+++ /dev/null
-/*
- * $XConsortium: ifparser.c /main/10 1996/09/28 16:15:18 rws $
- * $XFree86: xc/config/makedepend/ifparser.c,v 3.6 1996/12/30 13:57:55 dawes Exp $
- *
- * Copyright 1992 Network Computing Devices, Inc.
- *
- * Permission to use, copy, modify, and distribute this software and its
- * documentation for any purpose and without fee is hereby granted, provided
- * that the above copyright notice appear in all copies and that both that
- * copyright notice and this permission notice appear in supporting
- * documentation, and that the name of Network Computing Devices may not be
- * used in advertising or publicity pertaining to distribution of the software
- * without specific, written prior permission. Network Computing Devices makes
- * no representations about the suitability of this software for any purpose.
- * It is provided ``as is'' without express or implied warranty.
- *
- * NETWORK COMPUTING DEVICES DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
- * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
- * IN NO EVENT SHALL NETWORK COMPUTING DEVICES BE LIABLE FOR ANY SPECIAL,
- * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
- * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
- * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
- * PERFORMANCE OF THIS SOFTWARE.
- *
- * Author: Jim Fulton
- * Network Computing Devices, Inc.
- *
- * Simple if statement processor
- *
- * This module can be used to evaluate string representations of C language
- * if constructs. It accepts the following grammar:
- *
- * EXPRESSION := VALUE
- * | VALUE BINOP EXPRESSION
- * | VALUE '?' EXPRESSION ':' EXPRESSION
- *
- * VALUE := '(' EXPRESSION ')'
- * | '!' VALUE
- * | '-' VALUE
- * | '~' VALUE
- * | 'defined' '(' variable ')'
- * | 'defined' variable
- * | # variable '(' variable-list ')'
- * | variable
- * | number
- *
- * BINOP := '*' | '/' | '%'
- * | '+' | '-'
- * | '<<' | '>>'
- * | '<' | '>' | '<=' | '>='
- * | '==' | '!='
- * | '&' | '^' | '|'
- * | '&&' | '||'
- *
- * The normal C order of precedence is supported.
- *
- *
- * External Entry Points:
- *
- * ParseIfExpression parse a string for #if
- */
-
-#include "ifparser.h"
-#include <ctype.h>
-
-/****************************************************************************
- Internal Macros and Utilities for Parser
- ****************************************************************************/
-
-#define DO(val) if (!(val)) return NULL
-#define CALLFUNC(ggg,fff) (*((ggg)->funcs.fff))
-#define SKIPSPACE(ccc) while (isspace(*ccc)) ccc++
-#define isvarfirstletter(ccc) (isalpha(ccc) || (ccc) == '_')
-
-
-static const char *
-parse_variable (g, cp, varp)
- IfParser *g;
- const char *cp;
- const char **varp;
-{
- SKIPSPACE (cp);
-
- if (!isvarfirstletter (*cp))
- return CALLFUNC(g, handle_error) (g, cp, "variable name");
-
- *varp = cp;
- /* EMPTY */
- for (cp++; isalnum(*cp) || *cp == '_'; cp++) ;
- return cp;
-}
-
-
-static const char *
-parse_number (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- SKIPSPACE (cp);
-
- if (!isdigit(*cp))
- return CALLFUNC(g, handle_error) (g, cp, "number");
-
- *valp = strtol(cp, &cp, 0);
- /* skip trailing qualifiers */
- while (*cp == 'U' || *cp == 'u' || *cp == 'L' || *cp == 'l') cp++;
-#if 0
- *valp = atoi (cp);
- /* EMPTY */
- for (cp++; isdigit(*cp); cp++) ;
-#endif
- return cp;
-}
-
-static const char *
-parse_character (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- char val;
-
- SKIPSPACE (cp);
- if (*cp == '\\')
- switch (cp[1]) {
- case 'n': val = '\n'; break;
- case 't': val = '\t'; break;
- case 'v': val = '\v'; break;
- case 'b': val = '\b'; break;
- case 'r': val = '\r'; break;
