1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17// Copied from system/extras/memory_replay/LineBuffer.cpp
18// TODO(ccross): find a way to share between libmemunreachable and memory_replay?
19
20#include <errno.h>
21#include <string.h>
22#include <unistd.h>
23
24#include "LineBuffer.h"
25
26namespace android {
27
28LineBuffer::LineBuffer(int fd, char* buffer, size_t buffer_len)
29    : fd_(fd), buffer_(buffer), buffer_len_(buffer_len) {}
30
31bool LineBuffer::GetLine(char** line, size_t* line_len) {
32  while (true) {
33    if (bytes_ > 0) {
34      char* newline = reinterpret_cast<char*>(memchr(buffer_ + start_, '\n', bytes_));
35      if (newline != nullptr) {
36        *newline = '\0';
37        *line = buffer_ + start_;
38        start_ = newline - buffer_ + 1;
39        bytes_ -= newline - *line + 1;
40        *line_len = newline - *line;
41        return true;
42      }
43    }
44    if (start_ > 0) {
45      // Didn't find anything, copy the current to the front of the buffer.
46      memmove(buffer_, buffer_ + start_, bytes_);
47      start_ = 0;
48    }
49    ssize_t bytes = TEMP_FAILURE_RETRY(read(fd_, buffer_ + bytes_, buffer_len_ - bytes_ - 1));
50    if (bytes <= 0) {
51      if (bytes_ > 0) {
52        // The read data might not contain a nul terminator, so add one.
53        buffer_[bytes_] = '\0';
54        *line = buffer_ + start_;
55        *line_len = bytes_;
56        bytes_ = 0;
57        start_ = 0;
58        return true;
59      }
60      return false;
61    }
62    bytes_ += bytes;
63  }
64}
65
66}  // namespace android
67