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// Copyright (c) 2012 Baidu, Inc.
//
// Licensed 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.
// Author: Ge,Jun (gejun@baidu.com)
// Date: Thu Nov 22 13:57:56 CST 2012
#include "butil/macros.h"
#include "butil/zero_copy_stream_as_streambuf.h"
namespace butil {
BAIDU_CASSERT(sizeof(std::streambuf::char_type) == sizeof(char),
only_support_char);
int ZeroCopyStreamAsStreamBuf::overflow(int ch) {
if (ch == std::streambuf::traits_type::eof()) {
return ch;
}
void* block = NULL;
int size = 0;
if (_zero_copy_stream->Next(&block, &size)) {
setp((char*)block, (char*)block + size);
// if size == 1, this function will call overflow again.
return sputc(ch);
} else {
setp(NULL, NULL);
return std::streambuf::traits_type::eof();
}
}
int ZeroCopyStreamAsStreamBuf::sync() {
// data are already in IOBuf.
return 0;
}
ZeroCopyStreamAsStreamBuf::~ZeroCopyStreamAsStreamBuf() {
shrink();
}
void ZeroCopyStreamAsStreamBuf::shrink() {
if (pbase() != NULL) {
_zero_copy_stream->BackUp(epptr() - pptr());
setp(NULL, NULL);
}
}
std::streampos ZeroCopyStreamAsStreamBuf::seekoff(
std::streamoff off,
std::ios_base::seekdir way,
std::ios_base::openmode which) {
if (off == 0 && way == std::ios_base::cur) {
return _zero_copy_stream->ByteCount() - (epptr() - pptr());
}
return (std::streampos)(std::streamoff)-1;
}
} // namespace butil