fileio.h

/*
 * Copyright (C) 2012 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef FILEIO_H_
#define FILEIO_H_

#include"types.h"

/**
 * File utility primitives somewhat patterned on RandomAccessFile.
 */

/** Moves the file pointer to given position */
bool FileIo_seek(FILE* file, uint32_t position);

/** Writes buffer to file, flushes to media. */
bool FileIo_write(FILE* file, const byte* buffer, uint32_t buffer_offset,
                  uint32_t length);

bool FileIo_read(FILE* file, void* buffer, uint32_t buffer_offset,
                 uint32_t length);

/** @return file length or -1 on error */
off_t FileIo_getLength(FILE* file);

/**
  * Writes length 0s to file, flushes to media. Starts at current file position.
  * @param length must be multiple of 4.
  */
bool FileIo_writeZeros(FILE* file, uint32_t length);

/**
 * Sets the file length.
 * (Some systems allow the file length to be adjusted using truncate, as
 * some JVMs do for RandomAccessFile.setLength.
 * TODO(jochen): test this for iOS and Android).
 */
bool FileIo_setLength(FILE* file, uint32_t length);

/**
 * Copies part of a file to another offset, the caller is responsible for
 * checking that there is enough data from the source to cover length.
 * The parts to transfer may not overlap.
 * TODO: investigate whether fread and fwrite make efficient use of the
 *       FILE's read cache.
 */
bool FileIo_transferTo(FILE* file, uint32_t source, uint32_t destination,
                       uint32_t length);

/**
 * For testing only, enable or disable writes, for some reason the _Bool
 * macro expansion causes warnings? when called with a bool??
 */
void _for_testing_FileIo_failAllWrites(int fail);

/**
 * For testing only, set the size of the copy buffer for the transferTo function.
 * returns the old size.
 */
uint32_t _for_testing_setTransferToCopyBufferSize(uint32_t newSize);

#endif