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#include "arena.h"
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
bool ArenaInit(Arena *arena, size_t capacity) {
arena->mem = malloc(capacity);
if (!arena->mem) {
return false;
}
arena->head = 0;
arena->capacity = capacity;
return true;
}
void *ArenaAlloc(Arena *arena, size_t size) {
uintptr_t current_ptr = (uintptr_t)arena->mem + arena->head;
// Alignment
uintptr_t aligned_ptr = (current_ptr + 7) & ~7;
size_t alignment_padding = aligned_ptr - current_ptr;
size_t total_needed = size + alignment_padding;
if (arena->head + total_needed > arena->capacity) {
return NULL;
}
arena->head += total_needed;
return (void *)aligned_ptr;
}
char *ArenaStrdup(Arena *arena, const char *str) {
size_t len = strlen(str) + 1; // adding a \0
char *ptr = ArenaAlloc(arena, len);
if (ptr == NULL) return NULL;
memcpy(ptr, str, len);
return ptr;
}
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