gecko-dev/gfx/ots/include/ots-memory-stream.h

106 строки
2.4 KiB
C++

// 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.
#ifndef OTS_MEMORY_STREAM_H_
#define OTS_MEMORY_STREAM_H_
#include <cstring>
#include <limits>
#include "opentype-sanitiser.h"
namespace ots {
class MemoryStream : public OTSStream {
public:
MemoryStream(void *ptr, size_t length)
: ptr_(ptr), length_(length), off_(0) {
}
virtual bool WriteRaw(const void *data, size_t length) {
if ((off_ + length > length_) ||
(length > std::numeric_limits<size_t>::max() - off_)) {
return false;
}
std::memcpy(static_cast<char*>(ptr_) + off_, data, length);
off_ += length;
return true;
}
virtual bool Seek(off_t position) {
if (position < 0) return false;
if (static_cast<size_t>(position) > length_) return false;
off_ = position;
return true;
}
virtual off_t Tell() const {
return off_;
}
private:
void* const ptr_;
size_t length_;
off_t off_;
};
class ExpandingMemoryStream : public OTSStream {
public:
ExpandingMemoryStream(size_t initial, size_t limit)
: length_(initial), limit_(limit), off_(0) {
ptr_ = new uint8_t[length_];
}
~ExpandingMemoryStream() {
delete[] static_cast<uint8_t*>(ptr_);
}
void* get() const {
return ptr_;
}
bool WriteRaw(const void *data, size_t length) {
if ((off_ + length > length_) ||
(length > std::numeric_limits<size_t>::max() - off_)) {
if (length_ == limit_)
return false;
size_t new_length = (length_ + 1) * 2;
if (new_length < length_)
return false;
if (new_length > limit_)
new_length = limit_;
uint8_t* new_buf = new uint8_t[new_length];
std::memcpy(new_buf, ptr_, length_);
length_ = new_length;
delete[] static_cast<uint8_t*>(ptr_);
ptr_ = new_buf;
return WriteRaw(data, length);
}
std::memcpy(static_cast<char*>(ptr_) + off_, data, length);
off_ += length;
return true;
}
bool Seek(off_t position) {
if (position < 0) return false;
if (static_cast<size_t>(position) > length_) return false;
off_ = position;
return true;
}
off_t Tell() const {
return off_;
}
private:
void* ptr_;
size_t length_;
const size_t limit_;
off_t off_;
};
} // namespace ots
#endif // OTS_MEMORY_STREAM_H_