usr/dash/arith_yacc.c

/*-
 * Copyright (c) 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 2007
 *	Herbert Xu <herbert@gondor.apana.org.au>.  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 <inttypes.h>
#include <stdint.h>
#include <stdlib.h>
#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),
};

#define ARITH_MAX_PREC 8

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 arith_prec(int op)
{
	return prec[op - ARITH_BINOP_MIN];
}

static inline int higher_prec(int op1, int op2)
{
	return arith_prec(op1) < arith_prec(op2);
}

static intmax_t do_binop(int op, intmax_t a, intmax_t b)
{
#ifdef HAVE_IMAXDIV
	imaxdiv_t div;
#endif

	switch (op) {
	default:
	case ARITH_REM:
	case ARITH_DIV:
		if (!b)
			yyerror("division by zero");
#ifdef HAVE_IMAXDIV
		div = imaxdiv(a, b);
		return op == ARITH_REM ? div.rem : div.quot;
#else
		return op == ARITH_REM ? a % b : a / b;
#endif
	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 prec, 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 &&
		    higher_prec(op2, op)) {
			b = binop2(b, op2, arith_prec(op), noeval);
			op2 = last_token;
		}

		a = noeval ? b : do_binop(op, a, b);

		if (op2 < ARITH_BINOP_MIN || op2 >= ARITH_BINOP_MAX ||
		    arith_prec(op2) >= prec)
			return a;

		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, ARITH_MAX_PREC, 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), 0);
}

