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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