diff options
Diffstat (limited to 'src/cksum.c')
| -rw-r--r-- | src/cksum.c | 144 |
1 files changed, 75 insertions, 69 deletions
diff --git a/src/cksum.c b/src/cksum.c index 97fc70626..35fe32fce 100644 --- a/src/cksum.c +++ b/src/cksum.c @@ -24,8 +24,8 @@ verify the correctness of the "crctab". To recreate the "crctab", do something like the following: - cc -DCRCTAB -o crctab cksum.c - crctab > crctab.h + cc -I../lib -DCRCTAB -o crctab cksum.c + crctab > cksum.h This software is compatible with neither the System V nor the BSD 'sum' program. It is supposed to conform to POSIX, except perhaps @@ -45,6 +45,12 @@ #include "system.h" #include "fadvise.h" #include "xbinary-io.h" +#include <byteswap.h> +#ifdef WORDS_BIGENDIAN +# define SWAP(n) (n) +#else +# define SWAP(n) bswap_32 (n) +#endif #ifdef CRCTAB @@ -87,16 +93,49 @@ crc_remainder (int m) int main (void) { + int i; + static uint_fast32_t crctab[8][256]; + fill_r (); - printf ("static uint_fast32_t const crctab[256] =\n{\n 0x00000000"); - for (int i = 0; i < 51; i++) + + for (i = 0; i < 256; i++) { - printf (",\n 0x%08x, 0x%08x, 0x%08x, 0x%08x, 0x%08x", - crc_remainder (i * 5 + 1), crc_remainder (i * 5 + 2), - crc_remainder (i * 5 + 3), crc_remainder (i * 5 + 4), - crc_remainder (i * 5 + 5)); + crctab[0][i] = crc_remainder (i); } - printf ("\n};\n"); + + /* CRC(0x11 0x22 0x33 0x44) + is equal to + CRC(0x11 0x00 0x00 0x00) XOR CRC(0x22 0x00 0x00) XOR + CRC(0x33 0x00) XOR CRC(0x44) + We precompute the CRC values for the offset values into + separate CRC tables. We can then use them to speed up + CRC calculation by processing multiple bytes at the time. */ + for (i = 0; i < 256; i++) + { + uint32_t crc = 0; + + crc = (crc << 8) ^ crctab[0][((crc >> 24) ^ (i & 0xFF)) & 0xFF]; + for (unsigned int offset = 1; offset < 8; offset++) + { + crc = (crc << 8) ^ crctab[0][((crc >> 24) ^ 0x00) & 0xFF]; + crctab[offset][i] = crc; + } + } + + printf ("static uint_fast32_t const crctab[8][256] = {\n"); + for (int y = 0; y < 8; y++) + { + printf ("{\n 0x%08x", crctab[y][0]); + for (i = 0; i < 51; i++) + { + printf (",\n 0x%08x, 0x%08x, 0x%08x, 0x%08x, 0x%08x", + crctab[y][i * 5 + 1], crctab[y][i * 5 + 2], + crctab[y][i * 5 + 3], crctab[y][i * 5 + 4], + crctab[y][i * 5 + 5]); + } + printf ("\n},\n"); + } + printf ("};\n"); return EXIT_SUCCESS; } @@ -106,65 +145,11 @@ main (void) # include "die.h" # include "error.h" +# include "cksum.h" + /* Number of bytes to read at once. */ # define BUFLEN (1 << 16) -static uint_fast32_t const crctab[256] = -{ - 0x00000000, - 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, - 0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, - 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, - 0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, - 0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f, - 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, - 0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, - 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58, - 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, - 0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe, - 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95, - 0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, - 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0, - 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, - 0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, - 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07, - 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, - 0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, - 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba, - 0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, - 0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698, - 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, - 0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, - 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f, - 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, - 0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80, - 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, - 0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, - 0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629, - 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, - 0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, - 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e, - 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, - 0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8, - 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3, - 0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, - 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71, - 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, - 0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, - 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21, - 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, - 0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087, - 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec, - 0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, - 0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce, - 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, - 0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, - 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09, - 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, - 0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf, - 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4 -}; - /* Nonzero if any of the files read were the standard input. */ static bool have_read_stdin; @@ -176,7 +161,7 @@ static bool have_read_stdin; static bool cksum (const char *file, bool print_name) { - unsigned char buf[BUFLEN]; + uint32_t buf[BUFLEN/sizeof (uint32_t)]; uint_fast32_t crc = 0; uintmax_t length = 0; size_t bytes_read; @@ -204,13 +189,34 @@ cksum (const char *file, bool print_name) while ((bytes_read = fread (buf, 1, BUFLEN, fp)) > 0) { - unsigned char *cp = buf; + uint32_t *datap; + uint32_t second = 0; if (length + bytes_read < length) die (EXIT_FAILURE, 0, _("%s: file too long"), quotef (file)); length += bytes_read; + + /* Process multiples of 8 bytes */ + datap = (uint32_t *)buf; + while (bytes_read >= 8) + { + crc ^= SWAP (*(datap++)); + second = SWAP (*(datap++)); + crc = crctab[7][(crc >> 24) & 0xFF] + ^ crctab[6][(crc >> 16) & 0xFF] + ^ crctab[5][(crc >> 8) & 0xFF] + ^ crctab[4][(crc) & 0xFF] + ^ crctab[3][(second >> 24) & 0xFF] + ^ crctab[2][(second >> 16) & 0xFF] + ^ crctab[1][(second >> 8) & 0xFF] + ^ crctab[0][(second) & 0xFF]; + bytes_read -= 8; + } + + /* And finish up last 0-7 bytes in a byte by byte fashion */ + unsigned char *cp = (unsigned char *)datap; while (bytes_read--) - crc = (crc << 8) ^ crctab[((crc >> 24) ^ *cp++) & 0xFF]; + crc = (crc << 8) ^ crctab[0][((crc >> 24) ^ *cp++) & 0xFF]; if (feof (fp)) break; } @@ -232,7 +238,7 @@ cksum (const char *file, bool print_name) hp = umaxtostr (length, length_buf); for (; length; length >>= 8) - crc = (crc << 8) ^ crctab[((crc >> 24) ^ length) & 0xFF]; + crc = (crc << 8) ^ crctab[0][((crc >> 24) ^ length) & 0xFF]; crc = ~crc & 0xFFFFFFFF; |