michael@0: /*
michael@0:  * $Xorg: ifparser.c,v 1.3 2000/08/17 19:41:50 cpqbld Exp $
michael@0:  *
michael@0:  * Copyright 1992 Network Computing Devices, Inc.
michael@0:  * 
michael@0:  * Permission to use, copy, modify, and distribute this software and its
michael@0:  * documentation for any purpose and without fee is hereby granted, provided
michael@0:  * that the above copyright notice appear in all copies and that both that
michael@0:  * copyright notice and this permission notice appear in supporting
michael@0:  * documentation, and that the name of Network Computing Devices may not be
michael@0:  * used in advertising or publicity pertaining to distribution of the software
michael@0:  * without specific, written prior permission.  Network Computing Devices makes
michael@0:  * no representations about the suitability of this software for any purpose.
michael@0:  * It is provided ``as is'' without express or implied warranty.
michael@0:  * 
michael@0:  * NETWORK COMPUTING DEVICES DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
michael@0:  * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
michael@0:  * IN NO EVENT SHALL NETWORK COMPUTING DEVICES BE LIABLE FOR ANY SPECIAL,
michael@0:  * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
michael@0:  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
michael@0:  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
michael@0:  * PERFORMANCE OF THIS SOFTWARE.
michael@0:  * 
michael@0:  * Author:  Jim Fulton
michael@0:  *          Network Computing Devices, Inc.
michael@0:  * 
michael@0:  * Simple if statement processor
michael@0:  *
michael@0:  * This module can be used to evaluate string representations of C language
michael@0:  * if constructs.  It accepts the following grammar:
michael@0:  * 
michael@0:  *     EXPRESSION	:=	VALUE
michael@0:  * 			 |	VALUE  BINOP	EXPRESSION
michael@0:  *			 |	VALUE	'?'	EXPRESSION ':'	EXPRESSION
michael@0:  * 
michael@0:  *     VALUE		:=	'('  EXPRESSION  ')'
michael@0:  * 			 |	'!'  VALUE
michael@0:  * 			 |	'-'  VALUE
michael@0:  * 			 |	'+'  VALUE
michael@0:  *			 |	'~'  VALUE
michael@0:  * 			 |	'defined'  '('  variable  ')'
michael@0:  * 			 |	'defined'  variable
michael@0:  *			 |	# variable '(' variable-list ')'
michael@0:  * 			 |	variable
michael@0:  * 			 |	number
michael@0:  * 
michael@0:  *     BINOP		:=	'*'	|  '/'	|  '%'
michael@0:  * 			 |	'+'	|  '-'
michael@0:  * 			 |	'<<'	|  '>>'
michael@0:  * 			 |	'<'	|  '>'	|  '<='  |  '>='
michael@0:  * 			 |	'=='	|  '!='
michael@0:  * 			 |	'&'	|  '^'  |  '|'
michael@0:  * 			 |	'&&'	|  '||'
michael@0:  * 
michael@0:  * The normal C order of precedence is supported.
michael@0:  * 
michael@0:  * 
michael@0:  * External Entry Points:
michael@0:  * 
michael@0:  *     ParseIfExpression		parse a string for #if
michael@0:  */
michael@0: /* $XFree86: xc/config/makedepend/ifparser.c,v 3.11 2002/09/23 01:48:08 tsi Exp $ */
michael@0: 
michael@0: #include "ifparser.h"
michael@0: #include <ctype.h>
michael@0: #include <stdlib.h>
michael@0: #include <string.h>
michael@0: 
michael@0: /****************************************************************************
michael@0: 		   Internal Macros and Utilities for Parser
michael@0:  ****************************************************************************/
michael@0: 
michael@0: #define DO(val) if (!(val)) return NULL
michael@0: #define CALLFUNC(ggg,fff) (*((ggg)->funcs.fff))
michael@0: #define SKIPSPACE(ccc) while (isspace(*ccc)) ccc++
michael@0: #define isvarfirstletter(ccc) (isalpha(ccc) || (ccc) == '_')
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_variable (IfParser *g, const char *cp, const char **varp)
michael@0: {
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     if (!isvarfirstletter (*cp))
michael@0: 	return CALLFUNC(g, handle_error) (g, cp, "variable name");
michael@0: 
michael@0:     *varp = cp;
michael@0:     /* EMPTY */
michael@0:     for (cp++; isalnum(*cp) || *cp == '_'; cp++) ;
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_number (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long base = 10;
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     if (!isdigit(*cp))
michael@0: 	return CALLFUNC(g, handle_error) (g, cp, "number");
