996
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1 #include <stdio.h>
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2 #include <stdlib.h>
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3 #include <string.h>
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4 #include <assert.h>
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5
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6 typedef unsigned char cell;
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7
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8 cell *read_arbitrary_length_string(FILE *fp);
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9 void run(cell **code, int lines, int maxline);
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10
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11 int main(int argc, char *argv[])
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12 {
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13 cell **code;
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14 FILE *src;
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15 int codespace, codelines = 0, maxline = 0;
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16
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17 if (argc != 2)
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18 {
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19 fprintf(stderr, "Incorrect invocation\n");
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20 return 1;
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21 }
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22
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23 src = fopen(argv[1], "r");
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24 if (src == NULL)
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25 {
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26 fprintf(stderr, "Unreadable file\n");
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27 return 2;
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28 }
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29
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30 codespace = 10;
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31 code = malloc(codespace * sizeof(cell*));
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32 if (!code)
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33 return 3;
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34
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35 for (;;)
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36 {
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37 int len;
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38 if (codelines == codespace)
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39 {
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40 codespace *= 2;
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41 code = realloc(code, codespace * sizeof(cell*));
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42 if (!code)
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43 return 4;
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44 }
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45 code[codelines] = read_arbitrary_length_string(src);
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46 if (code[codelines] == NULL)
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47 break;
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48 len = strlen(code[codelines]);
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49 if (len > maxline)
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50 maxline = len;
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51 codelines++;
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52 }
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53 fclose(src);
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54
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55 run(code, codelines, maxline);
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56 free(code);
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57 return 0;
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58 }
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59
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60 cell *addmem(cell *mem, int cursize, int newsize)
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61 {
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62 mem = realloc(mem, newsize);
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63 if (!mem)
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64 {
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65 fprintf(stderr, "Out of memory\n");
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66 exit(-1);
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67 }
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68 memset(&mem[cursize], 0, newsize - cursize);
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69 return mem;
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70 }
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71
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72 /* For 2 <= n <= 126, next[n] = n / gpf[n]. */
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73 cell next[127] =
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74 {
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75 0, 0, 1, 1, 2, 1, 2, 1,
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76 4, 3, 2, 1, 4, 1, 2, 3,
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77 8, 1, 6, 1, 4, 3, 2, 1,
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78 8, 5, 2, 9, 4, 1, 6, 1,
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79 16, 3, 2, 5, 12, 1, 2, 3,
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80 8, 1, 6, 1, 4, 9, 2, 1,
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81 16, 7, 10, 3, 4, 1, 18, 5,
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82 8, 3, 2, 1, 12, 1, 2, 9,
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83 32, 5, 6, 1, 4, 3, 10, 1,
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84 24, 1, 2, 15, 4, 7, 6, 1,
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85 16, 27, 2, 1, 12, 5, 2, 3,
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86 8, 1, 18, 7, 4, 3, 2, 5,
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87 32, 1, 14, 9, 20, 1, 6, 1,
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88 8, 15, 2, 1, 36, 1, 10, 3,
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89 16, 1, 6, 5, 4, 9, 2, 7,
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90 24, 11, 2, 3, 4, 25, 18
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91 };
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92
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93 /* For 2 <= n <= 126, gpf[n] is n's greatest prime factor. */
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94 cell gpf[127] =
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95 {
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96 0, 0, 2, 3, 2, 5, 3, 7,
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97 2, 3, 5, 11, 3, 13, 7, 5,
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98 2, 17, 3, 19, 5, 7, 11, 23,
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99 3, 5, 13, 3, 7, 29, 5, 31,
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100 2, 11, 17, 7, 3, 37, 19, 13,
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101 5, 41, 7, 43, 11, 5, 23, 47,
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102 3, 7, 5, 17, 13, 53, 3, 11,
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103 7, 19, 29, 59, 5, 61, 31, 7,
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104 2, 13, 11, 67, 17, 23, 7, 71,
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105 3, 73, 37, 5, 19, 11, 13, 79,
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106 5, 3, 41, 83, 7, 17, 43, 29,
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107 11, 89, 5, 13, 23, 31, 47, 19,
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108 3, 97, 7, 11, 5, 101, 17, 103,
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109 13, 7, 53, 107, 3, 109, 11, 37,
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110 7, 113, 19, 23, 29, 13, 59, 17,
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111 5, 11, 61, 41, 31, 5, 7
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112 };
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113
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114 cell bitsset[256] =
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115 {
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116 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
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117 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
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118 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
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119 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
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120 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
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121 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
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122 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
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123 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
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124 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
