51 lines
961 B
C
Executable File
51 lines
961 B
C
Executable File
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#include "sysconfig.h"
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#include "sysdeps.h"
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#include "crc32.h"
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static uae_u32 crc_table32[256];
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static uae_u16 crc_table16[256];
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static void make_crc_table (void)
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{
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uae_u32 c;
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uae_u16 w;
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unsigned int n, k;
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for (n = 0; n < 256; n++) {
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c = (uae_u32) n;
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w = n << 8;
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for (k = 0; k < 8; k++) {
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c = (c >> 1) ^ (c & 1 ? 0xedb88320 : 0);
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w = (w << 1) ^ ((w & 0x8000) ? 0x1021 : 0);
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}
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crc_table32[n] = c;
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crc_table16[n] = w;
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}
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}
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uae_u32 get_crc32 (const uae_u8 *buf, unsigned int len)
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{
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uae_u32 crc;
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if (!crc_table32[1])
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make_crc_table ();
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crc = 0xffffffff;
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while (len-- > 0)
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crc = crc_table32[(crc ^ (*buf++)) & 0xff] ^ (crc >> 8);
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return crc ^ 0xffffffff;
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}
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uae_u16 get_crc16 (const uae_u8 *buf, unsigned int len)
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{
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uae_u16 crc;
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if (!crc_table32[1])
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make_crc_table ();
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crc = 0xffff;
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while (len-- > 0)
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crc = (crc << 8) ^ crc_table16[((crc >> 8) ^ (*buf++)) & 0xff];
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return crc;
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}
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