michael@0: 
michael@0:     *valp = 0;
michael@0: 
michael@0:     if (*cp == '0') {
michael@0: 	cp++;
michael@0: 	if ((*cp == 'x') || (*cp == 'X')) {
michael@0: 	    base = 16;
michael@0: 	    cp++;
michael@0: 	} else {
michael@0: 	    base = 8;
michael@0: 	}
michael@0:     }
michael@0: 
michael@0:     /* Ignore overflows and assume ASCII, what source is usually written in */
michael@0:     while (1) {
michael@0: 	int increment = -1;
michael@0: 	if (base == 8) {
michael@0: 	    if ((*cp >= '0') && (*cp <= '7'))
michael@0: 		increment = *cp++ - '0';
michael@0: 	} else if (base == 16) {
michael@0: 	    if ((*cp >= '0') && (*cp <= '9'))
michael@0: 		increment = *cp++ - '0';
michael@0: 	    else if ((*cp >= 'A') &&  (*cp <= 'F'))
michael@0: 		increment = *cp++ - ('A' - 10);
michael@0: 	    else if ((*cp >= 'a') && (*cp <= 'f'))
michael@0: 		increment = *cp++ - ('a' - 10);
michael@0: 	} else {	/* Decimal */
michael@0: 	    if ((*cp >= '0') && (*cp <= '9'))
michael@0: 		increment = *cp++ - '0';
michael@0: 	}
michael@0: 	if (increment < 0)
michael@0: 	    break;
michael@0: 	*valp = (*valp * base) + increment;
michael@0:     }
michael@0: 
michael@0:     /* Skip trailing qualifiers */
michael@0:     while (*cp == 'U' || *cp == 'u' || *cp == 'L' || *cp == 'l') cp++;
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: static const char *
michael@0: parse_character (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     char val;
michael@0: 
michael@0:     SKIPSPACE (cp);
michael@0:     if (*cp == '\\')
michael@0: 	switch (cp[1]) {
michael@0: 	case 'n': val = '\n'; break;
michael@0: 	case 't': val = '\t'; break;
michael@0: 	case 'v': val = '\v'; break;
michael@0: 	case 'b': val = '\b'; break;
michael@0: 	case 'r': val = '\r'; break;
michael@0: 	case 'f': val = '\f'; break;
michael@0: 	case 'a': val = '\a'; break;
michael@0: 	case '\\': val = '\\'; break;
michael@0: 	case '?': val = '\?'; break;
michael@0: 	case '\'': val = '\''; break;
michael@0: 	case '\"': val = '\"'; break;
michael@0: 	case 'x': val = (char) strtol (cp + 2, NULL, 16); break;
michael@0: 	default: val = (char) strtol (cp + 1, NULL, 8); break;
michael@0: 	}
michael@0:     else
michael@0: 	val = *cp;
michael@0:     while (*cp != '\'') cp++;
michael@0:     *valp = (long) val;
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: static const char *
michael@0: parse_value (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     const char *var, *varend;
michael@0: 
michael@0:     *valp = 0;
michael@0: 
michael@0:     SKIPSPACE (cp);
michael@0:     if (!*cp)
michael@0: 	return cp;
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '(':
michael@0: 	DO (cp = ParseIfExpression (g, cp + 1, valp));
michael@0: 	SKIPSPACE (cp);
michael@0: 	if (*cp != ')') 
michael@0: 	    return CALLFUNC(g, handle_error) (g, cp, ")");
michael@0: 
michael@0: 	return cp + 1;			/* skip the right paren */
michael@0: 
michael@0:       case '!':
michael@0: 	DO (cp = parse_value (g, cp + 1, valp));
michael@0: 	*valp = !(*valp);
michael@0: 	return cp;
michael@0: 
michael@0:       case '-':
michael@0: 	DO (cp = parse_value (g, cp + 1, valp));
michael@0: 	*valp = -(*valp);
michael@0: 	return cp;
michael@0: 
michael@0:       case '+':
michael@0: 	DO (cp = parse_value (g, cp + 1, valp));
michael@0: 	return cp;
michael@0: 
michael@0:       case '~':
michael@0: 	DO (cp = parse_value (g, cp + 1, valp));
michael@0: 	*valp = ~(*valp);
michael@0: 	return cp;
michael@0: 
michael@0:       case '#':
michael@0: 	DO (cp = parse_variable (g, cp + 1, &var));
michael@0: 	SKIPSPACE (cp);
michael@0: 	if (*cp != '(')
michael@0: 	    return CALLFUNC(g, handle_error) (g, cp, "(");
michael@0: 	do {
michael@0: 	    DO (cp = parse_variable (g, cp + 1, &var));
michael@0: 	    SKIPSPACE (cp);
michael@0: 	} while (*cp && *cp != ')');
michael@0: 	if (*cp != ')')
michael@0: 	    return CALLFUNC(g, handle_error) (g, cp, ")");
michael@0: 	*valp = 1; /* XXX */
michael@0: 	return cp + 1;
michael@0: 
michael@0:       case '\'':
michael@0: 	DO (cp = parse_character (g, cp + 1, valp));
michael@0: 	if (*cp != '\'')
michael@0: 	    return CALLFUNC(g, handle_error) (g, cp, "'");
michael@0: 	return cp + 1;
michael@0: 
michael@0:       case 'd':
