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| author | Glenn L McGrath <bug1@ihug.co.nz> | 2001-12-05 13:08:03 +0000 |
|---|---|---|
| committer | Glenn L McGrath <bug1@ihug.co.nz> | 2001-12-05 13:08:03 +0000 |
| commit | ef03dbcd4db03fcab7b6f48a7038226d202775ca (patch) | |
| tree | d8631e9e4c384462c0268179b23ed40bbdccd70d /archival/libunarchive | |
| parent | aad44fb37a3f68dc82e5387c1bf13e3b29daab24 (diff) | |
| download | busybox-ef03dbcd4db03fcab7b6f48a7038226d202775ca.tar.gz | |
Simplify CRC table generation
Diffstat (limited to 'archival/libunarchive')
| -rw-r--r-- | archival/libunarchive/decompress_unzip.c | 16 | ||||
| -rw-r--r-- | archival/libunarchive/unzip.c | 16 |
2 files changed, 10 insertions, 22 deletions
diff --git a/archival/libunarchive/decompress_unzip.c b/archival/libunarchive/decompress_unzip.c index 69cc8198b..c28ca836c 100644 --- a/archival/libunarchive/decompress_unzip.c +++ b/archival/libunarchive/decompress_unzip.c @@ -123,22 +123,16 @@ static void abort_gzip(void) static void make_crc_table(void) { - unsigned long table_entry; /* crc shift register */ - unsigned long poly = 0; /* 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 int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26}; + const unsigned long poly = 0xedb88320; /* polynomial exclusive-or pattern */ + unsigned short i; /* counter for all possible eight bit values */ crc_table = (unsigned long *) malloc(256 * sizeof(unsigned long)); - /* Make exclusive-or pattern from polynomial (0xedb88320) */ - for (i = 0; i < sizeof(p)/sizeof(int); i++) - poly |= 1L << (31 - p[i]); - /* Compute and print table of CRC's, five per line */ for (i = 0; i < 256; i++) { + unsigned long table_entry; /* crc shift register */ + 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 diff --git a/archival/libunarchive/unzip.c b/archival/libunarchive/unzip.c index 69cc8198b..c28ca836c 100644 --- a/archival/libunarchive/unzip.c +++ b/archival/libunarchive/unzip.c @@ -123,22 +123,16 @@ static void abort_gzip(void) static void make_crc_table(void) { - unsigned long table_entry; /* crc shift register */ - unsigned long poly = 0; /* 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 int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26}; + const unsigned long poly = 0xedb88320; /* polynomial exclusive-or pattern */ + unsigned short i; /* counter for all possible eight bit values */ crc_table = (unsigned long *) malloc(256 * sizeof(unsigned long)); - /* Make exclusive-or pattern from polynomial (0xedb88320) */ - for (i = 0; i < sizeof(p)/sizeof(int); i++) - poly |= 1L << (31 - p[i]); - /* Compute and print table of CRC's, five per line */ for (i = 0; i < 256; i++) { + unsigned long table_entry; /* crc shift register */ + 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 |