[3320] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 4 | */
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| 5 |
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| 6 | #include "libbb.h"
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| 7 | #include <math.h>
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| 8 |
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| 9 | //usage:#define dc_trivial_usage
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| 10 | //usage: "EXPRESSION..."
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| 11 | //usage:
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| 12 | //usage:#define dc_full_usage "\n\n"
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| 13 | //usage: "Tiny RPN calculator. Operations:\n"
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| 14 | //usage: "+, add, -, sub, *, mul, /, div, %, mod, **, exp, and, or, not, eor,\n"
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| 15 | //usage: "p - print top of the stack (without popping),\n"
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| 16 | //usage: "f - print entire stack,\n"
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| 17 | //usage: "o - pop the value and set output radix (must be 10, 16, 8 or 2).\n"
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| 18 | //usage: "Examples: 'dc 2 2 add' -> 4, 'dc 8 8 * 2 2 + /' -> 16"
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| 19 | //usage:
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| 20 | //usage:#define dc_example_usage
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| 21 | //usage: "$ dc 2 2 + p\n"
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| 22 | //usage: "4\n"
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| 23 | //usage: "$ dc 8 8 \\* 2 2 + / p\n"
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| 24 | //usage: "16\n"
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| 25 | //usage: "$ dc 0 1 and p\n"
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| 26 | //usage: "0\n"
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| 27 | //usage: "$ dc 0 1 or p\n"
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| 28 | //usage: "1\n"
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| 29 | //usage: "$ echo 72 9 div 8 mul p | dc\n"
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| 30 | //usage: "64\n"
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| 31 |
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| 32 | #if 0
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| 33 | typedef unsigned data_t;
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| 34 | #define DATA_FMT ""
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| 35 | #elif 0
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| 36 | typedef unsigned long data_t;
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| 37 | #define DATA_FMT "l"
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| 38 | #else
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| 39 | typedef unsigned long long data_t;
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| 40 | #define DATA_FMT "ll"
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| 41 | #endif
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| 42 |
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| 43 |
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| 44 | struct globals {
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| 45 | unsigned pointer;
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| 46 | unsigned base;
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| 47 | double stack[1];
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| 48 | } FIX_ALIASING;
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| 49 | enum { STACK_SIZE = (COMMON_BUFSIZE - offsetof(struct globals, stack)) / sizeof(double) };
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| 50 | #define G (*(struct globals*)&bb_common_bufsiz1)
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| 51 | #define pointer (G.pointer )
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| 52 | #define base (G.base )
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| 53 | #define stack (G.stack )
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| 54 | #define INIT_G() do { \
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| 55 | base = 10; \
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| 56 | } while (0)
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| 57 |
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| 58 |
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| 59 | static void push(double a)
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| 60 | {
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| 61 | if (pointer >= STACK_SIZE)
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| 62 | bb_error_msg_and_die("stack overflow");
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| 63 | stack[pointer++] = a;
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| 64 | }
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| 65 |
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| 66 | static double pop(void)
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| 67 | {
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| 68 | if (pointer == 0)
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| 69 | bb_error_msg_and_die("stack underflow");
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| 70 | return stack[--pointer];
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| 71 | }
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| 72 |
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| 73 | static void add(void)
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| 74 | {
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| 75 | push(pop() + pop());
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| 76 | }
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| 77 |
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| 78 | static void sub(void)
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| 79 | {
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| 80 | double subtrahend = pop();
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| 81 |
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| 82 | push(pop() - subtrahend);
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| 83 | }
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| 84 |
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| 85 | static void mul(void)
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| 86 | {
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| 87 | push(pop() * pop());
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| 88 | }
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| 89 |
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| 90 | #if ENABLE_FEATURE_DC_LIBM
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| 91 | static void power(void)
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| 92 | {
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| 93 | double topower = pop();
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| 94 |
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| 95 | push(pow(pop(), topower));
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| 96 | }
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| 97 | #endif
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| 98 |
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| 99 | static void divide(void)
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| 100 | {
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| 101 | double divisor = pop();
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| 102 |
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| 103 | push(pop() / divisor);
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| 104 | }
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| 105 |
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| 106 | static void mod(void)
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| 107 | {
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| 108 | data_t d = pop();
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| 109 |
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| 110 | push((data_t) pop() % d);
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| 111 | }
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| 112 |
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| 113 | static void and(void)
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| 114 | {
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| 115 | push((data_t) pop() & (data_t) pop());
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| 116 | }
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| 117 |
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| 118 | static void or(void)
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| 119 | {
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| 120 | push((data_t) pop() | (data_t) pop());
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| 121 | }
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| 122 |
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| 123 | static void eor(void)
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| 124 | {
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| 125 | push((data_t) pop() ^ (data_t) pop());
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| 126 | }
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| 127 |
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| 128 | static void not(void)
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| 129 | {
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| 130 | push(~(data_t) pop());
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| 131 | }
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| 132 |
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| 133 | static void set_output_base(void)
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| 134 | {
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| 135 | static const char bases[] ALIGN1 = { 2, 8, 10, 16, 0 };
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| 136 | unsigned b = (unsigned)pop();
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| 137 |
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| 138 | base = *strchrnul(bases, b);
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| 139 | if (base == 0) {
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| 140 | bb_error_msg("error, base %u is not supported", b);
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| 141 | base = 10;
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| 142 | }
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| 143 | }
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| 144 |
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| 145 | static void print_base(double print)
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| 146 | {
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| 147 | data_t x, i;
