aom/third_party/libwebm/mkvreader.cpp

133 строки
2.4 KiB
C++

// Copyright (c) 2010 The WebM project authors. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
#include "mkvreader.hpp"
#include <cassert>
namespace mkvparser {
MkvReader::MkvReader() : m_file(NULL), reader_owns_file_(true) {}
MkvReader::MkvReader(FILE* fp) : m_file(fp), reader_owns_file_(false) {
GetFileSize();
}
MkvReader::~MkvReader() {
if (reader_owns_file_)
Close();
m_file = NULL;
}
int MkvReader::Open(const char* fileName) {
if (fileName == NULL)
return -1;
if (m_file)
return -1;
#ifdef _MSC_VER
const errno_t e = fopen_s(&m_file, fileName, "rb");
if (e)
return -1; // error
#else
m_file = fopen(fileName, "rb");
if (m_file == NULL)
return -1;
#endif
return !GetFileSize();
}
bool MkvReader::GetFileSize() {
if (m_file == NULL)
return false;
#ifdef _MSC_VER
int status = _fseeki64(m_file, 0L, SEEK_END);
if (status)
return false; // error
m_length = _ftelli64(m_file);
#else
fseek(m_file, 0L, SEEK_END);
m_length = ftell(m_file);
#endif
assert(m_length >= 0);
if (m_length < 0)
return false;
#ifdef _MSC_VER
status = _fseeki64(m_file, 0L, SEEK_SET);
if (status)
return false; // error
#else
fseek(m_file, 0L, SEEK_SET);
#endif
return true;
}
void MkvReader::Close() {
if (m_file != NULL) {
fclose(m_file);
m_file = NULL;
}
}
int MkvReader::Length(long long* total, long long* available) {
if (m_file == NULL)
return -1;
if (total)
*total = m_length;
if (available)
*available = m_length;
return 0;
}
int MkvReader::Read(long long offset, long len, unsigned char* buffer) {
if (m_file == NULL)
return -1;
if (offset < 0)
return -1;
if (len < 0)
return -1;
if (len == 0)
return 0;
if (offset >= m_length)
return -1;
#ifdef _MSC_VER
const int status = _fseeki64(m_file, offset, SEEK_SET);
if (status)
return -1; // error
#else
fseek(m_file, offset, SEEK_SET);
#endif
const size_t size = fread(buffer, 1, len, m_file);
if (size < size_t(len))
return -1; // error
return 0; // success
}
} // end namespace mkvparser