tree, int k);
local void gen_bitlen (tree_desc near * desc);
local void gen_codes (ct_data near * tree, int max_code);
local void build_tree (tree_desc near * desc);
local void scan_tree (ct_data near * tree, int max_code);
local void send_tree (ct_data near * tree, int max_code);
local int build_bl_tree (void);
local void send_all_trees (int lcodes, int dcodes, int blcodes);
local void compress_block (ct_data near * ltree, ct_data near * dtree);
local void set_file_type (void);


#ifndef DEBUG
#  define send_code(c, tree) send_bits(tree[c].Code, tree[c].Len)
   /* Send a code of the given tree. c and tree must not have side effects */

#else							/* DEBUG */
#  define send_code(c, tree) \
     { if (verbose>1) fprintf(stderr,"\ncd %3d ",(c)); \
       send_bits(tree[c].Code, tree[c].Len); }
#endif

#define d_code(dist) \
   ((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)])
/* Mapping from a distance to a distance code. dist is the distance - 1 and
 * must not have side effects. dist_code[256] and dist_code[257] are never
 * used.
 */

/* the arguments must not have side effects */

/* ===========================================================================
 * Allocate the match buffer, initialize the various tables and save the
 * location of the internal file attribute (ascii/binary) and method
 * (DEFLATE/STORE).
 */
void ct_init(attr, methodp)
ush *attr;						/* pointer to internal file attribute */
int *methodp;					/* pointer to compression method */
{
	int n;						/* iterates over tree elements */
	int bits;					/* bit counter */
	int length;					/* length value */
	int code;					/* code value */
	int dist;					/* distance index */

	file_type = attr;
	file_method = methodp;
	compressed_len = input_len = 0L;

	if (static_dtree[0].Len != 0)
		return;					/* ct_init already called */

	/* Initialize the mapping length (0..255) -> length code (0..28) */
	length = 0;
	for (code = 0; code < LENGTH_CODES - 1; code++) {
		base_length[code] = length;
		for (n = 0; n < (1 << extra_lbits[code]); n++) {
			length_code[length++] = (uch) code;
		}
	}
	Assert(length == 256, "ct_init: length != 256");
	/* Note that the length 255 (match length 258) can be represented
	 * in two different ways: code 284 + 5 bits or code 285, so we
	 * overwrite length_code[255] to use the best encoding:
	 */
	length_code[length - 1] = (uch) code;

	/* Initialize the mapping dist (0..32K) -> dist code (0..29) */
	dist = 0;
	for (code = 0; code < 16; code++) {
		base_dist[code] = dist;
		for (n = 0; n < (1 << extra_dbits[code]); n++) {
			dist_code[dist++] = (uch) code;
		}
	}
	Assert(dist == 256, "ct_init: dist != 256");
	dist >>= 7;					/* from now on, all distances are divided by 128 */
	for (; code < D_CODES; code++) {
		base_dist[code] = dist << 7;
		for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) {
			dist_code[256 + dist++] = (uch) code;
		}
	}
	Assert(dist == 256, "ct_init: 256+dist != 512");

	/* Construct the codes of the static literal tree */
	for (bits = 0; bits <= MAX_BITS; bits++)
		bl_count[bits] = 0;
	n = 0;
	while (n <= 143)
		static_ltree[n++].Len = 8, bl_count[8]++;
	while (n <= 255)
		static_ltree[n++].Len = 9, bl_count[9]++;
	while (n <= 279)
		static_ltree[n++].Len = 7, bl_count[7]++;
	while (n <= 287)
		static_ltree[n++].Len = 8, bl_count[8]++;
	/* Codes 286 and 287 do not exist, but we must include them in the
	 * tree construction to get a canonical Huffman tree (longest code
	 * all ones)
	 */
	gen_codes((ct_data near *) static_ltree, L_CODES + 1);

	/* The static distance tree is trivial: */
	for (n = 0; n < D_CODES; n++) {
		static_dtree[n].Len = 5;
		static_dtree[n].Code = bi_reverse(n, 5);
	}

	/* Initialize the first block of the first file: */
	init_block();
}

/* ===========================================================================
 * Initialize a new block.
 */
local void init_block()
{
	int n;						/* iterates over tree elements */

	/* Initialize the trees. */
	for (n = 0; n < L_CODES; n++)
		dyn_ltree[n].Freq = 0;
	for (n = 0; n < D_CODES; n++)
		dyn_dtree[n].Freq = 0;
	for (n = 0; n < BL_CODES; n++)
		bl_tree[n].Freq = 0;

	dyn_ltree[END_BLOCK].Freq = 1;
	opt_len = static_len = 0L;
	last_lit = last_dist = last_flags = 0;
	flags = 0;
	flag_bit = 1;
}

