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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// http://code.google.com/p/protobuf/
//
// 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.

// Author: kenton@google.com (Kenton Varda)
// Based on original Protocol Buffers design by
// Sanjay Ghemawat, Jeff Dean, and others.
//
// This file contains the CodedInputStream and CodedOutputStream classes,
// which wrap a ZeroCopyInputStream or ZeroCopyOutputStream, respectively,
// and allow you to read or write individual pieces of data in various
// formats. In particular, these implement the varint encoding for
// integers, a simple variable-length encoding in which smaller numbers
// take fewer bytes.
//
// Typically these classes will only be used internally by the protocol
// buffer library in order to encode and decode protocol buffers. Clients
// of the library only need to know about this class if they wish to write
// custom message parsing or serialization procedures.
//
// CodedOutputStream example:
// // Write some data to "myfile". First we write a 4-byte "magic number"
// // to identify the file type, then write a length-delimited string. The
// // string is composed of a varint giving the length followed by the raw
// // bytes.
// int fd = open("myfile", O_WRONLY);
// ZeroCopyOutputStream* raw_output = new FileOutputStream(fd);
// CodedOutputStream* coded_output = new CodedOutputStream(raw_output);
//
// int magic_number = 1234;
// char text[] = "Hello world!";
// coded_output->WriteLittleEndian32(magic_number);
// coded_output->WriteVarint32(strlen(text));
// coded_output->WriteRaw(text, strlen(text));
//
// delete coded_output;
// delete raw_output;
// close(fd);
//
// CodedInputStream example:
// // Read a file created by the above code.
// int fd = open("myfile", O_RDONLY);
// ZeroCopyInputStream* raw_input = new FileInputStream(fd);
// CodedInputStream coded_input = new CodedInputStream(raw_input);
//
// coded_input->ReadLittleEndian32(&magic_number);
// if (magic_number != 1234) {
// cerr << "File not in expected format." << endl;
// return;
// }
//
// uint32 size;
// coded_input->ReadVarint32(&size);
//
// char* text = new char[size + 1];
// coded_input->ReadRaw(buffer, size);
// text[size] = '\0';
//
// delete coded_input;
// delete raw_input;
// close(fd);
//
// cout << "Text is: " << text << endl;
// delete [] text;
//
// For those who are interested, varint encoding is defined as follows:
//
// The encoding operates on unsigned integers of up to 64 bits in length.
// Each byte of the encoded value has the format:
// * bits 0-6: Seven bits of the number being encoded.
// * bit 7: Zero if this is the last byte in the encoding (in which
// case all remaining bits of the number are zero) or 1 if
// more bytes follow.
// The first byte contains the least-significant 7 bits of the number, the
// second byte (if present) contains the next-least-significant 7 bits,
// and so on. So, the binary number 1011000101011 would be encoded in two
// bytes as "10101011 00101100".
//
// In theory, varint could be used to encode integers of any length.
// However, for practicality we set a limit at 64 bits. The maximum encoded
// length of a number is thus 10 bytes.

#ifndef GOOGLE_PROTOBUF_IO_CODED_STREAM_H__
#define GOOGLE_PROTOBUF_IO_CODED_STREAM_H__

#include <string>
#ifdef _MSC_VER
#if defined(_M_IX86) && \
!defined(PROTOBUF_DISABLE_LITTLE_ENDIAN_OPT_FOR_TEST)
#define PROTOBUF_LITTLE_ENDIAN 1
#endif
#if _MSC_VER >= 1300
// If MSVC has "/RTCc" set, it will complain about truncating casts at
// runtime. This file contains some intentional truncating casts.
#pragma runtime_checks("c", off)
#endif
#else
#include <sys/param.h> // __BYTE_ORDER
#if defined(__BYTE_ORDER) && __BYTE_ORDER == __LITTLE_ENDIAN && \
!defined(PROTOBUF_DISABLE_LITTLE_ENDIAN_OPT_FOR_TEST)
#define PROTOBUF_LITTLE_ENDIAN 1
#endif
#endif
#include <google/protobuf/stubs/common.h>


namespace google {
namespace protobuf {

class DescriptorPool;
class MessageFactory;

namespace io {

// Defined in this file.
class CodedInputStream;
class CodedOutputStream;

// Defined in other files.
class ZeroCopyInputStream; // zero_copy_stream.h
class ZeroCopyOutputStream; // zero_copy_stream.h

// Class which reads and decodes binary data which is composed of varint-
// encoded integers and fixed-width pieces. Wraps a ZeroCopyInputStream.
// Most users will not need to deal with CodedInputStream.
//
// Most methods of CodedInputStream that return a bool return false if an
// underlying I/O error occurs or if the data is malformed. Once such a
// failure occurs, the CodedInputStream is broken and is no longer useful.
class LIBPROTOBUF_EXPORT CodedInputStream {
public:
// Create a CodedInputStream that reads from the given ZeroCopyInputStream.
explicit CodedInputStream(ZeroCopyInputStream* input);

// Create a CodedInputStream that reads from the given flat array. This is
// faster than using an ArrayInputStream. PushLimit(size) is implied by
// this constructor.
explicit CodedInputStream(const uint8* buffer, int size);

