[821] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Mini expr implementation for busybox
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| 4 | *
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| 5 | * based on GNU expr Mike Parker.
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| 6 | * Copyright (C) 86, 1991-1997, 1999 Free Software Foundation, Inc.
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| 7 | *
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| 8 | * Busybox modifications
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| 9 | * Copyright (c) 2000 Edward Betts <edward@debian.org>.
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| 10 | * Copyright (C) 2003-2005 Vladimir Oleynik <dzo@simtreas.ru>
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| 11 | * - reduced 464 bytes.
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| 12 | * - 64 math support
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| 13 | *
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[2725] | 14 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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[821] | 15 | */
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| 16 |
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| 17 | /* This program evaluates expressions. Each token (operator, operand,
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| 18 | * parenthesis) of the expression must be a separate argument. The
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| 19 | * parser used is a reasonably general one, though any incarnation of
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| 20 | * it is language-specific. It is especially nice for expressions.
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| 21 | *
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| 22 | * No parse tree is needed; a new node is evaluated immediately.
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| 23 | * One function can handle multiple operators all of equal precedence,
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| 24 | * provided they all associate ((x op x) op x). */
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| 25 |
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| 26 | /* no getopt needed */
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| 27 |
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[3232] | 28 | //usage:#define expr_trivial_usage
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| 29 | //usage: "EXPRESSION"
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| 30 | //usage:#define expr_full_usage "\n\n"
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| 31 | //usage: "Print the value of EXPRESSION to stdout\n"
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| 32 | //usage: "\n"
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| 33 | //usage: "EXPRESSION may be:\n"
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| 34 | //usage: " ARG1 | ARG2 ARG1 if it is neither null nor 0, otherwise ARG2\n"
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| 35 | //usage: " ARG1 & ARG2 ARG1 if neither argument is null or 0, otherwise 0\n"
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| 36 | //usage: " ARG1 < ARG2 1 if ARG1 is less than ARG2, else 0. Similarly:\n"
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| 37 | //usage: " ARG1 <= ARG2\n"
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| 38 | //usage: " ARG1 = ARG2\n"
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| 39 | //usage: " ARG1 != ARG2\n"
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| 40 | //usage: " ARG1 >= ARG2\n"
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| 41 | //usage: " ARG1 > ARG2\n"
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| 42 | //usage: " ARG1 + ARG2 Sum of ARG1 and ARG2. Similarly:\n"
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| 43 | //usage: " ARG1 - ARG2\n"
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| 44 | //usage: " ARG1 * ARG2\n"
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| 45 | //usage: " ARG1 / ARG2\n"
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| 46 | //usage: " ARG1 % ARG2\n"
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| 47 | //usage: " STRING : REGEXP Anchored pattern match of REGEXP in STRING\n"
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| 48 | //usage: " match STRING REGEXP Same as STRING : REGEXP\n"
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| 49 | //usage: " substr STRING POS LENGTH Substring of STRING, POS counted from 1\n"
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| 50 | //usage: " index STRING CHARS Index in STRING where any CHARS is found, or 0\n"
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| 51 | //usage: " length STRING Length of STRING\n"
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| 52 | //usage: " quote TOKEN Interpret TOKEN as a string, even if\n"
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| 53 | //usage: " it is a keyword like 'match' or an\n"
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| 54 | //usage: " operator like '/'\n"
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| 55 | //usage: " (EXPRESSION) Value of EXPRESSION\n"
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| 56 | //usage: "\n"
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| 57 | //usage: "Beware that many operators need to be escaped or quoted for shells.\n"
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| 58 | //usage: "Comparisons are arithmetic if both ARGs are numbers, else\n"
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| 59 | //usage: "lexicographical. Pattern matches return the string matched between\n"
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| 60 | //usage: "\\( and \\) or null; if \\( and \\) are not used, they return the number\n"
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| 61 | //usage: "of characters matched or 0."
