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authorEric Andersen <andersen@codepoet.org>2001-08-22 04:15:47 +0000
committerEric Andersen <andersen@codepoet.org>2001-08-22 04:15:47 +0000
commit39eb040757c9025f18866741ff3de9e2a1aaa0fc (patch)
tree1fd48243f4ce204326f01f83dd5270e1b4af0b4b /archival
parenta07c9026486043359b84a16576cccc635075c300 (diff)
downloadbusybox-39eb040757c9025f18866741ff3de9e2a1aaa0fc.tar.gz
Patch from Rodney Brown <RDBrown@mira.net>, shrinking 1.5k
from gzip by careful optimization. Appears to work just fine (I've tested the changes on x86, ARM, and powerpc).
Diffstat (limited to 'archival')
-rw-r--r--archival/gzip.c72
1 files changed, 45 insertions, 27 deletions
diff --git a/archival/gzip.c b/archival/gzip.c
index 54bb72745..53646df7c 100644
--- a/archival/gzip.c
+++ b/archival/gzip.c
@@ -110,8 +110,7 @@ static int method; /* compression method */
#ifdef DYN_ALLOC
# define DECLARE(type, array, size) static type * array
# define ALLOC(type, array, size) { \
- array = (type*)calloc((size_t)(((size)+1L)/2), 2*sizeof(type)); \
- if (array == NULL) error_msg(memory_exhausted); \
+ array = (type*)xcalloc((size_t)(((size)+1L)/2), 2*sizeof(type)); \
}
# define FREE(array) {if (array != NULL) free(array), array=NULL;}
#else
@@ -181,16 +180,17 @@ typedef int file_t; /* Do not use stdio */
outbuf[outcnt++] = (uch) ((w) & 0xff); \
outbuf[outcnt++] = (uch) ((ush)(w) >> 8); \
} else { \
- put_byte((uch)((w) & 0xff)); \
- put_byte((uch)((ush)(w) >> 8)); \
+ put_short_when_full(w); \
} \
}
/* Output a 32 bit value to the bit stream, lsb first */
+#if 0
#define put_long(n) { \
put_short((n) & 0xffff); \
put_short(((ulg)(n)) >> 16); \
}
+#endif
#define seekable() 0 /* force sequential output */
#define translate_eol 0 /* no option -a yet */
@@ -220,7 +220,6 @@ typedef int file_t; /* Do not use stdio */
#endif
-
/* from zip.c: */
static int zip (int in, int out);
static int file_read (char *buf, unsigned size);
@@ -248,6 +247,9 @@ static int (*read_buf) (char *buf, unsigned size);
/* from util.c: */
static void flush_outbuf (void);
+static void put_short_when_full (ush);
+
+
/* 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
@@ -388,18 +390,11 @@ static ulg updcrc(uch *s, unsigned n)
static unsigned long crc_32_tab[256];
if (crc_table_empty) {
unsigned long csr; /* crc shift register */
- unsigned long e=0; /* polynomial exclusive-or pattern */
+ const unsigned long e = 0xedb88320L; /* polynomial exclusive-or pattern */
int i; /* counter for all possible eight bit values */
int k; /* byte being shifted into crc apparatus */
- /* terms of polynomial defining this crc (except x^32): */
- static const int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
-
- /* Make exclusive-or pattern from polynomial (0xedb88320) */
- for (i = 0; i < sizeof(p)/sizeof(int); i++)
- e |= 1L << (31 - p[i]);
-
- /* Compute and print table of CRC's, five per line */
+ /* Compute table of CRC's. */
crc_32_tab[0] = 0x00000000L;
for (i = 1; i < 256; i++) {
csr = i;
@@ -1206,7 +1201,6 @@ typedef struct dirent dir_type;
typedef RETSIGTYPE(*sig_type) (int);
-
/* ======================================================================== */
// int main (argc, argv)
// int argc;
@@ -1291,11 +1285,9 @@ int gzip_main(int argc, char **argv)
/* Open input file */
inFileNum = open(ifname, O_RDONLY);
- if (inFileNum < 0)
+ if (inFileNum < 0 || stat(ifname, &statBuf) < 0)
perror_msg_and_die("%s", ifname);
/* Get the time stamp on the input file. */
- if (stat(ifname, &statBuf) < 0)
- perror_msg_and_die("%s", ifname);
time_stamp = statBuf.st_ctime;
ifile_size = statBuf.st_size;
}
@@ -1433,16 +1425,20 @@ int gzip_main(int argc, char **argv)
#define BL_CODES 19
/* number of codes used to transfer the bit lengths */
+typedef uch extra_bits_t;
-static const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
+/* extra bits for each length code */
+static const extra_bits_t extra_lbits[LENGTH_CODES]
= { 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 };
-static const int extra_dbits[D_CODES] /* extra bits for each distance code */
+/* extra bits for each distance code */
+static const extra_bits_t extra_dbits[D_CODES]
= { 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 };
-static const int extra_blbits[BL_CODES] /* extra bits for each bit length code */
+/* extra bits for each bit length code */
+static const extra_bits_t extra_blbits[BL_CODES]
= { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 };
#define STORED_BLOCK 0
@@ -1537,7 +1533,7 @@ static ct_data bl_tree[2 * BL_CODES + 1];
typedef struct tree_desc {
ct_data *dyn_tree; /* the dynamic tree */
ct_data *static_tree; /* corresponding static tree or NULL */
- const int *extra_bits; /* extra bits for each code or NULL */
+ const extra_bits_t *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 */
@@ -1834,7 +1830,7 @@ static void pqdownheap(ct_data *tree, int k)
static void gen_bitlen(tree_desc *desc)
{
ct_data *tree = desc->dyn_tree;
- const int *extra = desc->extra_bits;
+ const extra_bits_t *extra = desc->extra_bits;
int base = desc->extra_base;
int max_code = desc->max_code;
int max_length = desc->max_length;
@@ -2466,6 +2462,28 @@ static void set_file_type()
static ulg crc; /* crc on uncompressed file data */
static long header_bytes; /* number of bytes in gzip header */
+static void put_short_when_full(ush w)
+{
+ put_byte((uch)((w) & 0xff));
+ put_byte((uch)((ush)(w) >> 8));
+}
+
+static void put_short_function(ush n)
+{
+ put_short(n);
+}
+
+static void put_long(ulg n)
+{
+ put_short_function((n) & 0xffff);
+ put_short_function(((ulg)(n)) >> 16);
+}
+
+/* put_header_byte is used for the compressed output
+ * - for the initial 4 bytes that can't overflow the buffer.
+ */
+#define put_header_byte(c) {outbuf[outcnt++]=(uch)(c);}
+
/* ===========================================================================
* Deflate in to out.
* IN assertions: the input and output buffers are cleared.
@@ -2485,11 +2503,11 @@ static int zip(int in, int out)
method = DEFLATED;
- put_byte(GZIP_MAGIC[0]); /* magic header */
- put_byte(GZIP_MAGIC[1]);
- put_byte(DEFLATED); /* compression method */
+ put_header_byte(GZIP_MAGIC[0]); /* magic header */
+ put_header_byte(GZIP_MAGIC[1]);
+ put_header_byte(DEFLATED); /* compression method */
- put_byte(my_flags); /* general flags */
+ put_header_byte(my_flags); /* general flags */
put_long(time_stamp);
/* Write deflated file to zip file */