#include "buffer.h"
#include "alloc.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>

void buffer_init(Buffer *self) {
    self->data = NULL;
    self->size = 0;
    self->capacity = 0;
}

void buffer_deinit(Buffer *self) {
    free(self->data);
    self->data = NULL;
    self->size = 0;
    self->capacity = 0;
}

static void buffer_ensure_capacity(Buffer *self, size_t new_size) {
    size_t new_capacity = self->capacity;
    if(new_size <= self->capacity)
        return;

    if(new_capacity == 0)
        new_capacity = 8;
    
    while(new_capacity < new_size) {
        /* new_capacity *= 1.5 */
        new_capacity += (new_capacity >> 1);
    }

    self->data = realloc_or_crash(self->data, new_capacity);
    self->capacity = new_capacity;
}

void buffer_append(Buffer *self, const void *data, size_t size) {
    buffer_ensure_capacity(self, self->size + size);
    memcpy((char*)self->data + self->size, data, size);
    self->size += size;
}

void* buffer_pop(Buffer *self, size_t size) {
    assert(self->size >= size);
    self->size -= size;
    return (char*)self->data + self->size;
}

void* buffer_begin(Buffer *self) {
    return self->data;
}

void* buffer_end(Buffer *self) {
    return (char*)self->data + self->size;
}

size_t buffer_get_size(Buffer *self, size_t type_size) {
    return self->size / type_size;
}

void buffer_clear(Buffer *self) {
    self->size = 0;
}