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;
}
1	/*-
2	* Copyright (c) 1993
3	* The Regents of the University of California. All rights reserved.
4	* Copyright (c) 2007
5	* Herbert Xu <herbert@gondor.apana.org.au>. All rights reserved.
6	*
7	* This code is derived from software contributed to Berkeley by
8	* Kenneth Almquist.
9	*
10	* Redistribution and use in source and binary forms, with or without
11	* modification, are permitted provided that the following conditions
12	* are met:
13	* 1. Redistributions of source code must retain the above copyright
14	* notice, this list of conditions and the following disclaimer.
15	* 2. Redistributions in binary form must reproduce the above copyright
16	* notice, this list of conditions and the following disclaimer in the
17	* documentation and/or other materials provided with the distribution.
18	* 3. Neither the name of the University nor the names of its contributors
19	* may be used to endorse or promote products derived from this software
20	* without specific prior written permission.
21	*
22	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32	* SUCH DAMAGE.
33	*/
34
35	#include <inttypes.h>
36	#include <stdint.h>
37	#include <stdlib.h>
38	#include "arith_yacc.h"
39	#include "expand.h"
40	#include "shell.h"
41	#include "error.h"
42	#include "output.h"
43	#include "var.h"
44
45	#if ARITH_BOR + 11 != ARITH_BORASS \|\| ARITH_ASS + 11 != ARITH_EQ
46	#error Arithmetic tokens are out of order.
47	#endif
48
49	static const char *arith_startbuf;
50
51	const char *arith_buf;
52	union yystype yylval;
53
54	static int last_token;
55
56	#define ARITH_PRECEDENCE(op, prec) [op - ARITH_BINOP_MIN] = prec
57
58	static const char prec[ARITH_BINOP_MAX - ARITH_BINOP_MIN] = {
59	ARITH_PRECEDENCE(ARITH_MUL, 0),
60	ARITH_PRECEDENCE(ARITH_DIV, 0),
61	ARITH_PRECEDENCE(ARITH_REM, 0),
62	ARITH_PRECEDENCE(ARITH_ADD, 1),
63	ARITH_PRECEDENCE(ARITH_SUB, 1),
64	ARITH_PRECEDENCE(ARITH_LSHIFT, 2),
65	ARITH_PRECEDENCE(ARITH_RSHIFT, 2),
66	ARITH_PRECEDENCE(ARITH_LT, 3),
67	ARITH_PRECEDENCE(ARITH_LE, 3),
68	ARITH_PRECEDENCE(ARITH_GT, 3),
69	ARITH_PRECEDENCE(ARITH_GE, 3),
70	ARITH_PRECEDENCE(ARITH_EQ, 4),
71	ARITH_PRECEDENCE(ARITH_NE, 4),
72	ARITH_PRECEDENCE(ARITH_BAND, 5),
73	ARITH_PRECEDENCE(ARITH_BXOR, 6),
74	ARITH_PRECEDENCE(ARITH_BOR, 7),
75	};
76
77	#define ARITH_MAX_PREC 8
78
79	static void yyerror(const char *s) __attribute__ ((noreturn));
80	static void yyerror(const char *s)
81	{
82	sh_error("arithmetic expression: %s: \"%s\"", s, arith_startbuf);
83	/* NOTREACHED */
84	}
85
86	static inline int arith_prec(int op)
87	{
88	return prec[op - ARITH_BINOP_MIN];
89	}
90
91	static inline int higher_prec(int op1, int op2)
92	{
93	return arith_prec(op1) < arith_prec(op2);
94	}
95
96	static intmax_t do_binop(int op, intmax_t a, intmax_t b)
97	{
98	#ifdef HAVE_IMAXDIV
99	imaxdiv_t div;
100	#endif
101
102	switch (op) {
103	default:
104	case ARITH_REM:
105	case ARITH_DIV:
106	if (!b)
107	yyerror("division by zero");
108	#ifdef HAVE_IMAXDIV
109	div = imaxdiv(a, b);
110	return op == ARITH_REM ? div.rem : div.quot;
111	#else
112	return op == ARITH_REM ? a % b : a / b;
113	#endif
114	case ARITH_MUL:
115	return a * b;
116	case ARITH_ADD:
117	return a + b;
118	case ARITH_SUB:
119	return a - b;
120	case ARITH_LSHIFT:
121	return a << b;
122	case ARITH_RSHIFT:
123	return a >> b;
124	case ARITH_LT:
125	return a < b;
126	case ARITH_LE:
127	return a <= b;
128	case ARITH_GT:
129	return a > b;
130	case ARITH_GE:
131	return a >= b;
132	case ARITH_EQ:
133	return a == b;
134	case ARITH_NE:
135	return a != b;
136	case ARITH_BAND:
137	return a & b;
138	case ARITH_BXOR:
139	return a ^ b;
140	case ARITH_BOR:
141	return a \| b;
142	}
143	}
144
145	static intmax_t assignment(int var, int noeval);
146
147	static intmax_t primary(int token, union yystype *val, int op, int noeval)
148	{
149	intmax_t result;
150
151	again:
152	switch (token) {
153	case ARITH_LPAREN:
154	result = assignment(op, noeval);
155	if (last_token != ARITH_RPAREN)
156	yyerror("expecting ')'");
157	last_token = yylex();
158	return result;
159	case ARITH_NUM:
160	last_token = op;
161	return val->val;
162	case ARITH_VAR:
163	last_token = op;
164	return noeval ? val->val : lookupvarint(val->name);
165	case ARITH_ADD:
166	token = op;
167	*val = yylval;
168	op = yylex();
169	goto again;
170	case ARITH_SUB:
171	*val = yylval;
172	return -primary(op, val, yylex(), noeval);
173	case ARITH_NOT:
174	*val = yylval;
175	return !primary(op, val, yylex(), noeval);
176	case ARITH_BNOT:
177	*val = yylval;
178	return ~primary(op, val, yylex(), noeval);
179	default:
180	yyerror("expecting primary");
181	}
182	}
183
184	static intmax_t binop2(intmax_t a, int op, int prec, int noeval)
185	{
186	for (;;) {
187	union yystype val;
188	intmax_t b;
189	int op2;
190	int token;
191
192	token = yylex();
193	val = yylval;
194
195	b = primary(token, &val, yylex(), noeval);
196
197	op2 = last_token;
198	if (op2 >= ARITH_BINOP_MIN && op2 < ARITH_BINOP_MAX &&
199	higher_prec(op2, op)) {
200	b = binop2(b, op2, arith_prec(op), noeval);
201	op2 = last_token;
202	}
203
204	a = noeval ? b : do_binop(op, a, b);
205
206	if (op2 < ARITH_BINOP_MIN \|\| op2 >= ARITH_BINOP_MAX \|\|
207	arith_prec(op2) >= prec)
208	return a;
209
210	op = op2;
211	}
212	}
213
214	static intmax_t binop(int token, union yystype *val, int op, int noeval)
215	{
216	intmax_t a = primary(token, val, op, noeval);
217
218	op = last_token;
219	if (op < ARITH_BINOP_MIN \|\| op >= ARITH_BINOP_MAX)
220	return a;
221
222	return binop2(a, op, ARITH_MAX_PREC, noeval);
223	}
224
225	static intmax_t and(int token, union yystype *val, int op, int noeval)
226	{
227	intmax_t a = binop(token, val, op, noeval);
228	intmax_t b;
229
230	op = last_token;
231	if (op != ARITH_AND)
232	return a;
233
234	token = yylex();
235	*val = yylval;
236
237	b = and(token, val, yylex(), noeval \| !a);
238
239	return a && b;
240	}
241
242	static intmax_t or(int token, union yystype *val, int op, int noeval)
243	{
244	intmax_t a = and(token, val, op, noeval);
245	intmax_t b;
246
247	op = last_token;
248	if (op != ARITH_OR)
249	return a;
250
251	token = yylex();
252	*val = yylval;
253
254	b = or(token, val, yylex(), noeval \| !!a);
255
256	return a \|\| b;
257	}
258
259	static intmax_t cond(int token, union yystype *val, int op, int noeval)
260	{
261	intmax_t a = or(token, val, op, noeval);
262	intmax_t b;
263	intmax_t c;
264
265	if (last_token != ARITH_QMARK)
266	return a;
267
268	b = assignment(yylex(), noeval \| !a);
269
270	if (last_token != ARITH_COLON)
271	yyerror("expecting ':'");
272
273	token = yylex();
274	*val = yylval;
275
276	c = cond(token, val, yylex(), noeval \| !!a);
277
278	return a ? b : c;
279	}
280
281	static intmax_t assignment(int var, int noeval)
282	{
283	union yystype val = yylval;
284	int op = yylex();
285	intmax_t result;
286
287	if (var != ARITH_VAR)
288	return cond(var, &val, op, noeval);
289
290	if (op != ARITH_ASS && (op < ARITH_ASS_MIN \|\| op >= ARITH_ASS_MAX))
291	return cond(var, &val, op, noeval);
292
293	result = assignment(yylex(), noeval);
294	if (noeval)
295	return result;
296
297	return setvarint(val.name,
298	op == ARITH_ASS ? result :
299	do_binop(op - 11, lookupvarint(val.name), result), 0);
300	}
301
302	intmax_t arith(const char *s)
303	{
304	intmax_t result;
305
306	arith_buf = arith_startbuf = s;
307
308	result = assignment(yylex(), 0);
309
310	if (last_token)
311	yyerror("expecting EOF");
312
313	return result;
314	}