Geografic-Information-System/lib/gis/token.c

/*!
  \file lib/gis/token.c
  
  \brief GIS Library - Tokenize strings
  
  (C) 2001-2008, 2011-2013 by the GRASS Development Team
  
  This program is free software under the GNU General Public License
  (>=v2). Read the file COPYING that comes with GRASS for details.
  
  \author USA CERL and others
*/

#include <stdlib.h>
#include <string.h>
#include <grass/gis.h>

static char **tokenize(const char *, const char *, const char *);

/*!
  \brief Tokenize string
  
  Given a string, <em>buf</em>, turn delimiter, <em>delim</em>, into
  '\0' (NULL) and place pointers to tokens in tokens. <em>buf</em>
  must not contain a new line (\n). <em>delim</em> may consist of more
  than one character. G_free_tokens() must be called when finished
  with tokens to release memory.
  
  Example:
  \code
  char **tokens;
  int ntok, i;
  tokens = G_tokenize(buf, " |:,");
  ntok = G_number_of_tokens(tokens);
  for (i=0; i < ntok; i++) {
     G_debug(1, "%d=[%s]", i, tokens[i]);
  }
  G_free_tokens(tokens);
  \endcode
  
  \param buf input string
  \param delim string delimiter
  
  \return pointer to string token
*/
char **G_tokenize(const char *buf, const char *delim)
{
    return tokenize(buf, delim, NULL);
}

/*!
  \brief Tokenize string
  
  This fuction behaves similarly to G_tokenize().

  It introduces <em>valchar</em> which defines borders of token. Within
  token <em>delim</em> is ignored.
  
  Example:
  \code
  char *str = "a,'b,c',d";

  char **tokens1, **tokens2;
  int ntok1, ntok2; 
  
  tokens1 = G_tokenize(str, ",");
  ntok1 = G_number_of_tokens(tokens1);

  tokens1 = G_tokenize2(str, ",", "'");
  ntok2 = G_number_of_tokens(tokens2);
  \endcode

  In this example <em>ntok1</em> will be 4, <em>ntok2</em> only 3,
  i.e. { "a", "'b, c'", "d"}

  \param buf input string
  \param delim string delimiter
  \param valchar character defining border of token

  \return pointer to string token
*/
char **G_tokenize2(const char *buf, const char *delim, const char *valchar)
{
    return tokenize(buf, delim, valchar);
}

char **tokenize(const char *buf, const char *delim, const char *inchar)
{
    int i;
    char **tokens;
    char *p;

    /* do not modify buf, make a copy */
    p = G_store(buf);

    i = 0;
    tokens = (char **)G_malloc(2 * sizeof(char *));

    /* always one token */
    tokens[i++] = p;

    while (TRUE) {
	/* find next delimiter */
	while (!strchr(delim, *p)) {
	    /* opening border ? */
	    if (inchar && *p == *inchar) {
		p++;
		/* find closing border */
		while (*p != *inchar && *p != 0)
		    p++;
		if (*p == 0)
		    break;
	    }
	    p++;
	}
	if (*p == 0)
	    break;
	/* replace delim with '\0' */
	*p++ = 0;
	/* set next token */
	tokens[i++] = p;
	tokens = (char **)G_realloc((char *)tokens, (i + 1) * sizeof(char *));
    }
    tokens[i] = NULL;

    return tokens;
}

/*!
  \brief Return number of tokens
  
  \param tokens
  
  \return number of tokens
*/

int G_number_of_tokens(char **tokens)
{
    int n;

    n = 0;
    for (n = 0; tokens[n] != NULL; n++)
      ;
    
    return n;
}

/*!
  \brief Free memory allocated to tokens.
  
  <b>Note:</b> <i>G_free_tokens()</i> must be called when finished with 
  tokens to release memory.
  
  \param[out] tokens
*/
void G_free_tokens(char **tokens)
{
    if (tokens[0] != NULL)
	G_free(tokens[0]);
    G_free(tokens);
}