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Patch from Rob Sullivan to consolidate crc32 table generation.

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This commit is contained in:
Rob Landley
2006-04-10 17:07:15 +00:00
parent 998f449375
commit c57ec37959
6 changed files with 65 additions and 71 deletions
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42
archival/libunarchive/decompress_unzip.c
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@@ -95,8 +95,8 @@ static unsigned int gunzip_outbuf_count; /* bytes in output buffer */
enum { gunzip_wsize = 0x8000 };
static unsigned char *gunzip_window;
static unsigned int *gunzip_crc_table;
unsigned int gunzip_crc;
static uint32_t *gunzip_crc_table;
uint32_t gunzip_crc;
/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
#define BMAX 16 /* maximum bit length of any code (16 for explode) */
@@ -168,35 +168,6 @@ static unsigned int fill_bitbuffer(unsigned int bitbuffer, unsigned int *current
return(bitbuffer);
}
static void make_gunzip_crc_table(void)
{
const unsigned int poly = 0xedb88320; /* polynomial exclusive-or pattern */
unsigned short i; /* counter for all possible eight bit values */
/* initial shift register value */
gunzip_crc = 0xffffffffL;
gunzip_crc_table = (unsigned int *) xmalloc(256 * sizeof(unsigned int));
/* Compute and print table of CRC's, five per line */
for (i = 0; i < 256; i++) {
unsigned int table_entry; /* crc shift register */
unsigned char k; /* byte being shifted into crc apparatus */
table_entry = i;
/* The idea to initialize the register with the byte instead of
* zero was stolen from Haruhiko Okumura's ar002
*/
for (k = 8; k; k--) {
if (table_entry & 1) {
table_entry = (table_entry >> 1) ^ poly;
} else {
table_entry >>= 1;
}
}
gunzip_crc_table[i] = table_entry;
}
}
/*
* Free the malloc'ed tables built by huft_build(), which makes a linked
* list of the tables it made, with the links in a dummy first entry of
@@ -922,8 +893,9 @@ int inflate_unzip(int in, int out)
gunzip_bb = 0;
/* Create the crc table */
make_gunzip_crc_table();
gunzip_crc_table = bb_crc32_filltable(0);
gunzip_crc = ~0;
/* Allocate space for buffer */
bytebuffer = xmalloc(bytebuffer_max);
@@ -955,7 +927,7 @@ int inflate_unzip(int in, int out)
int inflate_gunzip(int in, int out)
{
unsigned int stored_crc = 0;
uint32_t stored_crc = 0;
unsigned int count;
inflate_unzip(in, out);
@@ -972,7 +944,7 @@ int inflate_gunzip(int in, int out)
}
/* Validate decompression - crc */
if (stored_crc != (gunzip_crc ^ 0xffffffffL)) {
if (stored_crc != (~gunzip_crc)) {
bb_error_msg("crc error");
return -1;
}