// Copyright 2014 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. #include "base/big_endian.h" #include #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 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(ptr_), len); ptr_ += len; return true; } bool BigEndianReader::ReadSpan(base::span* out, size_t len) { if (len > remaining()) return false; *out = base::make_span(ptr_, len); ptr_ += len; return true; } template bool BigEndianReader::Read(T* value) { if (sizeof(T) > remaining()) return false; ReadBigEndian(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 bool BigEndianReader::ReadLengthPrefixed(base::StringPiece* out) { T t_len; if (!Read(&t_len)) return false; size_t len = strict_cast(t_len); const uint8_t* original_ptr = ptr_; if (!Skip(len)) { ptr_ -= sizeof(T); return false; } *out = base::StringPiece(reinterpret_cast(original_ptr), len); return true; } bool BigEndianReader::ReadU8LengthPrefixed(base::StringPiece* out) { return ReadLengthPrefixed(out); } bool BigEndianReader::ReadU16LengthPrefixed(base::StringPiece* out) { return ReadLengthPrefixed(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 bool BigEndianWriter::Write(T value) { if (sizeof(T) > remaining()) return false; WriteBigEndian(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