1// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15#include "Input.h"
16
17#include <algorithm>
18#include <cassert>
19#include <cstring>
20
21namespace pp
22{
23
24Input::Input() : mCount(0), mString(0)
25{
26}
27
28Input::~Input()
29{
30}
31
32Input::Input(size_t count, const char *const string[], const int length[])
33 : mCount(count), mString(string)
34{
35 mLength.reserve(mCount);
36 for (size_t i = 0; i < mCount; ++i)
37 {
38 int len = length ? length[i] : -1;
39 mLength.push_back(len < 0 ? std::strlen(mString[i]) : len);
40 }
41}
42
43const char *Input::skipChar()
44{
45 // This function should only be called when there is a character to skip.
46 assert(mReadLoc.cIndex < mLength[mReadLoc.sIndex]);
47 ++mReadLoc.cIndex;
48 if (mReadLoc.cIndex == mLength[mReadLoc.sIndex])
49 {
50 ++mReadLoc.sIndex;
51 mReadLoc.cIndex = 0;
52 }
53 if (mReadLoc.sIndex >= mCount)
54 {
55 return nullptr;
56 }
57 return mString[mReadLoc.sIndex] + mReadLoc.cIndex;
58}
59
60size_t Input::read(char *buf, size_t maxSize, int *lineNo)
61{
62 size_t nRead = 0;
63 // The previous call to read might have stopped copying the string when encountering a line
64 // continuation. Check for this possibility first.
65 if (mReadLoc.sIndex < mCount && maxSize > 0)
66 {
67 const char *c = mString[mReadLoc.sIndex] + mReadLoc.cIndex;
68 if ((*c) == '\\')
69 {
70 c = skipChar();
71 if (c != nullptr && (*c) == '\n')
72 {
73 // Line continuation of backslash + newline.
74 skipChar();
75 // Fake an EOF if the line number would overflow.
76 if (*lineNo == INT_MAX)
77 {
78 return 0;
79 }
80 ++(*lineNo);
81 }
82 else if (c != nullptr && (*c) == '\r')
83 {
84 // Line continuation. Could be backslash + '\r\n' or just backslash + '\r'.
85 c = skipChar();
86 if (c != nullptr && (*c) == '\n')
87 {
88 skipChar();
89 }
90 // Fake an EOF if the line number would overflow.
91 if (*lineNo == INT_MAX)
92 {
93 return 0;
94 }
95 ++(*lineNo);
96 }
97 else
98 {
99 // Not line continuation, so write the skipped backslash to buf.
100 *buf = '\\';
101 ++nRead;
102 }
103 }
104 }
105
106 size_t maxRead = maxSize;
107 while ((nRead < maxRead) && (mReadLoc.sIndex < mCount))
108 {
109 size_t size = mLength[mReadLoc.sIndex] - mReadLoc.cIndex;
110 size = std::min(size, maxSize);
111 for (size_t i = 0; i < size; ++i)
112 {
113 // Stop if a possible line continuation is encountered.
114 // It will be processed on the next call on input, which skips it
115 // and increments line number if necessary.
116 if (*(mString[mReadLoc.sIndex] + mReadLoc.cIndex + i) == '\\')
117 {
118 size = i;
119 maxRead = nRead + size; // Stop reading right before the backslash.
120 }
121 }
122 std::memcpy(buf + nRead, mString[mReadLoc.sIndex] + mReadLoc.cIndex, size);
123 nRead += size;
124 mReadLoc.cIndex += size;
125
126 // Advance string if we reached the end of current string.
127 if (mReadLoc.cIndex == mLength[mReadLoc.sIndex])
128 {
129 ++mReadLoc.sIndex;
130 mReadLoc.cIndex = 0;
131 }
132 }
133 return nRead;
134}
135
136} // namespace pp
137
138