include/tscore/SimpleTokenizer.h - trafficserver - Git at Google

 /** @file

   A brief file description

   @section license License

   Licensed to the Apache Software Foundation (ASF) under one
   or more contributor license agreements.  See the NOTICE file
   distributed with this work for additional information
   regarding copyright ownership.  The ASF licenses this file
   to you 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.
  */

 #pragma once

 #include <cstdlib>
 #include <cstring>
 #include <cctype>
 #include "tscore/ink_memory.h"

 /*-----------------------------------------------------------------------------
   SimpleTokenizer

   This class provides easy token parsing from an input string. It supports:

   1- ignoring (or not) of null fields
   2- left whitespace trimming
   3- right whitespace trimming
   4- escaping the delimiter character with a user defined escape character

   The class has two constructors, one that defines the input string,
   and another one that does not. If the latter is used, then the
   setString method should be used to set the data string.

   Both constructors set the delimiter, the operation mode (which
   defines bullets 1-3 above), and the escape character.

   The available methods are:

   void setString(char *s)
   sets the data string to s. The mode specified upon construction of the
   tokenizer determines whether s is copied or not.

   char *getNext()
   returns the next token, or NULL if there are no more tokens. This method
   uses the delimiter specified upon object construction.

   char *getNext(char delimiter)
   similar to getNext(), but allows the user to change the delimiter (just for
   this call).

   char *getNext(int count)
   get the next count tokens as a single token (ignoring the delimiters in
   between).

   char *getNext(char delimiter, int count)
   this is similar to getNext(int count) but allows user to specify the
   delimiter.

   IMPORTANT: the char pointers returned by the SimpleTokenizer are valid
   ONLY during the lifetime of the object. The copy of the input string
   is destroyed by the object's destructor.

   char *getRest()
   returns the rest of the tokens all together. Advances pointer so a
   subsequent call to getNext returns NULL;

   char *peekAtRestOfString()
   returns the rest of the input string, but DOES NOT advance pointer so a
   subsequent call to getNext does return the next token (if there is still
   one).

   size_t getNumTokensRemaining()
   returns the number of tokens remaining in the string (using the delimiter
   specified upon object construction).

   size_t getNumTokensRemaining(char delimiter)
   similar to the above, but allows the user to change the delimiter (just for
   this call).

   Note that multiple delimiters are not supported (more than one per call).

   examples:

   SimpleTokenizer tok("one    two\\ and\\ three four:   five : six");
   tok.getNumTokensRemaining() --> 5     note calculation is done assuming
                                         space is the delimiter
   tok.getNext() -> "one"
   tok.getNext() -> "two and three"
   tok.getNext(':') -> "four"
   tok.peekAtRestOfString() -> "   five  : six"
   tok.getNext(':') -> "five"

   SimpleTokenizer tok(",  with null fields ,,,", ',',
                       CONSIDER_NULL_FIELDS | KEEP_WHITESPACE);
   tok.getNext() -> ""
   tok.getNext() -> "  with null fields "
   tok.getNumTokensRemaining() -> 3

   ---------------------------------------------------------------------------*/

 class SimpleTokenizer
 {
 public:
   // by default, null fields are disregarded, whitespace is trimmed left
   // and right, and input string is copied (not overwritten)
   //
   enum {
     CONSIDER_NULL_FIELDS   = 1,
     KEEP_WHITESPACE_LEFT   = 2,
     KEEP_WHITESPACE_RIGHT  = 4,
     KEEP_WHITESPACE        = KEEP_WHITESPACE_LEFT + KEEP_WHITESPACE_RIGHT,
     OVERWRITE_INPUT_STRING = 8
   };

   SimpleTokenizer(char delimiter = ' ', unsigned mode = 0, char escape = '\\') : _delimiter(delimiter), _mode(mode), _escape(escape)
   {
   }

   // NOTE: The input string 's' is overwritten for mode OVERWRITE_INPUT_STRING.
   SimpleTokenizer(const char *s, char delimiter = ' ', unsigned mode = 0, char escape = '\\')
     : _delimiter(delimiter), _mode(mode), _escape(escape)
   {
     setString(s);
   }

