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/* Copyright (C) 2025 Aryadev Chavali
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Unlicense
* for details.
* You may distribute and modify this code under the terms of the
* Unlicense, which you should have received a copy of along with this
* program. If not, please go to <https://unlicense.org/>.
* Created: 2025-08-19
* Description: Entrypoint
*/
#include <malloc.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#define MAX(A, B) ((A) > (B) ? (A) : (B))
#define MIN(A, B) ((A) < (B) ? (A) : (B))
typedef uint8_t u8;
typedef uint16_t u16;
typedef uint32_t u32;
typedef uint64_t u64;
typedef int8_t i8;
typedef int16_t i16;
typedef int32_t i32;
typedef int64_t i64;
typedef struct
{
u64 size, capacity;
u8 bytes[];
} vec_t;
#define VEC_GET(P) (((vec_t *)(P)) - 1)
#define VEC_SIZE(P) (VEC_GET(P)->size)
#define VEC_CAP(P) (VEC_GET(P)->capacity)
#define VEC_MULT 2
void vec_make(void **ptr, u64 size)
{
if (!ptr)
return;
vec_t *vector = calloc(1, sizeof(*vector) + size);
vector->size = 0;
vector->capacity = size;
*ptr = (vector + 1);
}
void vec_free(void **data)
{
if (!data || !*data)
return;
free(VEC_GET(*data));
*data = NULL;
}
void vec_ensure_remaining(void **ptr, u64 space)
{
if (!ptr || !*ptr)
return;
vec_t *vec = VEC_GET(*ptr);
if (vec->capacity - vec->size < space)
{
void *new_vec = NULL;
vec_make(&new_vec, MAX(vec->capacity * VEC_MULT, vec->size + space));
VEC_SIZE(new_vec) = vec->size;
memcpy(new_vec, *ptr, vec->size);
vec_free(ptr);
*ptr = new_vec;
}
}
void vec_append_byte(void **ptr, u8 byte)
{
vec_ensure_remaining(ptr, 1);
vec_t *vec = VEC_GET(*ptr);
vec->bytes[vec->size++] = byte;
}
void vec_append(void **ptr, void *data, u64 size)
{
vec_ensure_remaining(ptr, size);
vec_t *vec = VEC_GET(*ptr);
memcpy(*ptr + vec->size, data, size);
vec->size += size;
}
void vec_clone(void **dest, void **src)
{
if (!dest || !src || !*src)
return;
vec_make(dest, VEC_SIZE(*src));
memcpy(*dest, *src, VEC_SIZE(*src));
VEC_SIZE(*dest) = VEC_SIZE(*src);
}
typedef struct
{
u64 size;
char *data;
} sv_t;
#define SV(DATA, SIZE) ((sv_t){.data = (DATA), .size = (SIZE)})
#define SV_FMT(SV) (int)(SV).size, (SV).data
#define PR_SV "%.*s"
sv_t sv_copy(sv_t old)
{
char *newstr = calloc(1, old.size * sizeof(*newstr));
memcpy(newstr, old.data, old.size);
return SV(newstr, old.size);
}
typedef struct
{
u64 count; // How many strings?
u64 capacity; // How many entry buckets?
sv_t *entries; // this is actually a vector on the inside lol
} sym_table_t;
u64 djb2(sv_t string)
{
u64 hash = 5381;
for (u64 i = 0; i < string.size; ++i)
hash = string.data[i] + (hash + (hash << 5));
return hash;
}
#define SYM_TABLE_INIT_SIZE 1024
void sym_table_init(sym_table_t *table)
{
table->capacity = MAX(table->capacity, SYM_TABLE_INIT_SIZE);
table->count = 0;
vec_make((void **)&table->entries, table->capacity * sizeof(*table->entries));
}
sv_t sym_table_find(sym_table_t *table, sv_t sv)
{
// TODO: Deal with resizing this when table->count > table->size / 2
u64 index = djb2(sv) & (table->capacity - 1);
for (sv_t comp = table->entries[index]; comp.data; index += 1,
index = index & (table->capacity - 1), comp = table->entries[index])
// Is it present in the table?
if (sv.size == comp.size && strncmp(sv.data, comp.data, sv.size) == 0)
return comp;
// Otherwise we need to duplicate and make it permanently interned
sv_t newsv = sv_copy(sv);
table->entries[index] = newsv;
++table->count;
return newsv;
}
void sym_table_cleanup(sym_table_t *table)
{
for (u64 i = 0; i < table->capacity; ++i)
if (table->entries[i].data)
free(table->entries[i].data);
vec_free((void **)&table->entries);
memset(table, 0, sizeof(*table));
}
int main(void)
{
sym_table_t table = {0};
sym_table_init(&table);
// Let's hash the words of lorem ipsum
const char *words[] = {
"aliquam", "erat", "volutpat", "nunc", "eleifend",
"leo", "vitae", "magna", "in", "id",
"erat", "non", "orci", "commodo", "lobortis",
"proin", "neque", "massa", "cursus", "ut",
"gravida", "ut", "lobortis", "eget", "lacus",
"sed", "diam", "praesent", "fermentum", "tempor",
"tellus", "nullam", "tempus", "mauris", "ac",
"felis", "vel", "velit", "tristique", "imperdiet",
"donec", "at", "pede", "etiam", "vel",
"neque", "nec", "dui", "dignissim", "bibendum",
"vivamus", "id", "enim", "phasellus", "neque",
"orci", "porta", "a", "aliquet", "quis",
"semper", "a", "massa", "phasellus", "purus",
"pellentesque", "tristique", "imperdiet", "tortor", "nam",
"euismod", "tellus", "id", "erat",
};
for (u64 i = 0; i < sizeof(words) / sizeof(words[0]); ++i)
{
sv_t sv = sym_table_find(&table, SV(words[i], strlen(words[i])));
printf("%s => %p\n", words[i], sv.data);
}
return 0;
}
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