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32 lines
693 B
C
32 lines
693 B
C
/* Copyright (C) radare2 - 2007-2016 - pancake */
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#include <r_types.h>
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#include <r_util.h>
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static bool crc_table_is_init = false;
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static ut32 crc_table[256];
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R_API ut32 r_hash_crc32(const ut8 *buf, ut64 len) {
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ut32 crc = 0;
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ut8 tmp[sizeof (ut32)];
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if (!crc_table_is_init) {
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ut32 i, j, h = 1;
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crc_table_is_init = true;
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crc_table[0] = 0;
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for (i = 128; i; i >>= 1) {
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h = (h >> 1) ^ ((h & 1) ? (int)0xedb88320 : 0);
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for (j = 0; j < 256; j += 2*i)
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crc_table[i+j] = crc_table[j] ^ h;
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}
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}
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crc ^= UT32_MAX;
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while (len--) {
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crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
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}
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crc ^= UT32_MAX;
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// unswap endian
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r_write_le32 (tmp, crc);
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return r_read_le32 (tmp);
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}
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