michael@0: 	if (strncmp (cp, "defined", 7) == 0 && !isalnum(cp[7])) {
michael@0: 	    int paren = 0;
michael@0: 	    int len;
michael@0: 
michael@0: 	    cp += 7;
michael@0: 	    SKIPSPACE (cp);
michael@0: 	    if (*cp == '(') {
michael@0: 		paren = 1;
michael@0: 		cp++;
michael@0: 	    }
michael@0: 	    DO (cp = parse_variable (g, cp, &var));
michael@0: 	    len = cp - var;
michael@0: 	    SKIPSPACE (cp);
michael@0: 	    if (paren && *cp != ')')
michael@0: 		return CALLFUNC(g, handle_error) (g, cp, ")");
michael@0: 	    *valp = (*(g->funcs.eval_defined)) (g, var, len);
michael@0: 	    return cp + paren;		/* skip the right paren */
michael@0: 	}
michael@0: 	/* fall out */
michael@0:     }
michael@0: 
michael@0:     if (isdigit(*cp)) {
michael@0: 	DO (cp = parse_number (g, cp, valp));
michael@0:     } else if (!isvarfirstletter(*cp))
michael@0: 	return CALLFUNC(g, handle_error) (g, cp, "variable or number");
michael@0:     else {
michael@0: 	DO (cp = parse_variable (g, cp, &var));
michael@0: 	varend = cp;
michael@0: 	SKIPSPACE(cp);
michael@0: 	if (*cp != '(') {
michael@0: 	    *valp = (*(g->funcs.eval_variable)) (g, var, varend - var);
michael@0: 	} else {
michael@0: 	    do {
michael@0: 		long dummy;
michael@0: 		DO (cp = ParseIfExpression (g, cp + 1, &dummy));
michael@0: 		SKIPSPACE(cp);
michael@0: 		if (*cp == ')')
michael@0: 		    break;
michael@0: 		if (*cp != ',')
michael@0: 		    return CALLFUNC(g, handle_error) (g, cp, ",");
michael@0: 	    } while (1);
michael@0: 
michael@0: 	    *valp = 1;	/* XXX */
michael@0: 	    cp++;
michael@0: 	}
michael@0:     }
michael@0:     
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_product (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long rightval;
michael@0: 
michael@0:     DO (cp = parse_value (g, cp, valp));
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '*':
michael@0: 	DO (cp = parse_product (g, cp + 1, &rightval));
michael@0: 	*valp = (*valp * rightval);
michael@0: 	break;
michael@0: 
michael@0:       case '/':
michael@0: 	DO (cp = parse_product (g, cp + 1, &rightval));
michael@0: 	if (rightval == 0)
michael@0: 	  return CALLFUNC(g, handle_error) (g, cp, "0");
michael@0: 	*valp = (*valp / rightval);
michael@0: 	break;
michael@0: 
michael@0:       case '%':
michael@0: 	DO (cp = parse_product (g, cp + 1, &rightval));
michael@0: 	*valp = (*valp % rightval);
michael@0: 	break;
michael@0:     }
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_sum (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long rightval;
michael@0: 
michael@0:     DO (cp = parse_product (g, cp, valp));
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '+':
michael@0: 	DO (cp = parse_sum (g, cp + 1, &rightval));
michael@0: 	*valp = (*valp + rightval);
michael@0: 	break;
michael@0: 
michael@0:       case '-':
michael@0: 	DO (cp = parse_sum (g, cp + 1, &rightval));
michael@0: 	*valp = (*valp - rightval);
michael@0: 	break;
michael@0:     }
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_shift (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long rightval;
michael@0: 
michael@0:     DO (cp = parse_sum (g, cp, valp));
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '<':
michael@0: 	if (cp[1] == '<') {
michael@0: 	    DO (cp = parse_shift (g, cp + 2, &rightval));
michael@0: 	    *valp = (*valp << rightval);
michael@0: 	}
michael@0: 	break;
michael@0: 
michael@0:       case '>':
michael@0: 	if (cp[1] == '>') {
michael@0: 	    DO (cp = parse_shift (g, cp + 2, &rightval));
michael@0: 	    *valp = (*valp >> rightval);
michael@0: 	}
michael@0: 	break;
michael@0:     }
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_inequality (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long rightval;
michael@0: 
michael@0:     DO (cp = parse_shift (g, cp, valp));
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '<':
michael@0: 	if (cp[1] == '=') {
michael@0: 	    DO (cp = parse_inequality (g, cp + 2, &rightval));
michael@0: 	    *valp = (*valp <= rightval);
michael@0: 	} else {
michael@0: 	    DO (cp = parse_inequality (g, cp + 1, &rightval));
michael@0: 	    *valp = (*valp < rightval);
michael@0: 	}
michael@0: 	break;
michael@0: 
michael@0:       case '>':
michael@0: 	if (cp[1] == '=') {
michael@0: 	    DO (cp = parse_inequality (g, cp + 2, &rightval));
