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// Copyright (c) 2009 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 <limits>
#include "net/spdy/spdy_frame_builder.h"
#include "net/spdy/spdy_protocol.h"
namespace spdy {
// We mark a read only SpdyFrameBuilder with a special capacity_.
static const size_t kCapacityReadOnly = std::numeric_limits<size_t>::max();
SpdyFrameBuilder::SpdyFrameBuilder()
: buffer_(NULL),
capacity_(0),
length_(0),
variable_buffer_offset_(0) {
Resize(kInitialPayload);
}
SpdyFrameBuilder::SpdyFrameBuilder(const char* data, int data_len)
: buffer_(const_cast<char*>(data)),
capacity_(kCapacityReadOnly),
length_(data_len),
variable_buffer_offset_(0) {
}
SpdyFrameBuilder::~SpdyFrameBuilder() {
if (capacity_ != kCapacityReadOnly)
delete[] buffer_;
}
bool SpdyFrameBuilder::ReadUInt16(void** iter, uint16* result) const {
DCHECK(iter);
if (!*iter)
*iter = const_cast<char*>(buffer_);
if (!IteratorHasRoomFor(*iter, sizeof(*result)))
return false;
*result = ntohs(*(reinterpret_cast<uint16*>(*iter)));
UpdateIter(iter, sizeof(*result));
return true;
}
bool SpdyFrameBuilder::ReadUInt32(void** iter, uint32* result) const {
DCHECK(iter);
if (!*iter)
*iter = const_cast<char*>(buffer_);
if (!IteratorHasRoomFor(*iter, sizeof(*result)))
return false;
*result = ntohl(*(reinterpret_cast<uint32*>(*iter)));
UpdateIter(iter, sizeof(*result));
return true;
}
bool SpdyFrameBuilder::ReadString(void** iter, std::string* result) const {
DCHECK(iter);
uint16 len;
if (!ReadUInt16(iter, &len))
return false;
if (!IteratorHasRoomFor(*iter, len))
return false;
char* chars = reinterpret_cast<char*>(*iter);
result->assign(chars, len);
UpdateIter(iter, len);
return true;
}
bool SpdyFrameBuilder::ReadBytes(void** iter, const char** data,
uint16 length) const {
DCHECK(iter);
DCHECK(data);
if (!IteratorHasRoomFor(*iter, length))
return false;
*data = reinterpret_cast<const char*>(*iter);
UpdateIter(iter, length);
return true;
}
bool SpdyFrameBuilder::ReadData(void** iter, const char** data,
uint16* length) const {
DCHECK(iter);
DCHECK(data);
DCHECK(length);
if (!ReadUInt16(iter, length))
return false;
return ReadBytes(iter, data, *length);
}
char* SpdyFrameBuilder::BeginWrite(size_t length) {
size_t needed_size = length_ + length;
if (needed_size > capacity_ && !Resize(std::max(capacity_ * 2, needed_size)))
return NULL;
#ifdef ARCH_CPU_64_BITS
DCHECK_LE(length, std::numeric_limits<uint32>::max());
#endif
return buffer_ + length_;
}
void SpdyFrameBuilder::EndWrite(char* dest, int length) {
}
bool SpdyFrameBuilder::WriteBytes(const void* data, uint16 data_len) {
DCHECK(capacity_ != kCapacityReadOnly);
char* dest = BeginWrite(data_len);
if (!dest)
return false;
memcpy(dest, data, data_len);
EndWrite(dest, data_len);
length_ += data_len;
return true;
}
bool SpdyFrameBuilder::WriteString(const std::string& value) {
if (value.size() > 0xffff)
return false;
if (!WriteUInt16(static_cast<int>(value.size())))
return false;
return WriteBytes(value.data(), static_cast<uint16>(value.size()));
}
char* SpdyFrameBuilder::BeginWriteData(uint16 length) {
DCHECK_EQ(variable_buffer_offset_, 0U) <<
"There can only be one variable buffer in a SpdyFrameBuilder";
if (!WriteUInt16(length))
return NULL;
char *data_ptr = BeginWrite(length);
if (!data_ptr)
return NULL;
variable_buffer_offset_ = data_ptr - buffer_ - sizeof(int);
// EndWrite doesn't necessarily have to be called after the write operation,
// so we call it here to pad out what the caller will eventually write.
EndWrite(data_ptr, length);
return data_ptr;
}
bool SpdyFrameBuilder::Resize(size_t new_capacity) {
if (new_capacity <= capacity_)
return true;
char* p = new char[new_capacity];
if (!p)
return false;
if (buffer_) {
memcpy(p, buffer_, capacity_);
delete[] buffer_;
}
buffer_ = p;
capacity_ = new_capacity;
return true;
}
} // namespace spdy
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