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fused decoder for hash_set

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krosh
2026-08-03 12:26:01 +03:00
parent e8d99cf676
commit da43582394
2 changed files with 90 additions and 82 deletions
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new_version/direct_hash/about.md
+14
View File
@@ -5,3 +5,17 @@
- позволить индексироваться по элементам хэша - позволить индексироваться по элементам хэша
- кратно сократить время на дешифровку - кратно сократить время на дешифровку
- кэшировать можно соответствия индекс - значение, чтобы не работать с битами (может и не стоит того) - кэшировать можно соответствия индекс - значение, чтобы не работать с битами (может и не стоит того)
- стоит этого
```text
symbols=1000 required=500 bpp=32
implementation set_chars format
set9 3994 golomb/base62
direct 5340 D1/base64
operation set9 direct direct/set9
set_fini only 150.44 us 99.28 us 0.66x
new+add+fini 1034.22 us 949.62 us 0.92x
rpmsetcmp cold 292.86 us 210.30 us 0.72x
rpmsetcmp warm 5.89 us 23.02 us 3.91x
```
new_version/direct_hash/hash_set.c
+76 -82
View File
@@ -245,56 +245,45 @@ const char* set_fini(struct set* set, int bpp) {
return output; return output;
} }
static int base64_value(unsigned char c) { static const unsigned char base64_values[256] = {
if (c >= 'A' && c <= 'Z') return c - 'A'; ['A'] = 1, ['B'] = 2, ['C'] = 3, ['D'] = 4, ['E'] = 5, ['F'] = 6, ['G'] = 7, ['H'] = 8,
if (c >= 'a' && c <= 'z') return c - 'a' + 26; ['I'] = 9, ['J'] = 10, ['K'] = 11, ['L'] = 12, ['M'] = 13, ['N'] = 14, ['O'] = 15, ['P'] = 16,
if (c >= '0' && c <= '9') return c - '0' + 52; ['Q'] = 17, ['R'] = 18, ['S'] = 19, ['T'] = 20, ['U'] = 21, ['V'] = 22, ['W'] = 23, ['X'] = 24,
if (c == '+') return 62; ['Y'] = 25, ['Z'] = 26, ['a'] = 27, ['b'] = 28, ['c'] = 29, ['d'] = 30, ['e'] = 31, ['f'] = 32,
if (c == '/') return 63; ['g'] = 33, ['h'] = 34, ['i'] = 35, ['j'] = 36, ['k'] = 37, ['l'] = 38, ['m'] = 39, ['n'] = 40,
return -1; ['o'] = 41, ['p'] = 42, ['q'] = 43, ['r'] = 44, ['s'] = 45, ['t'] = 46, ['u'] = 47, ['v'] = 48,
} ['w'] = 49, ['x'] = 50, ['y'] = 51, ['z'] = 52, ['0'] = 53, ['1'] = 54, ['2'] = 55, ['3'] = 56,
['4'] = 57, ['5'] = 58, ['6'] = 59, ['7'] = 60, ['8'] = 61, ['9'] = 62, ['+'] = 63, ['/'] = 64,
};
static int base64_decode(const char* input, size_t input_len, unsigned char** bytes, static inline int base64_value(unsigned char c) { return (int)base64_values[c] - 1; }
size_t* byte_count) {
if (input_len == 0 || input_len % 4 != 0) return -1;
if (input_len / 4 > SIZE_MAX / 3) return -1;
size_t capacity = input_len / 4 * 3; struct decode_writer {
unsigned char* output = xmalloc(capacity); unsigned* hashes;
unsigned char* destination = output; size_t capacity;
size_t written;
uint64_t bits;
uint64_t mask;
unsigned filled;
unsigned bpp;
};
for (size_t offset = 0; offset < input_len; offset += 4) { static inline int decode_writer_put(struct decode_writer* writer, uint32_t bytes,
int v0 = base64_value((unsigned char)input[offset]); unsigned byte_count) {
int v1 = base64_value((unsigned char)input[offset + 1]); writer->bits |= (uint64_t)bytes << writer->filled;
int last = offset + 4 == input_len; writer->filled += byte_count * 8;
if (v0 < 0 || v1 < 0) goto invalid;
*destination++ = (unsigned char)((v0 << 2) | (v1 >> 4)); while (writer->filled >= writer->bpp) {
if (input[offset + 2] == '=') { if (writer->written == writer->capacity) return -1;
if (!last || input[offset + 3] != '=' || (v1 & 0x0f) != 0) goto invalid;
continue;
}
int v2 = base64_value((unsigned char)input[offset + 2]); unsigned current = (unsigned)(writer->bits & writer->mask);
if (v2 < 0) goto invalid; writer->bits >>= writer->bpp;
*destination++ = (unsigned char)((v1 << 4) | (v2 >> 2)); writer->filled -= writer->bpp;
if (input[offset + 3] == '=') { if (writer->written > 0 && writer->hashes[writer->written - 1] >= current) return -1;