#define SMALLEST 1
/* Index within the heap array of least frequent node in the Huffman tree */


/* ===========================================================================
 * Remove the smallest element from the heap and recreate the heap with
 * one less element. Updates heap and heap_len.
 */
#define pqremove(tree, top) \
{\
    top = heap[SMALLEST]; \
    heap[SMALLEST] = heap[heap_len--]; \
    pqdownheap(tree, SMALLEST); \
}

/* ===========================================================================
 * Compares to subtrees, using the tree depth as tie breaker when
 * the subtrees have equal frequency. This minimizes the worst case length.
 */
#define smaller(tree, n, m) \
   (tree[n].Freq < tree[m].Freq || \
   (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))

/* ===========================================================================
 * Restore the heap property by moving down the tree starting at node k,
 * exchanging a node with the smallest of its two sons if necessary, stopping
 * when the heap property is re-established (each father smaller than its
 * two sons).
 */
local void pqdownheap(tree, k)
ct_data near *tree;				/* the tree to restore */
int k;							/* node to move down */
{
	int v = heap[k];
	int j = k << 1;				/* left son of k */

	while (j <= heap_len) {
		/* Set j to the smallest of the two sons: */
		if (j < heap_len && smaller(tree, heap[j + 1], heap[j]))
			j++;

		/* Exit if v is smaller than both sons */
		if (smaller(tree, v, heap[j]))
			break;

		/* Exchange v with the smallest son */
		heap[k] = heap[j];
		k = j;

		/* And continue down the tree, setting j to the left son of k */
		j <<= 1;
	}
	heap[k] = v;
}

/* ===========================================================================
 * Compute the optimal bit lengths for a tree and update the total bit length
 * for the current block.
 * IN assertion: the fields freq and dad are set, heap[heap_max] and
 *    above are the tree nodes sorted by increasing frequency.
 * OUT assertions: the field len is set to the optimal bit length, the
 *     array bl_count contains the frequencies for each bit length.
 *     The length opt_len is updated; static_len is also updated if stree is
 *     not null.
 */
local void gen_bitlen(desc)
tree_desc near *desc;			/* the tree descriptor */
{
	ct_data near *tree = desc->dyn_tree;
	int near *extra = desc->extra_bits;
	int base = desc->extra_base;
	int max_code = desc->max_code;
	int max_length = desc->max_length;
	ct_data near *stree = desc->static_tree;
	int h;						/* heap index */
	int n, m;					/* iterate over the tree elements */
	int bits;					/* bit length */
	int xbits;					/* extra bits */
	ush f;						/* frequency */
	int overflow = 0;			/* number of elements with bit length too large */

	for (bits = 0; bits <= MAX_BITS; bits++)
		bl_count[bits] = 0;

	/* In a first pass, compute the optimal bit lengths (which may
	 * overflow in the case of the bit length tree).
	 */
	tree[heap[heap_max]].Len = 0;	/* root of the heap */

	for (h = heap_max + 1; h < HEAP_SIZE; h++) {
		n = heap[h];
		bits = tree[tree[n].Dad].Len + 1;
		if (bits > max_length)
			bits = max_length, overflow++;
		tree[n].Len = (ush) bits;
		/* We overwrite tree[n].Dad which is no longer needed */

		if (n > max_code)
			continue;			/* not a leaf node */

		bl_count[bits]++;
		xbits = 0;
		if (n >= base)
			xbits = extra[n - base];
		f = tree[n].Freq;
		opt_len += (ulg) f *(bits + xbits);

		if (stree)
			static_len += (ulg) f *(stree[n].Len + xbits);
	}
	if (overflow == 0)
		return;

	Trace((stderr, "\nbit length overflow\n"));
	/* This happens for example on obj2 and pic of the Calgary corpus */

	/* Find the first bit length which could increase: */
	do {
		bits = max_length - 1;
		while (bl_count[bits] == 0)
			bits--;
		bl_count[bits]--;		/* move one leaf down the tree */
		bl_count[bits + 1] += 2;	/* move one overflow item as its brother */
		bl_count[max_length]--;
		/* The brother of the overflow item also moves one step up,
		 * but this does not affect bl_count[max_length]
		 */
		overflow -= 2;
	} while (overflow > 0);

	/* Now recompute all bit lengths, scanning in increasing frequency.
	 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
	 * lengths instead of fixing only the wrong ones. This idea is taken
	 * from 'ar' written by Haruhiko Okumura.)
	 */
	for (bits = max_length; bits != 0; bits--) {
		n = bl_count[bits];
		while (n != 0) {
			m = heap[--h];
			if (m > max_code)
				continue;
			if (tree[m].Len != (unsigned) bits) {
				Trace(
					  (stderr, "code %d bits %d->%d\n", m, tree[m].Len,
					   bits));
				opt_len +=
					((long) bits -
					 (long) tree[m].Len) * (long) tree[m].Freq;
				tree[m].Len = (ush) bits;
			}
			n--;
		}
	}
}