- case 'f': val = '\f'; break;
- case 'a': val = '\a'; break;
- case '\\': val = '\\'; break;
- case '?': val = '\?'; break;
- case '\'': val = '\''; break;
- case '\"': val = '\"'; break;
- case 'x': val = (char) strtol (cp + 2, NULL, 16); break;
- default: val = (char) strtol (cp + 1, NULL, 8); break;
- }
- else
- val = *cp;
- while (*cp != '\'') cp++;
- *valp = (long) val;
- return cp;
-}
-
-static const char *
-parse_value (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- const char *var;
-
- *valp = 0;
-
- SKIPSPACE (cp);
- if (!*cp)
- return cp;
-
- switch (*cp) {
- case '(':
- DO (cp = ParseIfExpression (g, cp + 1, valp));
- SKIPSPACE (cp);
- if (*cp != ')')
- return CALLFUNC(g, handle_error) (g, cp, ")");
-
- return cp + 1; /* skip the right paren */
-
- case '!':
- DO (cp = parse_value (g, cp + 1, valp));
- *valp = !(*valp);
- return cp;
-
- case '-':
- DO (cp = parse_value (g, cp + 1, valp));
- *valp = -(*valp);
- return cp;
-
- case '~':
- DO (cp = parse_value (g, cp + 1, valp));
- *valp = ~(*valp);
- return cp;
-
- case '#':
- DO (cp = parse_variable (g, cp + 1, &var));
- SKIPSPACE (cp);
- if (*cp != '(')
- return CALLFUNC(g, handle_error) (g, cp, "(");
- do {
- DO (cp = parse_variable (g, cp + 1, &var));
- SKIPSPACE (cp);
- } while (*cp && *cp != ')');
- if (*cp != ')')
- return CALLFUNC(g, handle_error) (g, cp, ")");
- *valp = 1; /* XXX */
- return cp + 1;
-
- case '\'':
- DO (cp = parse_character (g, cp + 1, valp));
- if (*cp != '\'')
- return CALLFUNC(g, handle_error) (g, cp, "'");
- return cp + 1;
-
- case 'd':
- if (strncmp (cp, "defined", 7) == 0 && !isalnum(cp[7])) {
- int paren = 0;
- int len;
-
- cp += 7;
- SKIPSPACE (cp);
- if (*cp == '(') {
- paren = 1;
- cp++;
- }
- DO (cp = parse_variable (g, cp, &var));
- len = cp - var;
- SKIPSPACE (cp);
- if (paren && *cp != ')')
- return CALLFUNC(g, handle_error) (g, cp, ")");
- *valp = (*(g->funcs.eval_defined)) (g, var, len);
- return cp + paren; /* skip the right paren */
- }
- /* fall out */
- }
-
- if (isdigit(*cp)) {
- DO (cp = parse_number (g, cp, valp));
- } else if (!isvarfirstletter(*cp))
- return CALLFUNC(g, handle_error) (g, cp, "variable or number");
- else {
- DO (cp = parse_variable (g, cp, &var));
- *valp = (*(g->funcs.eval_variable)) (g, var, cp - var);
- }
-
- return cp;
-}
-
-
-
-static const char *
-parse_product (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- long rightval;
-
- DO (cp = parse_value (g, cp, valp));
- SKIPSPACE (cp);
-
- switch (*cp) {
- case '*':
- DO (cp = parse_product (g, cp + 1, &rightval));
- *valp = (*valp * rightval);
- break;
-
- case '/':
- DO (cp = parse_product (g, cp + 1, &rightval));
- *valp = (*valp / rightval);
- break;
-
- case '%':
- DO (cp = parse_product (g, cp + 1, &rightval));
- *valp = (*valp % rightval);
- break;
- }
- return cp;
-}
-
-
-static const char *
-parse_sum (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- long rightval;
-
- DO (cp = parse_product (g, cp, valp));
- SKIPSPACE (cp);
-
- switch (*cp) {
- case '+':
- DO (cp = parse_sum (g, cp + 1, &rightval));
- *valp = (*valp + rightval);
- break;
-
- case '-':
- DO (cp = parse_sum (g, cp + 1, &rightval));
- *valp = (*valp - rightval);
- break;
- }
- return cp;
-}
-
-
-static const char *
-parse_shift (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- long rightval;
-
- DO (cp = parse_sum (g, cp, valp));
- SKIPSPACE (cp);
-
- switch (*cp) {
- case '<':
- if (cp[1] == '<') {
- DO (cp = parse_shift (g, cp + 2, &rightval));
- *valp = (*valp << rightval);
- }
- break;
-
- case '>':
- if (cp[1] == '>') {
- DO (cp = parse_shift (g, cp + 2, &rightval));
- *valp = (*valp >> rightval);
- }
- break;
- }
- return cp;