   ~SimpleTokenizer() { _clearData(); }
   void
   setString(const char *s)
   {
     _clearData();

     _start  = 0;
     _length = strlen(s);
     _data   = (_mode & OVERWRITE_INPUT_STRING ? const_cast<char *>(s) : ats_strdup(s));

     // to handle the case where there is a null field at the end of the
     // input string, we replace the null character at the end of the
     // string with the delimiter (and consider the string to be one
     // character larger).
     //
     _data[_length++] = _delimiter;
   };
   char *
   getNext(int count = 1)
   {
     return _getNext(_delimiter, false, count);
   };
   char *
   getNext(char delimiter, int count = 1)
   {
     return _getNext(delimiter, false, count);
   }
   char *
   getRest()
   {
     // there can't be more than _length tokens, so we get the rest
     // of the tokens by requesting _length of them
     //
     return _getNext(_delimiter, false, _length);
   }
   size_t
   getNumTokensRemaining()
   {
     return _getNumTokensRemaining(_delimiter);
   };
   size_t
   getNumTokensRemaining(char delimiter)
   {
     return _getNumTokensRemaining(delimiter);
   };
   char *
   peekAtRestOfString()
   {
     _data[_length - 1] = 0;
     return (_start < _length ? &_data[_start] : &_data[_length - 1]);
   }

 private:
   char *_data = nullptr; // a pointer to the input data itself,
   // or to a copy of it
   char _delimiter; // the token delimiter
   unsigned _mode;  // flags that determine the
   // mode of operation
   char _escape;      // the escape character
   size_t _start = 0; // pointer to the start of the next
   // token
   size_t _length = 0; // the length of _data

   void
   _clearData()
   {
     if (_data && !(_mode & OVERWRITE_INPUT_STRING)) {
       ats_free(_data);
     }
   }

   char *
   _getNext(char delimiter, bool countOnly = false, int numTokens = 1)
   {
     char *next = nullptr;

     if (_start < _length) {
       // set start
       //
       bool hasEsc = false; // escape character seen
       while (_start < _length &&
              ((!(_mode & CONSIDER_NULL_FIELDS) &&
                (_data[_start] == delimiter && !(_start && (_data[_start - 1] == _escape ? (hasEsc = true) : 0)))) ||
               (!(_mode & KEEP_WHITESPACE_LEFT) && isspace(_data[_start])))) {
         ++_start;
       }

       if (_start < _length) // data still available
       {
         // update the extra delimiter just in case the function
         // is called with a different delimiter from the previous one
         //
         _data[_length - 1] = delimiter;

         next = &_data[_start];

         // set end
         //
         size_t end     = _start;
         int delimCount = 0;
         while (end < _length && (_data[end] != delimiter || (end && (_data[end - 1] == _escape ? (hasEsc = true) : 0)) ||
                                  ((++delimCount < numTokens) && (end < _length - 1)))) {
           ++end;
         }

         _start = end + 1;

         // there can be delimiters at the end if the number of tokens
         // requested is larger than 1, remove them if the
         // CONSIDER_NULL_FIELDS flag is not set
         //
         if (!(_mode & CONSIDER_NULL_FIELDS)) {
           while (_data[--end] == delimiter)
             ;
           ++end;
         }

         if (!(_mode & KEEP_WHITESPACE_RIGHT)) {
           while (isspace(_data[--end]))
             ;
           ++end;
         }

         if (!countOnly) {
           _data[end] = 0;

           // remove escape characters only if the number of
           // delimiters is one
           //
           if (hasEsc && delimCount == 1) {
             int numEscape = 0, i = 0;
             while (next[i]) {
               if (next[i] == _escape) {
                 ++numEscape;
               } else {
                 next[i - numEscape] = next[i];
               }
               ++i;
             }
             _data[end - numEscape] = 0;
           }
         }
       }
     }
     return next;
   };

   size_t
   _getNumTokensRemaining(char delimiter)
   {
     size_t startSave = _start; // save current position
     size_t count     = 0;
     while (_getNext(delimiter, true)) {
       ++count;
     };
     _start = startSave;
     return count;
   };
 };
	/** @file

