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-rw-r--r--expr.c608
1 files changed, 608 insertions, 0 deletions
diff --git a/expr.c b/expr.c
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+++ b/expr.c
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+/* $NetBSD: expr.c,v 1.12 2018/05/08 16:37:59 kamil Exp $ */
+
+/*
+ * Korn expression evaluation
+ */
+/*
+ * todo: better error handling: if in builtin, should be builtin error, etc.
+ */
+#include <sys/cdefs.h>
+
+#ifndef lint
+__RCSID("$NetBSD: expr.c,v 1.12 2018/05/08 16:37:59 kamil Exp $");
+#endif
+
+
+#include "sh.h"
+#include <ctype.h>
+#include <stdbool.h>
+
+/* The order of these enums is constrained by the order of opinfo[] */
+enum token {
+ /* some (long) unary operators */
+ O_PLUSPLUS = 0, O_MINUSMINUS,
+ /* binary operators */
+ O_EQ, O_NE,
+ /* assignments are assumed to be in range O_ASN .. O_BORASN */
+ O_ASN, O_TIMESASN, O_DIVASN, O_MODASN, O_PLUSASN, O_MINUSASN,
+ O_LSHIFTASN, O_RSHIFTASN, O_BANDASN, O_BXORASN, O_BORASN,
+ O_LSHIFT, O_RSHIFT,
+ O_LE, O_GE, O_LT, O_GT,
+ O_LAND,
+ O_LOR,
+ O_TIMES, O_DIV, O_MOD,
+ O_PLUS, O_MINUS,
+ O_BAND,
+ O_BXOR,
+ O_BOR,
+ O_TERN,
+ O_COMMA,
+ /* things after this aren't used as binary operators */
+ /* unary that are not also binaries */
+ O_BNOT, O_LNOT,
+ /* misc */
+ OPEN_PAREN, CLOSE_PAREN, CTERN,
+ /* things that don't appear in the opinfo[] table */
+ VAR, LIT, END, BAD
+ };
+#define IS_BINOP(op) (((int)op) >= (int)O_EQ && ((int)op) <= (int)O_COMMA)
+#define IS_ASSIGNOP(op) ((int)(op) >= (int)O_ASN && (int)(op) <= (int)O_BORASN)
+
+enum prec {
+ P_PRIMARY = 0, /* VAR, LIT, (), ~ ! - + */
+ P_MULT, /* * / % */
+ P_ADD, /* + - */
+ P_SHIFT, /* << >> */
+ P_RELATION, /* < <= > >= */
+ P_EQUALITY, /* == != */
+ P_BAND, /* & */
+ P_BXOR, /* ^ */
+ P_BOR, /* | */
+ P_LAND, /* && */
+ P_LOR, /* || */
+ P_TERN, /* ?: */
+ P_ASSIGN, /* = *= /= %= += -= <<= >>= &= ^= |= */
+ P_COMMA /* , */
+ };
+#define MAX_PREC P_COMMA
+
+struct opinfo {
+ char name[4];
+ int len; /* name length */
+ enum prec prec; /* precedence: lower is higher */
+};
+
+/* Tokens in this table must be ordered so the longest are first
+ * (eg, += before +). If you change something, change the order
+ * of enum token too.