-}
-
-
-static const char *
-parse_inequality (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- long rightval;
-
- DO (cp = parse_shift (g, cp, valp));
- SKIPSPACE (cp);
-
- switch (*cp) {
- case '<':
- if (cp[1] == '=') {
- DO (cp = parse_inequality (g, cp + 2, &rightval));
- *valp = (*valp <= rightval);
- } else {
- DO (cp = parse_inequality (g, cp + 1, &rightval));
- *valp = (*valp < rightval);
- }
- break;
-
- case '>':
- if (cp[1] == '=') {
- DO (cp = parse_inequality (g, cp + 2, &rightval));
- *valp = (*valp >= rightval);
- } else {
- DO (cp = parse_inequality (g, cp + 1, &rightval));
- *valp = (*valp > rightval);
- }
- break;
- }
- return cp;
-}
-
-
-static const char *
-parse_equality (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- long rightval;
-
- DO (cp = parse_inequality (g, cp, valp));
- SKIPSPACE (cp);
-
- switch (*cp) {
- case '=':
- if (cp[1] == '=')
- cp++;
- DO (cp = parse_equality (g, cp + 1, &rightval));
- *valp = (*valp == rightval);
- break;
-
- case '!':
- if (cp[1] != '=')
- break;
- DO (cp = parse_equality (g, cp + 2, &rightval));
- *valp = (*valp != rightval);
- break;
- }
- return cp;
-}
-
-
-static const char *
-parse_band (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- long rightval;
-
- DO (cp = parse_equality (g, cp, valp));
- SKIPSPACE (cp);
-
- switch (*cp) {
- case '&':
- if (cp[1] != '&') {
- DO (cp = parse_band (g, cp + 1, &rightval));
- *valp = (*valp & rightval);
- }
- break;
- }
- return cp;
-}
-
-
-static const char *
-parse_bxor (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- long rightval;
-
- DO (cp = parse_band (g, cp, valp));
- SKIPSPACE (cp);
-
- switch (*cp) {
- case '^':
- DO (cp = parse_bxor (g, cp + 1, &rightval));
- *valp = (*valp ^ rightval);
- break;
- }
- return cp;
-}
-
-
-static const char *
-parse_bor (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- long rightval;
-
- DO (cp = parse_bxor (g, cp, valp));
- SKIPSPACE (cp);
-
- switch (*cp) {
- case '|':
- if (cp[1] != '|') {
- DO (cp = parse_bor (g, cp + 1, &rightval));
- *valp = (*valp | rightval);
- }
- break;
- }
- return cp;
-}
-
-
-static const char *
-parse_land (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- long rightval;
-
- DO (cp = parse_bor (g, cp, valp));
- SKIPSPACE (cp);
-
- switch (*cp) {
- case '&':
- if (cp[1] != '&')
- return CALLFUNC(g, handle_error) (g, cp, "&&");
- DO (cp = parse_land (g, cp + 2, &rightval));
- *valp = (*valp && rightval);
- break;
- }
- return cp;
-}
-
-
-static const char *
-parse_lor (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- long rightval;
-
- DO (cp = parse_land (g, cp, valp));
- SKIPSPACE (cp);
-
- switch (*cp) {
- case '|':
- if (cp[1] != '|')
- return CALLFUNC(g, handle_error) (g, cp, "||");
- DO (cp = parse_lor (g, cp + 2, &rightval));
- *valp = (*valp || rightval);
- break;
- }
- return cp;
-}
-
-
-static const char *
-parse_cond(g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- long trueval, falseval;
-
- DO (cp = parse_lor (g, cp, valp));
- SKIPSPACE (cp);
-
- switch (*cp) {
- case '?':
- DO (cp = parse_cond (g, cp + 1, &trueval));
- SKIPSPACE (cp);
- if (*cp != ':')
- return CALLFUNC(g, handle_error) (g, cp, ":");
- DO (cp = parse_cond (g, cp + 1, &falseval));
- *valp = (*valp ? trueval : falseval);
- break;
- }
- return cp;
-}
-
-
-/****************************************************************************
- External Entry Points
- ****************************************************************************/
-
-const char *
-ParseIfExpression (g, cp, valp)
- IfParser *g;
- const char *cp;
- long *valp;
-{
- return parse_cond (g, cp, valp);
-}
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