/* ===========================================================================
 * Generate the codes for a given tree and bit counts (which need not be
 * optimal).
 * IN assertion: the array bl_count contains the bit length statistics for
 * the given tree and the field len is set for all tree elements.
 * OUT assertion: the field code is set for all tree elements of non
 *     zero code length.
 */
local void gen_codes(tree, max_code)
ct_data near *tree;				/* the tree to decorate */
int max_code;					/* largest code with non zero frequency */
{
	ush next_code[MAX_BITS + 1];	/* next code value for each bit length */
	ush code = 0;				/* running code value */
	int bits;					/* bit index */
	int n;						/* code index */

	/* The distribution counts are first used to generate the code values
	 * without bit reversal.
	 */
	for (bits = 1; bits <= MAX_BITS; bits++) {
		next_code[bits] = code = (code + bl_count[bits - 1]) << 1;
	}
	/* Check that the bit counts in bl_count are consistent. The last code
	 * must be all ones.
	 */
	Assert(code + bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1,
		   "inconsistent bit counts");
	Tracev((stderr, "\ngen_codes: max_code %d ", max_code));

	for (n = 0; n <= max_code; n++) {
		int len = tree[n].Len;

		if (len == 0)
			continue;
		/* Now reverse the bits */
		tree[n].Code = bi_reverse(next_code[len]++, len);

		Tracec(tree != static_ltree,
			   (stderr, "\nn %3d %c l %2d c %4x (%x) ", n,
				(isgraph(n) ? n : ' '), len, tree[n].Code,
				next_code[len] - 1));
	}
}

/* ===========================================================================
 * Construct one Huffman tree and assigns the code bit strings and lengths.
 * Update the total bit length for the current block.
 * IN assertion: the field freq is set for all tree elements.
 * OUT assertions: the fields len and code are set to the optimal bit length
 *     and corresponding code. The length opt_len is updated; static_len is
 *     also updated if stree is not null. The field max_code is set.
 */
local void build_tree(desc)
tree_desc near *desc;			/* the tree descriptor */
{
	ct_data near *tree = desc->dyn_tree;
	ct_data near *stree = desc->static_tree;
	int elems = desc->elems;
	int n, m;					/* iterate over heap elements */
	int max_code = -1;			/* largest code with non zero frequency */
	int node = elems;			/* next internal node of the tree */

	/* Construct the initial heap, with least frequent element in
	 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
	 * heap[0] is not used.
	 */
	heap_len = 0, heap_max = HEAP_SIZE;

	for (n = 0; n < elems; n++) {
		if (tree[n].Freq != 0) {
			heap[++heap_len] = max_code = n;
			depth[n] = 0;
		} else {
			tree[n].Len = 0;
		}
	}

	/* The pkzip format requires that at least one distance code exists,
	 * and that at least one bit should be sent even if there is only one
	 * possible code. So to avoid special checks later on we force at least
	 * two codes of non zero frequency.
	 */
	while (heap_len < 2) {
		int new = heap[++heap_len] = (max_code < 2 ? ++max_code : 0);

		tree[new].Freq = 1;
		depth[new] = 0;
		opt_len--;
		if (stree)
			static_len -= stree[new].Len;
		/* new is 0 or 1 so it does not have extra bits */
	}
	desc->max_code = max_code;

	/* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
	 * establish sub-heaps of increasing lengths:
	 */
	for (n = heap_len / 2; n >= 1; n--)
		pqdownheap(tree, n);

	/* Construct the Huffman tree by repeatedly combining the least two
	 * frequent nodes.
	 */
	do {
		pqremove(tree, n);		/* n = node of least frequency */
		m = heap[SMALLEST];		/* m = node of next least frequency */

		heap[--heap_max] = n;	/* keep the nodes sorted by frequency */
		heap[--heap_max] = m;

		/* Create a new node father of n and m */
		tree[node].Freq = tree[n].Freq + tree[m].Freq;
		depth[node] = (uch) (MAX(depth[n], depth[m]) + 1);
		tree[n].Dad = tree[m].Dad = (ush) node;
#ifdef DUMP_BL_TREE
		if (tree == bl_tree) {
			fprintf(stderr, "\nnode %d(%d), sons %d(%d) %d(%d)",
					node, tree[node].Freq, n, tree[n].Freq, m,
					tree[m].Freq);
		}
#endif
		/* and insert the new node in the heap */
		heap[SMALLEST] = node++;
		pqdownheap(tree, SMALLEST);