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| 62 |
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[1765] | 63 | #include "libbb.h"
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| 64 | #include "xregex.h"
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[821] | 65 |
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| 66 | #if ENABLE_EXPR_MATH_SUPPORT_64
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| 67 | typedef int64_t arith_t;
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[1765] | 68 |
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[821] | 69 | #define PF_REZ "ll"
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| 70 | #define PF_REZ_TYPE (long long)
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| 71 | #define STRTOL(s, e, b) strtoll(s, e, b)
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| 72 | #else
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| 73 | typedef long arith_t;
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[1765] | 74 |
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[821] | 75 | #define PF_REZ "l"
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| 76 | #define PF_REZ_TYPE (long)
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| 77 | #define STRTOL(s, e, b) strtol(s, e, b)
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| 78 | #endif
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| 79 |
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[1765] | 80 | /* TODO: use bb_strtol[l]? It's easier to check for errors... */
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| 81 |
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[2725] | 82 | /* The kinds of value we can have. */
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| 83 | enum {
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| 84 | INTEGER,
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| 85 | STRING
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| 86 | };
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| 87 |
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[821] | 88 | /* A value is.... */
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| 89 | struct valinfo {
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[2725] | 90 | smallint type; /* Which kind. */
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| 91 | union { /* The value itself. */
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[821] | 92 | arith_t i;
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| 93 | char *s;
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| 94 | } u;
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| 95 | };
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| 96 | typedef struct valinfo VALUE;
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| 97 |
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| 98 | /* The arguments given to the program, minus the program name. */
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[1765] | 99 | struct globals {
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| 100 | char **args;
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[2725] | 101 | } FIX_ALIASING;
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[1765] | 102 | #define G (*(struct globals*)&bb_common_bufsiz1)
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[3232] | 103 | #define INIT_G() do { } while (0)
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[821] | 104 |
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[1765] | 105 | /* forward declarations */
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| 106 | static VALUE *eval(void);
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[821] | 107 |
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| 108 |
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| 109 | /* Return a VALUE for I. */
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| 110 |
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[1765] | 111 | static VALUE *int_value(arith_t i)
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[821] | 112 | {
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| 113 | VALUE *v;
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| 114 |
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[2725] | 115 | v = xzalloc(sizeof(VALUE));
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| 116 | if (INTEGER) /* otherwise xzaaloc did it already */
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| 117 | v->type = INTEGER;
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[821] | 118 | v->u.i = i;
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| 119 | return v;
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| 120 | }
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| 121 |
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| 122 | /* Return a VALUE for S. */
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| 123 |
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[1765] | 124 | static VALUE *str_value(const char *s)
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[821] | 125 | {
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| 126 | VALUE *v;
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| 127 |
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[2725] | 128 | v = xzalloc(sizeof(VALUE));
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| 129 | if (STRING) /* otherwise xzaaloc did it already */
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| 130 | v->type = STRING;
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[1765] | 131 | v->u.s = xstrdup(s);
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[821] | 132 | return v;
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| 133 | }
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| 134 |
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| 135 | /* Free VALUE V, including structure components. */
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| 136 |
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[2725] | 137 | static void freev(VALUE *v)
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[821] | 138 | {
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[2725] | 139 | if (v->type == STRING)
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[1765] | 140 | free(v->u.s);
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| 141 | free(v);
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[821] | 142 | }
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| 143 |
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| 144 | /* Return nonzero if V is a null-string or zero-number. */
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| 145 |
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[2725] | 146 | static int null(VALUE *v)
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[821] | 147 | {
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[2725] | 148 | if (v->type == INTEGER)
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[1765] | 149 | return v->u.i == 0;
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[2725] | 150 | /* STRING: */
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[1765] | 151 | return v->u.s[0] == '\0' || LONE_CHAR(v->u.s, '0');
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[821] | 152 | }
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| 153 |
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[2725] | 154 | /* Coerce V to a STRING value (can't fail). */
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[821] | 155 |
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[2725] | 156 | static void tostring(VALUE *v)
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[821] | 157 | {
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[2725] | 158 | if (v->type == INTEGER) {
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[1765] | 159 | v->u.s = xasprintf("%" PF_REZ "d", PF_REZ_TYPE v->u.i);
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[2725] | 160 | v->type = STRING;
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[821] | 161 | }
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| 162 | }
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| 163 |
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[2725] | 164 | /* Coerce V to an INTEGER value. Return 1 on success, 0 on failure. */
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[821] | 165 |
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[2725] | 166 | static bool toarith(VALUE *v)
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[821] | 167 | {
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[2725] | 168 | if (v->type == STRING) {
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[821] | 169 | arith_t i;
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| 170 | char *e;
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| 171 |
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| 172 | /* Don't interpret the empty string as an integer. */
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| 173 | /* Currently does not worry about overflow or int/long differences. */
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| 174 | i = STRTOL(v->u.s, &e, 10);
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| 175 | if ((v->u.s == e) || *e)
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| 176 | return 0;
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[1765] | 177 | free(v->u.s);
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[821] | 178 | v->u.i = i;
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[2725] | 179 | v->type = INTEGER;
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[821] | 180 | }
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| 181 | return 1;
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| 182 | }
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| 183 |
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[2725] | 184 | /* Return str[0]+str[1] if the next token matches STR exactly.
