[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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[3621] | 64 | #include "common_bufsiz.h"
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[1765] | 65 | #include "xregex.h"
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[821] | 66 |
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| 67 | #if ENABLE_EXPR_MATH_SUPPORT_64
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| 68 | typedef int64_t arith_t;
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[1765] | 69 |
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[821] | 70 | #define PF_REZ "ll"
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| 71 | #define PF_REZ_TYPE (long long)
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| 72 | #define STRTOL(s, e, b) strtoll(s, e, b)
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| 73 | #else
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| 74 | typedef long arith_t;
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[1765] | 75 |
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[821] | 76 | #define PF_REZ "l"
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| 77 | #define PF_REZ_TYPE (long)
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| 78 | #define STRTOL(s, e, b) strtol(s, e, b)
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| 79 | #endif
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| 80 |
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[1765] | 81 | /* TODO: use bb_strtol[l]? It's easier to check for errors... */
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| 82 |
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[2725] | 83 | /* The kinds of value we can have. */
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| 84 | enum {
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| 85 | INTEGER,
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| 86 | STRING
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| 87 | };
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| 88 |
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[821] | 89 | /* A value is.... */
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| 90 | struct valinfo {
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[2725] | 91 | smallint type; /* Which kind. */
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| 92 | union { /* The value itself. */
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[821] | 93 | arith_t i;
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| 94 | char *s;
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| 95 | } u;
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| 96 | };
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| 97 | typedef struct valinfo VALUE;
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| 98 |
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| 99 | /* The arguments given to the program, minus the program name. */
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[1765] | 100 | struct globals {
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| 101 | char **args;
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[2725] | 102 | } FIX_ALIASING;
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[3621] | 103 | #define G (*(struct globals*)bb_common_bufsiz1)
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| 104 | #define INIT_G() do { setup_common_bufsiz(); } while (0)
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[821] | 105 |
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[1765] | 106 | /* forward declarations */
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| 107 | static VALUE *eval(void);
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[821] | 108 |
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| 109 |
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| 110 | /* Return a VALUE for I. */
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| 111 |
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[1765] | 112 | static VALUE *int_value(arith_t i)
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[821] | 113 | {
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| 114 | VALUE *v;
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| 115 |
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[2725] | 116 | v = xzalloc(sizeof(VALUE));
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| 117 | if (INTEGER) /* otherwise xzaaloc did it already */
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| 118 | v->type = INTEGER;
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[821] | 119 | v->u.i = i;
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| 120 | return v;
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| 121 | }
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| 122 |
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| 123 | /* Return a VALUE for S. */
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| 124 |
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[1765] | 125 | static VALUE *str_value(const char *s)
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[821] | 126 | {
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| 127 | VALUE *v;
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| 128 |
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[2725] | 129 | v = xzalloc(sizeof(VALUE));
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| 130 | if (STRING) /* otherwise xzaaloc did it already */
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| 131 | v->type = STRING;
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[1765] | 132 | v->u.s = xstrdup(s);
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[821] | 133 | return v;
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| 134 | }
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| 135 |
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| 136 | /* Free VALUE V, including structure components. */
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| 137 |
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[2725] | 138 | static void freev(VALUE *v)
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[821] | 139 | {
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[2725] | 140 | if (v->type == STRING)
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[1765] | 141 | free(v->u.s);
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| 142 | free(v);
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[821] | 143 | }
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| 144 |
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| 145 | /* Return nonzero if V is a null-string or zero-number. */
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| 146 |
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[2725] | 147 | static int null(VALUE *v)
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[821] | 148 | {
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[2725] | 149 | if (v->type == INTEGER)
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[1765] | 150 | return v->u.i == 0;
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[2725] | 151 | /* STRING: */
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[1765] | 152 | return v->u.s[0] == '\0' || LONE_CHAR(v->u.s, '0');
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[821] | 153 | }
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| 154 |
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[2725] | 155 | /* Coerce V to a STRING value (can't fail). */
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[821] | 156 |
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[2725] | 157 | static void tostring(VALUE *v)
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[821] | 158 | {
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[2725] | 159 | if (v->type == INTEGER) {
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[1765] | 160 | v->u.s = xasprintf("%" PF_REZ "d", PF_REZ_TYPE v->u.i);
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[2725] | 161 | v->type = STRING;
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[821] | 162 | }
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| 163 | }
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| 164 |
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[2725] | 165 | /* Coerce V to an INTEGER value. Return 1 on success, 0 on failure. */
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[821] | 166 |
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[2725] | 167 | static bool toarith(VALUE *v)
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[821] | 168 | {
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[2725] | 169 | if (v->type == STRING) {
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[821] | 170 | arith_t i;
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| 171 | char *e;
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| 172 |
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| 173 | /* Don't interpret the empty string as an integer. */
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| 174 | /* Currently does not worry about overflow or int/long differences. */
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| 175 | i = STRTOL(v->u.s, &e, 10);
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| 176 | if ((v->u.s == e) || *e)
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| 177 | return 0;
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[1765] | 178 | free(v->u.s);
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[821] | 179 | v->u.i = i;
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[2725] | 180 | v->type = INTEGER;
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[821] | 181 | }
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| 182 | return 1;
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| 183 | }
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| 184 |
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[2725] | 185 | /* Return str[0]+str[1] if the next token matches STR exactly.