	A brief file description

	@section license License

	Licensed to the Apache Software Foundation (ASF) under one
	or more contributor license agreements. See the NOTICE file
	distributed with this work for additional information
	regarding copyright ownership. The ASF licenses this file
	to you 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.
	*/

	#pragma once

	#include <cstdlib>
	#include <cstring>
	#include <cctype>
	#include "tscore/ink_memory.h"

	/*-----------------------------------------------------------------------------
	SimpleTokenizer

	This class provides easy token parsing from an input string. It supports:

	1- ignoring (or not) of null fields
	2- left whitespace trimming
	3- right whitespace trimming
	4- escaping the delimiter character with a user defined escape character

	The class has two constructors, one that defines the input string,
	and another one that does not. If the latter is used, then the
	setString method should be used to set the data string.

	Both constructors set the delimiter, the operation mode (which
	defines bullets 1-3 above), and the escape character.

	The available methods are:

	void setString(char *s)
	sets the data string to s. The mode specified upon construction of the
	tokenizer determines whether s is copied or not.

	char *getNext()
	returns the next token, or NULL if there are no more tokens. This method
	uses the delimiter specified upon object construction.

	char *getNext(char delimiter)
	similar to getNext(), but allows the user to change the delimiter (just for
	this call).

	char *getNext(int count)
	get the next count tokens as a single token (ignoring the delimiters in
	between).

	char *getNext(char delimiter, int count)
	this is similar to getNext(int count) but allows user to specify the
	delimiter.

	IMPORTANT: the char pointers returned by the SimpleTokenizer are valid
	ONLY during the lifetime of the object. The copy of the input string
	is destroyed by the object's destructor.

	char *getRest()
	returns the rest of the tokens all together. Advances pointer so a
	subsequent call to getNext returns NULL;

	char *peekAtRestOfString()
	returns the rest of the input string, but DOES NOT advance pointer so a
	subsequent call to getNext does return the next token (if there is still
	one).

	size_t getNumTokensRemaining()
	returns the number of tokens remaining in the string (using the delimiter
	specified upon object construction).

	size_t getNumTokensRemaining(char delimiter)
	similar to the above, but allows the user to change the delimiter (just for
	this call).

	Note that multiple delimiters are not supported (more than one per call).

	examples:

	SimpleTokenizer tok("one two\\ and\\ three four: five : six");
	tok.getNumTokensRemaining() --> 5 note calculation is done assuming
	space is the delimiter
	tok.getNext() -> "one"
	tok.getNext() -> "two and three"
	tok.getNext(':') -> "four"
	tok.peekAtRestOfString() -> " five : six"
	tok.getNext(':') -> "five"

	SimpleTokenizer tok(", with null fields ,,,", ',',
	CONSIDER_NULL_FIELDS \| KEEP_WHITESPACE);
	tok.getNext() -> ""
	tok.getNext() -> " with null fields "
	tok.getNumTokensRemaining() -> 3

	---------------------------------------------------------------------------*/

	class SimpleTokenizer
	{
	public:
	// by default, null fields are disregarded, whitespace is trimmed left
	// and right, and input string is copied (not overwritten)
	//
	enum {
	CONSIDER_NULL_FIELDS = 1,
	KEEP_WHITESPACE_LEFT = 2,
	KEEP_WHITESPACE_RIGHT = 4,
	KEEP_WHITESPACE = KEEP_WHITESPACE_LEFT + KEEP_WHITESPACE_RIGHT,
	OVERWRITE_INPUT_STRING = 8
	};

	SimpleTokenizer(char delimiter = ' ', unsigned mode = 0, char escape = '\\') : _delimiter(delimiter), _mode(mode), _escape(escape)
	{
	}

	// NOTE: The input string 's' is overwritten for mode OVERWRITE_INPUT_STRING.
	SimpleTokenizer(const char *s, char delimiter = ' ', unsigned mode = 0, char escape = '\\')
	: _delimiter(delimiter), _mode(mode), _escape(escape)
	{
	setString(s);
	}