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[821] | 185 | STR must not be NULL. */
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| 186 |
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[2725] | 187 | static int nextarg(const char *str)
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[821] | 188 | {
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[2725] | 189 | if (*G.args == NULL || strcmp(*G.args, str) != 0)
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[821] | 190 | return 0;
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[2725] | 191 | return (unsigned char)str[0] + (unsigned char)str[1];
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[821] | 192 | }
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| 193 |
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| 194 | /* The comparison operator handling functions. */
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| 195 |
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[2725] | 196 | static int cmp_common(VALUE *l, VALUE *r, int op)
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[821] | 197 | {
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[2725] | 198 | arith_t ll, rr;
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[821] | 199 |
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[2725] | 200 | ll = l->u.i;
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| 201 | rr = r->u.i;
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| 202 | if (l->type == STRING || r->type == STRING) {
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[1765] | 203 | tostring(l);
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| 204 | tostring(r);
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[2725] | 205 | ll = strcmp(l->u.s, r->u.s);
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| 206 | rr = 0;
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| 207 | }
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| 208 | /* calculating ll - rr and checking the result is prone to overflows.
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| 209 | * We'll do it differently: */
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[1765] | 210 | if (op == '<')
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[2725] | 211 | return ll < rr;
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| 212 | if (op == ('<' + '='))
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| 213 | return ll <= rr;
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| 214 | if (op == '=' || (op == '=' + '='))
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| 215 | return ll == rr;
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| 216 | if (op == '!' + '=')
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| 217 | return ll != rr;
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[1765] | 218 | if (op == '>')
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[2725] | 219 | return ll > rr;
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[1765] | 220 | /* >= */
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[2725] | 221 | return ll >= rr;
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[821] | 222 | }
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| 223 |
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| 224 | /* The arithmetic operator handling functions. */
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| 225 |
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[2725] | 226 | static arith_t arithmetic_common(VALUE *l, VALUE *r, int op)
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[821] | 227 | {
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[1765] | 228 | arith_t li, ri;
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[821] | 229 |
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[1765] | 230 | if (!toarith(l) || !toarith(r))
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| 231 | bb_error_msg_and_die("non-numeric argument");
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| 232 | li = l->u.i;
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| 233 | ri = r->u.i;
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| 234 | if (op == '+')
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[821] | 235 | return li + ri;
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[2725] | 236 | if (op == '-')
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[821] | 237 | return li - ri;
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[2725] | 238 | if (op == '*')
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[821] | 239 | return li * ri;
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[2725] | 240 | if (ri == 0)
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| 241 | bb_error_msg_and_die("division by zero");
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| 242 | if (op == '/')
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[821] | 243 | return li / ri;
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[2725] | 244 | return li % ri;
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[821] | 245 | }
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| 246 |
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| 247 | /* Do the : operator.