	} while (heap_len >= 2);

	heap[--heap_max] = heap[SMALLEST];

	/* At this point, the fields freq and dad are set. We can now
	 * generate the bit lengths.
	 */
	gen_bitlen((tree_desc near *) desc);

	/* The field len is now set, we can generate the bit codes */
	gen_codes((ct_data near *) tree, max_code);
}

/* ===========================================================================
 * Scan a literal or distance tree to determine the frequencies of the codes
 * in the bit length tree. Updates opt_len to take into account the repeat
 * counts. (The contribution of the bit length codes will be added later
 * during the construction of bl_tree.)
 */
local void scan_tree(tree, max_code)
ct_data near *tree;				/* the tree to be scanned */
int max_code;					/* and its largest code of non zero frequency */
{
	int n;						/* iterates over all tree elements */
	int prevlen = -1;			/* last emitted length */
	int curlen;					/* length of current code */
	int nextlen = tree[0].Len;	/* length of next code */
	int count = 0;				/* repeat count of the current code */
	int max_count = 7;			/* max repeat count */
	int min_count = 4;			/* min repeat count */

	if (nextlen == 0)
		max_count = 138, min_count = 3;
	tree[max_code + 1].Len = (ush) 0xffff;	/* guard */

	for (n = 0; n <= max_code; n++) {
		curlen = nextlen;
		nextlen = tree[n + 1].Len;
		if (++count < max_count && curlen == nextlen) {
			continue;
		} else if (count < min_count) {
			bl_tree[curlen].Freq += count;
		} else if (curlen != 0) {
			if (curlen != prevlen)
				bl_tree[curlen].Freq++;
			bl_tree[REP_3_6].Freq++;
		} else if (count <= 10) {
			bl_tree[REPZ_3_10].Freq++;
		} else {
			bl_tree[REPZ_11_138].Freq++;
		}
		count = 0;
		prevlen = curlen;
		if (nextlen == 0) {
			max_count = 138, min_count = 3;
		} else if (curlen == nextlen) {
			max_count = 6, min_count = 3;
		} else {
			max_count = 7, min_count = 4;
		}
	}
}

/* ===========================================================================
 * Send a literal or distance tree in compressed form, using the codes in
 * bl_tree.
 */
local void send_tree(tree, max_code)
ct_data near *tree;				/* the tree to be scanned */
int max_code;					/* and its largest code of non zero frequency */
{
	int n;						/* iterates over all tree elements */
	int prevlen = -1;			/* last emitted length */
	int curlen;					/* length of current code */
	int nextlen = tree[0].Len;	/* length of next code */
	int count = 0;				/* repeat count of the current code */
	int max_count = 7;			/* max repeat count */
	int min_count = 4;			/* min repeat count */

/* tree[max_code+1].Len = -1; *//* guard already set */
	if (nextlen == 0)
		max_count = 138, min_count = 3;

	for (n = 0; n <= max_code; n++) {
		curlen = nextlen;
		nextlen = tree[n + 1].Len;
		if (++count < max_count && curlen == nextlen) {
			continue;
		} else if (count < min_count) {
			do {
				send_code(curlen, bl_tree);
			} while (--count != 0);

		} else if (curlen != 0) {
			if (curlen != prevlen) {
				send_code(curlen, bl_tree);
				count--;
			}
			Assert(count >= 3 && count <= 6, " 3_6?");
			send_code(REP_3_6, bl_tree);
			send_bits(count - 3, 2);

		} else if (count <= 10) {
			send_code(REPZ_3_10, bl_tree);
			send_bits(count - 3, 3);

		} else {
			send_code(REPZ_11_138, bl_tree);
			send_bits(count - 11, 7);
		}
		count = 0;
		prevlen = curlen;
		if (nextlen == 0) {
			max_count = 138, min_count = 3;
		} else if (curlen == nextlen) {
			max_count = 6, min_count = 3;
		} else {
			max_count = 7, min_count = 4;
		}
	}
}

/* ===========================================================================
 * Construct the Huffman tree for the bit lengths and return the index in
 * bl_order of the last bit length code to send.
 */
local int build_bl_tree()
{
	int max_blindex;			/* index of last bit length code of non zero freq */

	/* Determine the bit length frequencies for literal and distance trees */
	scan_tree((ct_data near *) dyn_ltree, l_desc.max_code);
	scan_tree((ct_data near *) dyn_dtree, d_desc.max_code);

	/* Build the bit length tree: */
	build_tree((tree_desc near *) (&bl_desc));
	/* opt_len now includes the length of the tree representations, except
	 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
	 */

