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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/big_endian.h"
#include <string.h>
#include "base/numerics/checked_math.h"
#include "base/strings/string_piece.h"
namespace base {
BigEndianReader BigEndianReader::FromStringPiece(
base::StringPiece string_piece) {
return BigEndianReader(base::as_bytes(base::make_span(string_piece)));
}
BigEndianReader::BigEndianReader(const uint8_t* buf, size_t len)
: ptr_(buf), end_(ptr_ + len) {
// Ensure `len` does not cause `end_` to wrap around.
CHECK_GE(end_, ptr_);
}
BigEndianReader::BigEndianReader(base::span<const uint8_t> buf)
: ptr_(buf.data()), end_(buf.data() + buf.size()) {}
bool BigEndianReader::Skip(size_t len) {
if (len > remaining())
return false;
ptr_ += len;
return true;
}
bool BigEndianReader::ReadBytes(void* out, size_t len) {
if (len > remaining())
return false;
memcpy(out, ptr_, len);
ptr_ += len;
return true;
}
bool BigEndianReader::ReadPiece(base::StringPiece* out, size_t len) {
if (len > remaining())
return false;
*out = base::StringPiece(reinterpret_cast<const char*>(ptr_), len);
ptr_ += len;
return true;
}
bool BigEndianReader::ReadSpan(base::span<const uint8_t>* out, size_t len) {
if (len > remaining())
return false;
*out = base::make_span(ptr_, len);
ptr_ += len;
return true;
}
template<typename T>
bool BigEndianReader::Read(T* value) {
if (sizeof(T) > remaining())
return false;
ReadBigEndian<T>(ptr_, value);
ptr_ += sizeof(T);
return true;
}
bool BigEndianReader::ReadU8(uint8_t* value) {
return Read(value);
}
bool BigEndianReader::ReadU16(uint16_t* value) {
return Read(value);
}
bool BigEndianReader::ReadU32(uint32_t* value) {
return Read(value);
}
bool BigEndianReader::ReadU64(uint64_t* value) {
return Read(value);
}
template <typename T>
bool BigEndianReader::ReadLengthPrefixed(base::StringPiece* out) {
T t_len;
if (!Read(&t_len))
return false;
size_t len = strict_cast<size_t>(t_len);
const uint8_t* original_ptr = ptr_;
if (!Skip(len)) {
ptr_ -= sizeof(T);
return false;
}
*out = base::StringPiece(reinterpret_cast<const char*>(original_ptr), len);
return true;
}
bool BigEndianReader::ReadU8LengthPrefixed(base::StringPiece* out) {
return ReadLengthPrefixed<uint8_t>(out);
}
bool BigEndianReader::ReadU16LengthPrefixed(base::StringPiece* out) {
return ReadLengthPrefixed<uint16_t>(out);
}
BigEndianWriter::BigEndianWriter(char* buf, size_t len)
: ptr_(buf), end_(ptr_ + len) {
// Ensure `len` does not cause `end_` to wrap around.
CHECK_GE(end_, ptr_);
}
bool BigEndianWriter::Skip(size_t len) {
if (len > remaining())
return false;
ptr_ += len;
return true;
}
bool BigEndianWriter::WriteBytes(const void* buf, size_t len) {
if (len > remaining())
return false;
memcpy(ptr_, buf, len);
ptr_ += len;
return true;
}
template<typename T>
bool BigEndianWriter::Write(T value) {
if (sizeof(T) > remaining())
return false;
WriteBigEndian<T>(ptr_, value);
ptr_ += sizeof(T);
return true;
}
bool BigEndianWriter::WriteU8(uint8_t value) {
return Write(value);
}
bool BigEndianWriter::WriteU16(uint16_t value) {
return Write(value);
}
bool BigEndianWriter::WriteU32(uint32_t value) {
return Write(value);
}
bool BigEndianWriter::WriteU64(uint64_t value) {
return Write(value);
}
} // namespace base
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