// Destroy the CodedInputStream and position the underlying
// ZeroCopyInputStream at the first unread byte. If an error occurred while
// reading (causing a method to return false), then the exact position of
// the input stream may be anywhere between the last value that was read
// successfully and the stream's byte limit.
~CodedInputStream();


// Skips a number of bytes. Returns false if an underlying read error
// occurs.
bool Skip(int count);

// Sets *data to point directly at the unread part of the CodedInputStream's
// underlying buffer, and *size to the size of that buffer, but does not
// advance the stream's current position. This will always either produce
// a non-empty buffer or return false. If the caller consumes any of
// this data, it should then call Skip() to skip over the consumed bytes.
// This may be useful for implementing external fast parsing routines for
// types of data not covered by the CodedInputStream interface.
bool GetDirectBufferPointer(const void** data, int* size);

// Like GetDirectBufferPointer, but this method is inlined, and does not
// attempt to Refresh() if the buffer is currently empty.
inline void GetDirectBufferPointerInline(const void** data,
int* size) GOOGLE_ATTRIBUTE_ALWAYS_INLINE;

// Read raw bytes, copying them into the given buffer.
bool ReadRaw(void* buffer, int size);

// Like ReadRaw, but reads into a string.
//
// Implementation Note: ReadString() grows the string gradually as it
// reads in the data, rather than allocating the entire requested size
// upfront. This prevents denial-of-service attacks in which a client
// could claim that a string is going to be MAX_INT bytes long in order to
// crash the server because it can't allocate this much space at once.
bool ReadString(string* buffer, int size);
// Like the above, with inlined optimizations. This should only be used
// by the protobuf implementation.
inline bool InternalReadStringInline(string* buffer,
int size) GOOGLE_ATTRIBUTE_ALWAYS_INLINE;


// Read a 32-bit little-endian integer.
bool ReadLittleEndian32(uint32* value);
// Read a 64-bit little-endian integer.
bool ReadLittleEndian64(uint64* value);

// These methods read from an externally provided buffer. The caller is
// responsible for ensuring that the buffer has sufficient space.
// Read a 32-bit little-endian integer.
static const uint8* ReadLittleEndian32FromArray(const uint8* buffer,
uint32* value);
// Read a 64-bit little-endian integer.
static const uint8* ReadLittleEndian64FromArray(const uint8* buffer,
uint64* value);

// Read an unsigned integer with Varint encoding, truncating to 32 bits.
// Reading a 32-bit value is equivalent to reading a 64-bit one and casting
// it to uint32, but may be more efficient.
bool ReadVarint32(uint32* value);
// Read an unsigned integer with Varint encoding.
bool ReadVarint64(uint64* value);

// Read a tag. This calls ReadVarint32() and returns the result, or returns
// zero (which is not a valid tag) if ReadVarint32() fails. Also, it updates
// the last tag value, which can be checked with LastTagWas().
// Always inline because this is only called in once place per parse loop
// but it is called for every iteration of said loop, so it should be fast.
// GCC doesn't want to inline this by default.
uint32 ReadTag() GOOGLE_ATTRIBUTE_ALWAYS_INLINE;

// Usually returns true if calling ReadVarint32() now would produce the given
// value. Will always return false if ReadVarint32() would not return the
// given value. If ExpectTag() returns true, it also advances past
// the varint. For best performance, use a compile-time constant as the
// parameter.
// Always inline because this collapses to a small number of instructions
// when given a constant parameter, but GCC doesn't want to inline by default.
bool ExpectTag(uint32 expected) GOOGLE_ATTRIBUTE_ALWAYS_INLINE;

// Like above, except this reads from the specified buffer. The caller is
// responsible for ensuring that the buffer is large enough to read a varint
// of the expected size. For best performance, use a compile-time constant as
// the expected tag parameter.
//
// Returns a pointer beyond the expected tag if it was found, or NULL if it
// was not.
static const uint8* ExpectTagFromArray(
const uint8* buffer,
uint32 expected) GOOGLE_ATTRIBUTE_ALWAYS_INLINE;

// Usually returns true if no more bytes can be read. Always returns false
// if more bytes can be read. If ExpectAtEnd() returns true, a subsequent
// call to LastTagWas() will act as if ReadTag() had been called and returned
// zero, and ConsumedEntireMessage() will return true.
bool ExpectAtEnd();

// If the last call to ReadTag() returned the given value, returns true.
// Otherwise, returns false;
//
// This is needed because parsers for some types of embedded messages
// (with field type TYPE_GROUP) don't actually know that they've reached the
// end of a message until they see an ENDGROUP tag, which was actually part
// of the enclosing message. The enclosing message would like to check that
// tag to make sure it had the right number, so it calls LastTagWas() on
// return from the embedded parser to check.
bool LastTagWas(uint32 expected);

// When parsing message (but NOT a group), this method must be called
// immediately after MergeFromCodedStream() returns (if it returns true)
// to further verify that the message ended in a legitimate way. For
// example, this verifies that parsing did not end on an end-group tag.
// It also checks for some cases where, due to optimizations,
// MergeFromCodedStream() can incorrectly return true.
bool ConsumedEntireMessage();

// Limits ----------------------------------------------------------
// Limits are used when parsing length-delimited embedded messages.
// After the message's length is read, PushLimit() is used to prevent
// the CodedInputStream from reading beyond that length. Once the
// embedded message has been parsed, PopLimit() is called to undo the
// limit.

