Add base to the repository.
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@8 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/base/pickle.h b/base/pickle.h
new file mode 100644
index 0000000..5e97ff5
--- /dev/null
+++ b/base/pickle.h
@@ -0,0 +1,259 @@
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef BASE_PICKLE_H__
+#define BASE_PICKLE_H__
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/logging.h"
+#include "testing/gtest/include/gtest/gtest_prod.h"
+
+// This class provides facilities for basic binary value packing and unpacking.
+//
+// The Pickle class supports appending primitive values (ints, strings, etc.)
+// to a pickle instance. The Pickle instance grows its internal memory buffer
+// dynamically to hold the sequence of primitive values. The internal memory
+// buffer is exposed as the "data" of the Pickle. This "data" can be passed
+// to a Pickle object to initialize it for reading.
+//
+// When reading from a Pickle object, it is important for the consumer to know
+// what value types to read and in what order to read them as the Pickle does
+// not keep track of the type of data written to it.
+//
+// The Pickle's data has a header which contains the size of the Pickle's
+// payload. It can optionally support additional space in the header. That
+// space is controlled by the header_size parameter passed to the Pickle
+// constructor.
+//
+class Pickle {
+ public:
+ ~Pickle();
+
+ // Initialize a Pickle object using the default header size.
+ Pickle();
+
+ // Initialize a Pickle object with the specified header size in bytes, which
+ // must be greater-than-or-equal-to sizeof(Pickle::Header). The header size
+ // will be rounded up to ensure that the header size is 32bit-aligned.
+ explicit Pickle(int header_size);
+
+ // Initializes a Pickle from a const block of data. The data is not copied;
+ // instead the data is merely referenced by this Pickle. Only const methods
+ // should be used on the Pickle when initialized this way. The header
+ // padding size is deduced from the data length.
+ Pickle(const char* data, int data_len);
+
+ // Initializes a Pickle as a deep copy of another Pickle.
+ Pickle(const Pickle& other);
+
+ // Performs a deep copy.
+ Pickle& operator=(const Pickle& other);
+
+ // Returns the size of the Pickle's data.
+ int size() const { return static_cast<int>(header_size_ +
+ header_->payload_size); }
+
+ // Returns the data for this Pickle.
+ const void* data() const { return header_; }
+
+ // Methods for reading the payload of the Pickle. To read from the start of
+ // the Pickle, initialize *iter to NULL. If successful, these methods return
+ // true. Otherwise, false is returned to indicate that the result could not
+ // be extracted.
+ bool ReadBool(void** iter, bool* result) const;
+ bool ReadInt(void** iter, int* result) const;
+ bool ReadSize(void** iter, size_t* result) const;
+ bool ReadInt64(void** iter, int64* result) const;
+ bool ReadIntPtr(void** iter, intptr_t* result) const;
+ bool ReadString(void** iter, std::string* result) const;
+ bool ReadWString(void** iter, std::wstring* result) const;
+ bool ReadData(void** iter, const char** data, int* length) const;
+ bool ReadBytes(void** iter, const char** data, int length) const;
+
+ // Safer version of ReadInt() checks for the result not being negative.
+ // Use it for reading the object sizes.
+ bool Pickle::ReadLength(void** iter, int* result) const;
+
+ // Methods for adding to the payload of the Pickle. These values are
+ // appended to the end of the Pickle's payload. When reading values from a
+ // Pickle, it is important to read them in the order in which they were added
+ // to the Pickle.
+ bool WriteBool(bool value) {
+ return WriteInt(value ? 1 : 0);
+ }
+ bool WriteInt(int value) {
+ return WriteBytes(&value, sizeof(value));
+ }
+ bool WriteSize(size_t value) {
+ return WriteBytes(&value, sizeof(value));
+ }
+ bool WriteInt64(int64 value) {
+ return WriteBytes(&value, sizeof(value));
+ }
+ bool WriteIntPtr(intptr_t value) {
+ return WriteBytes(&value, sizeof(value));
+ }
+ bool WriteString(const std::string& value);
+ bool WriteWString(const std::wstring& value);
+ bool WriteData(const char* data, int length);
+ bool WriteBytes(const void* data, int data_len);
+
+ // Same as WriteData, but allows the caller to write directly into the
+ // Pickle. This saves a copy in cases where the data is not already
+ // available in a buffer. The caller should take care to not write more
+ // than the length it declares it will. Use ReadData to get the data.
+ // Returns NULL on failure.
+ //
+ // The returned pointer will only be valid until the next write operation
+ // on this Pickle.