+ */
+static const struct opinfo opinfo[] = {
+ { "++", 2, P_PRIMARY }, /* before + */
+ { "--", 2, P_PRIMARY }, /* before - */
+ { "==", 2, P_EQUALITY }, /* before = */
+ { "!=", 2, P_EQUALITY }, /* before ! */
+ { "=", 1, P_ASSIGN }, /* keep assigns in a block */
+ { "*=", 2, P_ASSIGN },
+ { "/=", 2, P_ASSIGN },
+ { "%=", 2, P_ASSIGN },
+ { "+=", 2, P_ASSIGN },
+ { "-=", 2, P_ASSIGN },
+ { "<<=", 3, P_ASSIGN },
+ { ">>=", 3, P_ASSIGN },
+ { "&=", 2, P_ASSIGN },
+ { "^=", 2, P_ASSIGN },
+ { "|=", 2, P_ASSIGN },
+ { "<<", 2, P_SHIFT },
+ { ">>", 2, P_SHIFT },
+ { "<=", 2, P_RELATION },
+ { ">=", 2, P_RELATION },
+ { "<", 1, P_RELATION },
+ { ">", 1, P_RELATION },
+ { "&&", 2, P_LAND },
+ { "||", 2, P_LOR },
+ { "*", 1, P_MULT },
+ { "/", 1, P_MULT },
+ { "%", 1, P_MULT },
+ { "+", 1, P_ADD },
+ { "-", 1, P_ADD },
+ { "&", 1, P_BAND },
+ { "^", 1, P_BXOR },
+ { "|", 1, P_BOR },
+ { "?", 1, P_TERN },
+ { ",", 1, P_COMMA },
+ { "~", 1, P_PRIMARY },
+ { "!", 1, P_PRIMARY },
+ { "(", 1, P_PRIMARY },
+ { ")", 1, P_PRIMARY },
+ { ":", 1, P_PRIMARY },
+ { "", 0, P_PRIMARY } /* end of table */
+ };
+
+
+typedef struct expr_state Expr_state;
+struct expr_state {
+ const char *expression; /* expression being evaluated */
+ const char *tokp; /* lexical position */
+ enum token tok; /* token from token() */
+ int noassign; /* don't do assigns (for ?:,&&,||) */
+ struct tbl *val; /* value from token() */
+ struct tbl *evaling; /* variable that is being recursively
+ * expanded (EXPRINEVAL flag set)
+ */
+};
+
+enum error_type { ET_UNEXPECTED, ET_BADLIT, ET_RECURSIVE,
+ ET_LVALUE, ET_RDONLY, ET_STR };
+
+static void evalerr ARGS((Expr_state *es, enum error_type type,
+ const char *str)) GCC_FUNC_ATTR(noreturn);
+static struct tbl *evalexpr ARGS((Expr_state *es, enum prec prec));
+static void token ARGS((Expr_state *es));
+static struct tbl *do_ppmm(Expr_state *, enum token, struct tbl *, bool);
+static void assign_check ARGS((Expr_state *es, enum token op,
+ struct tbl *vasn));
+static struct tbl *tempvar ARGS((void));
+static struct tbl *intvar ARGS((Expr_state *es, struct tbl *vp));
+
+/*
+ * parse and evaluate expression
+ */
+int
+evaluate(expr, rval, error_ok)
+ const char *expr;
+ long *rval;
+ int error_ok;
+{
+ struct tbl v;
+ int ret;
+
+ v.flag = DEFINED|INTEGER;
+ v.type = 0;
+ ret = v_evaluate(&v, expr, error_ok);
+ *rval = v.val.i;
+ return ret;
+}
+
+/*
+ * parse and evaluate expression, storing result in vp.
+ */
+int
+v_evaluate(vp, expr, error_ok)
+ struct tbl *vp;
+ const char *expr;
+ volatile int error_ok;
+{
+ struct tbl *v;
+ Expr_state curstate;
+ Expr_state * const es = &curstate;
+ int i;
+
+ /* save state to allow recursive calls */
+ curstate.expression = curstate.tokp = expr;
+ curstate.noassign = 0;
+ curstate.evaling = (struct tbl *) 0;
+
+ newenv(E_ERRH);
+ i = ksh_sigsetjmp(e->jbuf, 0);
+ if (i) {