// Opaque type used with PushLimit() and PopLimit(). Do not modify
// values of this type yourself. The only reason that this isn't a
// struct with private internals is for efficiency.
typedef int Limit;

// Places a limit on the number of bytes that the stream may read,
// starting from the current position. Once the stream hits this limit,
// it will act like the end of the input has been reached until PopLimit()
// is called.
//
// As the names imply, the stream conceptually has a stack of limits. The
// shortest limit on the stack is always enforced, even if it is not the
// top limit.
//
// The value returned by PushLimit() is opaque to the caller, and must
// be passed unchanged to the corresponding call to PopLimit().
Limit PushLimit(int byte_limit);

// Pops the last limit pushed by PushLimit(). The input must be the value
// returned by that call to PushLimit().
void PopLimit(Limit limit);

// Returns the number of bytes left until the nearest limit on the
// stack is hit, or -1 if no limits are in place.
int BytesUntilLimit();

// Total Bytes Limit -----------------------------------------------
// To prevent malicious users from sending excessively large messages
// and causing integer overflows or memory exhaustion, CodedInputStream
// imposes a hard limit on the total number of bytes it will read.

// Sets the maximum number of bytes that this CodedInputStream will read
// before refusing to continue. To prevent integer overflows in the
// protocol buffers implementation, as well as to prevent servers from
// allocating enormous amounts of memory to hold parsed messages, the
// maximum message length should be limited to the shortest length that
// will not harm usability. The theoretical shortest message that could
// cause integer overflows is 512MB. The default limit is 64MB. Apps
// should set shorter limits if possible. If warning_threshold is not -1,
// a warning will be printed to stderr after warning_threshold bytes are
// read. An error will always be printed to stderr if the limit is
// reached.
//
// This is unrelated to PushLimit()/PopLimit().
//
// Hint: If you are reading this because your program is printing a
// warning about dangerously large protocol messages, you may be
// confused about what to do next. The best option is to change your
// design such that excessively large messages are not necessary.
// For example, try to design file formats to consist of many small
// messages rather than a single large one. If this is infeasible,
// you will need to increase the limit. Chances are, though, that
// your code never constructs a CodedInputStream on which the limit
// can be set. You probably parse messages by calling things like
// Message::ParseFromString(). In this case, you will need to change
// your code to instead construct some sort of ZeroCopyInputStream
// (e.g. an ArrayInputStream), construct a CodedInputStream around
// that, then call Message::ParseFromCodedStream() instead. Then
// you can adjust the limit. Yes, it's more work, but you're doing
// something unusual.
void SetTotalBytesLimit(int total_bytes_limit, int warning_threshold);

// Recursion Limit -------------------------------------------------
// To prevent corrupt or malicious messages from causing stack overflows,
// we must keep track of the depth of recursion when parsing embedded
// messages and groups. CodedInputStream keeps track of this because it
// is the only object that is passed down the stack during parsing.

// Sets the maximum recursion depth. The default is 64.
void SetRecursionLimit(int limit);

// Increments the current recursion depth. Returns true if the depth is
// under the limit, false if it has gone over.
bool IncrementRecursionDepth();

// Decrements the recursion depth.
void DecrementRecursionDepth();

// Extension Registry ----------------------------------------------
// ADVANCED USAGE: 99.9% of people can ignore this section.
//
// By default, when parsing extensions, the parser looks for extension
// definitions in the pool which owns the outer message's Descriptor.
// However, you may call SetExtensionRegistry() to provide an alternative
// pool instead. This makes it possible, for example, to parse a message
// using a generated class, but represent some extensions using
// DynamicMessage.

// Set the pool used to look up extensions. Most users do not need to call
// this as the correct pool will be chosen automatically.
//
// WARNING: It is very easy to misuse this. Carefully read the requirements
// below. Do not use this unless you are sure you need it. Almost no one
// does.
//
// Let's say you are parsing a message into message object m, and you want
// to take advantage of SetExtensionRegistry(). You must follow these
// requirements:
//
// The given DescriptorPool must contain m->GetDescriptor(). It is not
// sufficient for it to simply contain a descriptor that has the same name
// and content -- it must be the *exact object*. In other words:
// assert(pool->FindMessageTypeByName(m->GetDescriptor()->full_name()) ==
// m->GetDescriptor());
// There are two ways to satisfy this requirement:
// 1) Use m->GetDescriptor()->pool() as the pool. This is generally useless
// because this is the pool that would be used anyway if you didn't call
// SetExtensionRegistry() at all.
// 2) Use a DescriptorPool which has m->GetDescriptor()->pool() as an
// "underlay". Read the documentation for DescriptorPool for more
// information about underlays.
//
// You must also provide a MessageFactory. This factory will be used to
// construct Message objects representing extensions. The factory's
// GetPrototype() MUST return non-NULL for any Descriptor which can be found
// through the provided pool.
//
// If the provided factory might return instances of protocol-compiler-
// generated (i.e. compiled-in) types, or if the outer message object m is
// a generated type, then the given factory MUST have this property: If
// GetPrototype() is given a Descriptor which resides in
// DescriptorPool::generated_pool(), the factory MUST return the same
// prototype which MessageFactory::generated_factory() would return. That
// is, given a descriptor for a generated type, the factory must return an
// instance of the generated class (NOT DynamicMessage). However, when
// given a descriptor for a type that is NOT in generated_pool, the factory
// is free to return any implementation.
//
// The reason for this requirement is that generated sub-objects may be
// accessed via the standard (non-reflection) extension accessor methods,
// and these methods will down-cast the object to the generated class type.
// If the object is not actually of that type, the results would be undefined.
// On the other hand, if an extension is not compiled in, then there is no
// way the code could end up accessing it via the standard accessors -- the
// only way to access the extension is via reflection. When using reflection,
// DynamicMessage and generated messages are indistinguishable, so it's fine
// if these objects are represented using DynamicMessage.
//
// Using DynamicMessageFactory on which you have called
// SetDelegateToGeneratedFactory(true) should be sufficient to satisfy the
// above requirement.
//
// If either pool or factory is NULL, both must be NULL.
//
// Note that this feature is ignored when parsing "lite" messages as they do
// not have descriptors.
void SetExtensionRegistry(DescriptorPool* pool, MessageFactory* factory);