	/* Determine the number of bit length codes to send. The pkzip format
	 * requires that at least 4 bit length codes be sent. (appnote.txt says
	 * 3 but the actual value used is 4.)
	 */
	for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) {
		if (bl_tree[bl_order[max_blindex]].Len != 0)
			break;
	}
	/* Update opt_len to include the bit length tree and counts */
	opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4;
	Tracev(
		   (stderr, "\ndyn trees: dyn %ld, stat %ld", opt_len,
			static_len));

	return max_blindex;
}

/* ===========================================================================
 * Send the header for a block using dynamic Huffman trees: the counts, the
 * lengths of the bit length codes, the literal tree and the distance tree.
 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
 */
local void send_all_trees(lcodes, dcodes, blcodes)
int lcodes, dcodes, blcodes;	/* number of codes for each tree */
{
	int rank;					/* index in bl_order */

	Assert(lcodes >= 257 && dcodes >= 1
		   && blcodes >= 4, "not enough codes");
	Assert(lcodes <= L_CODES && dcodes <= D_CODES
		   && blcodes <= BL_CODES, "too many codes");
	Tracev((stderr, "\nbl counts: "));
	send_bits(lcodes - 257, 5);	/* not +255 as stated in appnote.txt */
	send_bits(dcodes - 1, 5);
	send_bits(blcodes - 4, 4);	/* not -3 as stated in appnote.txt */
	for (rank = 0; rank < blcodes; rank++) {
		Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
		send_bits(bl_tree[bl_order[rank]].Len, 3);
	}
	Tracev((stderr, "\nbl tree: sent %ld", bits_sent));

	send_tree((ct_data near *) dyn_ltree, lcodes - 1);	/* send the literal tree */
	Tracev((stderr, "\nlit tree: sent %ld", bits_sent));

	send_tree((ct_data near *) dyn_dtree, dcodes - 1);	/* send the distance tree */
	Tracev((stderr, "\ndist tree: sent %ld", bits_sent));
}

/* ===========================================================================
 * Determine the best encoding for the current block: dynamic trees, static
 * trees or store, and output the encoded block to the zip file. This function
 * returns the total compressed length for the file so far.
 */
ulg flush_block(buf, stored_len, eof)
char *buf;						/* input block, or NULL if too old */
ulg stored_len;					/* length of input block */
int eof;						/* true if this is the last block for a file */
{
	ulg opt_lenb, static_lenb;	/* opt_len and static_len in bytes */
	int max_blindex;			/* index of last bit length code of non zero freq */

	flag_buf[last_flags] = flags;	/* Save the flags for the last 8 items */

	/* Check if the file is ascii or binary */
	if (*file_type == (ush) UNKNOWN)
		set_file_type();

	/* Construct the literal and distance trees */
	build_tree((tree_desc near *) (&l_desc));
	Tracev((stderr, "\nlit data: dyn %ld, stat %ld", opt_len, static_len));

	build_tree((tree_desc near *) (&d_desc));
	Tracev(
		   (stderr, "\ndist data: dyn %ld, stat %ld", opt_len,
			static_len));
	/* At this point, opt_len and static_len are the total bit lengths of
	 * the compressed block data, excluding the tree representations.
	 */

	/* Build the bit length tree for the above two trees, and get the index
	 * in bl_order of the last bit length code to send.
	 */
	max_blindex = build_bl_tree();

	/* Determine the best encoding. Compute first the block length in bytes */
	opt_lenb = (opt_len + 3 + 7) >> 3;
	static_lenb = (static_len + 3 + 7) >> 3;
	input_len += stored_len;	/* for debugging only */

	Trace(
		  (stderr,
		   "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",
		   opt_lenb, opt_len, static_lenb, static_len, stored_len,
		   last_lit, last_dist));

	if (static_lenb <= opt_lenb)
		opt_lenb = static_lenb;

	/* If compression failed and this is the first and last block,
	 * and if the zip file can be seeked (to rewrite the local header),
	 * the whole file is transformed into a stored file:
	 */
#ifdef FORCE_METHOD
#else
	if (stored_len <= opt_lenb && eof && compressed_len == 0L
		&& seekable()) {
#endif
		/* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
		if (buf == (char *) 0)
			errorMsg("block vanished");

		copy_block(buf, (unsigned) stored_len, 0);	/* without header */
		compressed_len = stored_len << 3;
		*file_method = STORED;

