#include "../include/buffer.h"
#include "../include/alloc.h"
#include "../include/mem.h"
#include <assert.h>

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

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

static CHECK_RESULT int buffer_ensure_capacity_for(Buffer *self, usize size) {
    usize capacity;
    void *new_mem;
    int alloc_result;
    usize new_capacity;
    new_capacity = self->size + size;

    if(self->capacity >= new_capacity)
        return BUFFER_OK;
    
    capacity = self->capacity;
    if(capacity == 0) {
        capacity = new_capacity;
    } else {
        while(capacity < new_capacity) {
            capacity *= 1.5;
        }
    }

    alloc_result = am_realloc(self->data, capacity, &new_mem);
    if(alloc_result != ALLOC_OK)
        return BUFFER_ALLOC_FAIL;
    
    self->data = new_mem;
    self->capacity = capacity;
    return BUFFER_OK;
}

int buffer_append(Buffer *self, void *data, usize size) {
    return_if_error(buffer_ensure_capacity_for(self, size));
    am_memcpy(self->data + self->size, data, size);
    self->size += size;
    return BUFFER_OK; 
}

void* buffer_get(Buffer *self, usize index, usize type_size) {
    usize real_index;
    real_index = index * type_size;
    assert(real_index < self->size);
    return &self->data[real_index];
}