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// Copyright (c) 2009, 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.
#include <stdint.h>
#include <assert.h>
#include <string.h>
#include "breakpad/linux/linux_syscall_support.h"
namespace google_breakpad {
// A class for reading a file, line by line, without using fopen/fgets or other
// functions which may allocate memory.
class LineReader {
public:
LineReader(int fd)
: fd_(fd),
hit_eof_(false),
buf_used_(0) {
}
// The maximum length of a line.
static const size_t kMaxLineLen = 512;
// Return the next line from the file.
// line: (output) a pointer to the start of the line. The line is NUL
// terminated.
// len: (output) the length of the line (not inc the NUL byte)
//
// Returns true iff successful (false on EOF).
//
// One must call |PopLine| after this function, otherwise you'll continue to
// get the same line over and over.
bool GetNextLine(const char **line, unsigned *len) {
for (;;) {
if (buf_used_ == 0 && hit_eof_)
return false;
for (unsigned i = 0; i < buf_used_; ++i) {
if (buf_[i] == '\n' || buf_[i] == 0) {
buf_[i] = 0;
*len = i;
*line = buf_;
return true;
}
}
if (buf_used_ == sizeof(buf_)) {
// we scanned the whole buffer and didn't find an end-of-line marker.
// This line is too long to process.
return false;
}
// We didn't find any end-of-line terminators in the buffer. However, if
// this is the last line in the file it might not have one:
if (hit_eof_) {
assert(buf_used_);
// There's room for the NUL because of the buf_used_ == sizeof(buf_)
// check above.
buf_[buf_used_] = 0;
*len = buf_used_;
buf_used_ += 1; // since we appended the NUL.
*line = buf_;
return true;
}
// Otherwise, we should pull in more data from the file
const ssize_t n = sys_read(fd_, buf_ + buf_used_,
sizeof(buf_) - buf_used_);
if (n < 0) {
return false;
} else if (n == 0) {
hit_eof_ = true;
} else {
buf_used_ += n;
}
// At this point, we have either set the hit_eof_ flag, or we have more
// data to process...
}
}
void PopLine(unsigned len) {
// len doesn't include the NUL byte at the end.
assert(buf_used_ >= len + 1);
buf_used_ -= len + 1;
memmove(buf_, buf_ + len + 1, buf_used_);
}
private:
const int fd_;
bool hit_eof_;
unsigned buf_used_;
char buf_[kMaxLineLen];
};
} // namespace google_breakpad
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