chrome/utility/safe_browsing/mac/read_stream.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/utility/safe_browsing/mac/read_stream.h"
   6
   7 #include <string.h>
   8 #include <unistd.h>
   9
  10 #include <algorithm>
  11
  12 #include "base/logging.h"
  13 #include "base/posix/eintr_wrapper.h"
  14
  15 namespace safe_browsing {
  16 namespace dmg {
  17
  18 bool ReadStream::ReadExact(uint8_t* data, size_t size) {
  19   size_t bytes_read = 0;
  20   return Read(data, size, &bytes_read) && bytes_read == size;
  21 }
  22
  23 FileReadStream::FileReadStream(int fd) : fd_(fd) {}
  24
  25 FileReadStream::~FileReadStream() {}
  26
  27 bool FileReadStream::Read(uint8_t* data, size_t size, size_t* bytes_read) {
  28   *bytes_read = 0;
  29   ssize_t signed_bytes_read = HANDLE_EINTR(read(fd_, data, size));
  30   if (signed_bytes_read < 0)
  31     return false;
  32   *bytes_read = signed_bytes_read;
  33   return true;
  34 }
  35
  36 off_t FileReadStream::Seek(off_t offset, int whence) {
  37   return lseek(fd_, offset, whence);
  38 }
  39
  40 MemoryReadStream::MemoryReadStream(const uint8_t* data, size_t size)
  41     : data_(data), size_(size), offset_(0) {}
  42
  43 MemoryReadStream::~MemoryReadStream() {}
  44
  45 bool MemoryReadStream::Read(uint8_t* data, size_t size, size_t* bytes_read) {
  46   *bytes_read = 0;
  47
  48   if (data_ == nullptr)
  49     return false;
  50
  51   size_t bytes_remaining = size_ - offset_;
  52   if (bytes_remaining == 0)
  53     return true;
  54
  55   *bytes_read = std::min(size, bytes_remaining);
  56   memcpy(data, data_ + offset_, *bytes_read);
  57   offset_ += *bytes_read;
  58   return true;
  59 }
  60
  61 off_t MemoryReadStream::Seek(off_t offset, int whence) {
  62   switch (whence) {
  63     case SEEK_SET:
  64       offset_ = offset;
  65       break;
  66     case SEEK_CUR:
  67       offset_ += offset;
  68       break;
  69     case SEEK_END:
  70       offset_ = size_ + offset;
  71       break;
  72     default:
  73       NOTREACHED();
  74       return -1;
  75   }
  76   if (static_cast<size_t>(offset_) >= size_)
  77     offset_ = size_;
  78   return offset_;
  79 }
  80
  81 }  // namespace dmg
  82 }  // namespace safe_browsing