16
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1 #include <stdlib.h>
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2 #include <string.h>
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3 #include <limits.h>
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4 #include <errno.h>
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5
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6 #include "utils.h"
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7 #include "array.h"
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8 #include "mode.h"
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9 #include "place.h"
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10 #include "eval.h"
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11
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12 /*
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13 * e ::=
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14 * e1 ? e2 : e3
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15 * e1 || e2
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16 * e1 && e2
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17 * e1 | e2
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18 * e1 ^ e2
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19 * e1 & e2
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20 * e1 == e2 | e1 != e2
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21 * e1 < e2 | e1 <= e2 | e1 > e2 | e1 >= e2
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22 * e1 << e2 | e1 >> e2
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23 * e1 + e2 | e1 - e2
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24 * e1 * e2 | e1 / e2 | e1 % e2
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25 * !e | ~e | -e | +e
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26 * ( e ) | ident
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27 */
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28
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29 enum tokens {
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30 T_EOF, /* end of input */
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31 T_VAL, /* value */
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32 T_LPAREN, /* parens */
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33 T_RPAREN,
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34 T_PIPEPIPE, /* operators */
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35 T_AMPAMP,
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36 T_EQEQ,
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37 T_BANGEQ,
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38 T_LTEQ,
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39 T_GTEQ,
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40 T_LTLT,
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41 T_GTGT,
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42 T_QUES,
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43 T_COLON,
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44 T_PIPE,
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45 T_CARET,
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46 T_AMP,
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47 T_LT,
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48 T_GT,
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49 T_PLUS,
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50 T_MINUS,
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51 T_STAR,
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52 T_SLASH,
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53 T_PCT,
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54 T_BANG,
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55 T_TILDE,
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56 };
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57
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58 static const struct {
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59 char c1, c2;
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60 enum tokens tok;
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61 } tokens_2[] = {
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62 { '|', '|', T_PIPEPIPE },
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63 { '&', '&', T_AMPAMP },
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64 { '=', '=', T_EQEQ },
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65 { '!', '=', T_BANGEQ },
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66 { '<', '=', T_LTEQ },
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67 { '>', '=', T_GTEQ },
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68 { '<', '<', T_LTLT },
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69 { '>', '>', T_GTGT },
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70 };
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71 static const unsigned num_tokens_2 = HOWMANY(tokens_2);
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72
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73 static const struct {
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74 char c1;
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75 enum tokens tok;
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76 } tokens_1[] = {
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77 { '?', T_QUES },
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78 { ':', T_COLON },
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79 { '|', T_PIPE },
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80 { '^', T_CARET },
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81 { '&', T_AMP },
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82 { '<', T_LT },
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83 { '>', T_GT },
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84 { '+', T_PLUS },
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85 { '-', T_MINUS },
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86 { '*', T_STAR },
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87 { '/', T_SLASH },
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88 { '%', T_PCT },
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89 { '!', T_BANG },
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90 { '~', T_TILDE },
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91 { '(', T_LPAREN },
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92 { ')', T_RPAREN },
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93 };
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94 static const unsigned num_tokens_1 = HOWMANY(tokens_1);
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95
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96 struct token {
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97 struct place place;
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98 enum tokens tok;
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99 int val;
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100 };
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101 DECLARRAY(token);
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102 DEFARRAY(token, );
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103
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104 static struct tokenarray tokens;
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105
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106 static
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107 struct token *
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108 token_create(const struct place *p, enum tokens tok, int val)
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109 {
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110 struct token *t;
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111
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112 t = domalloc(sizeof(*t));
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113 t->place = *p;
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114 t->tok = tok;
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115 t->val = val;
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116 return t;
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117 }
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118
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119 static
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120 void
