Tokenizer.cpp revision 6ed68cc412752e4c78755df9a1516e610ec66fa8 
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
32namespace android {
33
34static inline bool isDelimiter(char ch, const char* delimiters) {
35    return strchr(delimiters, ch) != NULL;
36}
37
38Tokenizer::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
45Tokenizer::~Tokenizer() {
46    delete mFileMap;
47    if (mOwnBuffer) {
48        delete[] mBuffer;
49    }
50}
51
52status_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
103status_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
110String8 Tokenizer::getLocation() const {
111    String8 result;
112    result.appendFormat("%s:%d", mFilename.string(), mLineNumber);
113    return result;
114}
115
116String8 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
129String8 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
145void 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
159void 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