#ifdef FORCE_METHOD
#else
	} else if (stored_len + 4 <= opt_lenb && buf != (char *) 0) {
		/* 4: two words for the lengths */
#endif
		/* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
		 * Otherwise we can't have processed more than WSIZE input bytes since
		 * the last block flush, because compression would have been
		 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
		 * transform a block into a stored block.
		 */
		send_bits((STORED_BLOCK << 1) + eof, 3);	/* send block type */
		compressed_len = (compressed_len + 3 + 7) & ~7L;
		compressed_len += (stored_len + 4) << 3;

		copy_block(buf, (unsigned) stored_len, 1);	/* with header */

#ifdef FORCE_METHOD
#else
	} else if (static_lenb == opt_lenb) {
#endif
		send_bits((STATIC_TREES << 1) + eof, 3);
		compress_block((ct_data near *) static_ltree,
					   (ct_data near *) static_dtree);
		compressed_len += 3 + static_len;
	} else {
		send_bits((DYN_TREES << 1) + eof, 3);
		send_all_trees(l_desc.max_code + 1, d_desc.max_code + 1,
					   max_blindex + 1);
		compress_block((ct_data near *) dyn_ltree,
					   (ct_data near *) dyn_dtree);
		compressed_len += 3 + opt_len;
	}
	Assert(compressed_len == bits_sent, "bad compressed size");
	init_block();

	if (eof) {
		Assert(input_len == isize, "bad input size");
		bi_windup();
		compressed_len += 7;	/* align on byte boundary */
	}
	Tracev((stderr, "\ncomprlen %lu(%lu) ", compressed_len >> 3,
			compressed_len - 7 * eof));

	return compressed_len >> 3;
}

/* ===========================================================================
 * Save the match info and tally the frequency counts. Return true if
 * the current block must be flushed.
 */
int ct_tally(dist, lc)
int dist;						/* distance of matched string */
int lc;							/* match length-MIN_MATCH or unmatched char (if dist==0) */
{
	l_buf[last_lit++] = (uch) lc;
	if (dist == 0) {
		/* lc is the unmatched char */
		dyn_ltree[lc].Freq++;
	} else {
		/* Here, lc is the match length - MIN_MATCH */
		dist--;					/* dist = match distance - 1 */
		Assert((ush) dist < (ush) MAX_DIST &&
			   (ush) lc <= (ush) (MAX_MATCH - MIN_MATCH) &&
			   (ush) d_code(dist) < (ush) D_CODES, "ct_tally: bad match");

		dyn_ltree[length_code[lc] + LITERALS + 1].Freq++;
		dyn_dtree[d_code(dist)].Freq++;

		d_buf[last_dist++] = (ush) dist;
		flags |= flag_bit;
	}
	flag_bit <<= 1;

	/* Output the flags if they fill a byte: */
	if ((last_lit & 7) == 0) {
		flag_buf[last_flags++] = flags;
		flags = 0, flag_bit = 1;
	}
	/* Try to guess if it is profitable to stop the current block here */
	if ((last_lit & 0xfff) == 0) {
		/* Compute an upper bound for the compressed length */
		ulg out_length = (ulg) last_lit * 8L;
		ulg in_length = (ulg) strstart - block_start;
		int dcode;

		for (dcode = 0; dcode < D_CODES; dcode++) {
			out_length +=
				(ulg) dyn_dtree[dcode].Freq * (5L + extra_dbits[dcode]);
		}
		out_length >>= 3;
		Trace(
			  (stderr,
			   "\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ",
			   last_lit, last_dist, in_length, out_length,
			   100L - out_length * 100L / in_length));
		if (last_dist < last_lit / 2 && out_length < in_length / 2)
			return 1;
	}
	return (last_lit == LIT_BUFSIZE - 1 || last_dist == DIST_BUFSIZE);
	/* We avoid equality with LIT_BUFSIZE because of wraparound at 64K
	 * on 16 bit machines and because stored blocks are restricted to
	 * 64K-1 bytes.
	 */
}

/* ===========================================================================
 * Send the block data compressed using the given Huffman trees
 */
local void compress_block(ltree, dtree)
ct_data near *ltree;			/* literal tree */
ct_data near *dtree;			/* distance tree */
{
	unsigned dist;				/* distance of matched string */
	int lc;						/* match length or unmatched char (if dist == 0) */
	unsigned lx = 0;			/* running index in l_buf */
	unsigned dx = 0;			/* running index in d_buf */
	unsigned fx = 0;			/* running index in flag_buf */
	uch flag = 0;				/* current flags */
	unsigned code;				/* the code to send */
	int extra;					/* number of extra bits to send */