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[821] | 186 | STR must not be NULL. */
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| 187 |
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[2725] | 188 | static int nextarg(const char *str)
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[821] | 189 | {
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[2725] | 190 | if (*G.args == NULL || strcmp(*G.args, str) != 0)
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[821] | 191 | return 0;
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[2725] | 192 | return (unsigned char)str[0] + (unsigned char)str[1];
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[821] | 193 | }
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| 194 |
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| 195 | /* The comparison operator handling functions. */
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| 196 |
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[2725] | 197 | static int cmp_common(VALUE *l, VALUE *r, int op)
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[821] | 198 | {
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[2725] | 199 | arith_t ll, rr;
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[821] | 200 |
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[2725] | 201 | ll = l->u.i;
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| 202 | rr = r->u.i;
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| 203 | if (l->type == STRING || r->type == STRING) {
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[1765] | 204 | tostring(l);
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| 205 | tostring(r);
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[2725] | 206 | ll = strcmp(l->u.s, r->u.s);
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| 207 | rr = 0;
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| 208 | }
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| 209 | /* calculating ll - rr and checking the result is prone to overflows.
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| 210 | * We'll do it differently: */
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[1765] | 211 | if (op == '<')
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[2725] | 212 | return ll < rr;
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| 213 | if (op == ('<' + '='))
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| 214 | return ll <= rr;
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| 215 | if (op == '=' || (op == '=' + '='))
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| 216 | return ll == rr;
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| 217 | if (op == '!' + '=')
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| 218 | return ll != rr;
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[1765] | 219 | if (op == '>')
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[2725] | 220 | return ll > rr;
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[1765] | 221 | /* >= */
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[2725] | 222 | return ll >= rr;
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[821] | 223 | }
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| 224 |
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| 225 | /* The arithmetic operator handling functions. */
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| 226 |
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[2725] | 227 | static arith_t arithmetic_common(VALUE *l, VALUE *r, int op)
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[821] | 228 | {
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[1765] | 229 | arith_t li, ri;
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[821] | 230 |
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[1765] | 231 | if (!toarith(l) || !toarith(r))
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| 232 | bb_error_msg_and_die("non-numeric argument");
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| 233 | li = l->u.i;
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| 234 | ri = r->u.i;
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| 235 | if (op == '+')
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[821] | 236 | return li + ri;
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[2725] | 237 | if (op == '-')
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[821] | 238 | return li - ri;
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[2725] | 239 | if (op == '*')
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[821] | 240 | return li * ri;
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[2725] | 241 | if (ri == 0)
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| 242 | bb_error_msg_and_die("division by zero");
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| 243 | if (op == '/')
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[821] | 244 | return li / ri;
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[2725] | 245 | return li % ri;
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[821] | 246 | }
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| 247 |
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| 248 | /* Do the : operator.