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121 token_destroy(struct token *t)
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122 {
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123 free(t);
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124 }
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125
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126 DESTROYALL_ARRAY(token, );
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127
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128 static
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129 bool
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130 isuop(enum tokens tok)
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131 {
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132 switch (tok) {
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133 case T_BANG:
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134 case T_TILDE:
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135 case T_MINUS:
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136 case T_PLUS:
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137 return true;
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138 default:
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139 break;
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140 }
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141 return false;
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142 }
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143
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144 static
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145 bool
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146 isbop(enum tokens tok)
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147 {
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148 switch (tok) {
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149 case T_EOF:
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150 case T_VAL:
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151 case T_LPAREN:
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152 case T_RPAREN:
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153 case T_COLON:
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154 case T_QUES:
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155 case T_BANG:
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156 case T_TILDE:
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157 return false;
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158 default:
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159 break;
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160 }
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161 return true;
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162 }
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163
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164 static
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165 bool
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166 isop(enum tokens tok)
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167 {
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168 switch (tok) {
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169 case T_EOF:
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170 case T_VAL:
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171 case T_LPAREN:
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172 case T_RPAREN:
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173 return false;
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174 default:
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175 break;
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176 }
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177 return true;
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178 }
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179
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180 static
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181 int
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182 getprec(enum tokens tok)
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183 {
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184 switch (tok) {
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185 case T_STAR: case T_SLASH: case T_PCT: return 0;
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186 case T_PLUS: case T_MINUS: return 1;
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187 case T_LTLT: case T_GTGT: return 2;
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188 case T_LT: case T_LTEQ: case T_GT: case T_GTEQ: return 3;
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189 case T_EQEQ: case T_BANGEQ: return 4;
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190 case T_AMP: return 5;
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191 case T_CARET: return 6;
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192 case T_PIPE: return 7;
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193 case T_AMPAMP: return 8;
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194 case T_PIPEPIPE: return 9;
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195 default: break;
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196 }
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197 return 10;
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198 }
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199
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200 static
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201 bool
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202 looser(enum tokens t1, enum tokens t2)
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203 {
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204 return getprec(t1) > getprec(t2);
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205 }
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206
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207 static
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208 int
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209 eval_uop(enum tokens op, int val)
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210 {
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211 switch (op) {
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212 case T_BANG: val = !val; break;
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213 case T_TILDE: val = (int)~(unsigned)val; break;
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214 case T_MINUS: val = -val; break;
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215 case T_PLUS: break;
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216 default: assert(0); break;
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217 }
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218 return val;
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219 }
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220
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221 static
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222 int
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28
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223 eval_bop(struct place *p, int lv, enum tokens op, int rv)
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224 {
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225 unsigned mask;
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226
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227 switch (op) {
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228 case T_PIPEPIPE: return lv || rv;
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229 case T_AMPAMP: return lv && rv;
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230 case T_PIPE: return (int)((unsigned)lv | (unsigned)rv);
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231 case T_CARET: return (int)((unsigned)lv ^ (unsigned)rv);
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232 case T_AMP: return (int)((unsigned)lv & (unsigned)rv);
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233 case T_EQEQ: return lv == rv;
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234 case T_BANGEQ: return lv != rv;
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235 case T_LT: return lv < rv;
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236 case T_GT: return lv > rv;