	if (last_lit != 0)
		do {
			if ((lx & 7) == 0)
				flag = flag_buf[fx++];
			lc = l_buf[lx++];
			if ((flag & 1) == 0) {
				send_code(lc, ltree);	/* send a literal byte */
				Tracecv(isgraph(lc), (stderr, " '%c' ", lc));
			} else {
				/* Here, lc is the match length - MIN_MATCH */
				code = length_code[lc];
				send_code(code + LITERALS + 1, ltree);	/* send the length code */
				extra = extra_lbits[code];
				if (extra != 0) {
					lc -= base_length[code];
					send_bits(lc, extra);	/* send the extra length bits */
				}
				dist = d_buf[dx++];
				/* Here, dist is the match distance - 1 */
				code = d_code(dist);
				Assert(code < D_CODES, "bad d_code");

				send_code(code, dtree);	/* send the distance code */
				extra = extra_dbits[code];
				if (extra != 0) {
					dist -= base_dist[code];
					send_bits(dist, extra);	/* send the extra distance bits */
				}
			}					/* literal or match pair ? */
			flag >>= 1;
		} while (lx < last_lit);

	send_code(END_BLOCK, ltree);
}

/* ===========================================================================
 * Set the file type to ASCII or BINARY, using a crude approximation:
 * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
 * IN assertion: the fields freq of dyn_ltree are set and the total of all
 * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
 */
local void set_file_type()
{
	int n = 0;
	unsigned ascii_freq = 0;
	unsigned bin_freq = 0;

	while (n < 7)
		bin_freq += dyn_ltree[n++].Freq;
	while (n < 128)
		ascii_freq += dyn_ltree[n++].Freq;
	while (n < LITERALS)
		bin_freq += dyn_ltree[n++].Freq;
	*file_type = bin_freq > (ascii_freq >> 2) ? BINARY : ASCII;
	if (*file_type == BINARY && translate_eol) {
		errorMsg("-l used on binary file");
	}
}

/* util.c -- utility functions for gzip support
 * Copyright (C) 1992-1993 Jean-loup Gailly
 * This is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License, see the file COPYING.
 */

#include <ctype.h>
#include <errno.h>
#include <sys/types.h>

#ifdef HAVE_UNISTD_H
#  include <unistd.h>
#endif
#ifndef NO_FCNTL_H
#  include <fcntl.h>
#endif

#if defined(STDC_HEADERS) || !defined(NO_STDLIB_H)
#  include <stdlib.h>
#else
extern int errno;
#endif

/* ===========================================================================
 * Copy input to output unchanged: zcat == cat with --force.
 * IN assertion: insize bytes have already been read in inbuf.
 */
int copy(in, out)
int in, out;					/* input and output file descriptors */
{
	errno = 0;
	while (insize != 0 && (int) insize != EOF) {
		write_buf(out, (char *) inbuf, insize);
		bytes_out += insize;
		insize = read(in, (char *) inbuf, INBUFSIZ);
	}
	if ((int) insize == EOF && errno != 0) {
		read_error_msg();
	}
	bytes_in = bytes_out;
	return OK;
}

/* ========================================================================
 * Put string s in lower case, return s.
 */
char *strlwr(s)
char *s;
{
	char *t;

	for (t = s; *t; t++)
		*t = tolow(*t);
	return s;
}

#if defined(NO_STRING_H) && !defined(STDC_HEADERS)

/* Provide missing strspn and strcspn functions. */

int strspn (const char *s, const char *accept);
int strcspn (const char *s, const char *reject);

/* ========================================================================
 * Return the length of the maximum initial segment
 * of s which contains only characters in accept.
 */
int strspn(s, accept)
const char *s;
const char *accept;
{
	register const char *p;
	register const char *a;
	register int count = 0;

	for (p = s; *p != '\0'; ++p) {
		for (a = accept; *a != '\0'; ++a) {
			if (*p == *a)
				break;
		}
		if (*a == '\0')
			return count;
		++count;
	}
	return count;
}

/* ========================================================================
 * Return the length of the maximum inital segment of s
 * which contains no characters from reject.
 */
int strcspn(s, reject)
const char *s;
const char *reject;
{
	register int count = 0;

	while (*s != '\0') {
		if (strchr(reject, *s++) != NULL)
			return count;
		++count;
	}
	return count;
}

