platform_system_core/include/utils/Tokenizer.h

137 lines
3.8 KiB
C++

/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _UTILS_TOKENIZER_H
#define _UTILS_TOKENIZER_H
#include <assert.h>
#include <utils/Errors.h>
#include <utils/FileMap.h>
#include <utils/String8.h>
namespace android {
/**
* A simple tokenizer for loading and parsing ASCII text files line by line.
*/
class Tokenizer {
Tokenizer(const String8& filename, FileMap* fileMap, char* buffer,
bool ownBuffer, size_t length);
public:
~Tokenizer();
/**
* Opens a file and maps it into memory.
*
* Returns NO_ERROR and a tokenizer for the file, if successful.
* Otherwise returns an error and sets outTokenizer to NULL.
*/
static status_t open(const String8& filename, Tokenizer** outTokenizer);
/**
* Prepares to tokenize the contents of a string.
*
* Returns NO_ERROR and a tokenizer for the string, if successful.
* Otherwise returns an error and sets outTokenizer to NULL.
*/
static status_t fromContents(const String8& filename,
const char* contents, Tokenizer** outTokenizer);
/**
* Returns true if at the end of the file.
*/
inline bool isEof() const { return mCurrent == getEnd(); }
/**
* Returns true if at the end of the line or end of the file.
*/
inline bool isEol() const { return isEof() || *mCurrent == '\n'; }
/**
* Gets the name of the file.
*/
inline String8 getFilename() const { return mFilename; }
/**
* Gets a 1-based line number index for the current position.
*/
inline int32_t getLineNumber() const { return mLineNumber; }
/**
* Formats a location string consisting of the filename and current line number.
* Returns a string like "MyFile.txt:33".
*/
String8 getLocation() const;
/**
* Gets the character at the current position.
* Returns null at end of file.
*/
inline char peekChar() const { return isEof() ? '\0' : *mCurrent; }
/**
* Gets the remainder of the current line as a string, excluding the newline character.
*/
String8 peekRemainderOfLine() const;
/**
* Gets the character at the current position and advances past it.
* Returns null at end of file.
*/
inline char nextChar() { return isEof() ? '\0' : *(mCurrent++); }
/**
* Gets the next token on this line stopping at the specified delimiters
* or the end of the line whichever comes first and advances past it.
* Also stops at embedded nulls.
* Returns the token or an empty string if the current character is a delimiter
* or is at the end of the line.
*/
String8 nextToken(const char* delimiters);
/**
* Advances to the next line.
* Does nothing if already at the end of the file.
*/
void nextLine();
/**
* Skips over the specified delimiters in the line.
* Also skips embedded nulls.
*/
void skipDelimiters(const char* delimiters);
private:
Tokenizer(const Tokenizer& other); // not copyable
String8 mFilename;
FileMap* mFileMap;
char* mBuffer;
bool mOwnBuffer;
size_t mLength;
const char* mCurrent;
int32_t mLineNumber;
inline const char* getEnd() const { return mBuffer + mLength; }
};
} // namespace android
#endif // _UTILS_TOKENIZER_H