From f6e3b2f8a59922405f42c8bc283e0f5546c25d0e Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Thu, 11 Oct 2007 22:36:28 +0800 Subject: [ARITH] Add assignment and intmax_t support This patch adds assignment operator support in arithmetic expansions. It also changes the type used to intmax_t. --- src/arith_yacc.c | 298 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 298 insertions(+) create mode 100644 src/arith_yacc.c (limited to 'src/arith_yacc.c') diff --git a/src/arith_yacc.c b/src/arith_yacc.c new file mode 100644 index 0000000..ad653ed --- /dev/null +++ b/src/arith_yacc.c @@ -0,0 +1,298 @@ +/*- + * Copyright (c) 1993 + * The Regents of the University of California. All rights reserved. + * Copyright (c) 2007 + * Herbert Xu . All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Kenneth Almquist. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include +#include +#include +#include "arith_yacc.h" +#include "expand.h" +#include "shell.h" +#include "error.h" +#include "output.h" +#include "var.h" + +#if ARITH_BOR + 11 != ARITH_BORASS || ARITH_ASS + 11 != ARITH_EQ +#error Arithmetic tokens are out of order. +#endif + +static const char *arith_startbuf; + +const char *arith_buf; +union yystype yylval; + +static int last_token; + +#define ARITH_PRECEDENCE(op, prec) [op - ARITH_BINOP_MIN] = prec + +static const char prec[ARITH_BINOP_MAX - ARITH_BINOP_MIN] = { + ARITH_PRECEDENCE(ARITH_MUL, 0), + ARITH_PRECEDENCE(ARITH_DIV, 0), + ARITH_PRECEDENCE(ARITH_REM, 0), + ARITH_PRECEDENCE(ARITH_ADD, 1), + ARITH_PRECEDENCE(ARITH_SUB, 1), + ARITH_PRECEDENCE(ARITH_LSHIFT, 2), + ARITH_PRECEDENCE(ARITH_RSHIFT, 2), + ARITH_PRECEDENCE(ARITH_LT, 3), + ARITH_PRECEDENCE(ARITH_LE, 3), + ARITH_PRECEDENCE(ARITH_GT, 3), + ARITH_PRECEDENCE(ARITH_GE, 3), + ARITH_PRECEDENCE(ARITH_EQ, 4), + ARITH_PRECEDENCE(ARITH_NE, 4), + ARITH_PRECEDENCE(ARITH_BAND, 5), + ARITH_PRECEDENCE(ARITH_BXOR, 6), + ARITH_PRECEDENCE(ARITH_BOR, 7), +}; + +static void yyerror(const char *s) __attribute__ ((noreturn)); +static void yyerror(const char *s) +{ + sh_error("arithmetic expression: %s: \"%s\"", s, arith_startbuf); + /* NOTREACHED */ +} + +static inline int higher_prec(int op1, int op2) +{ + return prec[op1 - ARITH_BINOP_MIN] < prec[op2 - ARITH_BINOP_MIN]; +} + +static intmax_t do_binop(int op, intmax_t a, intmax_t b) +{ + imaxdiv_t div; + + switch (op) { + default: + case ARITH_REM: + case ARITH_DIV: + if (!b) + yyerror("division by zero"); + div = imaxdiv(a, b); + return op == ARITH_REM ? div.rem : div.quot; + case ARITH_MUL: + return a * b; + case ARITH_ADD: + return a + b; + case ARITH_SUB: + return a - b; + case ARITH_LSHIFT: + return a << b; + case ARITH_RSHIFT: + return a >> b; + case ARITH_LT: + return a < b; + case ARITH_LE: + return a <= b; + case ARITH_GT: + return a > b; + case ARITH_GE: + return a >= b; + case ARITH_EQ: + return a == b; + case ARITH_NE: + return a != b; + case ARITH_BAND: + return a & b; + case ARITH_BXOR: + return a ^ b; + case ARITH_BOR: + return a | b; + } +} + +static intmax_t assignment(int var, int noeval); + +static intmax_t primary(int token, union yystype *val, int op, int noeval) +{ + intmax_t