token.c

CForms, by Lars Berntzon (Stockholm, Sweden), is a tool for building interactive forms-driven applic

/*******************************************************************************
*
*		T O K E N . C
*		-------------
*
* Description:
*	Reads tokens from input file. Tokens are the C-stype tokens. It is
*	allso possible to unget tokens for later recall by GetTok().
*
* Included functions:
*	GetTok()	- Get token
*
*
* Revision:
*	Ver    Date   By		Reason
*	---    ----   --		------
*	1.00   900619 Lars Berntzon	Created
*
******************************************************************************/
#ifndef lint
static volatile char sccs_id[] = "@(#) token.c,v 1.6 1993/05/13 21:55:48 lasse Exp";
#endif

#include "config.h"
#include "token.h"

#define isnormal(c) (isalnum(c) || (c) == '_')

	/* T y p e s */
typedef enum { st_init,
	       st_normal,
	       st_searching_quote,
	       st_got_slash,
	       st_got_comment,
	       st_got_star,
	       st_searching_endcomment,
	       st_got_backslash } state_t;

	/* G l o b a l   v a r i a b l e s */
	
int line = 1;		   /* Current line number			*/
FILE *in;		   /* The input file pointer			*/

	/* L o c a l   v a r i a b l e */

static int ch = 0; 	   /* Next input character			*/


/*******************************************************************************
 *
 *		G E T O K 
 *		---------
 *
 * Description:
 *	Reads one token from input file (skips c type comments).
 *
 * Output:
 *	ret_token	- String where data wil be put (if not NULL).
 *	ret_space	- Space string found before token (if not NULL).
 *
 * Return:
 *	String containing token, NULL if end of file.
 *
 ******************************************************************************/
char *
GetTok(char *ret_token, char *ret_space)
{
    static char token[TOKENSIZE];	/* Where read token is stored		*/
    static char space[TOKENSIZE];	/* Where spaces before token is stored	*/
    int token_pos = 0;			/* Current token write position		*/
    int space_pos = 0;			/* Current space positions		*/
    state_t state = st_init;		/* Current state			*/
    
    /*
     * Read first char of file.
     */
    if (ch == 0) {
	ch = getc(in);
    }
    
    if (ch == EOF) return NULL;
    
    for(; ch != EOF; ch = getc(in))
    {
	if (ch == '\n')
	{
	    line++;
	}

	switch(state) 
	{
	case st_init:
	    if (isspace(ch)) {
		space[space_pos++] = ch;
	    	break;
	    }
	    else if (ch == '"') {
		token[token_pos++] = ch;
		state = st_searching_quote;
	    }
	    else if (ch == '/') {
		token[token_pos++] = ch;
		state = st_got_slash;
	    }
	    else if (!isnormal(ch)) {
		token[token_pos++] = ch;
		token[token_pos++] = 0;
		ch = 0;
		goto found;
	    }
	    else if (isnormal(ch)) {
	    	token[token_pos++] = ch;
	    	state = st_normal;
	    }
	    break;

	case st_normal:
	    if (isnormal(ch)) {
	    	token[token_pos++] = ch;
	    }
	    else {
		token[token_pos++] = 0;
		goto found;
	    }
	    break;

	case st_searching_quote:
	    token[token_pos++] = ch;
	    if (ch == '\\') {
	    	state = st_got_backslash;
	    }
	    else {
	    	if (ch == '"') {
	    	    token[token_pos++] = 0;
	    	    ch = 0;
	    	    goto found;
	    	}
	    }
	    break;

	case st_got_backslash:
	    token[token_pos++] = ch;
	    state = st_searching_quote;
	    break;

	case st_got_slash:
	    if (ch == '*') {
		state = st_got_comment;

		/*
		 * Remove the slash from token.
		 */
		token_pos--;

		/*
		 * And save the comment in the space field instead.
		 */
		space[space_pos++] = '/';
		space[space_pos++] = '*';

	    }
	    else {
		goto found;
	    }
	    break;

	case st_got_comment:
	    if(ch == '*') {
		state = st_got_star;
	    }
	    space[space_pos++] = ch;
	    break;

	case st_got_star:
	    space[space_pos++] = ch;
	    if (ch == '/') {
		state = st_init;
	    }
	    else if (ch != '*') {
		state = st_got_comment;
	    }
	    break;
	
	default:
	    fprintf(stderr, "unknown state in file %s line %d, this should not happen\n",
		__FILE__, __LINE__);
	}
    }

found:
    space[space_pos] = 0;
    token[token_pos] = 0;

    if(ret_space) {
	strcpy(ret_space, space);
    }

    if (ret_token) {
	strcpy(ret_token, token);
    }
    else {
	ret_token = token;
    }

    if (token_pos == 0) return NULL;

    return ret_token;
}

/*******************************************************************************
 *
 *		O P E N T O K
 *		-------------
 *
 * Description:
 *	Open a file to read tokens from.
 *
 * Input:
 *	name	- Name of file.
 *
 * Return:
 *	Opened files pointer, of NULL if failure.
 *
 ******************************************************************************/
FILE *OpenTok(char *name)
{
    if (in != NULL) {
	fclose(in);
	ch = 0;
    }
    return in = fopen(name, "r");
}

#ifdef STANDALONE
/*******************************************************************************
 *
 *		M A I N
 *		-------
 *
 * Description:
 *	Main routine when compiled as standalone.
 *	This is only used for test.
 *
 ******************************************************************************/

main()
{
    char token[TOKENSIZE];
    char space[TOKENSIZE];
    char outstr[1000];
    char *p;
    
    in = stdin;

    while(GetTok(token, space))
    {
	sprintf(outstr, "'%s'-'%s'-%d", token, space, line);
	for(p = outstr; *p != NULL; p++)
	{
	    switch (*p)
	    {
	    case '\n':
		putchar('\\');
		putchar('n');
		break;

	    case '\t':
		putchar('\\');
		putchar('t');
		break;
	    
	    default:
		putchar(*p);
	    }
	}
	putchar('\n');
    }
}
#endif /* STANDALONE */