2 * \file build/expression.c
3 * Simple logical expression parser.
4 * This module implements a basic expression parser with support for
5 * integer and string datatypes. For ease of programming, we use the
6 * top-down "recursive descent" method of parsing. While a
7 * table-driven bottom-up parser might be faster, it does not really
8 * matter for the expressions we will be parsing.
10 * Copyright (C) 1998 Tom Dyas <tdyas@eden.rutgers.edu>
11 * This work is provided under the GPL or LGPL at your choice.
16 #include <rpm/rpmbuild.h>
17 #include <rpm/rpmlog.h>
21 /* #define DEBUG_PARSER 1 */
25 #define DEBUG(x) do { x ; } while (0)
31 * Encapsulation of a "value"
33 typedef struct _value {
34 enum { VALUE_TYPE_INTEGER, VALUE_TYPE_STRING } type;
43 static Value valueMakeInteger(int i)
47 v = (Value) xmalloc(sizeof(*v));
48 v->type = VALUE_TYPE_INTEGER;
55 static Value valueMakeString(const char *s)
59 v = (Value) xmalloc(sizeof(*v));
60 v->type = VALUE_TYPE_STRING;
67 static void valueFree( Value v)
70 if (v->type == VALUE_TYPE_STRING)
71 v->data.s = _constfree(v->data.s);
77 static void valueDump(const char *msg, Value v, FILE *fp)
80 fprintf(fp, "%s ", msg);
82 if (v->type == VALUE_TYPE_INTEGER)
83 fprintf(fp, "INTEGER %d\n", v->data.i);
85 fprintf(fp, "STRING '%s'\n", v->data.s);
87 fprintf(fp, "NULL\n");
91 #define valueIsInteger(v) ((v)->type == VALUE_TYPE_INTEGER)
92 #define valueIsString(v) ((v)->type == VALUE_TYPE_STRING)
93 #define valueSameType(v1,v2) ((v1)->type == (v2)->type)
99 typedef struct _parseState {
100 char *str; /*!< expression string */
101 char *p; /*!< current position in expression string */
102 int nextToken; /*!< current lookahead token */
103 Value tokenValue; /*!< valid when TOK_INTEGER or TOK_STRING */
104 rpmSpec spec; /*!< spec file that we are parsing inside of */
109 * \name Parser tokens
112 #define TOK_INTEGER 2
114 #define TOK_IDENTIFIER 4
117 #define TOK_MULTIPLY 7
120 #define TOK_CLOSE_P 10
128 #define TOK_LOGICAL_AND 18
129 #define TOK_LOGICAL_OR 19
131 #define EXPRBUFSIZ BUFSIZ
133 #if defined(DEBUG_PARSER)
134 typedef struct exprTokTableEntry {
139 ETTE_t exprTokTable[] = {
141 { "I", TOK_INTEGER },
143 { "ID", TOK_IDENTIFIER },
146 { "*", TOK_MULTIPLY },
148 { "( ", TOK_OPEN_P },
149 { " )", TOK_CLOSE_P },
157 { "&&", TOK_LOGICAL_AND },
158 { "||", TOK_LOGICAL_OR },
162 static const char *prToken(int val)
166 for (et = exprTokTable; et->name != NULL; et++) {
172 #endif /* DEBUG_PARSER */
175 * @param state expression parser state
177 static int rdToken(ParseState state)
183 /* Skip whitespace before the next token. */
184 while (*p && risspace(*p)) p++;
198 token = TOK_MULTIPLY;
214 rpmlog(RPMLOG_ERR, _("syntax error while parsing ==\n"));
241 token = TOK_LOGICAL_AND;
244 rpmlog(RPMLOG_ERR, _("syntax error while parsing &&\n"));
250 token = TOK_LOGICAL_OR;
253 rpmlog(RPMLOG_ERR, _("syntax error while parsing ||\n"));
260 char temp[EXPRBUFSIZ], *t = temp;
263 while (*p && risdigit(*p))
269 v = valueMakeInteger(atoi(temp));