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| 248 | SV is the VALUE for the lhs (the string),
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| 249 | PV is the VALUE for the rhs (the pattern). */
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| 250 |
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[2725] | 251 | static VALUE *docolon(VALUE *sv, VALUE *pv)
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[821] | 252 | {
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[2725] | 253 | enum { NMATCH = 2 };
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[821] | 254 | VALUE *v;
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| 255 | regex_t re_buffer;
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| 256 | regmatch_t re_regs[NMATCH];
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| 257 |
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[1765] | 258 | tostring(sv);
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| 259 | tostring(pv);
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[821] | 260 |
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| 261 | if (pv->u.s[0] == '^') {
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[2725] | 262 | bb_error_msg(
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| 263 | "warning: '%s': using '^' as the first character\n"
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| 264 | "of a basic regular expression is not portable; it is ignored", pv->u.s);
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[821] | 265 | }
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| 266 |
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[1765] | 267 | memset(&re_buffer, 0, sizeof(re_buffer));
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[2725] | 268 | memset(re_regs, 0, sizeof(re_regs));
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[1765] | 269 | xregcomp(&re_buffer, pv->u.s, 0);
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[821] | 270 |
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| 271 | /* expr uses an anchored pattern match, so check that there was a
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| 272 | * match and that the match starts at offset 0. */
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[2725] | 273 | if (regexec(&re_buffer, sv->u.s, NMATCH, re_regs, 0) != REG_NOMATCH
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| 274 | && re_regs[0].rm_so == 0
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| 275 | ) {
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[821] | 276 | /* Were \(...\) used? */
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[2725] | 277 | if (re_buffer.re_nsub > 0 && re_regs[1].rm_so >= 0) {
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[821] | 278 | sv->u.s[re_regs[1].rm_eo] = '\0';
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[1765] | 279 | v = str_value(sv->u.s + re_regs[1].rm_so);
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[2725] | 280 | } else {
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[1765] | 281 | v = int_value(re_regs[0].rm_eo);
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[2725] | 282 | }
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[1765] | 283 | } else {
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[821] | 284 | /* Match failed -- return the right kind of null. */
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| 285 | if (re_buffer.re_nsub > 0)
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[1765] | 286 | v = str_value("");
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[821] | 287 | else
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[1765] | 288 | v = int_value(0);
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[821] | 289 | }
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[2725] | 290 | regfree(&re_buffer);
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[821] | 291 | return v;
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| 292 | }
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| 293 |
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| 294 | /* Handle bare operands and ( expr ) syntax. */
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| 295 |
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[1765] | 296 | static VALUE *eval7(void)
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[821] | 297 | {
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| 298 | VALUE *v;
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| 299 |
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[1765] | 300 | if (!*G.args)
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| 301 | bb_error_msg_and_die("syntax error");
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[821] | 302 |
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[1765] | 303 | if (nextarg("(")) {
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| 304 | G.args++;
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| 305 | v = eval();
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| 306 | if (!nextarg(")"))
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| 307 | bb_error_msg_and_die("syntax error");
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| 308 | G.args++;
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| 309 | return v;
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| 310 | }
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[821] | 311 |
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[1765] | 312 | if (nextarg(")"))
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| 313 | bb_error_msg_and_die("syntax error");
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[821] | 314 |
