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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 <stdlib.h>
20 #include <unistd.h>
21 #include <fcntl.h>
22 #include <errno.h>
23 #include <sys/types.h>
24 #include <sys/stat.h>
25 #include <utils/Log.h>
26 #include <utils/Tokenizer.h>
27 
28 // Enables debug output for the tokenizer.
29 #define DEBUG_TOKENIZER 0
30 
31 
32 namespace android {
33 
isDelimiter(char ch,const char * delimiters)34 static inline bool isDelimiter(char ch, const char* delimiters) {
35     return strchr(delimiters, ch) != NULL;
36 }
37 
Tokenizer(const String8 & filename,FileMap * fileMap,char * buffer,bool ownBuffer,size_t length)38 Tokenizer::Tokenizer(const String8& filename, FileMap* fileMap, char* buffer,
39         bool ownBuffer, size_t length) :
40         mFilename(filename), mFileMap(fileMap),
41         mBuffer(buffer), mOwnBuffer(ownBuffer), mLength(length),
42         mCurrent(buffer), mLineNumber(1) {
43 }
44 
~Tokenizer()45 Tokenizer::~Tokenizer() {
46     delete mFileMap;
47     if (mOwnBuffer) {
48         delete[] mBuffer;
49     }
50 }
51 
open(const String8 & filename,Tokenizer ** outTokenizer)52 status_t Tokenizer::open(const String8& filename, Tokenizer** outTokenizer) {
53     *outTokenizer = NULL;
54 
55     int result = NO_ERROR;
56     int fd = ::open(filename.string(), O_RDONLY);
57     if (fd < 0) {
58         result = -errno;
59         ALOGE("Error opening file '%s': %s", filename.string(), strerror(errno));
60     } else {
61         struct stat stat;
62         if (fstat(fd, &stat)) {
63             result = -errno;
64             ALOGE("Error getting size of file '%s': %s", filename.string(), strerror(errno));
65         } else {
66             size_t length = size_t(stat.st_size);
67 
68             FileMap* fileMap = new FileMap();
69             bool ownBuffer = false;
70             char* buffer;
71             if (fileMap->create(NULL, fd, 0, length, true)) {
72                 fileMap->advise(FileMap::SEQUENTIAL);
73                 buffer = static_cast<char*>(fileMap->getDataPtr());
74             } else {
75                 delete fileMap;
76                 fileMap = NULL;
77 
78                 // Fall back to reading into a buffer since we can't mmap files in sysfs.
79                 // The length we obtained from stat is wrong too (it will always be 4096)
80                 // so we must trust that read will read the entire file.
81                 buffer = new char[length];
82                 ownBuffer = true;
83                 ssize_t nrd = read(fd, buffer, length);
84                 if (nrd < 0) {
85                     result = -errno;
86                     ALOGE("Error reading file '%s': %s", filename.string(), strerror(errno));
87                     delete[] buffer;
88                     buffer = NULL;
89                 } else {
90                     length = size_t(nrd);
91                 }
92             }
93 
94             if (!result) {
95                 *outTokenizer = new Tokenizer(filename, fileMap, buffer, ownBuffer, length);
96             }
97         }
98         close(fd);
99     }
100     return result;
101 }
102 
fromContents(const String8 & filename,const char * contents,Tokenizer ** outTokenizer)103 status_t Tokenizer::fromContents(const String8& filename,
104         const char* contents, Tokenizer** outTokenizer) {
105     *outTokenizer = new Tokenizer(filename, NULL,
106             const_cast<char*>(contents), false, strlen(contents));
107     return OK;
108 }
109 
getLocation() const110 String8 Tokenizer::getLocation() const {
111     String8 result;
112     result.appendFormat("%s:%d", mFilename.string(), mLineNumber);
113     return result;
114 }
115 
peekRemainderOfLine() const116 String8 Tokenizer::peekRemainderOfLine() const {
117     const char* end = getEnd();
118     const char* eol = mCurrent;
119     while (eol != end) {
120         char ch = *eol;
121         if (ch == '\n') {
122             break;
123         }
124         eol += 1;
125     }
126     return String8(mCurrent, eol - mCurrent);
127 }
128 
nextToken(const char * delimiters)129 String8 Tokenizer::nextToken(const char* delimiters) {
130 #if DEBUG_TOKENIZER
131     ALOGD("nextToken");
132 #endif
133     const char* end = getEnd();
134     const char* tokenStart = mCurrent;
135     while (mCurrent != end) {
136         char ch = *mCurrent;
137         if (ch == '\n' || isDelimiter(ch, delimiters)) {
138             break;
139         }
140         mCurrent += 1;
141     }
142     return String8(tokenStart, mCurrent - tokenStart);
143 }
144 
nextLine()145 void Tokenizer::nextLine() {
146 #if DEBUG_TOKENIZER
147     ALOGD("nextLine");
148 #endif
149     const char* end = getEnd();
150     while (mCurrent != end) {
151         char ch = *(mCurrent++);
152         if (ch == '\n') {
153             mLineNumber += 1;
154             break;
155         }
156     }
157 }
158 
skipDelimiters(const char * delimiters)159 void Tokenizer::skipDelimiters(const char* delimiters) {
160 #if DEBUG_TOKENIZER
161     ALOGD("skipDelimiters");
162 #endif
163     const char* end = getEnd();
164     while (mCurrent != end) {
165         char ch = *mCurrent;
166         if (ch == '\n' || !isDelimiter(ch, delimiters)) {
167             break;
168         }
169         mCurrent += 1;
170     }
171 }
172 
173 } // namespace android
174