CLK/Storage/FileHolder.cpp

//
//  FileHolder.cpp
//  Clock Signal
//
//  Created by Thomas Harte on 21/11/2016.
//  Copyright © 2016 Thomas Harte. All rights reserved.
//

#include "FileHolder.hpp"

#include <cstring>

using namespace Storage;

FileHolder::~FileHolder() {
	if(file_) fclose(file_);
}

FileHolder::FileHolder(const std::string &file_name) : file_(nullptr), name_(file_name) {
	stat(file_name.c_str(), &file_stats_);
	is_read_only_ = false;
	file_ = fopen(file_name.c_str(), "rb+");
	if(!file_) {
		is_read_only_ = true;
		file_ = fopen(file_name.c_str(), "rb");
	}
	if(!file_) throw ErrorCantOpen;
}

bool FileHolder::check_signature(const char *signature, size_t length) {
	if(!length) length = strlen(signature)+1;

	// read and check the file signature
	char stored_signature[12];
	if(fread(stored_signature, 1, length, file_) != length)	return false;
	if(memcmp(stored_signature, signature, length)) return false;
	return true;
}

uint32_t FileHolder::fgetc32le() {
	uint32_t result = (uint32_t)fgetc(file_);
	result |= (uint32_t)(fgetc(file_) << 8);
	result |= (uint32_t)(fgetc(file_) << 16);
	result |= (uint32_t)(fgetc(file_) << 24);

	return result;
}

uint32_t FileHolder::fgetc24le() {
	uint32_t result = (uint32_t)fgetc(file_);
	result |= (uint32_t)(fgetc(file_) << 8);
	result |= (uint32_t)(fgetc(file_) << 16);

	return result;
}

uint16_t FileHolder::fgetc16le() {
	uint16_t result = (uint16_t)fgetc(file_);
	result |= (uint16_t)(fgetc(file_) << 8);

	return result;
}

uint32_t FileHolder::fgetc32be() {
	uint32_t result = (uint32_t)(fgetc(file_) << 24);
	result |= (uint32_t)(fgetc(file_) << 16);
	result |= (uint32_t)(fgetc(file_) << 8);
	result |= (uint32_t)fgetc(file_);

	return result;
}

uint16_t FileHolder::fgetc16be() {
	uint16_t result = (uint16_t)(fgetc(file_) << 8);
	result |= (uint16_t)fgetc(file_);

	return result;
}

void FileHolder::ensure_file_is_at_least_length(long length) {
	fseek(file_, 0, SEEK_END);
	long bytes_to_write = length - ftell(file_);
	if(bytes_to_write > 0)
	{
		uint8_t *empty = new uint8_t[bytes_to_write];
		memset(empty, 0, (size_t)bytes_to_write);
		fwrite(empty, sizeof(uint8_t), (size_t)bytes_to_write, file_);
		delete[] empty;
	}
}

std::string FileHolder::extension() {
	size_t pointer = name_.size() - 1;
	while(pointer > 0 && name_[pointer] != '.') pointer--;
	if(name_[pointer] == '.') pointer++;

	std::string extension = name_.substr(pointer);
	std::transform(extension.begin(), extension.end(), extension.begin(), ::tolower);
	return extension;
}