diff options
Diffstat (limited to 'archival/gzip.c')
| -rw-r--r-- | archival/gzip.c | 139 |
1 files changed, 66 insertions, 73 deletions
diff --git a/archival/gzip.c b/archival/gzip.c index a16e36978..dcbcae0b3 100644 --- a/archival/gzip.c +++ b/archival/gzip.c @@ -61,8 +61,6 @@ aa: 85.1% -- replaced with aa.gz # endif #endif -#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 */ @@ -161,28 +159,26 @@ typedef unsigned short ush; typedef unsigned long ulg; - /* from zip.c: */ +/* from zip.c: */ static int zip(int in, int out); static unsigned file_read(void *buf, unsigned size); - /* from deflate.c */ +/* from deflate.c */ static void lm_init(ush * flags); static ulg deflate(void); - /* from trees.c */ +/* from trees.c */ static void ct_init(ush * attr, int *methodp); static int ct_tally(int dist, int lc); static ulg flush_block(char *buf, ulg stored_len, int eof); - /* from bits.c */ +/* from bits.c */ static void bi_init(int zipfile); static void send_bits(int value, int length); static unsigned bi_reverse(unsigned value, int length); static void bi_windup(void); static void copy_block(char *buf, unsigned len, int header); -static void flush_outbuf(void); - /* global buffers */ /* To save memory for 16 bit systems, some arrays are overlaid between @@ -250,6 +246,20 @@ static ulg bits_sent; /* bit length of the compressed data */ /* =========================================================================== + * Write the output buffer outbuf[0..outcnt-1] and update bytes_out. + * (used for the compressed data only) + */ +static void flush_outbuf(void) +{ + if (outcnt == 0) + return; + + xwrite(ofd, (char *) outbuf, outcnt); + outcnt = 0; +} + + +/* =========================================================================== */ /* put_8bit is used for the compressed output */ #define put_8bit(c) \ @@ -284,6 +294,7 @@ static void put_32bit(ulg n) outbuf[outcnt++] = (c); \ } + /* =========================================================================== * Clear input and output buffers */ @@ -296,29 +307,52 @@ static void clear_bufs(void) isize = 0L; } + /* =========================================================================== * Run a set of bytes through the crc shift register. If s is a NULL * pointer, then initialize the crc shift register contents instead. * Return the current crc in either case. */ +static uint32_t crc = ~0; /* shift register contents */ static uint32_t updcrc(uch * s, unsigned n) { - static uint32_t crc = ~0; /* shift register contents */ uint32_t c; /* temporary variable */ if (s == NULL) { c = ~0; } else { c = crc; - if (n) - do { - c = crc_32_tab[((int) c ^ (*s++)) & 0xff] ^ (c >> 8); - } while (--n); + while (n) { + c = crc_32_tab[(uch)(c ^ *s++)] ^ (c >> 8); + n--; + } } crc = c; return c; } + +/* =========================================================================== + * 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) + */ +static unsigned file_read(void *buf, unsigned size) +{ + unsigned len; + + Assert(insize == 0, "inbuf not empty"); + + len = safe_read(ifd, buf, size); + if (len == (unsigned)(-1) || len == 0) + return len; + + updcrc(buf, len); + isize += len; + return len; +} + + /* =========================================================================== * Initialize the bit string routines. */ @@ -332,6 +366,7 @@ static void bi_init(int zipfile) #endif } + /* =========================================================================== * Send a value on a given number of bits. * IN assertion: length <= 16 and value fits in length bits. @@ -414,16 +449,6 @@ static void copy_block(char *buf, unsigned len, int header) } } -/* 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. - */ - - /* =========================================================================== * Configuration parameters */ @@ -517,7 +542,7 @@ static unsigned ins_h; /* hash index of string to be inserted */ /* 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 + * H_SHIFT * MIN_MATCH >= HASH_BITS */ static unsigned int prev_length; @@ -664,8 +689,7 @@ static int longest_match(IPos cur_match) uch *match; /* matched string */ 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; + IPos limit = strstart > (IPos) MAX_DIST ? strstart - (IPos) MAX_DIST : 0; /* Stop when cur_match becomes <= limit. To simplify the code, * we prevent matches with the string of window index 0. */ @@ -739,8 +763,7 @@ static int longest_match(IPos cur_match) static void check_match(IPos start, IPos match, int length) { /* check that the match is indeed a match */ - if (memcmp((char *) window + match, - (char *) window + start, length) != EQUAL) { + if (memcmp(window + match, window + start, length) != EQUAL) { bb_error_msg(" start %d, match %d, length %d", start, match, length); bb_error_msg("invalid match"); } @@ -766,14 +789,13 @@ static void check_match(IPos start, IPos match, int length) static void fill_window(void) { unsigned n, m; - unsigned more = - (unsigned) (window_size - (ulg) lookahead - (ulg) strstart); + unsigned more = window_size - lookahead - 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) { + if (more == (unsigned) -1) { /* Very unlikely, but possible on 16 bit machine if strstart == 0 * and lookahead == 1 (input done one byte at time) */ @@ -784,7 +806,7 @@ static void fill_window(void) */ Assert(window_size == (ulg) 2 * WSIZE, "no sliding with BIG_MEM"); - memcpy((char *) window, (char *) window + WSIZE, (unsigned) WSIZE); + memcpy(window, window + WSIZE, WSIZE); match_start -= WSIZE; strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */ @@ -819,13 +841,19 @@ static void fill_window(void) * 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)) + 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. + * + * Processes a new input file and return its compressed length. Sets + * the compressed length, crc, deflate flags and internal file + * attributes. */ static ulg deflate(void) { @@ -930,6 +958,7 @@ static ulg deflate(void) return FLUSH_BLOCK(1); /* eof */ } + /* ======================================================================== */ static void abort_gzip(int ATTRIBUTE_UNUSED ignored) { @@ -2181,8 +2210,6 @@ static void set_file_type(void) } } -static uint32_t crc; /* crc on uncompressed file data */ - /* =========================================================================== * Deflate in to out. * IN assertions: the input and output buffers are cleared. @@ -2209,7 +2236,7 @@ static int zip(int in, int out) put_32bit(time_stamp); /* Write deflated file to zip file */ - crc = 0; + crc = ~0; bi_init(out); ct_init(&attr, &method); @@ -2218,46 +2245,12 @@ static int zip(int in, int out) put_8bit((uch) deflate_flags); /* extra flags */ put_8bit(3); /* OS identifier = 3 (Unix) */ - (void) deflate(); + deflate(); /* Write the crc and uncompressed size */ - put_32bit(crc); + put_32bit(~crc); put_32bit(isize); flush_outbuf(); return 0; } - -/* =========================================================================== - * 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) - */ -static unsigned file_read(void *buf, unsigned size) -{ - unsigned len; - - Assert(insize == 0, "inbuf not empty"); - - len = read(ifd, buf, size); - if (len == (unsigned)(-1) || len == 0) - return len; - - crc = ~updcrc((uch *) buf, len); - isize += len; - return len; -} - -/* =========================================================================== - * Write the output buffer outbuf[0..outcnt-1] and update bytes_out. - * (used for the compressed data only) - */ -static void flush_outbuf(void) -{ - if (outcnt == 0) - return; - - xwrite(ofd, (char *) outbuf, outcnt); - outcnt = 0; -} - |