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