	~SimpleTokenizer() { _clearData(); }
	void
	setString(const char *s)
	{
	_clearData();

	_start = 0;
	_length = strlen(s);
	_data = (_mode & OVERWRITE_INPUT_STRING ? const_cast<char *>(s) : ats_strdup(s));

	// to handle the case where there is a null field at the end of the
	// input string, we replace the null character at the end of the
	// string with the delimiter (and consider the string to be one
	// character larger).
	//
	_data[_length++] = _delimiter;
	};
	char *
	getNext(int count = 1)
	{
	return _getNext(_delimiter, false, count);
	};
	char *
	getNext(char delimiter, int count = 1)
	{
	return _getNext(delimiter, false, count);
	}
	char *
	getRest()
	{
	// there can't be more than _length tokens, so we get the rest
	// of the tokens by requesting _length of them
	//
	return _getNext(_delimiter, false, _length);
	}
	size_t
	getNumTokensRemaining()
	{
	return _getNumTokensRemaining(_delimiter);
	};
	size_t
	getNumTokensRemaining(char delimiter)
	{
	return _getNumTokensRemaining(delimiter);
	};
	char *
	peekAtRestOfString()
	{
	_data[_length - 1] = 0;
	return (_start < _length ? &_data[_start] : &_data[_length - 1]);
	}

	private:
	char *_data = nullptr; // a pointer to the input data itself,
	// or to a copy of it
	char _delimiter; // the token delimiter
	unsigned _mode; // flags that determine the
	// mode of operation
	char _escape; // the escape character
	size_t _start = 0; // pointer to the start of the next
	// token
	size_t _length = 0; // the length of _data

	void
	_clearData()
	{
	if (_data && !(_mode & OVERWRITE_INPUT_STRING)) {
	ats_free(_data);
	}
	}

	char *
	_getNext(char delimiter, bool countOnly = false, int numTokens = 1)
	{
	char *next = nullptr;

	if (_start < _length) {
	// set start
	//
	bool hasEsc = false; // escape character seen
	while (_start < _length &&
	((!(_mode & CONSIDER_NULL_FIELDS) &&
	(_data[_start] == delimiter && !(_start && (_data[_start - 1] == _escape ? (hasEsc = true) : 0)))) \|\|
	(!(_mode & KEEP_WHITESPACE_LEFT) && isspace(_data[_start])))) {
	++_start;
	}

	if (_start < _length) // data still available
	{
	// update the extra delimiter just in case the function
	// is called with a different delimiter from the previous one
	//
	_data[_length - 1] = delimiter;

	next = &_data[_start];

	// set end
	//
	size_t end = _start;
	int delimCount = 0;
	while (end < _length && (_data[end] != delimiter \|\| (end && (_data[end - 1] == _escape ? (hasEsc = true) : 0)) \|\|
	((++delimCount < numTokens) && (end < _length - 1)))) {
	++end;
	}

	_start = end + 1;

	// there can be delimiters at the end if the number of tokens
	// requested is larger than 1, remove them if the
	// CONSIDER_NULL_FIELDS flag is not set
	//
	if (!(_mode & CONSIDER_NULL_FIELDS)) {
	while (_data[--end] == delimiter)
	;
	++end;
	}

	if (!(_mode & KEEP_WHITESPACE_RIGHT)) {
	while (isspace(_data[--end]))
	;
	++end;
	}

	if (!countOnly) {
	_data[end] = 0;

	// remove escape characters only if the number of
	// delimiters is one
	//
	if (hasEsc && delimCount == 1) {
	int numEscape = 0, i = 0;
	while (next[i]) {
	if (next[i] == _escape) {
	++numEscape;
	} else {
	next[i - numEscape] = next[i];
	}
	++i;
	}
	_data[end - numEscape] = 0;
	}
	}
	}
	}
	return next;
	};

	size_t
	_getNumTokensRemaining(char delimiter)
	{
	size_t startSave = _start; // save current position
	size_t count = 0;
	while (_getNext(delimiter, true)) {
	++count;
	};
	_start = startSave;
	return count;
	};
	};