Split ByteBuffer into writer/reader objects.

webrtc/base/bytebuffer.cc

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/base/bytebuffer.h"
 
 #include <assert.h>
 #include <string.h>
 
 #include <algorithm>
 
 #include "webrtc/base/basictypes.h"
 #include "webrtc/base/byteorder.h"
 
 namespace rtc {
 
 static const int DEFAULT_SIZE = 4096;
 
-ByteBuffer::ByteBuffer() {
-  Construct(NULL, DEFAULT_SIZE, ORDER_NETWORK);
+ByteBufferWriter::ByteBufferWriter()
+    : ByteBuffer(ORDER_NETWORK) {
+  Construct(NULL, DEFAULT_SIZE);
 }
 
-ByteBuffer::ByteBuffer(ByteOrder byte_order) {
-  Construct(NULL, DEFAULT_SIZE, byte_order);
+ByteBufferWriter::ByteBufferWriter(ByteOrder byte_order)
+    : ByteBuffer(byte_order) {
+  Construct(NULL, DEFAULT_SIZE);
 }
 
-ByteBuffer::ByteBuffer(const char* bytes, size_t len) {
-  Construct(bytes, len, ORDER_NETWORK);
+ByteBufferWriter::ByteBufferWriter(const char* bytes, size_t len)
+    : ByteBuffer(ORDER_NETWORK) {
+  Construct(bytes, len);
 }
 
-ByteBuffer::ByteBuffer(const char* bytes, size_t len, ByteOrder byte_order) {
-  Construct(bytes, len, byte_order);
+ByteBufferWriter::ByteBufferWriter(const char* bytes, size_t len,
+                                   ByteOrder byte_order)
+    : ByteBuffer(byte_order) {
+  Construct(bytes, len);
 }
 
-ByteBuffer::ByteBuffer(const char* bytes) {
-  Construct(bytes, strlen(bytes), ORDER_NETWORK);
-}
-
-ByteBuffer::ByteBuffer(const Buffer& buf) {
-  Construct(buf.data<char>(), buf.size(), ORDER_NETWORK);
-}
-
-void ByteBuffer::Construct(const char* bytes, size_t len,
-                           ByteOrder byte_order) {
-  version_ = 0;
+void ByteBufferWriter::Construct(const char* bytes, size_t len) {
   start_ = 0;
   size_ = len;
-  byte_order_ = byte_order;
   bytes_ = new char[size_];
 
   if (bytes) {
     end_ = len;
     memcpy(bytes_, bytes, end_);
   } else {
     end_ = 0;
   }
 }
 
-ByteBuffer::~ByteBuffer() {
+ByteBufferWriter::~ByteBufferWriter() {
   delete[] bytes_;
 }
 