271 } else if (risalpha(*p)) {
272 char temp[EXPRBUFSIZ], *t = temp;
275 while (*p && (risalnum(*p) || *p == '_'))
280 token = TOK_IDENTIFIER;
281 v = valueMakeString( xstrdup(temp) );
283 } else if (*p == '\"') {
284 char temp[EXPRBUFSIZ], *t = temp;
288 while (*p && *p != '\"')
293 v = valueMakeString( rpmExpand(temp, NULL) );
296 rpmlog(RPMLOG_ERR, _("parse error in expression\n"));
302 state->nextToken = token;
303 state->tokenValue = v;
305 DEBUG(printf("rdToken: \"%s\" (%d)\n", prToken(token), token));
306 DEBUG(valueDump("rdToken:", state->tokenValue, stdout));
311 static Value doLogical(ParseState state);
314 * @param state expression parser state
316 static Value doPrimary(ParseState state)
320 DEBUG(printf("doPrimary()\n"));
322 switch (state->nextToken) {
326 v = doLogical(state);
327 if (state->nextToken != TOK_CLOSE_P) {
328 rpmlog(RPMLOG_ERR, _("unmatched (\n"));
337 v = state->tokenValue;
342 case TOK_IDENTIFIER: {
343 const char *name = state->tokenValue->data.s;
345 v = valueMakeString( rpmExpand(name, NULL) );
355 v = doPrimary(state);
359 if (! valueIsInteger(v)) {
360 rpmlog(RPMLOG_ERR, _("- only on numbers\n"));
364 v = valueMakeInteger(- v->data.i);
371 v = doPrimary(state);
375 if (! valueIsInteger(v)) {
376 rpmlog(RPMLOG_ERR, _("! only on numbers\n"));
380 v = valueMakeInteger(! v->data.i);
387 DEBUG(valueDump("doPrimary:", v, stdout));
392 * @param state expression parser state
394 static Value doMultiplyDivide(ParseState state)
398 DEBUG(printf("doMultiplyDivide()\n"));
400 v1 = doPrimary(state);
404 while (state->nextToken == TOK_MULTIPLY
405 || state->nextToken == TOK_DIVIDE) {
406 int op = state->nextToken;
411 if (v2) valueFree(v2);
413 v2 = doPrimary(state);
417 if (! valueSameType(v1, v2)) {
418 rpmlog(RPMLOG_ERR, _("types must match\n"));
422 if (valueIsInteger(v1)) {
423 int i1 = v1->data.i, i2 = v2->data.i;
426 if (op == TOK_MULTIPLY)
427 v1 = valueMakeInteger(i1 * i2);
429 v1 = valueMakeInteger(i1 / i2);
431 rpmlog(RPMLOG_ERR, _("* / not suported for strings\n"));
436 if (v2) valueFree(v2);
441 * @param state expression parser state
443 static Value doAddSubtract(ParseState state)
447 DEBUG(printf("doAddSubtract()\n"));
449 v1 = doMultiplyDivide(state);
453 while (state->nextToken == TOK_ADD || state->nextToken == TOK_MINUS) {
454 int op = state->nextToken;
459 if (v2) valueFree(v2);
461 v2 = doMultiplyDivide(state);
465 if (! valueSameType(v1, v2)) {
466 rpmlog(RPMLOG_ERR, _("types must match\n"));
470 if (valueIsInteger(v1)) {
471 int i1 = v1->data.i, i2 = v2->data.i;
475 v1 = valueMakeInteger(i1 + i2);
477 v1 = valueMakeInteger(i1 - i2);
481 if (op == TOK_MINUS) {
482 rpmlog(RPMLOG_ERR, _("- not suported for strings\n"));
486 copy = xmalloc(strlen(v1->data.s) + strlen(v2->data.s) + 1);
487 (void) stpcpy( stpcpy(copy, v1->data.s), v2->data.s);
490 v1 = valueMakeString(copy);
494 if (v2) valueFree(v2);
499 * @param state expression parser state
501 static Value doRelational(ParseState state)
505 DEBUG(printf("doRelational()\n"));