// Get the DescriptorPool set via SetExtensionRegistry(), or NULL if no pool
// has been provided.
const DescriptorPool* GetExtensionPool();

// Get the MessageFactory set via SetExtensionRegistry(), or NULL if no
// factory has been provided.
MessageFactory* GetExtensionFactory();

private:
GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CodedInputStream);

ZeroCopyInputStream* input_;
const uint8* buffer_;
const uint8* buffer_end_; // pointer to the end of the buffer.
int total_bytes_read_; // total bytes read from input_, including
// the current buffer

// If total_bytes_read_ surpasses INT_MAX, we record the extra bytes here
// so that we can BackUp() on destruction.
int overflow_bytes_;

// LastTagWas() stuff.
uint32 last_tag_; // result of last ReadTag().

// This is set true by ReadTag{Fallback/Slow}() if it is called when exactly
// at EOF, or by ExpectAtEnd() when it returns true. This happens when we
// reach the end of a message and attempt to read another tag.
bool legitimate_message_end_;

// See EnableAliasing().
bool aliasing_enabled_;

// Limits
Limit current_limit_; // if position = -1, no limit is applied

// For simplicity, if the current buffer crosses a limit (either a normal
// limit created by PushLimit() or the total bytes limit), buffer_size_
// only tracks the number of bytes before that limit. This field
// contains the number of bytes after it. Note that this implies that if
// buffer_size_ == 0 and buffer_size_after_limit_ > 0, we know we've
// hit a limit. However, if both are zero, it doesn't necessarily mean
// we aren't at a limit -- the buffer may have ended exactly at the limit.
int buffer_size_after_limit_;

// Maximum number of bytes to read, period. This is unrelated to
// current_limit_. Set using SetTotalBytesLimit().
int total_bytes_limit_;
int total_bytes_warning_threshold_;

// Current recursion depth, controlled by IncrementRecursionDepth() and
// DecrementRecursionDepth().
int recursion_depth_;
// Recursion depth limit, set by SetRecursionLimit().
int recursion_limit_;

// See SetExtensionRegistry().
const DescriptorPool* extension_pool_;
MessageFactory* extension_factory_;

// Private member functions.

// Advance the buffer by a given number of bytes.
void Advance(int amount);

// Back up input_ to the current buffer position.
void BackUpInputToCurrentPosition();

// Recomputes the value of buffer_size_after_limit_. Must be called after
// current_limit_ or total_bytes_limit_ changes.
void RecomputeBufferLimits();

// Writes an error message saying that we hit total_bytes_limit_.
void PrintTotalBytesLimitError();

// Called when the buffer runs out to request more data. Implies an
// Advance(BufferSize()).
bool Refresh();

// When parsing varints, we optimize for the common case of small values, and
// then optimize for the case when the varint fits within the current buffer
// piece. The Fallback method is used when we can't use the one-byte
// optimization. The Slow method is yet another fallback when the buffer is
// not large enough. Making the slow path out-of-line speeds up the common
// case by 10-15%. The slow path is fairly uncommon: it only triggers when a
// message crosses multiple buffers.
bool ReadVarint32Fallback(uint32* value);
bool ReadVarint64Fallback(uint64* value);
bool ReadVarint32Slow(uint32* value);
bool ReadVarint64Slow(uint64* value);
bool ReadLittleEndian32Fallback(uint32* value);
bool ReadLittleEndian64Fallback(uint64* value);
// Fallback/slow methods for reading tags. These do not update last_tag_,
// but will set legitimate_message_end_ if we are at the end of the input
// stream.
uint32 ReadTagFallback();
uint32 ReadTagSlow();
bool ReadStringFallback(string* buffer, int size);

// Return the size of the buffer.
int BufferSize() const;

static const int kDefaultTotalBytesLimit = 64 << 20; // 64MB

static const int kDefaultTotalBytesWarningThreshold = 32 << 20; // 32MB
static const int kDefaultRecursionLimit = 64;
};

