diff options
| author | magh <magh@maghmogh.com> | 2023-03-06 18:44:55 -0600 |
|---|---|---|
| committer | magh <magh@maghmogh.com> | 2023-03-06 18:44:55 -0600 |
| commit | e80d9d8871b325a04b18f90a9ea4bb7fd148fb25 (patch) | |
| tree | 79dbdb8506b7ff1e92549188d1b94cfc0b3503ae /tools/src/tinf/crc32.c | |
Diffstat (limited to 'tools/src/tinf/crc32.c')
| -rw-r--r-- | tools/src/tinf/crc32.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/tools/src/tinf/crc32.c b/tools/src/tinf/crc32.c new file mode 100644 index 0000000..b83232c --- /dev/null +++ b/tools/src/tinf/crc32.c @@ -0,0 +1,57 @@ +/* + * CRC32 checksum + * + * Copyright (c) 1998-2019 Joergen Ibsen + * + * This software is provided 'as-is', without any express or implied + * warranty. In no event will the authors be held liable for any damages + * arising from the use of this software. + * + * Permission is granted to anyone to use this software for any purpose, + * including commercial applications, and to alter it and redistribute it + * freely, subject to the following restrictions: + * + * 1. The origin of this software must not be misrepresented; you must + * not claim that you wrote the original software. If you use this + * software in a product, an acknowledgment in the product + * documentation would be appreciated but is not required. + * + * 2. Altered source versions must be plainly marked as such, and must + * not be misrepresented as being the original software. + * + * 3. This notice may not be removed or altered from any source + * distribution. + */ + +/* + * CRC32 algorithm taken from the zlib source, which is + * Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler + */ + +#include "tinf.h" + +static const unsigned int tinf_crc32tab[16] = { + 0x00000000, 0x1DB71064, 0x3B6E20C8, 0x26D930AC, 0x76DC4190, + 0x6B6B51F4, 0x4DB26158, 0x5005713C, 0xEDB88320, 0xF00F9344, + 0xD6D6A3E8, 0xCB61B38C, 0x9B64C2B0, 0x86D3D2D4, 0xA00AE278, + 0xBDBDF21C +}; + +unsigned int tinf_crc32(const void *data, unsigned int length) +{ + const unsigned char *buf = (const unsigned char *) data; + unsigned int crc = 0xFFFFFFFF; + unsigned int i; + + if (length == 0) { + return 0; + } + + for (i = 0; i < length; ++i) { + crc ^= buf[i]; + crc = tinf_crc32tab[crc & 0x0F] ^ (crc >> 4); + crc = tinf_crc32tab[crc & 0x0F] ^ (crc >> 4); + } + + return crc ^ 0xFFFFFFFF; +} |