-bool ByteBuffer::ReadUInt8(uint8_t* val) {
+void ByteBufferWriter::WriteUInt8(uint8_t val) {
+  WriteBytes(reinterpret_cast<const char*>(&val), 1);
+}
+
+void ByteBufferWriter::WriteUInt16(uint16_t val) {
+  uint16_t v = (Order() == ORDER_NETWORK) ? HostToNetwork16(val) : val;
+  WriteBytes(reinterpret_cast<const char*>(&v), 2);
+}
+
+void ByteBufferWriter::WriteUInt24(uint32_t val) {
+  uint32_t v = (Order() == ORDER_NETWORK) ? HostToNetwork32(val) : val;
+  char* start = reinterpret_cast<char*>(&v);
+  if (Order() == ORDER_NETWORK || IsHostBigEndian()) {
+    ++start;
+  }
+  WriteBytes(start, 3);
+}
+
+void ByteBufferWriter::WriteUInt32(uint32_t val) {
+  uint32_t v = (Order() == ORDER_NETWORK) ? HostToNetwork32(val) : val;
+  WriteBytes(reinterpret_cast<const char*>(&v), 4);
+}
+
+void ByteBufferWriter::WriteUInt64(uint64_t val) {
+  uint64_t v = (Order() == ORDER_NETWORK) ? HostToNetwork64(val) : val;
+  WriteBytes(reinterpret_cast<const char*>(&v), 8);
+}
+
+void ByteBufferWriter::WriteString(const std::string& val) {
+  WriteBytes(val.c_str(), val.size());
+}
+
+void ByteBufferWriter::WriteBytes(const char* val, size_t len) {
+  memcpy(ReserveWriteBuffer(len), val, len);
+}
+
+char* ByteBufferWriter::ReserveWriteBuffer(size_t len) {
+  if (Length() + len > Capacity())
+    Resize(Length() + len);
+
+  char* start = bytes_ + end_;
+  end_ += len;
+  return start;
+}
+
+void ByteBufferWriter::Resize(size_t size) {
+  size_t len = std::min(end_ - start_, size);
+  if (size <= size_) {
+    // Don't reallocate, just move data backwards
+    memmove(bytes_, bytes_ + start_, len);
+  } else {
+    // Reallocate a larger buffer.
+    size_ = std::max(size, 3 * size_ / 2);
+    char* new_bytes = new char[size_];
+    memcpy(new_bytes, bytes_ + start_, len);
+    delete [] bytes_;
+    bytes_ = new_bytes;
+  }
+  start_ = 0;
+  end_ = len;
+}
+
+void ByteBufferWriter::Clear() {
+  memset(bytes_, 0, size_);
+  start_ = end_ = 0;
+}
+
+
+ByteBufferReader::ByteBufferReader(const char* bytes, size_t len)
+    : ByteBuffer(ORDER_NETWORK) {
+  Construct(bytes, len);
+}
+
+ByteBufferReader::ByteBufferReader(const char* bytes, size_t len,
+                                   ByteOrder byte_order)
+    : ByteBuffer(byte_order) {
+  Construct(bytes, len);
+}
+
+ByteBufferReader::ByteBufferReader(const char* bytes)
+    : ByteBuffer(ORDER_NETWORK) {
+  Construct(bytes, strlen(bytes));
+}
+
+ByteBufferReader::ByteBufferReader(const Buffer& buf)
+    : ByteBuffer(ORDER_NETWORK) {
+  Construct(buf.data<char>(), buf.size());
+}
+
+ByteBufferReader::ByteBufferReader(const ByteBufferWriter& buf)
+    : ByteBuffer(buf.Order()) {
+  Construct(buf.Data(), buf.Length());
+}
+
+void ByteBufferReader::Construct(const char* bytes, size_t len) {
+  bytes_ = bytes;
+  size_ = len;
+  start_ = 0;
+  end_ = len;
+}
+
+bool ByteBufferReader::ReadUInt8(uint8_t* val) {
   if (!val) return false;
 
   return ReadBytes(reinterpret_cast<char*>(val), 1);
 }
 
-bool ByteBuffer::ReadUInt16(uint16_t* val) {
+bool ByteBufferReader::ReadUInt16(uint16_t* val) {
   if (!val) return false;
 
   uint16_t v;
   if (!ReadBytes(reinterpret_cast<char*>(&v), 2)) {
     return false;
   } else {
-    *val = (byte_order_ == ORDER_NETWORK) ? NetworkToHost16(v) : v;
+    *val = (Order() == ORDER_NETWORK) ? NetworkToHost16(v) : v;
     return true;
   }
 }
 
-bool ByteBuffer::ReadUInt24(uint32_t* val) {
+bool ByteBufferReader::ReadUInt24(uint32_t* val) {
   if (!val) return false;
 
   uint32_t v = 0;
   char* read_into = reinterpret_cast<char*>(&v);
-  if (byte_order_ == ORDER_NETWORK || IsHostBigEndian()) {
+  if (Order() == ORDER_NETWORK || IsHostBigEndian()) {
     ++read_into;
   }
 
   if (!ReadBytes(read_into, 3)) {
     return false;
   } else {
-    *val = (byte_order_ == ORDER_NETWORK) ? NetworkToHost32(v) : v;
+    *val = (Order() == ORDER_NETWORK) ? NetworkToHost32(v) : v;
     return true;
   }
 }
 
-bool ByteBuffer::ReadUInt32(uint32_t* val) {
+bool ByteBufferReader::ReadUInt32(uint32_t* val) {
   if (!val) return false;
 
   uint32_t v;
   if (!ReadBytes(reinterpret_cast<char*>(&v), 4)) {
     return false;
   } else {
-    *val = (byte_order_ == ORDER_NETWORK) ? NetworkToHost32(v) : v;
+    *val = (Order() == ORDER_NETWORK) ? NetworkToHost32(v) : v;
     return true;
   }
 }
 
