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authorRob Landley2006-04-10 17:07:15 +0000
committerRob Landley2006-04-10 17:07:15 +0000
commitc57ec37959390ff2e43faa5e4dd5281b2923ced3 (patch)
tree8325e7bd6a9a270e931b383d33b5901751dd2a5e /archival/gzip.c
parent998f4493756423877217239d2cc42eb8b83d50b3 (diff)
downloadbusybox-c57ec37959390ff2e43faa5e4dd5281b2923ced3.zip
busybox-c57ec37959390ff2e43faa5e4dd5281b2923ced3.tar.gz
Patch from Rob Sullivan to consolidate crc32 table generation.
Diffstat (limited to 'archival/gzip.c')
-rw-r--r--archival/gzip.c35
1 files changed, 10 insertions, 25 deletions
diff --git a/archival/gzip.c b/archival/gzip.c
index fa6e85b..41ed3a2 100644
--- a/archival/gzip.c
+++ b/archival/gzip.c
@@ -293,6 +293,7 @@ static int ofd; /* output file descriptor */
static unsigned insize; /* valid bytes in inbuf */
static unsigned outcnt; /* bytes in output buffer */
+static uint32_t *crc_32_tab;
/* Output a 16 bit value, lsb first */
static void put_short(ush w)
@@ -344,32 +345,13 @@ static void write_buf(int fd, void *buf, unsigned cnt)
* pointer, then initialize the crc shift register contents instead.
* Return the current crc in either case.
*/
-static ulg updcrc(uch * s, unsigned n)
+static uint32_t updcrc(uch * s, unsigned n)
{
- static ulg crc = (ulg) 0xffffffffL; /* shift register contents */
- register ulg c; /* temporary variable */
- static unsigned long crc_32_tab[256];
-
- if (crc_32_tab[1] == 0x00000000L) {
- unsigned long csr; /* crc shift register */
- 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 */
-
- /* Compute table of CRC's. */
- for (i = 1; i < 256; i++) {
- csr = 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--)
- csr = csr & 1 ? (csr >> 1) ^ e : csr >> 1;
- crc_32_tab[i] = csr;
- }
- }
+ static uint32_t crc = ~0; /* shift register contents */
+ uint32_t c; /* temporary variable */
if (s == NULL) {
- c = 0xffffffffL;
+ c = ~0;
} else {
c = crc;
if (n)
@@ -378,7 +360,7 @@ static ulg updcrc(uch * s, unsigned n)
} while (--n);
}
crc = c;
- return c ^ 0xffffffffL; /* (instead of ~c for 64-bit machines) */
+ return ~c;
}
/* bits.c -- output variable-length bit strings
@@ -1223,6 +1205,9 @@ int gzip_main(int argc, char **argv)
ALLOC(uch, window, 2L * WSIZE);
ALLOC(ush, tab_prefix, 1L << BITS);
+ /* Initialise the CRC32 table */
+ crc_32_tab = bb_crc32_filltable(0);
+
clear_bufs();
part_nb = 0;
@@ -2416,7 +2401,7 @@ static void set_file_type(void)
*/
-static ulg crc; /* crc on uncompressed file data */
+static uint32_t crc; /* crc on uncompressed file data */
static long header_bytes; /* number of bytes in gzip header */
static void put_long(ulg n)