net/spdy/spdy_frame_reader.cc

   1 // Copyright (c) 2012 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 <limits>
   6
   7 #include "base/sys_byteorder.h"
   8 #include "net/spdy/spdy_frame_reader.h"
   9
  10 namespace net {
  11
  12 SpdyFrameReader::SpdyFrameReader(const char* data, const size_t len)
  13     : data_(data),
  14       len_(len),
  15       ofs_(0) {
  16 }
  17
  18 bool SpdyFrameReader::ReadUInt16(uint16* result) {
  19   // Make sure that we have the whole uint16.
  20   if (!CanRead(2)) {
  21     OnFailure();
  22     return false;
  23   }
  24
  25   // Read into result.
  26   *result = ntohs(*(reinterpret_cast<const uint16*>(data_ + ofs_)));
  27
  28   // Iterate.
  29   ofs_ += 2;
  30
  31   return true;
  32 }
  33
  34 bool SpdyFrameReader::ReadUInt32(uint32* result) {
  35   // Make sure that we have the whole uint32.
  36   if (!CanRead(4)) {
  37     OnFailure();
  38     return false;
  39   }
  40
  41   // Read into result.
  42   *result = ntohl(*(reinterpret_cast<const uint32*>(data_ + ofs_)));
  43
  44   // Iterate.
  45   ofs_ += 4;
  46
  47   return true;
  48 }
  49
  50 bool SpdyFrameReader::ReadStringPiece16(base::StringPiece* result) {
  51   // Read resultant length.
  52   uint16 result_len;
  53   if (!ReadUInt16(&result_len)) {
  54     // OnFailure() already called.
  55     return false;
  56   }
  57
  58   // Make sure that we have the whole string.
  59   if (!CanRead(result_len)) {
  60     OnFailure();
  61     return false;
  62   }
  63
  64   // Set result.
  65   result->set(data_ + ofs_, result_len);
  66
  67   // Iterate.
  68   ofs_ += result_len;
  69
  70   return true;
  71 }
  72
  73 bool SpdyFrameReader::ReadStringPiece32(base::StringPiece* result) {
  74   // Read resultant length.
  75   uint32 result_len;
  76   if (!ReadUInt32(&result_len)) {
  77     // OnFailure() already called.
  78     return false;
  79   }
  80
  81   // Make sure that we have the whole string.
  82   if (!CanRead(result_len)) {
  83     OnFailure();
  84     return false;
  85   }
  86
  87   // Set result.
  88   result->set(data_ + ofs_, result_len);
  89
  90   // Iterate.
  91   ofs_ += result_len;
  92
  93   return true;
  94 }
  95
  96 bool SpdyFrameReader::ReadBytes(void* result, size_t size) {
  97   // Make sure that we have enough data to read.
  98   if (!CanRead(size)) {
  99     OnFailure();
 100     return false;
 101   }
 102
 103   // Read into result.
 104   memcpy(result, data_ + ofs_, size);
 105
 106   // Iterate.
 107   ofs_ += size;
 108
 109   return true;
 110 }
 111
 112 bool SpdyFrameReader::IsDoneReading() const {
 113   return len_ == ofs_;
 114 }
 115
 116 bool SpdyFrameReader::CanRead(size_t bytes) const {
 117   return bytes <= (len_ - ofs_);
 118 }
 119
 120 void SpdyFrameReader::OnFailure() {
 121   // Set our iterator to the end of the buffer so that further reads fail
 122   // immediately.
 123   ofs_ = len_;
 124 }
 125
 126 }  // namespace net