// Class which encodes and writes binary data which is composed of varint-
// encoded integers and fixed-width pieces. Wraps a ZeroCopyOutputStream.
// Most users will not need to deal with CodedOutputStream.
//
// Most methods of CodedOutputStream which return a bool return false if an
// underlying I/O error occurs. Once such a failure occurs, the
// CodedOutputStream is broken and is no longer useful. The Write* methods do
// not return the stream status, but will invalidate the stream if an error
// occurs. The client can probe HadError() to determine the status.
//
// Note that every method of CodedOutputStream which writes some data has
// a corresponding static "ToArray" version. These versions write directly
// to the provided buffer, returning a pointer past the last written byte.
// They require that the buffer has sufficient capacity for the encoded data.
// This allows an optimization where we check if an output stream has enough
// space for an entire message before we start writing and, if there is, we
// call only the ToArray methods to avoid doing bound checks for each
// individual value.
// i.e., in the example above:
//
// CodedOutputStream coded_output = new CodedOutputStream(raw_output);
// int magic_number = 1234;
// char text[] = "Hello world!";
//
// int coded_size = sizeof(magic_number) +
// CodedOutputStream::VarintSize32(strlen(text)) +
// strlen(text);
//
// uint8* buffer =
// coded_output->GetDirectBufferForNBytesAndAdvance(coded_size);
// if (buffer != NULL) {
// // The output stream has enough space in the buffer: write directly to
// // the array.
// buffer = CodedOutputStream::WriteLittleEndian32ToArray(magic_number,
// buffer);
// buffer = CodedOutputStream::WriteVarint32ToArray(strlen(text), buffer);
// buffer = CodedOutputStream::WriteRawToArray(text, strlen(text), buffer);
// } else {
// // Make bound-checked writes, which will ask the underlying stream for
// // more space as needed.
// coded_output->WriteLittleEndian32(magic_number);
// coded_output->WriteVarint32(strlen(text));
// coded_output->WriteRaw(text, strlen(text));
// }
//
// delete coded_output;
class LIBPROTOBUF_EXPORT CodedOutputStream {
public:
// Create an CodedOutputStream that writes to the given ZeroCopyOutputStream.
explicit CodedOutputStream(ZeroCopyOutputStream* output);

// Destroy the CodedOutputStream and position the underlying
// ZeroCopyOutputStream immediately after the last byte written.
~CodedOutputStream();

// Skips a number of bytes, leaving the bytes unmodified in the underlying
// buffer. Returns false if an underlying write error occurs. This is
// mainly useful with GetDirectBufferPointer().
bool Skip(int count);

// Sets *data to point directly at the unwritten part of the
// CodedOutputStream's underlying buffer, and *size to the size of that
// buffer, but does not advance the stream's current position. This will
// always either produce a non-empty buffer or return false. If the caller
// writes any data to this buffer, it should then call Skip() to skip over
// the consumed bytes. This may be useful for implementing external fast
// serialization routines for types of data not covered by the
// CodedOutputStream interface.
bool GetDirectBufferPointer(void** data, int* size);

// If there are at least "size" bytes available in the current buffer,
// returns a pointer directly into the buffer and advances over these bytes.
// The caller may then write directly into this buffer (e.g. using the
// *ToArray static methods) rather than go through CodedOutputStream. If
// there are not enough bytes available, returns NULL. The return pointer is
// invalidated as soon as any other non-const method of CodedOutputStream
// is called.
inline uint8* GetDirectBufferForNBytesAndAdvance(int size);

// Write raw bytes, copying them from the given buffer.
void WriteRaw(const void* buffer, int size);
// Like WriteRaw() but writing directly to the target array.
// This is _not_ inlined, as the compiler often optimizes memcpy into inline
// copy loops. Since this gets called by every field with string or bytes
// type, inlining may lead to a significant amount of code bloat, with only a
// minor performance gain.
static uint8* WriteRawToArray(const void* buffer, int size, uint8* target);

// Equivalent to WriteRaw(str.data(), str.size()).
void WriteString(const string& str);
// Like WriteString() but writing directly to the target array.
static uint8* WriteStringToArray(const string& str, uint8* target);


// Write a 32-bit little-endian integer.
void WriteLittleEndian32(uint32 value);
// Like WriteLittleEndian32() but writing directly to the target array.
static uint8* WriteLittleEndian32ToArray(uint32 value, uint8* target);
// Write a 64-bit little-endian integer.
void WriteLittleEndian64(uint64 value);
// Like WriteLittleEndian64() but writing directly to the target array.
static uint8* WriteLittleEndian64ToArray(uint64 value, uint8* target);

// Write an unsigned integer with Varint encoding. Writing a 32-bit value
// is equivalent to casting it to uint64 and writing it as a 64-bit value,
// but may be more efficient.
void WriteVarint32(uint32 value);
// Like WriteVarint32() but writing directly to the target array.
static uint8* WriteVarint32ToArray(uint32 value, uint8* target);
// Write an unsigned integer with Varint encoding.
void WriteVarint64(uint64 value);
// Like WriteVarint64() but writing directly to the target array.
static uint8* WriteVarint64ToArray(uint64 value, uint8* target);