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| 249 | SV is the VALUE for the lhs (the string),
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| 250 | PV is the VALUE for the rhs (the pattern). */
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| 251 |
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[2725] | 252 | static VALUE *docolon(VALUE *sv, VALUE *pv)
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[821] | 253 | {
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[2725] | 254 | enum { NMATCH = 2 };
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[821] | 255 | VALUE *v;
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| 256 | regex_t re_buffer;
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| 257 | regmatch_t re_regs[NMATCH];
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| 258 |
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[1765] | 259 | tostring(sv);
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| 260 | tostring(pv);
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[821] | 261 |
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| 262 | if (pv->u.s[0] == '^') {
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[2725] | 263 | bb_error_msg(
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| 264 | "warning: '%s': using '^' as the first character\n"
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| 265 | "of a basic regular expression is not portable; it is ignored", pv->u.s);
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[821] | 266 | }
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| 267 |
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[1765] | 268 | memset(&re_buffer, 0, sizeof(re_buffer));
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[2725] | 269 | memset(re_regs, 0, sizeof(re_regs));
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[1765] | 270 | xregcomp(&re_buffer, pv->u.s, 0);
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[821] | 271 |
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| 272 | /* expr uses an anchored pattern match, so check that there was a
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| 273 | * match and that the match starts at offset 0. */
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[2725] | 274 | if (regexec(&re_buffer, sv->u.s, NMATCH, re_regs, 0) != REG_NOMATCH
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| 275 | && re_regs[0].rm_so == 0
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| 276 | ) {
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[821] | 277 | /* Were \(...\) used? */
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[2725] | 278 | if (re_buffer.re_nsub > 0 && re_regs[1].rm_so >= 0) {
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[821] | 279 | sv->u.s[re_regs[1].rm_eo] = '\0';
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[1765] | 280 | v = str_value(sv->u.s + re_regs[1].rm_so);
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[2725] | 281 | } else {
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[1765] | 282 | v = int_value(re_regs[0].rm_eo);
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[2725] | 283 | }
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[1765] | 284 | } else {
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[821] | 285 | /* Match failed -- return the right kind of null. */
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| 286 | if (re_buffer.re_nsub > 0)
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[1765] | 287 | v = str_value("");
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[821] | 288 | else
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[1765] | 289 | v = int_value(0);
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[821] | 290 | }
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[2725] | 291 | regfree(&re_buffer);
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[821] | 292 | return v;
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| 293 | }
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| 294 |
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| 295 | /* Handle bare operands and ( expr ) syntax. */
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| 296 |
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[1765] | 297 | static VALUE *eval7(void)
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[821] | 298 | {
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| 299 | VALUE *v;
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| 300 |
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[1765] | 301 | if (!*G.args)
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| 302 | bb_error_msg_and_die("syntax error");
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[821] | 303 |
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[1765] | 304 | if (nextarg("(")) {
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| 305 | G.args++;
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| 306 | v = eval();
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| 307 | if (!nextarg(")"))
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| 308 | bb_error_msg_and_die("syntax error");
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| 309 | G.args++;
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| 310 | return v;
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| 311 | }
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[821] | 312 |
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[1765] | 313 | if (nextarg(")"))
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| 314 | bb_error_msg_and_die("syntax error");
