1 /*
2 * Copyright (C) 2010 The Android Open Source Project
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 #define LOG_TAG "Tokenizer"
18
19 #include <utils/Tokenizer.h>
20 #include <fcntl.h>
21 #include <sys/stat.h>
22 #include <utils/Log.h>
23
24 #ifndef DEBUG_TOKENIZER
25 // Enables debug output for the tokenizer.
26 #define DEBUG_TOKENIZER 0
27 #endif
28
29 namespace android {
30
isDelimiter(char ch,const char * delimiters)31 static inline bool isDelimiter(char ch, const char* delimiters) {
32 return strchr(delimiters, ch) != nullptr;
33 }
34
Tokenizer(const String8 & filename,FileMap * fileMap,char * buffer,bool ownBuffer,size_t length)35 Tokenizer::Tokenizer(const String8& filename, FileMap* fileMap, char* buffer,
36 bool ownBuffer, size_t length) :
37 mFilename(filename), mFileMap(fileMap),
38 mBuffer(buffer), mOwnBuffer(ownBuffer), mLength(length),
39 mCurrent(buffer), mLineNumber(1) {
40 }
41
~Tokenizer()42 Tokenizer::~Tokenizer() {
43 delete mFileMap;
44 if (mOwnBuffer) {
45 delete[] mBuffer;
46 }
47 }
48
open(const String8 & filename,Tokenizer ** outTokenizer)49 status_t Tokenizer::open(const String8& filename, Tokenizer** outTokenizer) {
50 *outTokenizer = nullptr;
51
52 int result = OK;
53 int fd = ::open(filename.string(), O_RDONLY);
54 if (fd < 0) {
55 result = -errno;
56 ALOGE("Error opening file '%s': %s", filename.string(), strerror(errno));
57 } else {
58 struct stat stat;
59 if (fstat(fd, &stat)) {
60 result = -errno;
61 ALOGE("Error getting size of file '%s': %s", filename.string(), strerror(errno));
62 } else {
63 size_t length = size_t(stat.st_size);
64
65 FileMap* fileMap = new FileMap();
66 bool ownBuffer = false;
67 char* buffer;
68 if (fileMap->create(nullptr, fd, 0, length, true)) {
69 fileMap->advise(FileMap::SEQUENTIAL);
70 buffer = static_cast<char*>(fileMap->getDataPtr());
71 } else {
72 delete fileMap;
73 fileMap = nullptr;
74
75 // Fall back to reading into a buffer since we can't mmap files in sysfs.
76 // The length we obtained from stat is wrong too (it will always be 4096)
77 // so we must trust that read will read the entire file.
78 buffer = new char[length];
79 ownBuffer = true;
80 ssize_t nrd = read(fd, buffer, length);
81 if (nrd < 0) {
82 result = -errno;
83 ALOGE("Error reading file '%s': %s", filename.string(), strerror(errno));
84 delete[] buffer;
85 buffer = nullptr;
86 } else {
87 length = size_t(nrd);
88 }
89 }
90
91 if (!result) {
92 *outTokenizer = new Tokenizer(filename, fileMap, buffer, ownBuffer, length);
93 }
94 }
95 close(fd);
96 }
97 return result;
98 }
99
fromContents(const String8 & filename,const char * contents,Tokenizer ** outTokenizer)100 status_t Tokenizer::fromContents(const String8& filename,
101 const char* contents, Tokenizer** outTokenizer) {
102 *outTokenizer = new Tokenizer(filename, nullptr,
103 const_cast<char*>(contents), false, strlen(contents));
104 return OK;
105 }
106
getLocation() const107 String8 Tokenizer::getLocation() const {
108 String8 result;
109 result.appendFormat("%s:%d", mFilename.string(), mLineNumber);
110 return result;
111 }
112
peekRemainderOfLine() const113 String8 Tokenizer::peekRemainderOfLine() const {
114 const char* end = getEnd();
115 const char* eol = mCurrent;
116 while (eol != end) {
117 char ch = *eol;
118 if (ch == '\n') {
119 break;
120 }
121 eol += 1;
122 }
123 return String8(mCurrent, eol - mCurrent);
124 }
125
nextToken(const char * delimiters)126 String8 Tokenizer::nextToken(const char* delimiters) {
127 #if DEBUG_TOKENIZER
128 ALOGD("nextToken");
129 #endif
130 const char* end = getEnd();
131 const char* tokenStart = mCurrent;
132 while (mCurrent != end) {
133 char ch = *mCurrent;
134 if (ch == '\n' || isDelimiter(ch, delimiters)) {
135 break;
136 }
137 mCurrent += 1;
138 }
139 return String8(tokenStart, mCurrent - tokenStart);
140 }
141
nextLine()142 void Tokenizer::nextLine() {
143 #if DEBUG_TOKENIZER
144 ALOGD("nextLine");
145 #endif
146 const char* end = getEnd();
147 while (mCurrent != end) {
148 char ch = *(mCurrent++);
149 if (ch == '\n') {
150 mLineNumber += 1;
151 break;
152 }
153 }
154 }
155
skipDelimiters(const char * delimiters)156 void Tokenizer::skipDelimiters(const char* delimiters) {
157 #if DEBUG_TOKENIZER
158 ALOGD("skipDelimiters");
159 #endif
160 const char* end = getEnd();
161 while (mCurrent != end) {
162 char ch = *mCurrent;
163 if (ch == '\n' || !isDelimiter(ch, delimiters)) {
164 break;
165 }
166 mCurrent += 1;
167 }
168 }
169
170 } // namespace android
171