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Refactor set version hashing constants

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krosh
2026-08-10 03:06:12 +03:00
parent ebb00ee69f
commit 4ed05f2061
1 changed files with 16 additions and 19 deletions
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reimplement/set9.c
+16 -19
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@@ -15,26 +15,29 @@
#include "set.h"
#include "system.h"
#define CACHE_SIZE 512
// #define CACHE_SIZE 512
#define SET_HASH_SEED UINT32_C(0x9e3779b9)
#define CACHE_FINGERPRINT_MULTIPLIER UINT32_C(0x9e3779b1)
#define CACHE_TARGET_BPP_MULTIPLIER UINT32_C(0x85ebca6b)
enum {
// SET_HASH_SEED = UINT32_C(0x9e3779b9),
CACHE_SIZE = 512,
CACHE_BUCKETS = 1024,
};
enum {
CACHE_BUCKETS = 1024,
SET_HEADER_SIZE = 2,
SET_PARAM_CHAR_OFFSET = 7,
SET_BPP_MIN = 10,
SET_BPP_MAX = 32,
SET_MSHIFT_MIN = 7,
SET_MSHIFT_MAX = 31,
};
enum {
BASE62_ESCAPE_BITS = 4,
BASE62_VALUE_BITS = 6,
BASE62_ESCAPE_CHUNK_BITS = BASE62_ESCAPE_BITS + BASE62_VALUE_BITS,
BASE62_MIN_BITS_PER_CHAR = BASE62_VALUE_BITS - 1,
BASE62_MIN_BITS_PER_CHAR = BASE62_ESCAPE_CHUNK_BITS / 2,
BASE62_MAX_PADDING_BITS = BASE62_VALUE_BITS - 1,
BASE62_LOWERCASE_OFFSET = 10,
BASE62_UPPERCASE_OFFSET = 36,
@@ -42,12 +45,14 @@ enum {
BASE62_VALUE_COUNT = 62,
BASE62_ESCAPE_LOW_MASK = (1u << BASE62_ESCAPE_BITS) - 1,
BASE62_ESCAPE_HIGH_MASK = 3u << BASE62_ESCAPE_BITS,
};
enum {
BASE62_INVALID = 0xee,
BASE62_END = UCHAR_MAX,
};
_Static_assert(CHAR_BIT == 8, "set:version requires 8-bit bytes");
_Static_assert(CHAR_BIT == 8, "set:version relies on 8-bit");
struct set {
size_t cnt;
@@ -82,7 +87,7 @@ void set_add(struct set* set, const char* sym) {
size_t length = strlen(sym) + 1;
size_t required = set->strings_len + length;
if (required > set->strings_cap) {
size_t capacity = set->strings_cap ? set->strings_cap : 4096;
size_t capacity = set->strings_cap ?: 4096;
while (capacity < required) capacity *= 2;
set->strings = xrealloc(set->strings, capacity);
@@ -94,8 +99,6 @@ void set_add(struct set* set, const char* sym) {
memcpy(set->strings + set->strings_len, sym, length);
set->strings_len = required;
set->cnt++;
return;
}
struct set* set_free(struct set* set) {
@@ -171,8 +174,6 @@ static void sort_symbols(struct symbols* values, size_t count, int bpp) {
}
if (source != values) memcpy(values, source, count * sizeof(*values));
return;
}
// ---
@@ -292,16 +293,12 @@ static inline void encode_writer_zeros(struct encode_writer* writer, unsigned co
encode_writer_flush(writer);
}
return;
}
static inline void encode_writer_put(struct encode_writer* writer, uint64_t value, unsigned width) {
writer->bits |= value << writer->filled;
writer->filled += width;
encode_writer_flush(writer);
return;
}
static int encode_set(int cnt, const unsigned* hash_arr, int bpp, char* base62_str) {
@@ -358,7 +355,7 @@ const char* set_fini(struct set* set, int bpp) {
const char* right = set->strings + set->symbols_v[i + 1].offset;
if (!strcmp(left, right)) continue;
fprintf(stderr, "warning: hash collision: %s %s\n", left, right);
fprintf(stderr, "warning: set-version hash collision: %s %s\n", left, right);
}
unsigned unique_hash[set->cnt];
@@ -556,9 +553,9 @@ static int decode_set(const struct set_meta* meta, unsigned* hash_arr) {
static int downsample_set(int cnt, const unsigned* hash_pt, unsigned* ds_pt, int bpp);
static inline unsigned cache_bucket(uint32_t fingerprint, int target_bpp) {
uint32_t mixed = fingerprint ^ ((uint32_t)target_bpp * CACHE_TARGET_BPP_MULTIPLIER);
uint32_t mixed = fingerprint ^ ((uint32_t)target_bpp * UINT32_C(0x85ebca6b));
mixed ^= mixed >> 11;
mixed *= CACHE_FINGERPRINT_MULTIPLIER;
mixed *= UINT32_C(0x9e3779b1);
mixed ^= mixed >> 16;
return mixed & (CACHE_BUCKETS - 1);