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[821] | 315 |
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[1765] | 316 | return str_value(*G.args++);
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[821] | 317 | }
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| 318 |
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| 319 | /* Handle match, substr, index, length, and quote keywords. */
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| 320 |
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[1765] | 321 | static VALUE *eval6(void)
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[821] | 322 | {
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[1765] | 323 | static const char keywords[] ALIGN1 =
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| 324 | "quote\0""length\0""match\0""index\0""substr\0";
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[821] | 325 |
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[1765] | 326 | VALUE *r, *i1, *i2;
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| 327 | VALUE *l = l; /* silence gcc */
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| 328 | VALUE *v = v; /* silence gcc */
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| 329 | int key = *G.args ? index_in_strings(keywords, *G.args) + 1 : 0;
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| 330 |
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| 331 | if (key == 0) /* not a keyword */
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| 332 | return eval7();
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| 333 | G.args++; /* We have a valid token, so get the next argument. */
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| 334 | if (key == 1) { /* quote */
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| 335 | if (!*G.args)
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| 336 | bb_error_msg_and_die("syntax error");
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| 337 | return str_value(*G.args++);
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[821] | 338 | }
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[1765] | 339 | if (key == 2) { /* length */
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| 340 | r = eval6();
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| 341 | tostring(r);
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| 342 | v = int_value(strlen(r->u.s));
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| 343 | freev(r);
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| 344 | } else
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| 345 | l = eval6();
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| 346 |
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| 347 | if (key == 3) { /* match */
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| 348 | r = eval6();
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| 349 | v = docolon(l, r);
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| 350 | freev(l);
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| 351 | freev(r);
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[821] | 352 | }
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[1765] | 353 | if (key == 4) { /* index */
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| 354 | r = eval6();
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| 355 | tostring(l);
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| 356 | tostring(r);
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| 357 | v = int_value(strcspn(l->u.s, r->u.s) + 1);
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| 358 | if (v->u.i == (arith_t) strlen(l->u.s) + 1)
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[821] | 359 | v->u.i = 0;
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[1765] | 360 | freev(l);
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| 361 | freev(r);
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[821] | 362 | }
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[1765] | 363 | if (key == 5) { /* substr */
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| 364 | i1 = eval6();
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| 365 | i2 = eval6();
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| 366 | tostring(l);
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| 367 | if (!toarith(i1) || !toarith(i2)
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| 368 | || i1->u.i > (arith_t) strlen(l->u.s)
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| 369 | || i1->u.i <= 0 || i2->u.i <= 0)
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| 370 | v = str_value("");
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[821] | 371 | else {
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[1765] | 372 | v = xmalloc(sizeof(VALUE));
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[2725] | 373 | v->type = STRING;
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[1765] | 374 | v->u.s = xstrndup(l->u.s + i1->u.i - 1, i2->u.i);
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[821] | 375 | }
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[1765] | 376 | freev(l);
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| 377 | freev(i1);
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| 378 | freev(i2);
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[821] | 379 | }
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[1765] | 380 | return v;
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[821] | 381 | }
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| 382 |
