#include "cig.h"

void *buffer_allocator_alloc(buffer_allocator_t *this, size_t bytes) {
    size_t new_size = this->size + bytes;
    if (new_size > this->capacity) {
        return NULL;
    }
    void *ptr = &this->data[this->size];
    this->size = new_size;
    return ptr;
}

void *buffer_allocator_resize(buffer_allocator_t *this, void *old_ptr, size_t bytes) {
    void *new_ptr = buffer_allocator_alloc(this, bytes);
    if (new_ptr == NULL) {
        return NULL;
    }
    for (size_t i = 0; i < bytes; i++) {
        unsigned char *new_ptr_b = (unsigned char *)new_ptr;
        unsigned char *old_ptr_b = (unsigned char *)old_ptr;
        new_ptr_b[i] = old_ptr_b[i];
    }
    return new_ptr;
}

void buffer_allocator_reset(buffer_allocator_t *this) {
    this->size = 0;
}

static void *buffer_alloc(void *this, size_t bytes, const char *file, int line) {
    (void)file;
    (void)line;
    return buffer_allocator_alloc((buffer_allocator_t *)this, bytes);
}

static void *buffer_resize(void *this, void *old_ptr, size_t bytes, const char *file, int line) {
    (void)file;
    (void)line;
    return buffer_allocator_resize(this, old_ptr, bytes);
}

static void buffer_free(void *this, void *ptr, const char *file, int line) {
    (void)this;
    (void)ptr;
    (void)file;
    (void)line;
}

static const allocator_vtbl_t buffer_vtbl = {
    .alloc = buffer_alloc,
    .resize = buffer_resize,
    .free = buffer_free,
};

allocator_t buffer_allocator_interface(buffer_allocator_t *this) {
    return (allocator_t) {
        .this=this,
        .vtbl=&buffer_vtbl,
    };
}