// Equivalent to WriteVarint32() except when the value is negative,
// in which case it must be sign-extended to a full 10 bytes.
void WriteVarint32SignExtended(int32 value);
// Like WriteVarint32SignExtended() but writing directly to the target array.
static uint8* WriteVarint32SignExtendedToArray(int32 value, uint8* target);

// This is identical to WriteVarint32(), but optimized for writing tags.
// In particular, if the input is a compile-time constant, this method
// compiles down to a couple instructions.
// Always inline because otherwise the aformentioned optimization can't work,
// but GCC by default doesn't want to inline this.
void WriteTag(uint32 value);
// Like WriteTag() but writing directly to the target array.
static uint8* WriteTagToArray(
uint32 value, uint8* target) GOOGLE_ATTRIBUTE_ALWAYS_INLINE;

// Returns the number of bytes needed to encode the given value as a varint.
static int VarintSize32(uint32 value);
// Returns the number of bytes needed to encode the given value as a varint.
static int VarintSize64(uint64 value);

// If negative, 10 bytes. Otheriwse, same as VarintSize32().
static int VarintSize32SignExtended(int32 value);

// Compile-time equivalent of VarintSize32().
template <uint32 Value>
struct StaticVarintSize32 {
static const int value =
(Value < (1 << 7))
? 1
: (Value < (1 << 14))
? 2
: (Value < (1 << 21))
? 3
: (Value < (1 << 28))
? 4
: 5;
};

// Returns the total number of bytes written since this object was created.
inline int ByteCount() const;

// Returns true if there was an underlying I/O error since this object was
// created.
bool HadError() const { return had_error_; }

private:
GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CodedOutputStream);

ZeroCopyOutputStream* output_;
uint8* buffer_;
int buffer_size_;
int total_bytes_; // Sum of sizes of all buffers seen so far.
bool had_error_; // Whether an error occurred during output.

// Advance the buffer by a given number of bytes.
void Advance(int amount);

// Called when the buffer runs out to request more data. Implies an
// Advance(buffer_size_).
bool Refresh();

static uint8* WriteVarint32FallbackToArray(uint32 value, uint8* target);

// Always-inlined versions of WriteVarint* functions so that code can be
// reused, while still controlling size. For instance, WriteVarint32ToArray()
// should not directly call this: since it is inlined itself, doing so
// would greatly increase the size of generated code. Instead, it should call
// WriteVarint32FallbackToArray. Meanwhile, WriteVarint32() is already
// out-of-line, so it should just invoke this directly to avoid any extra
// function call overhead.
static uint8* WriteVarint32FallbackToArrayInline(
uint32 value, uint8* target) GOOGLE_ATTRIBUTE_ALWAYS_INLINE;
static uint8* WriteVarint64ToArrayInline(
uint64 value, uint8* target) GOOGLE_ATTRIBUTE_ALWAYS_INLINE;

static int VarintSize32Fallback(uint32 value);
};

// inline methods ====================================================
// The vast majority of varints are only one byte. These inline
// methods optimize for that case.

inline bool CodedInputStream::ReadVarint32(uint32* value) {
if (GOOGLE_PREDICT_TRUE(buffer_ < buffer_end_) && *buffer_ < 0x80) {
*value = *buffer_;
Advance(1);
return true;
} else {
return ReadVarint32Fallback(value);
}
}

inline bool CodedInputStream::ReadVarint64(uint64* value) {
if (GOOGLE_PREDICT_TRUE(buffer_ < buffer_end_) && *buffer_ < 0x80) {
*value = *buffer_;
Advance(1);
return true;
} else {
return ReadVarint64Fallback(value);
}
}

// static
inline const uint8* CodedInputStream::ReadLittleEndian32FromArray(
const uint8* buffer,
uint32* value) {
#if defined(PROTOBUF_LITTLE_ENDIAN)
memcpy(value, buffer, sizeof(*value));
return buffer + sizeof(*value);
#else
*value = (static_cast<uint32>(buffer[0]) ) |
(static_cast<uint32>(buffer[1]) << 8) |
(static_cast<uint32>(buffer[2]) << 16) |
(static_cast<uint32>(buffer[3]) << 24);
return buffer + sizeof(*value);
#endif
}
// static
inline const uint8* CodedInputStream::ReadLittleEndian64FromArray(
const uint8* buffer,
uint64* value) {
#if defined(PROTOBUF_LITTLE_ENDIAN)
memcpy(value, buffer, sizeof(*value));
return buffer + sizeof(*value);
#else
uint32 part0 = (static_cast<uint32>(buffer[0]) ) |
(static_cast<uint32>(buffer[1]) << 8) |
(static_cast<uint32>(buffer[2]) << 16) |
(static_cast<uint32>(buffer[3]) << 24);
uint32 part1 = (static_cast<uint32>(buffer[4]) ) |
(static_cast<uint32>(buffer[5]) << 8) |
(static_cast<uint32>(buffer[6]) << 16) |
(static_cast<uint32>(buffer[7]) << 24);
*value = static_cast<uint64>(part0) |
(static_cast<uint64>(part1) << 32);
return buffer + sizeof(*value);
#endif
}