if (!last || (v2 & 0x03) != 0) goto invalid; writer->hashes[writer->written++] = current;
continue;
}
int v3 = base64_value((unsigned char)input[offset + 3]);
if (v3 < 0) goto invalid;
*destination++ = (unsigned char)((v2 << 6) | v3);
} }
*bytes = output;
*byte_count = (size_t)(destination - output);
return 0; return 0;
invalid:
_free(output);
return -1;
} }
static int decode_set(const char* str, struct decoded_set* decoded) { static int decode_set(const char* str, struct decoded_set* decoded) {
@@ -307,62 +296,67 @@ static int decode_set(const char* str, struct decoded_set* decoded) {
unsigned bpp = (unsigned)(str[2] - '0') * 10 + (unsigned)(str[3] - '0'); unsigned bpp = (unsigned)(str[2] - '0') * 10 + (unsigned)(str[3] - '0');
if (bpp < 10 || bpp > 32) return -1; if (bpp < 10 || bpp > 32) return -1;
unsigned char* bytes; const char* input = str + FORMAT_HEADER_LEN;
size_t byte_count; size_t input_len = str_len - FORMAT_HEADER_LEN;
if (base64_decode(str + FORMAT_HEADER_LEN, str_len - FORMAT_HEADER_LEN, &bytes, &byte_count) < 0) if (input_len == 0 || input_len % 4 != 0 || input_len / 4 > SIZE_MAX / 3) return -1;
return -1;
if (byte_count > SIZE_MAX / 8) { size_t byte_count = input_len / 4 * 3;
_free(bytes); if (input[input_len - 1] == '=') --byte_count;
return -1; if (input[input_len - 2] == '=') --byte_count;
} if (byte_count > SIZE_MAX / 8) return -1;
size_t count = byte_count * 8 / bpp; size_t count = byte_count * 8 / bpp;
if (count == 0 || count > (SIZE_MAX - 7) / bpp || (count * bpp + 7) / 8 != byte_count) { if (count == 0 || count > (SIZE_MAX - 7) / bpp || count > SIZE_MAX / sizeof(unsigned) ||
_free(bytes); (count * bpp + 7) / 8 != byte_count) {
return -1; return -1;
} }
unsigned* hashes = xmalloc(count * sizeof(*hashes)); unsigned* hashes = xmalloc(count * sizeof(*hashes));
const unsigned char* input = bytes; struct decode_writer writer = {
const unsigned char* input_end = bytes + byte_count; .hashes = hashes,
uint64_t bits = 0; .capacity = count,
unsigned filled = 0; .mask = bpp < 32 ? (UINT64_C(1) << bpp) - 1 : UINT32_MAX,
uint64_t mask = bpp < 32 ? (UINT64_C(1) << bpp) - 1 : UINT32_MAX; .bpp = bpp,
};
for (size_t i = 0; i < count; ++i) { for (size_t offset = 0; offset < input_len; offset += 4) {
while (filled < bpp) { int v0 = base64_value((unsigned char)input[offset]);
if (input == input_end) { int v1 = base64_value((unsigned char)input[offset + 1]);
_free(hashes); int last = offset + 4 == input_len;
_free(bytes); if (v0 < 0 || v1 < 0) goto invalid;
return -1;
} uint32_t bytes = (uint32_t)((v0 << 2) | (v1 >> 4));
bits |= (uint64_t)*input++ << filled; if (input[offset + 2] == '=') {
filled += 8; if (!last || input[offset + 3] != '=' || (v1 & 0x0f) != 0 ||
decode_writer_put(&writer, bytes, 1) < 0)
goto invalid;
continue;
} }
hashes[i] = (unsigned)(bits & mask);
bits >>= bpp; int v2 = base64_value((unsigned char)input[offset + 2]);
filled -= bpp; if (v2 < 0) goto invalid;
if (i > 0 && hashes[i - 1] >= hashes[i]) { bytes |= (uint32_t)(((v1 & 0x0f) << 4) | (v2 >> 2)) << 8;
_free(hashes); if (input[offset + 3] == '=') {
_free(bytes); if (!last || (v2 & 0x03) != 0 || decode_writer_put(&writer, bytes, 2) < 0) goto invalid;
return -1; continue;
} }
int v3 = base64_value((unsigned char)input[offset + 3]);
if (v3 < 0) goto invalid;
bytes |= (uint32_t)(((v2 & 0x03) << 6) | v3) << 16;
if (decode_writer_put(&writer, bytes, 3) < 0) goto invalid;
} }
while (input < input_end) { if (writer.written != count || writer.bits != 0) goto invalid;
bits |= (uint64_t)*input++ << filled;
filled += 8;
}
_free(bytes);
if (bits != 0) {
_free(hashes);
return -1;
}
decoded->hashes = hashes; decoded->hashes = hashes;
decoded->count = count; decoded->count = count;
decoded->bpp = bpp; decoded->bpp = bpp;
return 0; return 0;
invalid:
_free(hashes);
return -1;
} }
/* Reduce a sorted set of (bpp + 1)-bit values to a sorted set of bpp-bit values. */ /* Reduce a sorted set of (bpp + 1)-bit values to a sorted set of bpp-bit values. */