File size: 1,882 Bytes
9abace2 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 | /*
* Sovereign IDE — Interned Strings
* All strings in the IDE are length-prefixed, immutable, arena-allocated.
* Interning deduplicates identical strings via FNV-1a hash table.
*/
#include "strings.h"
#include "arena.h"
#include <string.h>
#define INTERN_BUCKET_COUNT 4096
static uint64_t fnv1a(const char *data, size_t len) {
uint64_t h = 0xcbf29ce484222325ULL;
for (size_t i = 0; i < len; i++) {
h ^= (uint8_t)data[i];
h *= 0x100000001b3ULL;
}
return h;
}
typedef struct InternEntry {
Str str;
struct InternEntry *next;
} InternEntry;
static struct {
Arena arena;
InternEntry *buckets[INTERN_BUCKET_COUNT];
size_t count;
} g_intern;
void strings_init(void) {
arena_init_default(&g_intern.arena);
memset(g_intern.buckets, 0, sizeof(g_intern.buckets));
g_intern.count = 0;
}
void strings_shutdown(void) {
arena_destroy(&g_intern.arena);
}
Str str_intern_len(const char *data, size_t len) {
uint64_t hash = fnv1a(data, len);
size_t bucket = hash % INTERN_BUCKET_COUNT;
for (InternEntry *e = g_intern.buckets[bucket]; e; e = e->next) {
if (e->str.len == len && memcmp(e->str.ptr, data, len) == 0) {
return e->str;
}
}
char *copy = (char *)arena_alloc(&g_intern.arena, len + 1);
memcpy(copy, data, len);
copy[len] = '\0';
InternEntry *entry = (InternEntry *)arena_alloc(&g_intern.arena, sizeof(InternEntry));
entry->str.ptr = copy;
entry->str.len = len;
entry->next = g_intern.buckets[bucket];
g_intern.buckets[bucket] = entry;
g_intern.count++;
return entry->str;
}
Str str_intern(const char *cstr) {
return str_intern_len(cstr, strlen(cstr));
}
bool str_eq(Str a, Str b) {
return a.ptr == b.ptr;
}
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