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[1765] | 315 | return str_value(*G.args++);
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[821] | 316 | }
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| 317 |
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| 318 | /* Handle match, substr, index, length, and quote keywords. */
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| 319 |
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[1765] | 320 | static VALUE *eval6(void)
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[821] | 321 | {
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[1765] | 322 | static const char keywords[] ALIGN1 =
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| 323 | "quote\0""length\0""match\0""index\0""substr\0";
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[821] | 324 |
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[1765] | 325 | VALUE *r, *i1, *i2;
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| 326 | VALUE *l = l; /* silence gcc */
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| 327 | VALUE *v = v; /* silence gcc */
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| 328 | int key = *G.args ? index_in_strings(keywords, *G.args) + 1 : 0;
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| 329 |
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| 330 | if (key == 0) /* not a keyword */
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| 331 | return eval7();
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| 332 | G.args++; /* We have a valid token, so get the next argument. */
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| 333 | if (key == 1) { /* quote */
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| 334 | if (!*G.args)
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| 335 | bb_error_msg_and_die("syntax error");
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| 336 | return str_value(*G.args++);
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[821] | 337 | }
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[1765] | 338 | if (key == 2) { /* length */
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| 339 | r = eval6();
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| 340 | tostring(r);
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| 341 | v = int_value(strlen(r->u.s));
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| 342 | freev(r);
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| 343 | } else
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| 344 | l = eval6();
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| 345 |
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| 346 | if (key == 3) { /* match */
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| 347 | r = eval6();
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| 348 | v = docolon(l, r);
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| 349 | freev(l);
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| 350 | freev(r);
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[821] | 351 | }
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[1765] | 352 | if (key == 4) { /* index */
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| 353 | r = eval6();
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| 354 | tostring(l);
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| 355 | tostring(r);
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| 356 | v = int_value(strcspn(l->u.s, r->u.s) + 1);
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| 357 | if (v->u.i == (arith_t) strlen(l->u.s) + 1)
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[821] | 358 | v->u.i = 0;
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[1765] | 359 | freev(l);
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| 360 | freev(r);
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[821] | 361 | }
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[1765] | 362 | if (key == 5) { /* substr */
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| 363 | i1 = eval6();
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| 364 | i2 = eval6();
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| 365 | tostring(l);
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| 366 | if (!toarith(i1) || !toarith(i2)
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| 367 | || i1->u.i > (arith_t) strlen(l->u.s)
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| 368 | || i1->u.i <= 0 || i2->u.i <= 0)
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| 369 | v = str_value("");
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[821] | 370 | else {
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[1765] | 371 | v = xmalloc(sizeof(VALUE));
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[2725] | 372 | v->type = STRING;
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[1765] | 373 | v->u.s = xstrndup(l->u.s + i1->u.i - 1, i2->u.i);
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[821] | 374 | }
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[1765] | 375 | freev(l);
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| 376 | freev(i1);
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| 377 | freev(i2);
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[821] | 378 | }
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[1765] | 379 | return v;
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[821] | 380 | }
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| 381 |
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| 382 | /* Handle : operator (pattern matching).
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| 383 | Calls docolon to do the real work. */