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| 148 |
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| 149 | x = (data_t) print;
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| 150 | if (base == 10) {
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| 151 | if (x == print) /* exactly representable as unsigned integer */
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| 152 | printf("%"DATA_FMT"u\n", x);
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| 153 | else
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| 154 | printf("%g\n", print);
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| 155 | return;
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| 156 | }
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| 157 |
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| 158 | switch (base) {
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| 159 | case 16:
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| 160 | printf("%"DATA_FMT"x\n", x);
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| 161 | break;
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| 162 | case 8:
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| 163 | printf("%"DATA_FMT"o\n", x);
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| 164 | break;
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| 165 | default: /* base 2 */
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| 166 | i = MAXINT(data_t) - (MAXINT(data_t) >> 1);
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| 167 | /* i is 100000...00000 */
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| 168 | do {
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| 169 | if (x & i)
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| 170 | break;
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| 171 | i >>= 1;
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| 172 | } while (i > 1);
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| 173 | do {
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| 174 | bb_putchar('1' - !(x & i));
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| 175 | i >>= 1;
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| 176 | } while (i);
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| 177 | bb_putchar('\n');
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| 178 | }
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| 179 | }
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| 180 |
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| 181 | static void print_stack_no_pop(void)
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| 182 | {
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| 183 | unsigned i = pointer;
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| 184 | while (i)
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| 185 | print_base(stack[--i]);
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| 186 | }
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| 187 |
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| 188 | static void print_no_pop(void)
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| 189 | {
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| 190 | print_base(stack[pointer-1]);
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| 191 | }
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| 192 |
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| 193 | struct op {
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| 194 | const char name[4];
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| 195 | void (*function) (void);
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| 196 | };
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| 197 |
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| 198 | static const struct op operators[] = {
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| 199 | {"+", add},
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| 200 | {"add", add},
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| 201 | {"-", sub},
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| 202 | {"sub", sub},
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| 203 | {"*", mul},
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| 204 | {"mul", mul},
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| 205 | {"/", divide},
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| 206 | {"div", divide},
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| 207 | #if ENABLE_FEATURE_DC_LIBM
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| 208 | {"**", power},
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| 209 | {"exp", power},
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| 210 | {"pow", power},
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| 211 | #endif
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| 212 | {"%", mod},
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| 213 | {"mod", mod},
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| 214 | {"and", and},
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| 215 | {"or", or},
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| 216 | {"not", not},
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| 217 | {"eor", eor},
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| 218 | {"xor", eor},
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| 219 | {"p", print_no_pop},
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| 220 | {"f", print_stack_no_pop},
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| 221 | {"o", set_output_base},
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| 222 | { "", NULL }
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| 223 | };
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| 224 |
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| 225 | static void stack_machine(const char *argument)
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| 226 | {
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| 227 | char *endPointer;
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| 228 | double d;
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| 229 | const struct op *o = operators;
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| 230 |
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| 231 | d = strtod(argument, &endPointer);
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| 232 |
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| 233 | if (endPointer != argument && *endPointer == '\0') {
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| 234 | push(d);
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| 235 | return;
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| 236 | }
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| 237 |
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| 238 | while (o->function) {
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| 239 | if (strcmp(o->name, argument) == 0) {
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| 240 | o->function();
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| 241 | return;
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| 242 | }
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| 243 | o++;
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| 244 | }
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| 245 | bb_error_msg_and_die("syntax error at '%s'", argument);
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| 246 | }
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| 247 |
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| 248 | /* return pointer to next token in buffer and set *buffer to one char
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| 249 | * past the end of the above mentioned token
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| 250 | */
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| 251 | static char *get_token(char **buffer)
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| 252 | {
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| 253 | char *current = skip_whitespace(*buffer);
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| 254 | if (*current != '\0') {
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| 255 | *buffer = skip_non_whitespace(current);
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| 256 | return current;
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| 257 | }
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| 258 | return NULL;
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| 259 | }
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| 260 |
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| 261 | int dc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 262 | int dc_main(int argc UNUSED_PARAM, char **argv)
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| 263 | {
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| 264 | INIT_G();
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| 265 |
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| 266 | argv++;
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| 267 | if (!argv[0]) {
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| 268 | /* take stuff from stdin if no args are given */
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| 269 | char *line;
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| 270 | char *cursor;
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| 271 | char *token;
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| 272 | while ((line = xmalloc_fgetline(stdin)) != NULL) {
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| 273 | cursor = line;
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| 274 | while (1) {
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| 275 | token = get_token(&cursor);
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| 276 | if (!token)
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| 277 | break;
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| 278 | *cursor++ = '\0';
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| 279 | stack_machine(token);
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| 280 | }
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| 281 | free(line);
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| 282 | }
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| 283 | } else {
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| 284 | // why? it breaks "dc -2 2 * p"
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| 285 | //if (argv[0][0] == '-')
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| 286 | // bb_show_usage();
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| 287 | do {
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| 288 | stack_machine(*argv);
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| 289 | } while (*++argv);
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| 290 | }
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| 291 | return EXIT_SUCCESS;
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| 292 | }
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