net/http/http_byte_range.cc

   1 // Copyright (c) 2009 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 <algorithm>
   6
   7 #include "net/http/http_byte_range.h"
   8
   9 namespace {
  10
  11 const int64 kPositionNotSpecified = -1;
  12
  13 }  // namespace
  14
  15 namespace net {
  16
  17 HttpByteRange::HttpByteRange()
  18     : first_byte_position_(kPositionNotSpecified),
  19       last_byte_position_(kPositionNotSpecified),
  20       suffix_length_(kPositionNotSpecified),
  21       has_computed_bounds_(false) {
  22 }
  23
  24 bool HttpByteRange::IsSuffixByteRange() const {
  25   return suffix_length_ != kPositionNotSpecified;
  26 }
  27
  28 bool HttpByteRange::HasFirstBytePosition() const {
  29   return first_byte_position_ != kPositionNotSpecified;
  30 }
  31
  32 bool HttpByteRange::HasLastBytePosition() const {
  33   return last_byte_position_ != kPositionNotSpecified;
  34 }
  35
  36 bool HttpByteRange::IsValid() const {
  37   if (suffix_length_ > 0)
  38     return true;
  39   return (first_byte_position_ >= 0 &&
  40           (last_byte_position_ == kPositionNotSpecified ||
  41            last_byte_position_ >= first_byte_position_));
  42 }
  43
  44 bool HttpByteRange::ComputeBounds(int64 size) {
  45   if (size < 0)
  46     return false;
  47   if (has_computed_bounds_)
  48     return false;
  49   has_computed_bounds_ = true;
  50
  51   // Empty values.
  52   if (!HasFirstBytePosition() &&
  53       !HasLastBytePosition() &&
  54       !IsSuffixByteRange()) {
  55     first_byte_position_ = 0;
  56     last_byte_position_ = size - 1;
  57     return true;
  58   }
  59   if (!IsValid())
  60     return false;
  61   if (IsSuffixByteRange()) {
  62     first_byte_position_ = size - std::min(size, suffix_length_);
  63     last_byte_position_ = size - 1;
  64     return true;
  65   }
  66   if (first_byte_position_ < size) {
  67     if (HasLastBytePosition())
  68       last_byte_position_ = std::min(size - 1, last_byte_position_);
  69     else
  70       last_byte_position_ = size - 1;
  71     return true;
  72   }
  73   return false;
  74 }
  75
  76 }  // namespace net