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IABSD.fr/xenocara/util/makedepend/ifparser.c
matthieu
- util/makedepend/ifparser.c
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/* * * 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 * | '~' 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> #include <stdlib.h> #include <string.h> #include <limits.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(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(IfParser *g, const char *cp, long *valp) { long base = 10; SKIPSPACE(cp); if (!isdigit(*cp)) return CALLFUNC(g, handle_error) (g, cp, "number"); *valp = 0; if (*cp == '0') { cp++; if ((*cp == 'x') || (*cp == 'X')) { base = 16; cp++; } else { base = 8; } } /* Ignore overflows and assume ASCII, what source is usually written in */ while (1) { int increment = -1; if (base == 8) { if ((*cp >= '0') && (*cp <= '7')) increment = *cp++ - '0'; } else if (base == 16) { if ((*cp >= '0') && (*cp <= '9')) increment = *cp++ - '0'; else if ((*cp >= 'A') && (*cp <= 'F')) increment = *cp++ - ('A' - 10); else if ((*cp >= 'a') && (*cp <= 'f')) increment = *cp++ - ('a' - 10); } else { /* Decimal */ if ((*cp >= '0') && (*cp <= '9')) increment = *cp++ - '0'; } if (increment < 0) break; *valp = (*valp * base) + increment; } /* Skip trailing qualifiers */ while (*cp == 'U' || *cp == 'u' || *cp == 'L' || *cp == 'l') cp++; return cp; } static const char * parse_character(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(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)); 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 { const char *varend; DO(cp = parse_variable(g, cp, &var)); varend = cp; SKIPSPACE(cp); if (*cp != '(') { *valp = (*(g->funcs.eval_variable)) (g, var, varend - var); } else { do { long dummy; DO(cp = ParseIfExpression(g, cp + 1, &dummy)); SKIPSPACE(cp); if (*cp == ')') break; if (*cp != ',') return CALLFUNC(g, handle_error) (g, cp, ","); } while (1); *valp = 1; /* XXX */ cp++; } } return cp; } static const char * parse_product(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)); if (rightval) *valp = (*valp / rightval); else *valp = LONG_MAX; break; case '%': DO(cp = parse_product(g, cp + 1, &rightval)); if (rightval) *valp = (*valp % rightval); else *valp = LONG_MAX; break; } return cp; } static const char * parse_sum(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(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(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(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(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(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(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(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(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(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(IfParser *g, const char *cp, long *valp) { return parse_cond(g, cp, valp); }