-bool ByteBuffer::ReadUInt64(uint64_t* val) {
+bool ByteBufferReader::ReadUInt64(uint64_t* val) {
   if (!val) return false;
 
   uint64_t v;
   if (!ReadBytes(reinterpret_cast<char*>(&v), 8)) {
     return false;
   } else {
-    *val = (byte_order_ == ORDER_NETWORK) ? NetworkToHost64(v) : v;
+    *val = (Order() == ORDER_NETWORK) ? NetworkToHost64(v) : v;
     return true;
   }
 }
 
-bool ByteBuffer::ReadString(std::string* val, size_t len) {
+bool ByteBufferReader::ReadString(std::string* val, size_t len) {
   if (!val) return false;
 
   if (len > Length()) {
     return false;
   } else {
     val->append(bytes_ + start_, len);
     start_ += len;
     return true;
   }
 }
 
-bool ByteBuffer::ReadBytes(char* val, size_t len) {
+bool ByteBufferReader::ReadBytes(char* val, size_t len) {
   if (len > Length()) {
     return false;
   } else {
     memcpy(val, bytes_ + start_, len);
     start_ += len;
     return true;
   }
 }
 
-void ByteBuffer::WriteUInt8(uint8_t val) {
-  WriteBytes(reinterpret_cast<const char*>(&val), 1);
-}
-
-void ByteBuffer::WriteUInt16(uint16_t val) {
-  uint16_t v = (byte_order_ == ORDER_NETWORK) ? HostToNetwork16(val) : val;
-  WriteBytes(reinterpret_cast<const char*>(&v), 2);
-}
-
-void ByteBuffer::WriteUInt24(uint32_t val) {
-  uint32_t v = (byte_order_ == ORDER_NETWORK) ? HostToNetwork32(val) : val;
-  char* start = reinterpret_cast<char*>(&v);
-  if (byte_order_ == ORDER_NETWORK || IsHostBigEndian()) {
-    ++start;
-  }
-  WriteBytes(start, 3);
-}
-
-void ByteBuffer::WriteUInt32(uint32_t val) {
-  uint32_t v = (byte_order_ == ORDER_NETWORK) ? HostToNetwork32(val) : val;
-  WriteBytes(reinterpret_cast<const char*>(&v), 4);
-}
-
-void ByteBuffer::WriteUInt64(uint64_t val) {
-  uint64_t v = (byte_order_ == ORDER_NETWORK) ? HostToNetwork64(val) : val;
-  WriteBytes(reinterpret_cast<const char*>(&v), 8);
-}
-
-void ByteBuffer::WriteString(const std::string& val) {
-  WriteBytes(val.c_str(), val.size());
-}
-
-void ByteBuffer::WriteBytes(const char* val, size_t len) {
-  memcpy(ReserveWriteBuffer(len), val, len);
-}
-
-char* ByteBuffer::ReserveWriteBuffer(size_t len) {
-  if (Length() + len > Capacity())
-    Resize(Length() + len);
-
-  char* start = bytes_ + end_;
-  end_ += len;
-  return start;
-}
-
-void ByteBuffer::Resize(size_t size) {
-  size_t len = std::min(end_ - start_, size);
-  if (size <= size_) {
-    // Don't reallocate, just move data backwards
-    memmove(bytes_, bytes_ + start_, len);
-  } else {
-    // Reallocate a larger buffer.
-    size_ = std::max(size, 3 * size_ / 2);
-    char* new_bytes = new char[size_];
-    memcpy(new_bytes, bytes_ + start_, len);
-    delete [] bytes_;
-    bytes_ = new_bytes;
-  }
-  start_ = 0;
-  end_ = len;
-  ++version_;
-}
-
-bool ByteBuffer::Consume(size_t size) {
+bool ByteBufferReader::Consume(size_t size) {
   if (size > Length())
     return false;
   start_ += size;
   return true;
 }
 
-ByteBuffer::ReadPosition ByteBuffer::GetReadPosition() const {
-  return ReadPosition(start_, version_);
-}
-
-bool ByteBuffer::SetReadPosition(const ReadPosition &position) {
-  if (position.version_ != version_) {
-    return false;
-  }
-  start_ = position.start_;
-  return true;
-}
-
-void ByteBuffer::Clear() {
-  memset(bytes_, 0, size_);
-  start_ = end_ = 0;
-  ++version_;
-}
-
 }  // namespace rtc