blob: f0d074a54dd3264a16c2402fee195a3524bd9d29 [file] [log] [blame]
// Copyright 2023 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef SRC_TINT_UTILS_BYTES_READER_H_
#define SRC_TINT_UTILS_BYTES_READER_H_
#include <string>
#include "src/tint/utils/bytes/endianness.h"
#include "src/tint/utils/bytes/swap.h"
#include "src/tint/utils/result/result.h"
namespace tint::bytes {
/// A binary stream reader interface
class Reader {
public:
/// Destructor
virtual ~Reader();
/// Read reads bytes from the stream, blocking until there are @p count bytes available, or the
/// end of the stream has been reached.
/// @param out a pointer to the byte buffer that will be filled with the read data. Must be at
/// least @p count size.
/// @param count the number of bytes to read. Must be greater than 0.
/// @returns the number of bytes read from the stream. If Read() returns less than @p count,
/// then the end of the stream has been reached.
virtual size_t Read(std::byte* out, size_t count) = 0;
/// @returns true if the Reader has no more bytes to read.
virtual bool IsEOF() const = 0;
/// Reads an integer from the stream, performing byte swapping if the stream's endianness
/// differs from the native endianness.
/// If there are too few bytes remaining in the stream, then a failure is returned.
/// @param endianness the encoded endianness of the integer
/// @return the deserialized integer
template <typename T>
Result<T> Int(Endianness endianness = Endianness::kLittle) {
static_assert(std::is_integral_v<T>);
T out = 0;
if (size_t n = Read(reinterpret_cast<std::byte*>(&out), sizeof(T)); n != sizeof(T)) {
return Failure{"EOF"};
}
if (NativeEndianness() != endianness) {
out = Swap(out);
}
return out;
}
/// Reads a float from the stream.
/// If there are too few bytes remaining in the stream, then a failure is returned.
/// @return the deserialized floating point number
template <typename T>
Result<T> Float() {
static_assert(std::is_floating_point_v<T>);
T out = 0;
if (size_t n = Read(reinterpret_cast<std::byte*>(&out), sizeof(T)); n != sizeof(T)) {
return Failure{"EOF"};
}
return out;
}
/// Reads a boolean from the stream
/// If there are too few bytes remaining in the stream, then a failure is returned.
/// @returns true if the next byte is non-zero
Result<bool> Bool() {
std::byte b{0};
if (size_t n = Read(&b, 1); n != 1) {
return Failure{"EOF"};
}
return b != std::byte{0};
}
/// Reads a string of @p len bytes from the stream.
/// If there are too few bytes remaining in the stream, then a failure is returned.
/// @param len the length of the returned string in bytes
/// @return the deserialized string
Result<std::string> String(size_t len) {
std::string out;
out.resize(len);
if (size_t n = Read(reinterpret_cast<std::byte*>(out.data()), sizeof(char) * len);
n != len) {
return Failure{"EOF"};
}
return out;
}
};
} // namespace tint::bytes
#endif // SRC_TINT_UTILS_BYTES_READER_H_