brpc/include/json2pb/zero_copy_stream_reader.h
2022-12-14 19:05:52 +08:00

86 lines
2.4 KiB
C++

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
#ifndef BRPC_JSON2PB_ZERO_COPY_STREAM_READER_H
#define BRPC_JSON2PB_ZERO_COPY_STREAM_READER_H
#include <google/protobuf/io/zero_copy_stream.h> // ZeroCopyInputStream
namespace json2pb {
class ZeroCopyStreamReader {
public:
typedef char Ch;
ZeroCopyStreamReader(google::protobuf::io::ZeroCopyInputStream *stream)
: _data(NULL), _data_size(0), _nread(0), _stream(stream) {
}
//Take a charactor and return its address.
const char* PeekAddr() {
if (!ReadBlockTail()) {
return _data;
}
while (_stream->Next((const void **)&_data, &_data_size)) {
if (!ReadBlockTail()) {
return _data;
}
}
return NULL;
}
const char* TakeWithAddr() {
const char* c = PeekAddr();
if (c) {
++_nread;
--_data_size;
return _data++;
}
return NULL;
}
char Take() {
const char* c = PeekAddr();
if (c) {
++_nread;
--_data_size;
++_data;
return *c;
}
return '\0';
}
char Peek() {
const char* c = PeekAddr();
return (c ? *c : '\0');
}
//Tell whether read the end of this block.
bool ReadBlockTail() {
return !_data_size;
}
size_t Tell() { return _nread; }
void Put(char) {}
void Flush() {}
char *PutBegin() { return NULL; }
size_t PutEnd(char *) { return 0; }
private:
const char *_data;
int _data_size;
size_t _nread;
google::protobuf::io::ZeroCopyInputStream *_stream;
};
} // namespace json2pb
#endif //BRPC_JSON2PB_ZERO_COPY_STREAM_READER_H