+ /* Clear EXPRINEVAL in of any variables we were playing with */
+ if (curstate.evaling)
+ curstate.evaling->flag &= ~EXPRINEVAL;
+ quitenv();
+ if (i == LAEXPR) {
+ if (error_ok == KSH_RETURN_ERROR)
+ return 0;
+ errorf("%s", null);
+ }
+ unwind(i);
+ /*NOTREACHED*/
+ }
+
+ token(es);
+#if 1 /* ifdef-out to disallow empty expressions to be treated as 0 */
+ if (es->tok == END) {
+ es->tok = LIT;
+ es->val = tempvar();
+ }
+#endif /* 0 */
+ v = intvar(es, evalexpr(es, MAX_PREC));
+
+ if (es->tok != END)
+ evalerr(es, ET_UNEXPECTED, (char *) 0);
+
+ if (vp->flag & INTEGER)
+ setint_v(vp, v);
+ else
+ /* can fail if readonly */
+ setstr(vp, str_val(v), error_ok);
+
+ quitenv();
+
+ return 1;
+}
+
+static void
+evalerr(es, type, str)
+ Expr_state *es;
+ enum error_type type;
+ const char *str;
+{
+ char tbuf[2];
+ const char *s;
+
+ switch (type) {
+ case ET_UNEXPECTED:
+ switch (es->tok) {
+ case VAR:
+ s = es->val->name;
+ break;
+ case LIT:
+ s = str_val(es->val);
+ break;
+ case END:
+ s = "end of expression";
+ break;
+ case BAD:
+ tbuf[0] = *es->tokp;
+ tbuf[1] = '\0';
+ s = tbuf;
+ break;
+ default:
+ s = opinfo[(int)es->tok].name;
+ }
+ warningf(true, "%s: unexpected `%s'", es->expression, s);
+ break;
+
+ case ET_BADLIT:
+ warningf(true, "%s: bad number `%s'", es->expression, str);
+ break;
+
+ case ET_RECURSIVE:
+ warningf(true, "%s: expression recurses on parameter `%s'",
+ es->expression, str);
+ break;
+
+ case ET_LVALUE:
+ warningf(true, "%s: %s requires lvalue",
+ es->expression, str);
+ break;
+
+ case ET_RDONLY:
+ warningf(true, "%s: %s applied to read only variable",
+ es->expression, str);
+ break;
+
+ default: /* keep gcc happy */
+ case ET_STR:
+ warningf(true, "%s: %s", es->expression, str);
+ break;
+ }
+ unwind(LAEXPR);
+}
+
+static struct tbl *
+evalexpr(es, prec)
+ Expr_state *es;
+ enum prec prec;
+{
+ struct tbl *vl, UNINITIALIZED(*vr), *vasn;
+ enum token op;
+ long UNINITIALIZED(res);
+
+ if (prec == P_PRIMARY) {
+ op = es->tok;
+ if (op == O_BNOT || op == O_LNOT || op == O_MINUS
+ || op == O_PLUS)
+ {
+ token(es);
+ vl = intvar(es, evalexpr(es, P_PRIMARY));
+ if (op == O_BNOT)
+ vl->val.i = ~vl->val.i;
+ else if (op == O_LNOT)
+ vl->val.i = !vl->val.i;
+ else if (op == O_MINUS)
+ vl->val.i = -vl->val.i;
+ /* op == O_PLUS is a no-op */
+ } else if (op == OPEN_PAREN) {
+ token(es);
+ vl = evalexpr(es, MAX_PREC);
+ if (es->tok != CLOSE_PAREN)
+ evalerr(es, ET_STR, "missing )");
+ token(es);
+ } else if (op == O_PLUSPLUS || op == O_MINUSMINUS) {
+ token(es);
+ vl = do_ppmm(es, op, es->val, true);
+ token(es);
+ } else if (op == VAR || op == LIT) {
+ vl = es->val;
+ token(es);
+ } else {
+ evalerr(es, ET_UNEXPECTED, (char *) 0);
+ /*NOTREACHED*/
+ }
+ if (es->tok == O_PLUSPLUS || es->tok == O_MINUSMINUS) {
+ vl = do_ppmm(es, es->tok, vl, false);
+ token(es);
+ }
+ return vl;
+ }
+ vl = evalexpr(es, ((int) prec) - 1);
