fumiama/base16384
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fix(coder): incorrect hidden bits decoding in 32bit lib

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源文雨
2024-04-05 16:27:21 +09:00
parent cd15e63c86
commit 29e4019ed1
5 changed files with 70 additions and 38 deletions
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36
binary.h
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@@ -70,15 +70,15 @@
#define htobe64(x) (x)
#endif
#else
#define be16toh(x) _byteswap_ushort(x)
#define be32toh(x) _byteswap_ulong(x)
#define be16toh(x) _bitswap_ushort(x)
#define be32toh(x) _bitswap_ulong(x)
#ifdef IS_64BIT_PROCESSOR
#define be64toh(x) _byteswap_uint64(x)
#define be64toh(x) _bitswap_uint64(x)
#endif
#define htobe16(x) _byteswap_ushort(x)
#define htobe32(x) _byteswap_ulong(x)
#define htobe16(x) _bitswap_ushort(x)
#define htobe32(x) _bitswap_ulong(x)
#ifdef IS_64BIT_PROCESSOR
#define htobe64(x) _byteswap_uint64(x)
#define htobe64(x) _bitswap_uint64(x)
#endif
#endif
#endif
@@ -87,6 +87,9 @@
// leftrotate function definition
#define LEFTROTATE(x, c) (((x) << (c)) | ((x) >> (sizeof(x)*8 - (c))))
// initial sum value used in BASE16384_FLAG_SUM_CHECK_ON_REMAIN
#define BASE16384_SIMPLE_SUM_INIT_VALUE (0x8e29c213)
static inline uint32_t calc_sum(uint32_t sum, size_t cnt, const char* encbuf) {
size_t i;
uint32_t buf;
@@ -99,20 +102,21 @@ static inline uint32_t calc_sum(uint32_t sum, size_t cnt, const char* encbuf) {
return sum;
}
static inline uint32_t calc_and_embed_sum(uint32_t sum, size_t cnt, char* encbuf) {
sum = calc_sum(sum, cnt, encbuf);
if(cnt%7) { // last encode
*(uint32_t*)(&encbuf[cnt]) = htobe32(sum);
}
return sum;
}
static inline int check_sum(uint32_t sum, uint32_t sum_read_raw, int offset) {
int shift = (int[]){0, 26, 20, 28, 22, 30, 24}[offset%7];
offset = offset%7;
if(!offset--) return 0; // no remain bits, pass
// offset 1: 0011 1111 1100 0000 remain: 3*2 bits
// offset 2: 0011 1111 1111 1111 0011 0000 0000 0000 remain: 6*2 bits
// offset 3: 0011 1111 1111 0000 remain: 2*2 bits
// offset 4: 0011 1111 1111 1111 0011 1100 0000 0000 remain: 5*2 bits
// offset 5: 0011 1111 1111 1100 remain: 1*2 bits
// offset 6: 0011 1111 1111 1111 0011 1111 0000 0000 remain: 4*2 bits
// encode: 0415263 (6-1) per 3bits, thus 0x021ab3
int shift = sizeof(uint32_t)*8 - ((0x021ab3>>(offset*3))&0x07)*2;
uint32_t sum_read = be32toh(sum_read_raw) >> shift;
sum >>= shift;
#ifdef DEBUG
fprintf(stderr, "offset: %d, mysum: %08x, sumrd: %08x\n", offset, sum, sum_read);
fprintf(stderr, "shift: %d, offset: %d, mysum: %08x, sumrd: %08x\n", shift, offset+1, sum, sum_read);
#endif
return sum != sum_read;
}