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237 case T_LTEQ: return lv <= rv;
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238 case T_GTEQ: return lv >= rv;
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239
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240 case T_LTLT:
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241 case T_GTGT:
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242 if (rv < 0) {
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243 complain(p, "Negative bit-shift");
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244 complain_fail();
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245 rv = 0;
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246 }
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247 if ((unsigned)rv >= CHAR_BIT * sizeof(unsigned)) {
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248 complain(p, "Bit-shift farther than type width");
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249 complain_fail();
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250 rv = 0;
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251 }
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252 if (op == T_LTLT) {
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253 return (int)((unsigned)lv << (unsigned)rv);
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254 }
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255 mask = ((unsigned)-1) << (CHAR_BIT * sizeof(unsigned) - rv);
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256 lv = (int)(((unsigned)lv >> (unsigned)rv) | mask);
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257 return lv;
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258
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259 case T_MINUS:
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260 if (rv == INT_MIN) {
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261 if (lv == INT_MIN) {
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262 return 0;
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263 }
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264 lv--;
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265 rv++;
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266 }
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267 rv = -rv;
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268 /* FALLTHROUGH */
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269 case T_PLUS:
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270 if (rv > 0 && lv > (INT_MAX - rv)) {
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271 complain(p, "Integer overflow");
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272 complain_fail();
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273 return INT_MAX;
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274 }
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275 if (rv < 0 && lv < (INT_MIN - rv)) {
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276 complain(p, "Integer underflow");
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277 complain_fail();
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278 return INT_MIN;
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279 }
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280 return lv + rv;
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281
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282 case T_STAR:
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283 if (rv == 0) {
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284 return 0;
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285 }
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286 if (rv == 1) {
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287 return lv;
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288 }
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289 if (rv == -1 && lv == INT_MIN) {
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290 lv++;
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291 lv = -lv;
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292 if (lv == INT_MAX) {
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293 complain(p, "Integer overflow");
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294 complain_fail();
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295 return INT_MAX;
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296 }
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297 lv++;
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298 return lv;
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299 }
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300 if (lv == INT_MIN && rv < 0) {
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301 complain(p, "Integer overflow");
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302 complain_fail();
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303 return INT_MAX;
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304 }
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305 if (lv == INT_MIN && rv > 0) {
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306 complain(p, "Integer underflow");
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307 complain_fail();
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308 return INT_MIN;
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309 }
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310 if (rv < 0) {
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311 rv = -rv;
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312 lv = -lv;
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313 }
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314 if (lv > 0 && lv > INT_MAX / rv) {
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315 complain(p, "Integer overflow");
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316 complain_fail();
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317 return INT_MAX;
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318 }
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319 if (lv < 0 && lv < INT_MIN / rv) {
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320 complain(p, "Integer underflow");
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321 complain_fail();
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322 return INT_MIN;
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323 }
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324 return lv * rv;
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325
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326 case T_SLASH:
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327 if (rv == 0) {
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328 complain(p, "Division by zero");
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329 complain_fail();
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330 return 0;
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331 }
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332 return lv / rv;
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333
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334 case T_PCT:
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335 if (rv == 0) {
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336 complain(p, "Modulus by zero");
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337 complain_fail();
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338 return 0;
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339 }
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340 return lv % rv;
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341
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342 default: assert(0); break;
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343 }
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344 return 0;
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345 }
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346
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347 static
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348 void
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349 tryreduce(void)
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350 {
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351 unsigned num;
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352 struct token *t1, *t2, *t3, *t4, *t5, *t6;
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353