result; + +again: + switch (token) { + case ARITH_LPAREN: + result = assignment(op, noeval); + if (last_token != ARITH_RPAREN) + yyerror("expecting ')'"); + last_token = yylex(); + return result; + case ARITH_NUM: + last_token = op; + return val->val; + case ARITH_VAR: + last_token = op; + return noeval ? val->val : lookupvarint(val->name); + case ARITH_ADD: + token = op; + *val = yylval; + op = yylex(); + goto again; + case ARITH_SUB: + *val = yylval; + return -primary(op, val, yylex(), noeval); + case ARITH_NOT: + *val = yylval; + return !primary(op, val, yylex(), noeval); + case ARITH_BNOT: + *val = yylval; + return ~primary(op, val, yylex(), noeval); + default: + yyerror("expecting primary"); + } +} + +static intmax_t binop2(intmax_t a, int op, int noeval) +{ + for (;;) { + union yystype val; + intmax_t b; + int op2; + int token; + + token = yylex(); + val = yylval; + + b = primary(token, &val, yylex(), noeval); + + op2 = last_token; + if (op2 < ARITH_BINOP_MIN || op2 >= ARITH_BINOP_MAX) + return noeval ? b : do_binop(op, a, b); + + if (higher_prec(op2, op)) { + b = binop2(b, op2, noeval); + return noeval ? b : do_binop(op, a, b); + } + + a = do_binop(op, a, b); + op = op2; + } +} + +static intmax_t binop(int token, union yystype *val, int op, int noeval) +{ + intmax_t a = primary(token, val, op, noeval); + + op = last_token; + if (op < ARITH_BINOP_MIN || op >= ARITH_BINOP_MAX) + return a; + + return binop2(a, op, noeval); +} + +static intmax_t and(int token, union yystype *val, int op, int noeval) +{ + intmax_t a = binop(token, val, op, noeval); + intmax_t b; + + op = last_token; + if (op != ARITH_AND) + return a; + + token = yylex(); + *val = yylval; + + b = and(token, val, yylex(), noeval | !a); + + return a && b; +} + +static intmax_t or(int token, union yystype *val, int op, int noeval) +{ + intmax_t a = and(token, val, op, noeval); + intmax_t b; + + op = last_token; + if (op != ARITH_OR) + return a; + + token = yylex(); + *val = yylval; + + b = or(token, val, yylex(), noeval | !!a); + + return a | b; +} + +static intmax_t cond(int token, union yystype *val, int op, int noeval) +{ + intmax_t a = or(token, val, op, noeval); + intmax_t b; + intmax_t c; + + if (last_token != ARITH_QMARK) + return a; + + b = assignment(yylex(), noeval | !a); + + if (last_token != ARITH_COLON) + yyerror("expecting ':'"); + + token = yylex(); + *val = yylval; + + c = cond(token, val, yylex(), noeval | !!a); + + return a ? b : c; +} + +static intmax_t assignment(int var, int noeval) +{ + union yystype val = yylval; + int op = yylex(); + intmax_t result; + + if (var != ARITH_VAR) + return cond(var, &val, op, noeval); + + if (op != ARITH_ASS && (op < ARITH_ASS_MIN || op >= ARITH_ASS_MAX)) + return cond(var, &val, op, noeval); + + result = assignment(yylex(), noeval); + if (noeval) + return result; + + return setvarint(val.name, + op == ARITH_ASS ? result : + do_binop(op - 11, lookupvarint(val.name), result)); +} + +intmax_t arith(const char *s) +{ + intmax_t result; + + arith_buf = arith_startbuf = s; + + result = assignment(yylex(), 0); + + if (last_token) + yyerror("expecting EOF"); + + return result; +} -- cgit 1.4.1