net/der/input.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 "base/logging.h"
   6 #include "net/der/input.h"
   7
   8 namespace net {
   9
  10 namespace der {
  11
  12 Input::Input() : data_(nullptr), len_(0) {
  13 }
  14
  15 Input::Input(const uint8_t* data, size_t len) : data_(data), len_(len) {
  16 }
  17
  18 Input::Input(const std::string& s)
  19     : data_(reinterpret_cast<const uint8_t*>(s.data())), len_(s.size()) {
  20 }
  21
  22 ByteReader::ByteReader(const Input& in)
  23     : data_(in.UnsafeData()), len_(in.Length()) {
  24 }
  25
  26 bool ByteReader::ReadByte(uint8_t* byte_p) {
  27   if (!HasMore())
  28     return false;
  29   *byte_p = *data_;
  30   Advance(1);
  31   return true;
  32 }
  33
  34 bool ByteReader::ReadBytes(size_t len, Input* out) {
  35   if (len > len_)
  36     return false;
  37   *out = Input(data_, len);
  38   Advance(len);
  39   return true;
  40 }
  41
  42 // Returns whether there is any more data to be read.
  43 bool ByteReader::HasMore() {
  44   return len_ > 0;
  45 }
  46
  47 Mark ByteReader::NewMark() {
  48   return Mark(data_);
  49 }
  50
  51 bool ByteReader::AdvanceToMark(Mark mark) {
  52   if (mark.ptr_ < data_)
  53     return false;
  54   // mark.ptr_ >= data_, so no concern of integer underflow here.
  55   size_t advance_len = mark.ptr_ - data_;
  56   if (advance_len > len_)
  57     return false;
  58   Advance(advance_len);
  59   return true;
  60 }
  61
  62 bool ByteReader::ReadToMark(Mark mark, Input* out) {
  63   if (mark.ptr_ < data_)
  64     return false;
  65   // mark.ptr_ >= data_, so no concern of integer underflow here.
  66   size_t len = mark.ptr_ - data_;
  67   return ReadBytes(len, out);
  68 }
  69
  70 void ByteReader::Advance(size_t len) {
  71   CHECK_LE(len, len_);
  72   data_ += len;
  73   len_ -= len;
  74 }
  75
  76 Mark Mark::NullMark() {
  77   return Mark();
  78 }
  79
  80 bool Mark::IsEmpty() {
  81   return ptr_ == nullptr;
  82 }
  83
  84 Mark::Mark(const uint8_t* ptr) : ptr_(ptr) {
  85 }
  86
  87 Mark::Mark() : ptr_(nullptr) {
  88 }
  89
  90 }  // namespace der
  91
  92 }  // namespace net