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| 384 |
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[1765] | 385 | static VALUE *eval5(void)
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[821] | 386 | {
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| 387 | VALUE *l, *r, *v;
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| 388 |
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[1765] | 389 | l = eval6();
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| 390 | while (nextarg(":")) {
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| 391 | G.args++;
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| 392 | r = eval6();
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| 393 | v = docolon(l, r);
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| 394 | freev(l);
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| 395 | freev(r);
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[821] | 396 | l = v;
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| 397 | }
|
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| 398 | return l;
|
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| 399 | }
|
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| 400 |
|
---|
| 401 | /* Handle *, /, % operators. */
|
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| 402 |
|
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[1765] | 403 | static VALUE *eval4(void)
|
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[821] | 404 | {
|
---|
| 405 | VALUE *l, *r;
|
---|
| 406 | int op;
|
---|
| 407 | arith_t val;
|
---|
| 408 |
|
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[1765] | 409 | l = eval5();
|
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[821] | 410 | while (1) {
|
---|
[2725] | 411 | op = nextarg("*");
|
---|
| 412 | if (!op) { op = nextarg("/");
|
---|
| 413 | if (!op) { op = nextarg("%");
|
---|
| 414 | if (!op) return l;
|
---|
| 415 | }}
|
---|
[1765] | 416 | G.args++;
|
---|
| 417 | r = eval5();
|
---|
| 418 | val = arithmetic_common(l, r, op);
|
---|
| 419 | freev(l);
|
---|
| 420 | freev(r);
|
---|
| 421 | l = int_value(val);
|
---|
[821] | 422 | }
|
---|
| 423 | }
|
---|
| 424 |
|
---|
| 425 | /* Handle +, - operators. */
|
---|
| 426 |
|
---|
[1765] | 427 | static VALUE *eval3(void)
|
---|
[821] | 428 | {
|
---|
| 429 | VALUE *l, *r;
|
---|
| 430 | int op;
|
---|
| 431 | arith_t val;
|
---|
| 432 |
|
---|
[1765] | 433 | l = eval4();
|
---|
[821] | 434 | while (1) {
|
---|
[2725] | 435 | op = nextarg("+");
|
---|
| 436 | if (!op) {
|
---|
| 437 | op = nextarg("-");
|
---|
| 438 | if (!op) return l;
|
---|
| 439 | }
|
---|
[1765] | 440 | G.args++;
|
---|
| 441 | r = eval4();
|
---|
| 442 | val = arithmetic_common(l, r, op);
|
---|
| 443 | freev(l);
|
---|
| 444 | freev(r);
|
---|
| 445 | l = int_value(val);
|
---|
[821] | 446 | }
|
---|
| 447 | }
|
---|
| 448 |
|
---|
| 449 | /* Handle comparisons. */
|
---|
| 450 |
|
---|
[1765] | 451 | static VALUE *eval2(void)
|
---|
[821] | 452 | {
|
---|
| 453 | VALUE *l, *r;
|
---|
| 454 | int op;
|
---|
| 455 | arith_t val;
|
---|
| 456 |
|
---|
[1765] | 457 | l = eval3();
|
---|
[821] | 458 | while (1) {
|
---|
[2725] | 459 | op = nextarg("<");
|
---|
| 460 | if (!op) { op = nextarg("<=");
|
---|
| 461 | if (!op) { op = nextarg("=");
|
---|
| 462 | if (!op) { op = nextarg("==");
|
---|
| 463 | if (!op) { op = nextarg("!=");
|
---|
| 464 | if (!op) { op = nextarg(">=");
|
---|
| 465 | if (!op) { op = nextarg(">");
|
---|
| 466 | if (!op) return l;
|
---|
| 467 | }}}}}}
|
---|
[1765] | 468 | G.args++;
|
---|
| 469 | r = eval3();
|
---|
| 470 | toarith(l);
|
---|
| 471 | toarith(r);
|
---|
| 472 | val = cmp_common(l, r, op);
|
---|
| 473 | freev(l);
|
---|
| 474 | freev(r);
|
---|
| 475 | l = int_value(val);
|
---|
[821] | 476 | }
|
---|
| 477 | }
|
---|
| 478 |
|
---|
| 479 | /* Handle &. */
|
---|
| 480 |
|
---|
[1765] | 481 | static VALUE *eval1(void)
|
---|
[821] | 482 | {
|
---|
| 483 | VALUE *l, *r;
|
---|
| 484 |
|
---|
[1765] | 485 | l = eval2();
|
---|
| 486 | while (nextarg("&")) {
|
---|
| 487 | G.args++;
|
---|
| 488 | r = eval2();
|
---|
| 489 | if (null(l) || null(r)) {
|
---|
| 490 | freev(l);
|
---|
| 491 | freev(r);
|
---|
| 492 | l = int_value(0);
|
---|
| 493 | } else
|
---|
| 494 | freev(r);
|
---|
[821] | 495 | }
|
---|
| 496 | return l;
|
---|
| 497 | }
|
---|
| 498 |
|
---|
| 499 | /* Handle |. */
|
---|
| 500 |
|
---|
[1765] | 501 | static VALUE *eval(void)
|
---|
[821] | 502 | {
|
---|
| 503 | VALUE *l, *r;
|
---|
| 504 |
|
---|
[1765] | 505 | l = eval1();
|
---|
| 506 | while (nextarg("|")) {
|
---|
| 507 | G.args++;
|
---|
| 508 | r = eval1();
|
---|
| 509 | if (null(l)) {
|
---|
| 510 | freev(l);
|
---|
[821] | 511 | l = r;
|
---|
[1765] | 512 | } else
|
---|
| 513 | freev(r);
|
---|
[821] | 514 | }
|
---|
| 515 | return l;
|
---|
| 516 | }
|
---|
[1765] | 517 |
|
---|
[2725] | 518 | int expr_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
---|
| 519 | int expr_main(int argc UNUSED_PARAM, char **argv)
|
---|
[1765] | 520 | {
|
---|
| 521 | VALUE *v;
|
---|
| 522 |
|
---|
[3232] | 523 | INIT_G();
|
---|
| 524 |
|
---|
[2725] | 525 | xfunc_error_retval = 2; /* coreutils compat */
|
---|
| 526 | G.args = argv + 1;
|
---|
| 527 | if (*G.args == NULL) {
|
---|
[1765] | 528 | bb_error_msg_and_die("too few arguments");
|
---|
| 529 | }
|
---|
| 530 | v = eval();
|
---|
| 531 | if (*G.args)
|
---|
| 532 | bb_error_msg_and_die("syntax error");
|
---|
[2725] | 533 | if (v->type == INTEGER)
|
---|
[1765] | 534 | printf("%" PF_REZ "d\n", PF_REZ_TYPE v->u.i);
|
---|
| 535 | else
|
---|
| 536 | puts(v->u.s);
|
---|
| 537 | fflush_stdout_and_exit(null(v));
|
---|
| 538 | }
|
---|