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// Copyright 2016 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 "net/http2/decoder/decode_buffer.h"
namespace net {
uint8_t DecodeBuffer::DecodeUInt8() {
return static_cast<uint8_t>(DecodeChar());
}
uint16_t DecodeBuffer::DecodeUInt16() {
DCHECK_LE(2u, Remaining());
const uint8_t b1 = DecodeUInt8();
const uint8_t b2 = DecodeUInt8();
// Note that chars are automatically promoted to ints during arithmetic,
// so the b1 << 8 doesn't end up as zero before being or-ed with b2.
// And the left-shift operator has higher precedence than the or operator.
return b1 << 8 | b2;
}
uint32_t DecodeBuffer::DecodeUInt24() {
DCHECK_LE(3u, Remaining());
const uint8_t b1 = DecodeUInt8();
const uint8_t b2 = DecodeUInt8();
const uint8_t b3 = DecodeUInt8();
return b1 << 16 | b2 << 8 | b3;
}
uint32_t DecodeBuffer::DecodeUInt31() {
DCHECK_LE(4u, Remaining());
const uint8_t b1 = DecodeUInt8() & 0x7f; // Mask out the high order bit.
const uint8_t b2 = DecodeUInt8();
const uint8_t b3 = DecodeUInt8();
const uint8_t b4 = DecodeUInt8();
return b1 << 24 | b2 << 16 | b3 << 8 | b4;
}
uint32_t DecodeBuffer::DecodeUInt32() {
DCHECK_LE(4u, Remaining());
const uint8_t b1 = DecodeUInt8();
const uint8_t b2 = DecodeUInt8();
const uint8_t b3 = DecodeUInt8();
const uint8_t b4 = DecodeUInt8();
return b1 << 24 | b2 << 16 | b3 << 8 | b4;
}
#ifndef NDEBUG
void DecodeBuffer::set_subset_of_base(DecodeBuffer* base,
const DecodeBufferSubset* subset) {
DCHECK_EQ(this, subset);
base->set_subset(subset);
}
void DecodeBuffer::clear_subset_of_base(DecodeBuffer* base,
const DecodeBufferSubset* subset) {
DCHECK_EQ(this, subset);
base->clear_subset(subset);
}
void DecodeBuffer::set_subset(const DecodeBufferSubset* subset) {
DCHECK(subset != nullptr);
DCHECK_EQ(subset_, nullptr) << "There is already a subset";
subset_ = subset;
}
void DecodeBuffer::clear_subset(const DecodeBufferSubset* subset) {
DCHECK(subset != nullptr);
DCHECK_EQ(subset_, subset);
subset_ = nullptr;
}
void DecodeBufferSubset::DebugSetup() {
start_base_offset_ = base_buffer_->Offset();
max_base_offset_ = start_base_offset_ + FullSize();
DCHECK_LE(max_base_offset_, base_buffer_->FullSize());
// Ensure that there is only one DecodeBufferSubset at a time for a base.
set_subset_of_base(base_buffer_, this);
}
void DecodeBufferSubset::DebugTearDown() {
// Ensure that the base hasn't been modified.
DCHECK_EQ(start_base_offset_, base_buffer_->Offset())
<< "The base buffer was modified";
// Ensure that we haven't gone beyond the maximum allowed offset.
size_t offset = Offset();
DCHECK_LE(offset, FullSize());
DCHECK_LE(start_base_offset_ + offset, max_base_offset_);
DCHECK_LE(max_base_offset_, base_buffer_->FullSize());
clear_subset_of_base(base_buffer_, this);
}
#endif
} // namespace net
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