+ for (op = es->tok; IS_BINOP(op) && opinfo[(int) op].prec == prec;
+ op = es->tok)
+ {
+ token(es);
+ vasn = vl;
+ if (op != O_ASN) /* vl may not have a value yet */
+ vl = intvar(es, vl);
+ if (IS_ASSIGNOP(op)) {
+ assign_check(es, op, vasn);
+ vr = intvar(es, evalexpr(es, P_ASSIGN));
+ } else if (op != O_TERN && op != O_LAND && op != O_LOR)
+ vr = intvar(es, evalexpr(es, ((int) prec) - 1));
+ if ((op == O_DIV || op == O_MOD || op == O_DIVASN
+ || op == O_MODASN) && vr->val.i == 0)
+ {
+ if (es->noassign)
+ vr->val.i = 1;
+ else
+ evalerr(es, ET_STR, "zero divisor");
+ }
+ switch ((int) op) {
+ case O_TIMES:
+ case O_TIMESASN:
+ res = vl->val.i * vr->val.i;
+ break;
+ case O_DIV:
+ case O_DIVASN:
+ res = vl->val.i / vr->val.i;
+ break;
+ case O_MOD:
+ case O_MODASN:
+ res = vl->val.i % vr->val.i;
+ break;
+ case O_PLUS:
+ case O_PLUSASN:
+ res = vl->val.i + vr->val.i;
+ break;
+ case O_MINUS:
+ case O_MINUSASN:
+ res = vl->val.i - vr->val.i;
+ break;
+ case O_LSHIFT:
+ case O_LSHIFTASN:
+ res = vl->val.i << vr->val.i;
+ break;
+ case O_RSHIFT:
+ case O_RSHIFTASN:
+ res = vl->val.i >> vr->val.i;
+ break;
+ case O_LT:
+ res = vl->val.i < vr->val.i;
+ break;
+ case O_LE:
+ res = vl->val.i <= vr->val.i;
+ break;
+ case O_GT:
+ res = vl->val.i > vr->val.i;
+ break;
+ case O_GE:
+ res = vl->val.i >= vr->val.i;
+ break;
+ case O_EQ:
+ res = vl->val.i == vr->val.i;
+ break;
+ case O_NE:
+ res = vl->val.i != vr->val.i;
+ break;
+ case O_BAND:
+ case O_BANDASN:
+ res = vl->val.i & vr->val.i;
+ break;
+ case O_BXOR:
+ case O_BXORASN:
+ res = vl->val.i ^ vr->val.i;
+ break;
+ case O_BOR:
+ case O_BORASN:
+ res = vl->val.i | vr->val.i;
+ break;
+ case O_LAND:
+ if (!vl->val.i)
+ es->noassign++;
+ vr = intvar(es, evalexpr(es, ((int) prec) - 1));
+ res = vl->val.i && vr->val.i;
+ if (!vl->val.i)
+ es->noassign--;
+ break;
+ case O_LOR:
+ if (vl->val.i)
+ es->noassign++;
+ vr = intvar(es, evalexpr(es, ((int) prec) - 1));
+ res = vl->val.i || vr->val.i;
+ if (vl->val.i)
+ es->noassign--;
+ break;
+ case O_TERN:
+ {
+ int ex = vl->val.i != 0;
+ if (!ex)
+ es->noassign++;
+ vl = evalexpr(es, MAX_PREC);
+ if (!ex)
+ es->noassign--;
+ if (es->tok != CTERN)
+ evalerr(es, ET_STR, "missing :");
+ token(es);
+ if (ex)
+ es->noassign++;
+ vr = evalexpr(es, P_TERN);
+ if (ex)
+ es->noassign--;
+ vl = ex ? vl : vr;
+ }
+ break;
+ case O_ASN:
+ res = vr->val.i;
+ break;
+ case O_COMMA:
+ res = vr->val.i;
+ break;
+ }
+ if (IS_ASSIGNOP(op)) {
+ vr->val.i = res;
+ if (vasn->flag & INTEGER)
+ setint_v(vasn, vr);
+ else
+ setint(vasn, res);
+ vl = vr;
+ } else if (op != O_TERN)
+ vl->val.i = res;
+ }
+ return vl;
+}
+
+static void
+token(es)
+ Expr_state *es;
+{
+ const char *cp;
+ int c;
+ char *tvar;
+
+ /* skip white space */
+ for (cp = es->tokp; (c = *cp), isspace((unsigned char)c); cp++)
+ ;
+ es->tokp = cp;
+
+ if (c == '\0')