inline bool CodedInputStream::ReadLittleEndian32(uint32* value) {
#if defined(PROTOBUF_LITTLE_ENDIAN)
if (GOOGLE_PREDICT_TRUE(BufferSize() >= static_cast<int>(sizeof(*value)))) {
memcpy(value, buffer_, sizeof(*value));
Advance(sizeof(*value));
return true;
} else {
return ReadLittleEndian32Fallback(value);
}
#else
return ReadLittleEndian32Fallback(value);
#endif
}

inline bool CodedInputStream::ReadLittleEndian64(uint64* value) {
#if defined(PROTOBUF_LITTLE_ENDIAN)
if (GOOGLE_PREDICT_TRUE(BufferSize() >= static_cast<int>(sizeof(*value)))) {
memcpy(value, buffer_, sizeof(*value));
Advance(sizeof(*value));
return true;
} else {
return ReadLittleEndian64Fallback(value);
}
#else
return ReadLittleEndian64Fallback(value);
#endif
}

inline uint32 CodedInputStream::ReadTag() {
if (GOOGLE_PREDICT_TRUE(buffer_ < buffer_end_) && buffer_[0] < 0x80) {
last_tag_ = buffer_[0];
Advance(1);
return last_tag_;
} else {
last_tag_ = ReadTagFallback();
return last_tag_;
}
}

inline bool CodedInputStream::LastTagWas(uint32 expected) {
return last_tag_ == expected;
}

inline bool CodedInputStream::ConsumedEntireMessage() {
return legitimate_message_end_;
}

inline bool CodedInputStream::ExpectTag(uint32 expected) {
if (expected < (1 << 7)) {
if (GOOGLE_PREDICT_TRUE(buffer_ < buffer_end_) && buffer_[0] == expected) {
Advance(1);
return true;
} else {
return false;
}
} else if (expected < (1 << 14)) {
if (GOOGLE_PREDICT_TRUE(BufferSize() >= 2) &&
buffer_[0] == static_cast<uint8>(expected | 0x80) &&
buffer_[1] == static_cast<uint8>(expected >> 7)) {
Advance(2);
return true;
} else {
return false;
}
} else {
// Don't bother optimizing for larger values.
return false;
}
}

inline const uint8* CodedInputStream::ExpectTagFromArray(
const uint8* buffer, uint32 expected) {
if (expected < (1 << 7)) {
if (buffer[0] == expected) {
return buffer + 1;
}
} else if (expected < (1 << 14)) {
if (buffer[0] == static_cast<uint8>(expected | 0x80) &&
buffer[1] == static_cast<uint8>(expected >> 7)) {
return buffer + 2;
}
}
return NULL;
}

inline void CodedInputStream::GetDirectBufferPointerInline(const void** data,
int* size) {
*data = buffer_;
*size = buffer_end_ - buffer_;
}

inline bool CodedInputStream::ExpectAtEnd() {
// If we are at a limit we know no more bytes can be read. Otherwise, it's
// hard to say without calling Refresh(), and we'd rather not do that.

if (buffer_ == buffer_end_ && buffer_size_after_limit_ != 0) {
last_tag_ = 0; // Pretend we called ReadTag()...
legitimate_message_end_ = true; // ... and it hit EOF.
return true;
} else {
return false;
}
}

inline uint8* CodedOutputStream::GetDirectBufferForNBytesAndAdvance(int size) {
if (buffer_size_ < size) {
return NULL;
} else {
uint8* result = buffer_;
Advance(size);
return result;
}
}

inline uint8* CodedOutputStream::WriteVarint32ToArray(uint32 value,
uint8* target) {
if (value < 0x80) {
*target = value;
return target + 1;
} else {
return WriteVarint32FallbackToArray(value, target);
}
}

inline void CodedOutputStream::WriteVarint32SignExtended(int32 value) {
if (value < 0) {
WriteVarint64(static_cast<uint64>(value));
} else {
WriteVarint32(static_cast<uint32>(value));
}
}

inline uint8* CodedOutputStream::WriteVarint32SignExtendedToArray(
int32 value, uint8* target) {
if (value < 0) {
return WriteVarint64ToArray(static_cast<uint64>(value), target);
} else {
return WriteVarint32ToArray(static_cast<uint32>(value), target);
}
}

inline uint8* CodedOutputStream::WriteLittleEndian32ToArray(uint32 value,
uint8* target) {
#if defined(PROTOBUF_LITTLE_ENDIAN)
memcpy(target, &value, sizeof(value));
#else
target[0] = static_cast<uint8>(value);
target[1] = static_cast<uint8>(value >> 8);
target[2] = static_cast<uint8>(value >> 16);
target[3] = static_cast<uint8>(value >> 24);
#endif
return target + sizeof(value);
}

inline uint8* CodedOutputStream::WriteLittleEndian64ToArray(uint64 value,
uint8* target) {
#if defined(PROTOBUF_LITTLE_ENDIAN)
memcpy(target, &value, sizeof(value));
#else
uint32 part0 = static_cast<uint32>(value);
uint32 part1 = static_cast<uint32>(value >> 32);