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354 while (1) {
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355 num = tokenarray_num(&tokens);
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356 t1 = (num >= 1) ? tokenarray_get(&tokens, num-1) : NULL;
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357 t2 = (num >= 2) ? tokenarray_get(&tokens, num-2) : NULL;
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358 t3 = (num >= 3) ? tokenarray_get(&tokens, num-3) : NULL;
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359
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360 if (num >= 3 &&
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361 t3->tok == T_LPAREN &&
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362 t2->tok == T_VAL &&
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363 t1->tok == T_RPAREN) {
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364 /* (x) -> x */
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365 t2->place = t3->place;
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366 token_destroy(t1);
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367 token_destroy(t3);
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368 tokenarray_remove(&tokens, num-1);
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369 tokenarray_remove(&tokens, num-3);
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370 continue;
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371 }
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372
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373 if (num >= 2 &&
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374 (num == 2 || isop(t3->tok) || t3->tok == T_LPAREN) &&
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375 isuop(t2->tok) &&
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376 t1->tok == T_VAL) {
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377 /* unary operator */
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378 t1->val = eval_uop(t2->tok, t1->val);
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379 t1->place = t2->place;
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380 token_destroy(t2);
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381 tokenarray_remove(&tokens, num-2);
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382 continue;
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383 }
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384 if (num >= 2 &&
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385 (num == 2 || isop(t3->tok) || t3->tok == T_RPAREN) &&
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386 t2->tok != T_LPAREN && t2->tok != T_VAL &&
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387 t1->tok == T_VAL) {
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388 complain(&t2->place, "Invalid unary operator");
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389 complain_fail();
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390 token_destroy(t2);
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391 tokenarray_remove(&tokens, num-2);
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392 continue;
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393 }
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394
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395
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396 t4 = (num >= 4) ? tokenarray_get(&tokens, num-4) : NULL;
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397
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398 if (num >= 4 &&
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399 t4->tok == T_VAL &&
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400 isbop(t3->tok) &&
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401 t2->tok == T_VAL &&
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402 (isbop(t1->tok) || !isop(t1->tok))) {
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403 /* binary operator */
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404 if (looser(t1->tok, t3->tok)) {
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405 t4->val = eval_bop(&t3->place,
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406 t4->val, t3->tok, t2->val);
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407 token_destroy(t2);
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408 token_destroy(t3);
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409 tokenarray_remove(&tokens, num-2);
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410 tokenarray_remove(&tokens, num-3);
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411 continue;
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412 }
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413 break;
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414 }
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415
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416 t5 = (num >= 5) ? tokenarray_get(&tokens, num-5) : NULL;
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417 t6 = (num >= 6) ? tokenarray_get(&tokens, num-6) : NULL;
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418
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419 if (num >=6 &&
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420 t6->tok == T_VAL &&
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421 t5->tok == T_QUES &&
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422 t4->tok == T_VAL &&
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423 t3->tok == T_COLON &&
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424 t2->tok == T_VAL &&
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425 !isop(t1->tok)) {
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426 /* conditional expression */
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427 t6->val = t6->val ? t4->val : t2->val;
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428 token_destroy(t2);
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429 token_destroy(t3);
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430 token_destroy(t4);
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431 token_destroy(t5);
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432 tokenarray_remove(&tokens, num-2);
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433 tokenarray_remove(&tokens, num-3);
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434 tokenarray_remove(&tokens, num-4);
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435 tokenarray_remove(&tokens, num-5);
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436 continue;
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437 }
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438
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439 if (num >= 2 &&
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440 t2->tok == T_LPAREN &&
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441 t1->tok == T_RPAREN) {
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442 complain(&t1->place, "Value expected within ()");
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443 complain_fail();
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444 t1->tok = T_VAL;
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445 t1->val = 0;
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446 token_destroy(t1);
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447 tokenarray_remove(&tokens, num-1);
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448 continue;
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449 }
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450
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451 if (num >= 2 &&
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452 t2->tok == T_VAL &&
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453 t1->tok == T_VAL) {
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454 complain(&t1->place, "Operator expected");
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455 complain_fail();
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456 token_destroy(t1);
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457 tokenarray_remove(&tokens, num-1);
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458 continue;
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459 }
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460
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461 if (num >= 2 &&