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| 383 | /* Handle : operator (pattern matching).
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| 384 | Calls docolon to do the real work. */
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| 385 |
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[1765] | 386 | static VALUE *eval5(void)
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[821] | 387 | {
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| 388 | VALUE *l, *r, *v;
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| 389 |
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[1765] | 390 | l = eval6();
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| 391 | while (nextarg(":")) {
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| 392 | G.args++;
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| 393 | r = eval6();
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| 394 | v = docolon(l, r);
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| 395 | freev(l);
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| 396 | freev(r);
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[821] | 397 | l = v;
|
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| 398 | }
|
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| 399 | return l;
|
---|
| 400 | }
|
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| 401 |
|
---|
| 402 | /* Handle *, /, % operators. */
|
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| 403 |
|
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[1765] | 404 | static VALUE *eval4(void)
|
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[821] | 405 | {
|
---|
| 406 | VALUE *l, *r;
|
---|
| 407 | int op;
|
---|
| 408 | arith_t val;
|
---|
| 409 |
|
---|
[1765] | 410 | l = eval5();
|
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[821] | 411 | while (1) {
|
---|
[2725] | 412 | op = nextarg("*");
|
---|
| 413 | if (!op) { op = nextarg("/");
|
---|
| 414 | if (!op) { op = nextarg("%");
|
---|
| 415 | if (!op) return l;
|
---|
| 416 | }}
|
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[1765] | 417 | G.args++;
|
---|
| 418 | r = eval5();
|
---|
| 419 | val = arithmetic_common(l, r, op);
|
---|
| 420 | freev(l);
|
---|
| 421 | freev(r);
|
---|
| 422 | l = int_value(val);
|
---|
[821] | 423 | }
|
---|
| 424 | }
|
---|
| 425 |
|
---|
| 426 | /* Handle +, - operators. */
|
---|
| 427 |
|
---|
[1765] | 428 | static VALUE *eval3(void)
|
---|
[821] | 429 | {
|
---|
| 430 | VALUE *l, *r;
|
---|
| 431 | int op;
|
---|
| 432 | arith_t val;
|
---|
| 433 |
|
---|
[1765] | 434 | l = eval4();
|
---|
[821] | 435 | while (1) {
|
---|
[2725] | 436 | op = nextarg("+");
|
---|
| 437 | if (!op) {
|
---|
| 438 | op = nextarg("-");
|
---|
| 439 | if (!op) return l;
|
---|
| 440 | }
|
---|
[1765] | 441 | G.args++;
|
---|
| 442 | r = eval4();
|
---|
| 443 | val = arithmetic_common(l, r, op);
|
---|
| 444 | freev(l);
|
---|
| 445 | freev(r);
|
---|
| 446 | l = int_value(val);
|
---|
[821] | 447 | }
|
---|
| 448 | }
|
---|
| 449 |
|
---|
| 450 | /* Handle comparisons. */
|
---|
| 451 |
|
---|
[1765] | 452 | static VALUE *eval2(void)
|
---|
[821] | 453 | {
|
---|
| 454 | VALUE *l, *r;
|
---|
| 455 | int op;
|
---|
| 456 | arith_t val;
|
---|
| 457 |
|
---|
[1765] | 458 | l = eval3();
|
---|
[821] | 459 | while (1) {
|
---|
[2725] | 460 | 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) { op = nextarg(">");
|
---|
| 467 | if (!op) return l;
|
---|
| 468 | }}}}}}
|
---|
[1765] | 469 | G.args++;
|
---|
| 470 | r = eval3();
|
---|
| 471 | toarith(l);
|
---|
| 472 | toarith(r);
|
---|
| 473 | val = cmp_common(l, r, op);
|
---|
| 474 | freev(l);
|
---|
| 475 | freev(r);
|
---|
| 476 | l = int_value(val);
|
---|
[821] | 477 | }
|
---|
| 478 | }
|
---|
| 479 |
|
---|
| 480 | /* Handle &. */
|
---|
| 481 |
|
---|
[1765] | 482 | static VALUE *eval1(void)
|
---|
[821] | 483 | {
|
---|
| 484 | VALUE *l, *r;
|
---|
| 485 |
|
---|
[1765] | 486 | l = eval2();
|
---|
| 487 | while (nextarg("&")) {
|
---|
| 488 | G.args++;
|
---|
| 489 | r = eval2();
|
---|
| 490 | if (null(l) || null(r)) {
|
---|
| 491 | freev(l);
|
---|
| 492 | freev(r);
|
---|
| 493 | l = int_value(0);
|
---|
| 494 | } else
|
---|
| 495 | freev(r);
|
---|
[821] | 496 | }
|
---|
| 497 | return l;
|
---|
| 498 | }
|
---|
| 499 |
|
---|
| 500 | /* Handle |. */
|
---|
| 501 |
|
---|
[1765] | 502 | static VALUE *eval(void)
|
---|
[821] | 503 | {
|
---|
| 504 | VALUE *l, *r;
|
---|
| 505 |
|
---|
[1765] | 506 | l = eval1();
|
---|
| 507 | while (nextarg("|")) {
|
---|
| 508 | G.args++;
|
---|
| 509 | r = eval1();
|
---|
| 510 | if (null(l)) {
|
---|
| 511 | freev(l);
|
---|
[821] | 512 | l = r;
|
---|
[1765] | 513 | } else
|
---|
| 514 | freev(r);
|
---|
[821] | 515 | }
|
---|
| 516 | return l;
|
---|
| 517 | }
|
---|
[1765] | 518 |
|
---|
[2725] | 519 | int expr_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
---|
| 520 | int expr_main(int argc UNUSED_PARAM, char **argv)
|
---|
[1765] | 521 | {
|
---|
| 522 | VALUE *v;
|
---|
| 523 |
|
---|
[3232] | 524 | INIT_G();
|
---|
| 525 |
|
---|
[2725] | 526 | xfunc_error_retval = 2; /* coreutils compat */
|
---|
| 527 | G.args = argv + 1;
|
---|
| 528 | if (*G.args == NULL) {
|
---|
[1765] | 529 | bb_error_msg_and_die("too few arguments");
|
---|
| 530 | }
|
---|
| 531 | v = eval();
|
---|
| 532 | if (*G.args)
|
---|
| 533 | bb_error_msg_and_die("syntax error");
|
---|
[2725] | 534 | if (v->type == INTEGER)
|
---|
[1765] | 535 | printf("%" PF_REZ "d\n", PF_REZ_TYPE v->u.i);
|
---|
| 536 | else
|
---|
| 537 | puts(v->u.s);
|
---|
| 538 | fflush_stdout_and_exit(null(v));
|
---|
| 539 | }
|
---|