target[0] = static_cast<uint8>(part0);
target[1] = static_cast<uint8>(part0 >> 8);
target[2] = static_cast<uint8>(part0 >> 16);
target[3] = static_cast<uint8>(part0 >> 24);
target[4] = static_cast<uint8>(part1);
target[5] = static_cast<uint8>(part1 >> 8);
target[6] = static_cast<uint8>(part1 >> 16);
target[7] = static_cast<uint8>(part1 >> 24);
#endif
return target + sizeof(value);
}

inline void CodedOutputStream::WriteTag(uint32 value) {
WriteVarint32(value);
}

inline uint8* CodedOutputStream::WriteTagToArray(
uint32 value, uint8* target) {
if (value < (1 << 7)) {
target[0] = value;
return target + 1;
} else if (value < (1 << 14)) {
target[0] = static_cast<uint8>(value | 0x80);
target[1] = static_cast<uint8>(value >> 7);
return target + 2;
} else {
return WriteVarint32FallbackToArray(value, target);
}
}

inline int CodedOutputStream::VarintSize32(uint32 value) {
if (value < (1 << 7)) {
return 1;
} else {
return VarintSize32Fallback(value);
}
}

inline int CodedOutputStream::VarintSize32SignExtended(int32 value) {
if (value < 0) {
return 10; // TODO(kenton): Make this a symbolic constant.
} else {
return VarintSize32(static_cast<uint32>(value));
}
}

inline void CodedOutputStream::WriteString(const string& str) {
WriteRaw(str.data(), static_cast<int>(str.size()));
}

inline uint8* CodedOutputStream::WriteStringToArray(
const string& str, uint8* target) {
return WriteRawToArray(str.data(), static_cast<int>(str.size()), target);
}

inline int CodedOutputStream::ByteCount() const {
return total_bytes_ - buffer_size_;
}

inline void CodedInputStream::Advance(int amount) {
buffer_ += amount;
}

inline void CodedOutputStream::Advance(int amount) {
buffer_ += amount;
buffer_size_ -= amount;
}

inline void CodedInputStream::SetRecursionLimit(int limit) {
recursion_limit_ = limit;
}

inline bool CodedInputStream::IncrementRecursionDepth() {
++recursion_depth_;
return recursion_depth_ <= recursion_limit_;
}

inline void CodedInputStream::DecrementRecursionDepth() {
if (recursion_depth_ > 0) --recursion_depth_;
}

inline void CodedInputStream::SetExtensionRegistry(DescriptorPool* pool,
MessageFactory* factory) {
extension_pool_ = pool;
extension_factory_ = factory;
}

inline const DescriptorPool* CodedInputStream::GetExtensionPool() {
return extension_pool_;
}

inline MessageFactory* CodedInputStream::GetExtensionFactory() {
return extension_factory_;
}

inline int CodedInputStream::BufferSize() const {
return buffer_end_ - buffer_;
}

inline CodedInputStream::CodedInputStream(ZeroCopyInputStream* input)
: input_(input),
buffer_(NULL),
buffer_end_(NULL),
total_bytes_read_(0),
overflow_bytes_(0),
last_tag_(0),
legitimate_message_end_(false),
aliasing_enabled_(false),
current_limit_(kint32max),
buffer_size_after_limit_(0),
total_bytes_limit_(kDefaultTotalBytesLimit),
total_bytes_warning_threshold_(kDefaultTotalBytesWarningThreshold),
recursion_depth_(0),
recursion_limit_(kDefaultRecursionLimit),
extension_pool_(NULL),
extension_factory_(NULL) {
// Eagerly Refresh() so buffer space is immediately available.
Refresh();
}

inline CodedInputStream::CodedInputStream(const uint8* buffer, int size)
: input_(NULL),
buffer_(buffer),
buffer_end_(buffer + size),
total_bytes_read_(size),
overflow_bytes_(0),
last_tag_(0),
legitimate_message_end_(false),
aliasing_enabled_(false),
current_limit_(size),
buffer_size_after_limit_(0),
total_bytes_limit_(kDefaultTotalBytesLimit),
total_bytes_warning_threshold_(kDefaultTotalBytesWarningThreshold),
recursion_depth_(0),
recursion_limit_(kDefaultRecursionLimit),
extension_pool_(NULL),
extension_factory_(NULL) {
// Note that setting current_limit_ == size is important to prevent some
// code paths from trying to access input_ and segfaulting.
}

inline CodedInputStream::~CodedInputStream() {
if (input_ != NULL) {
BackUpInputToCurrentPosition();
}
}

} // namespace io
} // namespace protobuf


#if defined(_MSC_VER) && _MSC_VER >= 1300
#pragma runtime_checks("c", restore)
#endif // _MSC_VER

} // namespace google
#endif // GOOGLE_PROTOBUF_IO_CODED_STREAM_H__

Change log

r410 by pli...@google.com on Mar 2, 2012   Diff
Remove static initializer in
wire_format_lite.cc.
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Older revisions

r354 by liuj...@google.com on Dec 5, 2010   Diff
Fix issues: 200 202 211 215 237 246.
r352 by liuj...@google.com on Nov 30, 2010   Diff
Fix byte encoding macros.
r351 by ken...@google.com on Nov 30, 2010   Diff
Add some explicit casts to eliminate
some warnings as described in issue 83
comment 17.
All revisions of this file

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