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rm some magick numbers

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krosh
2026-08-07 04:23:20 +03:00
parent 3ecc491022
commit eda5e3454a
3 changed files with 64 additions and 100 deletions
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.clang-format
+1
View File
@@ -1,3 +1,4 @@
BasedOnStyle: Google
IndentWidth: 2
BracedInitializerIndentWidth: 2
ColumnLimit: 100
new_version/main_ideas.md
+1 -1
View File
@@ -36,5 +36,5 @@
## улучшение работы с хэшем
- если условно "отсортировать" массив provides/requires, можно получить лучшую работу с кжшом
- если условно "отсортировать" массив provides/requires, можно получить лучшую работу с кэшом
- (надеюсь, что под капотом оно уже и так это делает, но проверить стоит)
reimplement/set9.c
+41 -78
View File
@@ -15,6 +15,13 @@
#include "system.h"
#define CACHE_SIZE 512
#define SET_HASH_SEED UINT32_C(0x9e3779b9)
#define ERROR_CODE 0xee
#define EOF_CODE 0xff
#define CACHE_FINGERPRINT_MULTIPLIER UINT32_C(0x9e3779b1)
#define CACHE_TARGET_BPP_MULTIPLIER UINT32_C(0x85ebca6b)
struct set {
size_t cnt;
@@ -78,7 +85,7 @@ struct set* set_free(struct set* set) {
// ---
static unsigned hash(const char* str) {
unsigned hash = 0x9e3779b9;
unsigned hash = SET_HASH_SEED;
const unsigned char* p = (const unsigned char*)str;
while (*p) {
@@ -395,80 +402,35 @@ static int set_meta_fini(struct set_meta* meta) {
return 0;
}
// UCHAR_MAX == 255
__extension__ static const unsigned char char_to_num[255 + 1] = {[0] = 0xff, /* конец строки */
// clang-format off
__extension__ static const unsigned char char_to_num[255 + 1] = {
[0] = EOF_CODE, // конец строки
[1 ... ('0' - 1)] = ERROR_CODE,
[1 ...('0' - 1)] = 0xee,
['0'] = 0, ['1'] = 1, ['2'] = 2, ['3'] = 3, ['4'] = 4,
['5'] = 5, ['6'] = 6, ['7'] = 7, ['8'] = 8, ['9'] = 9,
['0'] = 0,
['1'] = 1,
['2'] = 2,
['3'] = 3,
['4'] = 4,
['5'] = 5,
['6'] = 6,
['7'] = 7,
['8'] = 8,
['9'] = 9,
[('9' + 1) ... ('A' - 1)] = ERROR_CODE,
[('9' + 1)...('A' - 1)] = 0xee,
['A'] = 36,
['B'] = 37,
['C'] = 38,
['D'] = 39,
['E'] = 40,
['F'] = 41,
['G'] = 42,
['H'] = 43,
['I'] = 44,
['J'] = 45,
['K'] = 46,
['L'] = 47,
['M'] = 48,
['N'] = 49,
['O'] = 50,
['P'] = 51,
['Q'] = 52,
['R'] = 53,
['S'] = 54,
['T'] = 55,
['U'] = 56,
['V'] = 57,
['W'] = 58,
['X'] = 59,
['Y'] = 60,
['A'] = 36, ['B'] = 37, ['C'] = 38, ['D'] = 39, ['E'] = 40,
['F'] = 41, ['G'] = 42, ['H'] = 43, ['I'] = 44, ['J'] = 45,
['K'] = 46, ['L'] = 47, ['M'] = 48, ['N'] = 49, ['O'] = 50,
['P'] = 51, ['Q'] = 52, ['R'] = 53, ['S'] = 54, ['T'] = 55,
['U'] = 56, ['V'] = 57, ['W'] = 58, ['X'] = 59, ['Y'] = 60,
['Z'] = 61,
[('Z' + 1)...('a' - 1)] = 0xee,
[('Z' + 1) ... ('a' - 1)] = ERROR_CODE,
['a'] = 10,
['b'] = 11,
['c'] = 12,
['d'] = 13,
['e'] = 14,
['f'] = 15,
['g'] = 16,
['h'] = 17,
['i'] = 18,
['j'] = 19,
['k'] = 20,
['l'] = 21,
['m'] = 22,
['n'] = 23,
['o'] = 24,
['p'] = 25,
['q'] = 26,
['r'] = 27,
['s'] = 28,
['t'] = 29,
['u'] = 30,
['v'] = 31,
['w'] = 32,
['x'] = 33,
['y'] = 34,
['a'] = 10, ['b'] = 11, ['c'] = 12, ['d'] = 13, ['e'] = 14,
['f'] = 15, ['g'] = 16, ['h'] = 17, ['i'] = 18, ['j'] = 19,
['k'] = 20, ['l'] = 21, ['m'] = 22, ['n'] = 23, ['o'] = 24,
['p'] = 25, ['q'] = 26, ['r'] = 27, ['s'] = 28, ['t'] = 29,
['u'] = 30, ['v'] = 31, ['w'] = 32, ['x'] = 33, ['y'] = 34,
['z'] = 35,
[('z' + 1)... 255] = 0xee};
[('z' + 1) ... 255] = ERROR_CODE,
};
// clang-format on
// Decode base62 and Golomb-Rice in one pass. Base62 is LSB-first; a Z escape contributes 10 stream
// bits.
