michael@0: // Copyright (c) 2009 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #ifndef OTS_MEMORY_STREAM_H_
michael@0: #define OTS_MEMORY_STREAM_H_
michael@0: 
michael@0: #include <cstring>
michael@0: #include <limits>
michael@0: 
michael@0: #include "opentype-sanitiser.h"
michael@0: 
michael@0: namespace ots {
michael@0: 
michael@0: class MemoryStream : public OTSStream {
michael@0:  public:
michael@0:   MemoryStream(void *ptr, size_t length)
michael@0:       : ptr_(ptr), length_(length), off_(0) {
michael@0:   }
michael@0: 
michael@0:   virtual bool WriteRaw(const void *data, size_t length) {
michael@0:     if ((off_ + length > length_) ||
michael@0:         (length > std::numeric_limits<size_t>::max() - off_)) {
michael@0:       return false;
michael@0:     }
michael@0:     std::memcpy(static_cast<char*>(ptr_) + off_, data, length);
michael@0:     off_ += length;
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   virtual bool Seek(off_t position) {
michael@0:     if (position < 0) return false;
michael@0:     if (static_cast<size_t>(position) > length_) return false;
michael@0:     off_ = position;
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   virtual off_t Tell() const {
michael@0:     return off_;
michael@0:   }
michael@0: 
michael@0:  private:
michael@0:   void* const ptr_;
michael@0:   size_t length_;
michael@0:   off_t off_;
michael@0: };
michael@0: 
michael@0: class ExpandingMemoryStream : public OTSStream {
michael@0:  public:
michael@0:   ExpandingMemoryStream(size_t initial, size_t limit)
michael@0:       : length_(initial), limit_(limit), off_(0) {
michael@0:     ptr_ = new uint8_t[length_];
michael@0:   }
michael@0: 
michael@0:   ~ExpandingMemoryStream() {
michael@0:     delete[] static_cast<uint8_t*>(ptr_);
michael@0:   }
michael@0: 
michael@0:   void* get() const {
michael@0:     return ptr_;
michael@0:   }
michael@0: 
michael@0:   bool WriteRaw(const void *data, size_t length) {
michael@0:     if ((off_ + length > length_) ||
michael@0:         (length > std::numeric_limits<size_t>::max() - off_)) {
michael@0:       if (length_ == limit_)
michael@0:         return false;
michael@0:       size_t new_length = (length_ + 1) * 2;
michael@0:       if (new_length < length_)
michael@0:         return false;
michael@0:       if (new_length > limit_)
michael@0:         new_length = limit_;
michael@0:       uint8_t* new_buf = new uint8_t[new_length];
michael@0:       std::memcpy(new_buf, ptr_, length_);
michael@0:       length_ = new_length;
michael@0:       delete[] static_cast<uint8_t*>(ptr_);
michael@0:       ptr_ = new_buf;
michael@0:       return WriteRaw(data, length);
michael@0:     }
michael@0:     std::memcpy(static_cast<char*>(ptr_) + off_, data, length);
michael@0:     off_ += length;
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   bool Seek(off_t position) {
michael@0:     if (position < 0) return false;
michael@0:     if (static_cast<size_t>(position) > length_) return false;
michael@0:     off_ = position;
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   off_t Tell() const {
michael@0:     return off_;
michael@0:   }
michael@0: 
michael@0:  private:
michael@0:   void* ptr_;
michael@0:   size_t length_;
michael@0:   const size_t limit_;
michael@0:   off_t off_;
michael@0: };
michael@0: 
michael@0: }  // namespace ots
michael@0: 
michael@0: #endif  // OTS_MEMORY_STREAM_H_