1 /*
2 * Copyright 2011 Google Inc. All Rights Reserved.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "sfntly/data/font_data.h"
18
19 #include <algorithm>
20 #include <functional>
21 #include <limits>
22
23 #include "sfntly/port/logging.h"
24
25 namespace sfntly {
26
Size() const27 int32_t FontData::Size() const {
28 return std::min<int32_t>(array_->Size() - bound_offset_, bound_length_);
29 }
30
Bound(int32_t offset,int32_t length)31 void FontData::Bound(int32_t offset, int32_t length) {
32 // Inputs should not be negative.
33 CHECK(offset >= 0);
34 CHECK(length >= 0);
35
36 // Check to make sure |bound_offset_| will not overflow.
37 CHECK(bound_offset_ <= std::numeric_limits<int32_t>::max() - offset);
38 const int32_t new_offset = bound_offset_ + offset;
39
40 if (length == GROWABLE_SIZE) {
41 // When |length| has the special value of GROWABLE_SIZE, it means the size
42 // should not have any artificial limits, thus it is just the underlying
43 // |array_|'s size. Just make sure |new_offset| is still within bounds.
44 CHECK(new_offset <= array_->Size());
45 } else {
46 // When |length| has any other value, |new_offset| + |length| points to the
47 // end of the array. Make sure that is within bounds, but use subtraction to
48 // avoid an integer overflow.
49 CHECK(new_offset <= array_->Size() - length);
50 }
51
52 bound_offset_ = new_offset;
53 bound_length_ = length;
54 }
55
Length() const56 int32_t FontData::Length() const {
57 return std::min<int32_t>(array_->Length() - bound_offset_, bound_length_);
58 }
59
FontData(ByteArray * ba)60 FontData::FontData(ByteArray* ba) {
61 Init(ba);
62 }
63
FontData(FontData * data,int32_t offset,int32_t length)64 FontData::FontData(FontData* data, int32_t offset, int32_t length) {
65 Init(data->array_);
66 Bound(data->bound_offset_ + offset, length);
67 }
68
FontData(FontData * data,int32_t offset)69 FontData::FontData(FontData* data, int32_t offset) {
70 Init(data->array_);
71 Bound(data->bound_offset_ + offset,
72 (data->bound_length_ == GROWABLE_SIZE)
73 ? GROWABLE_SIZE : data->bound_length_ - offset);
74 }
75
~FontData()76 FontData::~FontData() {}
77
Init(ByteArray * ba)78 void FontData::Init(ByteArray* ba) {
79 array_ = ba;
80 bound_offset_ = 0;
81 bound_length_ = GROWABLE_SIZE;
82 }
83
BoundOffset(int32_t offset) const84 int32_t FontData::BoundOffset(int32_t offset) const {
85 return offset + bound_offset_;
86 }
87
BoundLength(int32_t offset,int32_t length) const88 int32_t FontData::BoundLength(int32_t offset, int32_t length) const {
89 return std::min<int32_t>(length, bound_length_ - offset);
90 }
91
92 } // namespace sfntly
93