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Diffstat (limited to 'usr/src/lib/libsum/common/sum-crc.c')
| -rw-r--r-- | usr/src/lib/libsum/common/sum-crc.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/usr/src/lib/libsum/common/sum-crc.c b/usr/src/lib/libsum/common/sum-crc.c new file mode 100644 index 0000000000..eca34df603 --- /dev/null +++ b/usr/src/lib/libsum/common/sum-crc.c @@ -0,0 +1,191 @@ +/*********************************************************************** +* * +* This software is part of the ast package * +* Copyright (c) 1996-2008 AT&T Intellectual Property * +* and is licensed under the * +* Common Public License, Version 1.0 * +* by AT&T Intellectual Property * +* * +* A copy of the License is available at * +* http://www.opensource.org/licenses/cpl1.0.txt * +* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) * +* * +* Information and Software Systems Research * +* AT&T Research * +* Florham Park NJ * +* * +* Glenn Fowler <gsf@research.att.com> * +* * +***********************************************************************/ +#pragma prototyped + +/* + * crc + */ + +#define crc_description \ + "32 bit CRC (cyclic redundancy check)." +#define crc_options "\ +[+polynomial?The 32 bit crc polynomial bitmask with implicit bit 32.]:[mask:=0xedb88320]\ +[+done?XOR the final crc value with \anumber\a. 0xffffffff is used if \anumber\a is omitted.]:?[number:=0]\ +[+init?The initial crc value. 0xffffffff is used if \anumber\a is omitted.]:?[number:=0]\ +[+rotate?XOR each input character with the high order crc byte (instead of the low order).]\ +[+size?Include the total number of bytes in the crc. \anumber\a, if specified, is first XOR'd into the size.]:?[number:=0]\ +" +#define crc_match "crc" +#define crc_open crc_open +#define crc_print long_print +#define crc_data long_data +#define crc_scale 0 + +typedef uint32_t Crcnum_t; + +typedef struct Crc_s +{ + _SUM_PUBLIC_ + _SUM_PRIVATE_ + _INTEGRAL_PRIVATE_ + Crcnum_t init; + Crcnum_t done; + Crcnum_t xorsize; + Crcnum_t tab[256]; + unsigned int addsize; + unsigned int rotate; +} Crc_t; + +#define CRC(p,s,c) (s = (s >> 8) ^ (p)->tab[(s ^ (c)) & 0xff]) +#define CRCROTATE(p,s,c) (s = (s << 8) ^ (p)->tab[((s >> 24) ^ (c)) & 0xff]) + +static Sum_t* +crc_open(const Method_t* method, const char* name) +{ + register Crc_t* sum; + register const char* s; + register const char* t; + register const char* v; + register int i; + register int j; + Crcnum_t polynomial; + Crcnum_t x; + + if (sum = newof(0, Crc_t, 1, 0)) + { + sum->method = (Method_t*)method; + sum->name = name; + } + polynomial = 0xedb88320; + s = name; + while (*(t = s)) + { + for (t = s, v = 0; *s && *s != '-'; s++) + if (*s == '=' && !v) + v = s; + i = (v ? v : s) - t; + if (isdigit(*t) || v && i >= 4 && strneq(t, "poly", 4) && (t = v + 1)) + polynomial = strtoul(t, NiL, 0); + else if (strneq(t, "done", i)) + sum->done = v ? strtoul(v + 1, NiL, 0) : ~sum->done; + else if (strneq(t, "init", i)) + sum->init = v ? strtoul(v + 1, NiL, 0) : ~sum->init; + else if (strneq(t, "rotate", i)) + sum->rotate = 1; + else if (strneq(t, "size", i)) + { + sum->addsize = 1; + if (v) + sum->xorsize = strtoul(v + 1, NiL, 0); + } + if (*s == '-') + s++; + } + if (sum->rotate) + { + Crcnum_t t; + Crcnum_t p[8]; + + p[0] = polynomial; + for (i = 1; i < 8; i++) + p[i] = (p[i-1] << 1) ^ ((p[i-1] & 0x80000000) ? polynomial : 0); + for (i = 0; i < elementsof(sum->tab); i++) + { + t = 0; + x = i; + for (j = 0; j < 8; j++) + { + if (x & 1) + t ^= p[j]; + x >>= 1; + } + sum->tab[i] = t; + } + } + else + { + for (i = 0; i < elementsof(sum->tab); i++) + { + x = i; + for (j = 0; j < 8; j++) + x = (x>>1) ^ ((x & 1) ? polynomial : 0); + sum->tab[i] = x; + } + } + return (Sum_t*)sum; +} + +static int +crc_init(Sum_t* p) +{ + Crc_t* sum = (Crc_t*)p; + + sum->sum = sum->init; + return 0; +} + +static int +crc_block(Sum_t* p, const void* s, size_t n) +{ + Crc_t* sum = (Crc_t*)p; + register Crcnum_t c = sum->sum; + register unsigned char* b = (unsigned char*)s; + register unsigned char* e = b + n; + + if (sum->rotate) + while (b < e) + CRCROTATE(sum, c, *b++); + else + while (b < e) + CRC(sum, c, *b++); + sum->sum = c; + return 0; +} + +static int +crc_done(Sum_t* p) +{ + register Crc_t* sum = (Crc_t*)p; + register Crcnum_t c; + register uintmax_t n; + int i; + int j; + + c = sum->sum; + if (sum->addsize) + { + n = sum->size ^ sum->xorsize; + if (sum->rotate) + while (n) + { + CRCROTATE(sum, c, n); + n >>= 8; + } + else + for (i = 0, j = 32; i < 4; i++) + { + j -= 8; + CRC(sum, c, n >> j); + } + } + sum->sum = c ^ sum->done; + sum->total_sum ^= (sum->sum &= 0xffffffff); + return 0; +} |