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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROME_UTILITY_SAFE_BROWSING_MAC_READ_STREAM_H_
#define CHROME_UTILITY_SAFE_BROWSING_MAC_READ_STREAM_H_
#include <stddef.h>
#include <stdint.h>
#include <unistd.h>
#include "base/macros.h"
namespace safe_browsing {
namespace dmg {
// An interface for reading and seeking over a byte stream.
class ReadStream {
public:
virtual ~ReadStream() {}
// Copies up to |size| bytes into |data|. Returns |true| on success with the
// actual number of bytes written stored in |size|. Returns |false| on error.
// At end-of-stream, returns |true| with |bytes_read| set to 0.
virtual bool Read(uint8_t* data, size_t size, size_t* bytes_read) = 0;
// Calls |Read| but only returns true if the number of bytes read equals
// |size|.
bool ReadExact(uint8_t* data, size_t size);
template <typename T>
bool ReadType(T* t) {
return ReadExact(reinterpret_cast<uint8_t*>(t), sizeof(T));
}
// Seeks the read stream to |offset| from |whence|. |whence| is a POSIX-style
// SEEK_ constant. Returns the resulting offset location, or a negative value
// on failure.
virtual off_t Seek(off_t offset, int whence) = 0;
};
// An implementation of ReadStream backed by a file descriptor. This does not
// take ownership of the file descriptor.
class FileReadStream : public ReadStream {
public:
explicit FileReadStream(int fd);
~FileReadStream() override;
// ReadStream:
bool Read(uint8_t* data, size_t size, size_t* bytes_read) override;
off_t Seek(off_t offset, int whence) override;
private:
int fd_;
DISALLOW_COPY_AND_ASSIGN(FileReadStream);
};
// An implementation of ReadStream that operates on a byte buffer. This class
// does not take ownership of the underlying byte array.
class MemoryReadStream : public ReadStream {
public:
MemoryReadStream(const uint8_t* data, size_t size);
~MemoryReadStream() override;
// ReadStream:
bool Read(uint8_t* data, size_t size, size_t* bytes_read) override;
off_t Seek(off_t offset, int whence) override;
const uint8_t* data() const { return data_; }
size_t size() const { return size_; }
protected:
const uint8_t* data_;
size_t size_;
off_t offset_;
private:
DISALLOW_COPY_AND_ASSIGN(MemoryReadStream);
};
} // namespace dmg
} // namespace safe_browsing
#endif // CHROME_UTILITY_SAFE_BROWSING_MAC_READ_STREAM_H_