#endif							/* NO_STRING_H */

/* ========================================================================
 * Add an environment variable (if any) before argv, and update argc.
 * Return the expanded environment variable to be freed later, or NULL 
 * if no options were added to argv.
 */
#define SEPARATOR	" \t"		/* separators in env variable */

char *add_envopt(argcp, argvp, env)
int *argcp;						/* pointer to argc */
char ***argvp;					/* pointer to argv */
char *env;						/* name of environment variable */
{
	char *p;					/* running pointer through env variable */
	char **oargv;				/* runs through old argv array */
	char **nargv;				/* runs through new argv array */
	int oargc = *argcp;			/* old argc */
	int nargc = 0;				/* number of arguments in env variable */

	env = (char *) getenv(env);
	if (env == NULL)
		return NULL;

	p = (char *) xmalloc(strlen(env) + 1);
	env = strcpy(p, env);		/* keep env variable intact */

	for (p = env; *p; nargc++) {	/* move through env */
		p += strspn(p, SEPARATOR);	/* skip leading separators */
		if (*p == '\0')
			break;

		p += strcspn(p, SEPARATOR);	/* find end of word */
		if (*p)
			*p++ = '\0';		/* mark it */
	}
	if (nargc == 0) {
		free(env);
		return NULL;
	}
	*argcp += nargc;
	/* Allocate the new argv array, with an extra element just in case
	 * the original arg list did not end with a NULL.
	 */
	nargv = (char **) calloc(*argcp + 1, sizeof(char *));

	if (nargv == NULL)
		errorMsg(memory_exhausted);
	oargv = *argvp;
	*argvp = nargv;

	/* Copy the program name first */
	if (oargc-- < 0)
		errorMsg("argc<=0");
	*(nargv++) = *(oargv++);

	/* Then copy the environment args */
	for (p = env; nargc > 0; nargc--) {
		p += strspn(p, SEPARATOR);	/* skip separators */
		*(nargv++) = p;			/* store start */
		while (*p++);			/* skip over word */
	}

	/* Finally copy the old args and add a NULL (usual convention) */
	while (oargc--)
		*(nargv++) = *(oargv++);
	*nargv = NULL;
	return env;
}

/* ========================================================================
 * Display compression ratio on the given stream on 6 characters.
 */
void display_ratio(num, den, file)
long num;
long den;
FILE *file;
{
	long ratio;					/* 1000 times the compression ratio */

	if (den == 0) {
		ratio = 0;				/* no compression */
	} else if (den < 2147483L) {	/* (2**31 -1)/1000 */
		ratio = 1000L * num / den;
	} else {
		ratio = num / (den / 1000L);
	}
	if (ratio < 0) {
		putc('-', file);
		ratio = -ratio;
	} else {
		putc(' ', file);
	}
	fprintf(file, "%2ld.%1ld%%", ratio / 10L, ratio % 10L);
}


/* zip.c -- compress files to the gzip or pkzip format
 * Copyright (C) 1992-1993 Jean-loup Gailly
 * This is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License, see the file COPYING.
 */

#include <ctype.h>
#include <sys/types.h>

#ifdef HAVE_UNISTD_H
#  include <unistd.h>
#endif
#ifndef NO_FCNTL_H
#  include <fcntl.h>
#endif

local ulg crc;					/* crc on uncompressed file data */
long header_bytes;				/* number of bytes in gzip header */

/* ===========================================================================
 * Deflate in to out.
 * IN assertions: the input and output buffers are cleared.
 *   The variables time_stamp and save_orig_name are initialized.
 */
int zip(in, out)
int in, out;					/* input and output file descriptors */
{
	uch flags = 0;				/* general purpose bit flags */
	ush attr = 0;				/* ascii/binary flag */
	ush deflate_flags = 0;		/* pkzip -es, -en or -ex equivalent */

	ifd = in;
	ofd = out;
	outcnt = 0;

	/* Write the header to the gzip file. See algorithm.doc for the format */


	method = DEFLATED;
	put_byte(GZIP_MAGIC[0]);	/* magic header */
	put_byte(GZIP_MAGIC[1]);
	put_byte(DEFLATED);			/* compression method */

	put_byte(flags);			/* general flags */
	put_long(time_stamp);

	/* Write deflated file to zip file */
	crc = updcrc(0, 0);

	bi_init(out);
	ct_init(&attr, &method);
	lm_init(&deflate_flags);

	put_byte((uch) deflate_flags);	/* extra flags */
	put_byte(OS_CODE);			/* OS identifier */

	header_bytes = (long) outcnt;

	(void) deflate();

	/* Write the crc and uncompressed size */
	put_long(crc);
	put_long(isize);
	header_bytes += 2 * sizeof(long);

	flush_outbuf();
	return OK;
}


/* ===========================================================================
 * Read a new buffer from the current input file, perform end-of-line
 * translation, and update the crc and input file size.
 * IN assertion: size >= 2 (for end-of-line translation)
 */
int file_read(buf, size)
char *buf;
unsigned size;
{
	unsigned len;

	Assert(insize == 0, "inbuf not empty");

	len = read(ifd, buf, size);
	if (len == (unsigned) (-1) || len == 0)
		return (int) len;

	crc = updcrc((uch *) buf, len);
	isize += (ulg) len;
	return (int) len;
}