michael@0: 	    *valp = (*valp >= rightval);
michael@0: 	} else {
michael@0: 	    DO (cp = parse_inequality (g, cp + 1, &rightval));
michael@0: 	    *valp = (*valp > rightval);
michael@0: 	}
michael@0: 	break;
michael@0:     }
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_equality (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long rightval;
michael@0: 
michael@0:     DO (cp = parse_inequality (g, cp, valp));
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '=':
michael@0: 	if (cp[1] == '=')
michael@0: 	    cp++;
michael@0: 	DO (cp = parse_equality (g, cp + 1, &rightval));
michael@0: 	*valp = (*valp == rightval);
michael@0: 	break;
michael@0: 
michael@0:       case '!':
michael@0: 	if (cp[1] != '=')
michael@0: 	    break;
michael@0: 	DO (cp = parse_equality (g, cp + 2, &rightval));
michael@0: 	*valp = (*valp != rightval);
michael@0: 	break;
michael@0:     }
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_band (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long rightval;
michael@0: 
michael@0:     DO (cp = parse_equality (g, cp, valp));
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '&':
michael@0: 	if (cp[1] != '&') {
michael@0: 	    DO (cp = parse_band (g, cp + 1, &rightval));
michael@0: 	    *valp = (*valp & rightval);
michael@0: 	}
michael@0: 	break;
michael@0:     }
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_bxor (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long rightval;
michael@0: 
michael@0:     DO (cp = parse_band (g, cp, valp));
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '^':
michael@0: 	DO (cp = parse_bxor (g, cp + 1, &rightval));
michael@0: 	*valp = (*valp ^ rightval);
michael@0: 	break;
michael@0:     }
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_bor (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long rightval;
michael@0: 
michael@0:     DO (cp = parse_bxor (g, cp, valp));
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '|':
michael@0: 	if (cp[1] != '|') {
michael@0: 	    DO (cp = parse_bor (g, cp + 1, &rightval));
michael@0: 	    *valp = (*valp | rightval);
michael@0: 	}
michael@0: 	break;
michael@0:     }
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_land (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long rightval;
michael@0: 
michael@0:     DO (cp = parse_bor (g, cp, valp));
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '&':
michael@0: 	if (cp[1] != '&')
michael@0: 	    return CALLFUNC(g, handle_error) (g, cp, "&&");
michael@0: 	DO (cp = parse_land (g, cp + 2, &rightval));
michael@0: 	*valp = (*valp && rightval);
michael@0: 	break;
michael@0:     }
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_lor (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long rightval;
michael@0: 
michael@0:     DO (cp = parse_land (g, cp, valp));
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '|':
michael@0: 	if (cp[1] != '|')
michael@0: 	    return CALLFUNC(g, handle_error) (g, cp, "||");
michael@0: 	DO (cp = parse_lor (g, cp + 2, &rightval));
michael@0: 	*valp = (*valp || rightval);
michael@0: 	break;
michael@0:     }
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: static const char *
michael@0: parse_cond(IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     long trueval, falseval;
michael@0: 
michael@0:     DO (cp = parse_lor (g, cp, valp));
michael@0:     SKIPSPACE (cp);
michael@0: 
michael@0:     switch (*cp) {
michael@0:       case '?':
michael@0: 	DO (cp = parse_cond (g, cp + 1, &trueval));
michael@0: 	SKIPSPACE (cp);
michael@0: 	if (*cp != ':')
michael@0: 	    return CALLFUNC(g, handle_error) (g, cp, ":");
michael@0: 	DO (cp = parse_cond (g, cp + 1, &falseval));
michael@0: 	*valp = (*valp ? trueval : falseval);
michael@0: 	break;
michael@0:     }
michael@0:     return cp;
michael@0: }
michael@0: 
michael@0: 
michael@0: /****************************************************************************
michael@0: 			     External Entry Points
michael@0:  ****************************************************************************/
michael@0: 
michael@0: const char *
michael@0: ParseIfExpression (IfParser *g, const char *cp, long *valp)
michael@0: {
michael@0:     return parse_cond (g, cp, valp);
michael@0: }