507 v1 = doAddSubtract(state);
511 while (state->nextToken >= TOK_EQ && state->nextToken <= TOK_GE) {
512 int op = state->nextToken;
517 if (v2) valueFree(v2);
519 v2 = doAddSubtract(state);
523 if (! valueSameType(v1, v2)) {
524 rpmlog(RPMLOG_ERR, _("types must match\n"));
528 if (valueIsInteger(v1)) {
529 int i1 = v1->data.i, i2 = v2->data.i, r = 0;
553 v1 = valueMakeInteger(r);
555 const char * s1 = v1->data.s;
556 const char * s2 = v2->data.s;
560 r = (strcmp(s1,s2) == 0);
563 r = (strcmp(s1,s2) != 0);
566 r = (strcmp(s1,s2) < 0);
569 r = (strcmp(s1,s2) <= 0);
572 r = (strcmp(s1,s2) > 0);
575 r = (strcmp(s1,s2) >= 0);
581 v1 = valueMakeInteger(r);
585 if (v2) valueFree(v2);
590 * @param state expression parser state
592 static Value doLogical(ParseState state)
596 DEBUG(printf("doLogical()\n"));
598 v1 = doRelational(state);
602 while (state->nextToken == TOK_LOGICAL_AND
603 || state->nextToken == TOK_LOGICAL_OR) {
604 int op = state->nextToken;
609 if (v2) valueFree(v2);
611 v2 = doRelational(state);
615 if (! valueSameType(v1, v2)) {
616 rpmlog(RPMLOG_ERR, _("types must match\n"));
620 if (valueIsInteger(v1)) {
621 int i1 = v1->data.i, i2 = v2->data.i;
624 if (op == TOK_LOGICAL_AND)
625 v1 = valueMakeInteger(i1 && i2);
627 v1 = valueMakeInteger(i1 || i2);
629 rpmlog(RPMLOG_ERR, _("&& and || not suported for strings\n"));
634 if (v2) valueFree(v2);
638 int parseExpressionBoolean(rpmSpec spec, const char *expr)
640 struct _parseState state;
644 DEBUG(printf("parseExprBoolean(?, '%s')\n", expr));
646 /* Initialize the expression parser state. */
647 state.p = state.str = xstrdup(expr);
650 state.tokenValue = NULL;
651 (void) rdToken(&state);
653 /* Parse the expression. */
654 v = doLogical(&state);
656 state.str = _free(state.str);
660 /* If the next token is not TOK_EOF, we have a syntax error. */
661 if (state.nextToken != TOK_EOF) {
662 rpmlog(RPMLOG_ERR, _("syntax error in expression\n"));
663 state.str = _free(state.str);
667 DEBUG(valueDump("parseExprBoolean:", v, stdout));
670 case VALUE_TYPE_INTEGER:
671 result = v->data.i != 0;
673 case VALUE_TYPE_STRING:
674 result = v->data.s[0] != '\0';
680 state.str = _free(state.str);
685 char * parseExpressionString(rpmSpec spec, const char *expr)
687 struct _parseState state;
691 DEBUG(printf("parseExprString(?, '%s')\n", expr));
693 /* Initialize the expression parser state. */
694 state.p = state.str = xstrdup(expr);
697 state.tokenValue = NULL;
698 (void) rdToken(&state);
700 /* Parse the expression. */
701 v = doLogical(&state);
703 state.str = _free(state.str);
707 /* If the next token is not TOK_EOF, we have a syntax error. */
708 if (state.nextToken != TOK_EOF) {
709 rpmlog(RPMLOG_ERR, _("syntax error in expression\n"));
710 state.str = _free(state.str);
714 DEBUG(valueDump("parseExprString:", v, stdout));
717 case VALUE_TYPE_INTEGER: {
719 sprintf(buf, "%d", v->data.i);
720 result = xstrdup(buf);
722 case VALUE_TYPE_STRING:
723 result = xstrdup(v->data.s);
729 state.str = _free(state.str);