+ es->tok = END;
+ else if (letter(c)) {
+ for (; letnum(c); c = *cp)
+ cp++;
+ if (c == '[') {
+ int len;
+
+ len = array_ref_len(cp);
+ if (len == 0)
+ evalerr(es, ET_STR, "missing ]");
+ cp += len;
+ }
+#ifdef KSH
+ else if (c == '(' /*)*/ ) {
+ /* todo: add math functions (all take single argument):
+ * abs acos asin atan cos cosh exp int log sin sinh sqrt
+ * tan tanh
+ */
+ ;
+ }
+#endif /* KSH */
+ if (es->noassign) {
+ es->val = tempvar();
+ es->val->flag |= EXPRLVALUE;
+ } else {
+ tvar = str_nsave(es->tokp, cp - es->tokp, ATEMP);
+ es->val = global(tvar);
+ afree(tvar, ATEMP);
+ }
+ es->tok = VAR;
+ } else if (digit(c)) {
+ for (; c != '_' && (letnum(c) || c == '#'); c = *cp++)
+ ;
+ tvar = str_nsave(es->tokp, --cp - es->tokp, ATEMP);
+ es->val = tempvar();
+ es->val->flag &= ~INTEGER;
+ es->val->type = 0;
+ es->val->val.s = tvar;
+ if (setint_v(es->val, es->val) == NULL)
+ evalerr(es, ET_BADLIT, tvar);
+ afree(tvar, ATEMP);
+ es->tok = LIT;
+ } else {
+ int i, n0;
+
+ for (i = 0; (n0 = opinfo[i].name[0]); i++)
+ if (c == n0
+ && strncmp(cp, opinfo[i].name, opinfo[i].len) == 0)
+ {
+ es->tok = (enum token) i;
+ cp += opinfo[i].len;
+ break;
+ }
+ if (!n0)
+ es->tok = BAD;
+ }
+ es->tokp = cp;
+}
+
+/* Do a ++ or -- operation */
+static struct tbl *
+do_ppmm(Expr_state *es, enum token op, struct tbl *vasn, bool is_prefix)
+{
+ struct tbl *vl;
+ int oval;
+
+ assign_check(es, op, vasn);
+
+ vl = intvar(es, vasn);
+ oval = op == O_PLUSPLUS ? vl->val.i++ : vl->val.i--;
+ if (vasn->flag & INTEGER)
+ setint_v(vasn, vl);
+ else
+ setint(vasn, vl->val.i);
+ if (!is_prefix) /* undo the inc/dec */
+ vl->val.i = oval;
+
+ return vl;
+}
+
+static void
+assign_check(es, op, vasn)
+ Expr_state *es;
+ enum token op;
+ struct tbl *vasn;
+{
+ if (vasn->name[0] == '\0' && !(vasn->flag & EXPRLVALUE))
+ evalerr(es, ET_LVALUE, opinfo[(int) op].name);
+ else if (vasn->flag & RDONLY)
+ evalerr(es, ET_RDONLY, opinfo[(int) op].name);
+}
+
+static struct tbl *
+tempvar()
+{
+ struct tbl *vp;
+
+ vp = (struct tbl*) alloc(sizeof(struct tbl), ATEMP);
+ vp->flag = ISSET|INTEGER;
+ vp->type = 0;
+ vp->areap = ATEMP;
+ vp->val.i = 0;
+ vp->name[0] = '\0';
+ return vp;
+}
+
+/* cast (string) variable to temporary integer variable */
+static struct tbl *
+intvar(es, vp)
+ Expr_state *es;
+ struct tbl *vp;
+{
+ struct tbl *vq;
+
+ /* try to avoid replacing a temp var with another temp var */
+ if (vp->name[0] == '\0'
+ && (vp->flag & (ISSET|INTEGER|EXPRLVALUE)) == (ISSET|INTEGER))
+ return vp;
+
+ vq = tempvar();
+ if (setint_v(vq, vp) == NULL) {
+ if (vp->flag & EXPRINEVAL)
+ evalerr(es, ET_RECURSIVE, vp->name);
+ es->evaling = vp;
+ vp->flag |= EXPRINEVAL;
+ v_evaluate(vq, str_val(vp), KSH_UNWIND_ERROR);
+ vp->flag &= ~EXPRINEVAL;
+ es->evaling = (struct tbl *) 0;
+ }
+ return vq;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-24 13:45:26 +0000