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462 isop(t2->tok) &&
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463 t1->tok == T_EOF) {
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464 complain(&t1->place, "Value expected after operator");
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465 complain_fail();
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466 token_destroy(t2);
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467 tokenarray_remove(&tokens, num-2);
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468 continue;
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469 }
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470
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471 if (num == 2 &&
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472 t2->tok == T_VAL &&
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473 t1->tok == T_RPAREN) {
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474 complain(&t1->place, "Excess right parenthesis");
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475 complain_fail();
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476 token_destroy(t1);
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477 tokenarray_remove(&tokens, num-1);
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478 continue;
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479 }
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480
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481 if (num == 3 &&
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482 t3->tok == T_LPAREN &&
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483 t2->tok == T_VAL &&
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484 t1->tok == T_EOF) {
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485 complain(&t1->place, "Unclosed left parenthesis");
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486 complain_fail();
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487 token_destroy(t3);
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488 tokenarray_remove(&tokens, num-3);
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489 continue;
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490 }
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491
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492 if (num == 2 &&
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493 t2->tok == T_VAL &&
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494 t1->tok == T_EOF) {
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495 /* accepting state */
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496 break;
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497 }
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498
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499 if (num >= 1 &&
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500 t1->tok == T_EOF) {
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501 /* any other configuration at eof is an error */
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502 complain(&t1->place, "Parse error");
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503 complain_fail();
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504 break;
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505 }
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506
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507 /* otherwise, wait for more input */
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508 break;
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509 }
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510 }
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511
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512 static
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513 void
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514 token(struct place *p, enum tokens tok, int val)
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515 {
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516 struct token *t;
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517
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518 t = token_create(p, tok, val);
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519
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520 tokenarray_add(&tokens, t, NULL);
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521 tryreduce();
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522 }
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523
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524 static
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525 int
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526 wordval(struct place *p, char *word)
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527 {
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528 unsigned long val;
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529 char *t;
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530
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531 if (word[0] >= '0' && word[0] <= '9') {
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532 errno = 0;
|
|
533 val = strtoul(word, &t, 0);
|
|
534 if (errno || *t != '\0') {
|
|
535 complain(p, "Invalid integer constant");
|
|
536 complain_fail();
|
|
537 return 0;
|
|
538 }
|
|
539 if (val > INT_MAX) {
|
|
540 complain(p, "Integer constant too large");
|
|
541 complain_fail();
|
|
542 return INT_MAX;
|
|
543 }
|
|
544 return val;
|
|
545 }
|
|
546
|
|
547 /* if it's a symbol, warn and substitute 0. */
|
|
548 if (warns.undef) {
|
|
549 complain(p, "Warning: value of undefined symbol %s is 0",
|
|
550 word);
|
|
551 if (mode.werror) {
|
|
552 complain_fail();
|
|
553 }
|
|
554 }
|
|
555 return 0;
|
|
556 }
|
|
557
|
|
558 static
|
|
559 bool
|
|
560 check_word(struct place *p, char *expr, size_t pos, size_t *len_ret)
|
|
561 {
|
|
562 size_t len;
|
|
563 int val;
|
|
564 char tmp;
|
|
565
|
|
566 if (!strchr(alnum, expr[pos])) {
|
|
567 return false;
|
|
568 }
|
|
569 len = strspn(expr + pos, alnum);
|
|
570 tmp = expr[pos + len];
|
|
571 expr[pos + len] = '\0';
|
|
572 val = wordval(p, expr + pos);
|
|
573 expr[pos + len] = tmp;
|
|
574 token(p, T_VAL, val);
|
|
575 *len_ret = len;
|
|
576 return true;
|
|
577 }
|
|
578
|
|
579 static
|
|
580 bool
|
|
581 check_tokens_2(struct place *p, char *expr, size_t pos)
|
|
582 {
|
|
583 unsigned i;
|
|
584
|
|
585 for (i=0; i<num_tokens_2; i++) {
|
|
586 if (expr[pos] == tokens_2[i].c1 &&
|
|
587 expr[pos+1] == tokens_2[i].c2) {
|
|
588 token(p, tokens_2[i].tok, 0);
|
|
589 return true;
|
|
590 }
|
|
591 }
|
|
592 return false;
|
|
593 }
|
|
594
|
|
595 static
|
|
596 bool
|
|
597 check_tokens_1(struct place *p, char *expr, size_t pos)
|
|
598 {
|
|
599 unsigned i;
|
|
600
|
|
601 for (i=0; i<num_tokens_1; i++) {
|
|
602 if (expr[pos] == tokens_1[i].c1) {
|
|
603 token(p, tokens_1[i].tok, 0);
|
|
604 return true;
|
|
605 }
|
|
606 }
|
|
607 return false;
|
|
608 }
|
|
609
|
|
610 static
|
|
611 void
|
|
612 tokenize(struct place *p, char *expr)
|
|
613 {
|
|
614 size_t pos, len;
|
|
615
|
|
616 pos = 0;
|
|
617 while (expr[pos] != '\0') {
|
|
618 len = strspn(expr+pos, ws);
|
|
619 pos += len;
|
|
620 p->column += len;
|
|
621 if (check_word(p, expr, pos, &len)) {
|
|
622 pos += len;
|
|
623 p->column += len;
|
|
624 continue;
|
|
625 }
|
|
626 if (check_tokens_2(p, expr, pos)) {
|
|
627 pos += 2;
|
|
628 p->column += 2;
|
|
629 continue;
|
|
630 }
|
|
631 if (check_tokens_1(p, expr, pos)) {
|
|
632 pos++;
|
|
633 p->column++;
|
|
634 continue;
|
|
635 }
|
|
636 complain(p, "Invalid character %u in #if-expression",
|
|
637 (unsigned char)expr[pos]);
|
|
638 complain_fail();
|
|
639 pos++;
|
|
640 p->column++;
|
|
641 }
|
|
642 token(p, T_EOF, 0);
|
|
643 }
|
|
644
|
|
645 bool
|
|
646 eval(struct place *p, char *expr)
|
|
647 {
|
|
648 struct token *t1, *t2;
|
|
649 unsigned num;
|
|
650 bool result;
|
|
651
|
|
652 tokenarray_init(&tokens);
|
|
653 tokenize(p, expr);
|
|
654
|
|
655 result = false;
|
|
656 num = tokenarray_num(&tokens);
|
|
657 if (num == 2) {
|
|
658 t1 = tokenarray_get(&tokens, num-1);
|
|
659 t2 = tokenarray_get(&tokens, num-2);
|
|
660 if (t1->tok == T_VAL &&
|
|
661 t2->tok == T_EOF) {
|
|
662 result = t1->val != 0;
|
|
663 }
|
|
664 }
|
|
665
|
|
666 tokenarray_destroyall(&tokens);
|
|
667 tokenarray_cleanup(&tokens);
|
|
668 return result;
|
|
669 }
|