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#if defined (WIN32)
18#include <windows.h>
19#endif
20
21#include <string.h>
22
23#include "sfntly/port/memory_input_stream.h"
24#include "sfntly/port/exception_type.h"
25
26namespace sfntly {
27
28MemoryInputStream::MemoryInputStream()
29    : buffer_(NULL),
30      position_(0),
31      length_(0) {
32}
33
34MemoryInputStream::~MemoryInputStream() {
35  Close();
36}
37
38int32_t MemoryInputStream::Available() {
39  return length_ - position_;
40}
41
42void MemoryInputStream::Close() {
43}
44
45void MemoryInputStream::Mark(int32_t readlimit) {
46  // NOP
47  UNREFERENCED_PARAMETER(readlimit);
48}
49
50bool MemoryInputStream::MarkSupported() {
51  return false;
52}
53
54int32_t MemoryInputStream::Read() {
55  if (!buffer_) {
56#if !defined (SFNTLY_NO_EXCEPTION)
57    throw IOException("no memory attached");
58#endif
59    return 0;
60  }
61  if (position_ >= length_) {
62#if !defined (SFNTLY_NO_EXCEPTION)
63    throw IOException("eof reached");
64#endif
65    return 0;
66  }
67  byte_t value = buffer_[position_++];
68  return value;
69}
70
71int32_t MemoryInputStream::Read(ByteVector* b) {
72  return Read(b, 0, b->size());
73}
74
75int32_t MemoryInputStream::Read(ByteVector* b, int32_t offset, int32_t length) {
76  assert(b);
77  if (!buffer_) {
78#if !defined (SFNTLY_NO_EXCEPTION)
79    throw IOException("no memory attached");
80#endif
81    return 0;
82  }
83  if (position_ >= length_) {
84#if !defined (SFNTLY_NO_EXCEPTION)
85    throw IOException("eof reached");
86#endif
87    return 0;
88  }
89  size_t read_count = std::min<size_t>(length_ - position_, length);
90  if (b->size() < (size_t)(offset + read_count)) {
91    b->resize((size_t)(offset + read_count));
92  }
93  memcpy(&((*b)[offset]), buffer_ + position_, read_count);
94  position_ += read_count;
95  return read_count;
96}
97
98void MemoryInputStream::Reset() {
99  // NOP
100}
101
102int64_t MemoryInputStream::Skip(int64_t n) {
103  if (!buffer_) {
104#if !defined (SFNTLY_NO_EXCEPTION)
105    throw IOException("no memory attached");
106#endif
107    return 0;
108  }
109  int64_t skip_count = 0;
110  if (n < 0) {  // move backwards
111    skip_count = std::max<int64_t>(0 - (int64_t)position_, n);
112    position_ -= (size_t)(0 - skip_count);
113  } else {
114    skip_count = std::min<size_t>(length_ - position_, (size_t)n);
115    position_ += (size_t)skip_count;
116  }
117  return skip_count;
118}
119
120void MemoryInputStream::Unread(ByteVector* b) {
121  Unread(b, 0, b->size());
122}
123
124void MemoryInputStream::Unread(ByteVector* b, int32_t offset, int32_t length) {
125  assert(b);
126  assert(b->size() >= size_t(offset + length));
127  if (!buffer_) {
128#if !defined (SFNTLY_NO_EXCEPTION)
129    throw IOException("no memory attached");
130#endif
131    return;
132  }
133  size_t unread_count = std::min<size_t>(position_, length);
134  position_ -= unread_count;
135  Read(b, offset, length);
136  position_ -= unread_count;
137}
138
139bool MemoryInputStream::Attach(const byte_t* buffer, size_t length) {
140  assert(buffer);
141  assert(length);
142  buffer_ = buffer;
143  length_ = length;
144  return true;
145}
146
147}  // namespace sfntly
148