+ char* BeginWriteData(int length);
+
+ // For Pickles which contain variable length buffers (e.g. those created
+ // with BeginWriteData), the Pickle can
+ // be 'trimmed' if the amount of data required is less than originally
+ // requested. For example, you may have created a buffer with 10K of data,
+ // but decided to only fill 10 bytes of that data. Use this function
+ // to trim the buffer so that we don't send 9990 bytes of unused data.
+ // You cannot increase the size of the variable buffer; only shrink it.
+ // This function assumes that the length of the variable buffer has
+ // not been changed.
+ void TrimWriteData(int length);
+
+ // payload follows after allocation of Header (header size is customizable)
+ struct Header {
+ size_t payload_size; // specifies the size of the payload
+ };
+
+ // Returns the header, cast to a user-specified type T. The type T must be a
+ // subclass of Header and its size must correspond to the header_size passed
+ // to the Pickle constructor.
+ template <class T>
+ T* headerT() {
+ DCHECK(sizeof(T) == header_size_);
+ return static_cast<T*>(header_);
+ }
+ template <class T>
+ const T* headerT() const {
+ DCHECK(sizeof(T) == header_size_);
+ return static_cast<const T*>(header_);
+ }
+
+ // Returns true if the given iterator could point to data with the given
+ // length. If there is no room for the given data before the end of the
+ // payload, returns false.
+ bool IteratorHasRoomFor(const void* iter, int len) const {
+ if ((len < 0) || (iter < header_) || iter > end_of_payload())
+ return false;
+ const char* end_of_region = reinterpret_cast<const char*>(iter) + len;
+ // Watch out for overflow in pointer calculation, which wraps.
+ return (iter <= end_of_region) && (end_of_region <= end_of_payload());
+ }
+
+ protected:
+ size_t payload_size() const { return header_->payload_size; }
+
+ char* payload() {
+ return reinterpret_cast<char*>(header_) + header_size_;
+ }
+ const char* payload() const {
+ return reinterpret_cast<const char*>(header_) + header_size_;
+ }
+
+ // Returns the address of the byte immediately following the currently valid
+ // header + payload.
+ char* end_of_payload() {
+ return payload() + payload_size();
+ }
+ const char* end_of_payload() const {
+ return payload() + payload_size();
+ }
+
+ size_t capacity() const {
+ return capacity_;
+ }
+
+ // Resizes the buffer for use when writing the specified amount of data. The
+ // location that the data should be written at is returned, or NULL if there
+ // was an error. Call EndWrite with the returned offset and the given length
+ // to pad out for the next write.
+ char* BeginWrite(size_t length);
+
+ // Completes the write operation by padding the data with NULL bytes until it
+ // is padded. Should be paired with BeginWrite, but it does not necessarily
+ // have to be called after the data is written.
+ void EndWrite(char* dest, int length);
+
+ // Resize the capacity, note that the input value should include the size of
+ // the header: new_capacity = sizeof(Header) + desired_payload_capacity.
+ // A realloc() failure will cause a Resize failure... and caller should check
+ // the return result for true (i.e., successful resizing).
+ bool Resize(size_t new_capacity);
+
+ // Aligns 'i' by rounding it up to the next multiple of 'alignment'
+ static inline size_t AlignInt(size_t i, int alignment) {
+ return i + (alignment - (i % alignment)) % alignment;
+ }
+
+ // Moves the iterator by the given number of bytes, making sure it is aligned.
+ // Pointer (iterator) is NOT aligned, but the change in the pointer
+ // is guaranteed to be a multiple of sizeof(uint32).
+ static inline void UpdateIter(void** iter, int bytes) {
+ *iter = static_cast<char*>(*iter) + AlignInt(bytes, sizeof(uint32));
+ }
+
+ // Find the end of the pickled data that starts at range_start. Returns NULL
+ // if the entire Pickle is not found in the given data range.
+ static const char* FindNext(size_t header_size,
+ const char* range_start,
+ const char* range_end);
+
+ // The allocation granularity of the payload.
+ static const int kPayloadUnit;
+
+ private:
+ // A buffer of variable length; used internally
+ struct VariableLengthBuffer {
+ int length;
+ char data; // This is variable length.
+ };
+
+ Header* header_;
+ size_t header_size_; // Supports extra data between header and payload.
+ // Allocation size of payload (or -1 if allocation is const).
+ size_t capacity_;
+ size_t variable_buffer_offset_; // IF non-zero, then offset to a buffer.
+
+ FRIEND_TEST(PickleTest, Resize);
+ FRIEND_TEST(PickleTest, FindNext);
+ FRIEND_TEST(PickleTest, IteratorHasRoom);
+};
+
+#endif // BASE_PICKLE_H__
