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5 * Herbert Xu <herbert@gondor.apana.org.au>. All rights reserved.
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37 #include "arith_yacc.h"
44 #if ARITH_BOR + 11 != ARITH_BORASS || ARITH_ASS + 11 != ARITH_EQ
45 #error Arithmetic tokens are out of order.
48 static const char *arith_startbuf;
50 const char *arith_buf;
53 static int last_token;
55 #define ARITH_PRECEDENCE(op, prec) [op - ARITH_BINOP_MIN] = prec
57 static const char prec[ARITH_BINOP_MAX - ARITH_BINOP_MIN] = {
58 ARITH_PRECEDENCE(ARITH_MUL, 0),
59 ARITH_PRECEDENCE(ARITH_DIV, 0),
60 ARITH_PRECEDENCE(ARITH_REM, 0),
61 ARITH_PRECEDENCE(ARITH_ADD, 1),
62 ARITH_PRECEDENCE(ARITH_SUB, 1),
63 ARITH_PRECEDENCE(ARITH_LSHIFT, 2),
64 ARITH_PRECEDENCE(ARITH_RSHIFT, 2),
65 ARITH_PRECEDENCE(ARITH_LT, 3),
66 ARITH_PRECEDENCE(ARITH_LE, 3),
67 ARITH_PRECEDENCE(ARITH_GT, 3),
68 ARITH_PRECEDENCE(ARITH_GE, 3),
69 ARITH_PRECEDENCE(ARITH_EQ, 4),
70 ARITH_PRECEDENCE(ARITH_NE, 4),
71 ARITH_PRECEDENCE(ARITH_BAND, 5),
72 ARITH_PRECEDENCE(ARITH_BXOR, 6),
73 ARITH_PRECEDENCE(ARITH_BOR, 7),
76 #define ARITH_MAX_PREC 8
78 static void yyerror(const char *s) __attribute__ ((noreturn));
79 static void yyerror(const char *s)
81 sh_error("arithmetic expression: %s: \"%s\"", s, arith_startbuf);
85 static inline int arith_prec(int op)
87 return prec[op - ARITH_BINOP_MIN];
90 static inline int higher_prec(int op1, int op2)
92 return arith_prec(op1) < arith_prec(op2);
95 static intmax_t do_binop(int op, intmax_t a, intmax_t b)
102 yyerror("division by zero");
103 return op == ARITH_REM ? a % b : a / b;
135 static intmax_t assignment(int var, int noeval);
137 static intmax_t primary(int token, union yystype *val, int op, int noeval)
144 result = assignment(op, noeval);
145 if (last_token != ARITH_RPAREN)
146 yyerror("expecting ')'");
147 last_token = yylex();
154 return noeval ? val->val : lookupvarint(val->name);
162 return -primary(op, val, yylex(), noeval);
165 return !primary(op, val, yylex(), noeval);
168 return ~primary(op, val, yylex(), noeval);
170 yyerror("expecting primary");
174 static intmax_t binop2(intmax_t a, int op, int prec, int noeval)
185 b = primary(token, &val, yylex(), noeval);
188 if (op2 >= ARITH_BINOP_MIN && op2 < ARITH_BINOP_MAX &&
189 higher_prec(op2, op)) {
190 b = binop2(b, op2, arith_prec(op), noeval);
194 a = noeval ? b : do_binop(op, a, b);
196 if (op2 < ARITH_BINOP_MIN || op2 >= ARITH_BINOP_MAX ||
197 arith_prec(op2) >= prec)
204 static intmax_t binop(int token, union yystype *val, int op, int noeval)
206 intmax_t a = primary(token, val, op, noeval);
209 if (op < ARITH_BINOP_MIN || op >= ARITH_BINOP_MAX)
212 return binop2(a, op, ARITH_MAX_PREC, noeval);
215 static intmax_t and(int token, union yystype *val, int op, int noeval)
217 intmax_t a = binop(token, val, op, noeval);
227 b = and(token, val, yylex(), noeval | !a);
232 static intmax_t or(int token, union yystype *val, int op, int noeval)
234 intmax_t a = and(token, val, op, noeval);
244 b = or(token, val, yylex(), noeval | !!a);
249 static intmax_t cond(int token, union yystype *val, int op, int noeval)
251 intmax_t a = or(token, val, op, noeval);
255 if (last_token != ARITH_QMARK)
258 b = assignment(yylex(), noeval | !a);
260 if (last_token != ARITH_COLON)
261 yyerror("expecting ':'");
266 c = cond(token, val, yylex(), noeval | !!a);
271 static intmax_t assignment(int var, int noeval)
273 union yystype val = yylval;
277 if (var != ARITH_VAR)
278 return cond(var, &val, op, noeval);
280 if (op != ARITH_ASS && (op < ARITH_ASS_MIN || op >= ARITH_ASS_MAX))
281 return cond(var, &val, op, noeval);
283 result = assignment(yylex(), noeval);
287 return setvarint(val.name,
288 op == ARITH_ASS ? result :
289 do_binop(op - 11, lookupvarint(val.name), result), 0);
292 intmax_t arith(const char *s)
296 arith_buf = arith_startbuf = s;
298 result = assignment(yylex(), 0);
301 yyerror("expecting EOF");