#include "ByteBuffer.h"
#include <stdexcept>

using namespace std;

ByteBuffer::ByteBuffer(uint8_t *bytes, ssize_t size, ssize_t zero) :
        bytes(bytes), size(size), ptr(zero), zero(zero) {
}

ByteBuffer &ByteBuffer::add8(uint8_t value) {
    canAccessNextBytes(1);
    bytes[zero + ptr++] = value;
    return *this;
}

ByteBuffer &ByteBuffer::add16le(uint16_t value) {
    canAccessNextBytes(2);
    bytes[zero + ptr++] = (uint8_t) (value & 0xff);
    bytes[zero + ptr++] = (uint8_t) ((value >> 8) & 0xff);
    return *this;
}

uint8_t ByteBuffer::get8(ssize_t index) {
    canAccessIndex(index);
    return bytes[zero + ptr];
}

void ByteBuffer::canAccessNextBytes(ssize_t newBytes) {
    if (zero + ptr + newBytes >= size) {
        throw exception();
    }
}

void ByteBuffer::canAccessIndex(ssize_t index) {
    if (zero + index >= size) {
        throw exception();
    }
}