@@ -480,12 +442,12 @@ static inline int decode_chunk(const unsigned char** input, uint64_t* chunk, uns
*width = 6;
return 1;
}
if (value == 0xff) return 0;
if (value == 0xee) return -1;
if (value == EOF_CODE) return 0;
if (value == ERROR_CODE) return -1;
unsigned escaped = char_to_num[*(*input)++];
if (escaped == 0xff) return -2;
if (escaped == 0xee) return -3;
if (escaped == EOF_CODE) return -2;
if (escaped == ERROR_CODE) return -3;
unsigned high = escaped & 0x30u;
if (high == 0x30u) return -4;
@@ -589,9 +551,9 @@ static int cache_decode_set(struct set_meta* meta, int target_bpp, const unsigne
const unsigned char* str = (const unsigned char*)meta->str;
uint32_t fp = (uint32_t)str[0] | ((uint32_t)str[2] << 8) | ((uint32_t)str[3] << 16);
uint32_t mixed = fp ^ ((uint32_t)target_bpp * UINT32_C(0x85ebca6b));
uint32_t mixed = fp ^ ((uint32_t)target_bpp * CACHE_TARGET_BPP_MULTIPLIER);
mixed ^= mixed >> 11;
mixed *= UINT32_C(0x9e3779b1);
mixed *= CACHE_FINGERPRINT_MULTIPLIER;
mixed ^= mixed >> 16;
unsigned bucket = mixed & (CACHE_BUCKETS - 1);
@@ -660,9 +622,9 @@ static int cache_decode_set(struct set_meta* meta, int target_bpp, const unsigne
if (victim == newest[cache_id]) newest[cache_id] = NULL;
uint32_t victim_mixed =
victim->fingerprint ^ ((uint32_t)victim->target_bpp * UINT32_C(0x85ebca6b));
victim->fingerprint ^ ((uint32_t)victim->target_bpp * CACHE_TARGET_BPP_MULTIPLIER);
victim_mixed ^= victim_mixed >> 11;
victim_mixed *= UINT32_C(0x9e3779b1);
victim_mixed *= CACHE_FINGERPRINT_MULTIPLIER;
victim_mixed ^= victim_mixed >> 16;
unsigned victim_bucket = victim_mixed & (CACHE_BUCKETS - 1);
struct cache_ent** link = &buckets[cache_id][victim_bucket];
@@ -889,7 +851,8 @@ static void test_sort(void) {
for (size_t i = 0; i < LARGE_COUNT; ++i) {
values[i].offset = i;
values[i].hash = ((unsigned)i * UINT32_C(0x9e3779b1) ^ UINT32_C(0x85ebca6b)) & mask;
values[i].hash =
((unsigned)i * CACHE_FINGERPRINT_MULTIPLIER ^ CACHE_TARGET_BPP_MULTIPLIER) & mask;
}
memcpy(expected, values, sizeof(values));
qsort(expected, LARGE_COUNT, sizeof(*expected), cmp);
@@ -955,9 +918,9 @@ static void test_encode_decode(void) {
static void test_metadata_and_chunks(void) {
for (int c = 0; c <= 255; ++c) {
unsigned char expected = 0xee;
unsigned char expected = ERROR_CODE;
if (c == 0) {
expected = 0xff;
expected = EOF_CODE;
} else if (c >= '0' && c <= '9') {
expected = (unsigned char)(c - '0');
} else if (c >= 'a' && c <= 'z') {