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125 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
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126 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
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127 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
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128 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
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129 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
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130 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
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131 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
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132 };
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133
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134 #define LEFT 0
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135 #define UP_LEFT 1
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136 #define UP 2
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137 #define UP_RIGHT 3
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138 #define RIGHT 4
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139 #define DOWN_RIGHT 5
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140 #define DOWN 6
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141 #define DOWN_LEFT 7
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142
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143 #define RIGHT135(d) ((d) = right135((d)))
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144 #define RIGHT90(d) ((d) = right90((d)))
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145 #define RIGHT45(d) ((d) = right45((d)))
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146 #define LEFT45(d) ((d) = left45((d)))
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147 #define LEFT90(d) ((d) = left90((d)))
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148 static inline int right135(int dir) { return (dir+3)%8; }
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149 static inline int right90(int dir) { return (dir+2)%8; }
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150 static inline int right45(int dir) { return (dir+1)%8; }
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151 static inline int left45(int dir) { return (dir-1)%8; }
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152 static inline int left90(int dir) { return (dir-2)%8; }
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153 static inline void movefwd(int *x, int *y, int dir, int steps)
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154 {
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155 if (dir == LEFT || dir == UP_LEFT || dir == DOWN_LEFT)
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156 *x -= steps;
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157 else if (dir == RIGHT || dir == UP_RIGHT || dir == DOWN_RIGHT)
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158 *x += steps;
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159 if (dir == UP || dir == UP_LEFT || dir == UP_RIGHT)
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160 *y -= steps;
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161 else if (dir == DOWN || dir == DOWN_LEFT || dir == DOWN_RIGHT)
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162 *y += steps;
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163 }
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164 #ifdef UNSAFE
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165 static inline void checkmove(int x, int y, int w, int h) {}
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166 #else
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167 static inline void checkmove(int x, int y, int w, int h)
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168 {
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169 if (x < 0 || y < 0 || x >= w || y >= h)
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170 {
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171 fprintf(stderr, "Out of bounds\n");
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172 exit(-1);
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173 }
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174 }
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175 #endif
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176 static inline void push(cell val, cell **pstack, int *items, int *space)
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177 {
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178 if (*items == *space)
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179 {
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180 *pstack = addmem(*pstack, *space, 2**space);
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181 *space *= 2;
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182 }
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183 (*pstack)[(*items)++] = val;
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184 }
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185 static inline int pop(cell *stack, int *items)
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186 {
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187 if (*items == 0)
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188 return -1;
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189 return stack[--(*items)];
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190 }
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191 static inline int peek(cell *stack, int items)
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192 {
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193 if (items == 0)
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194 return -1;
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195 return stack[items - 1];
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196 }
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197
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198 void run(cell **code, int lines, int maxline)
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199 {
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200 cell acc, *stack1 = NULL, *stack2 = NULL;
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201 int stack1size = 10, stack2size = 10;
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202 int stack1pos = 0, stack2pos = 0;
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203 int dir = UP_RIGHT, codex, codey;
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204 int i, *lengths;
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205
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206 stack1 = addmem(stack1, 0, stack1size);
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207 stack2 = addmem(stack2, 0, stack2size);
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208 acc = 0;
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209 codex = 0;
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210 codey = lines - 1;
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211
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212 lengths = malloc(sizeof(int) * lines);
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213 for (i = 0; i < lines; i++)
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214 lengths[i] = strlen(code[i]);
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215
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216 for (;;)
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217 {
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218 cell c;
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219 if (codex >= lengths[codey])
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220 c = '!'; /* lines are padded with ! */
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221 else
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222 {
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223 c = code[codey][codex];
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224 #ifndef UNSAFE
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225 if (c < 32 || c > 126)
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226 {
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227 fprintf(stderr, "Invalid character\n");
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228 exit(-1);
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229 }
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230 #endif
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231 }
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232
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233 /* run the commands */
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234 for (; c > 1; c = next[(size_t) c]) switch(gpf[(size_t) c])
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235 {
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236 case 2:
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237 {
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238 cell tmp;
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239 tmp = (acc & 7) << 5;
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240 acc >>= 3;
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241 acc |= tmp;
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242 break;
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243 }
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244 case 3:
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245 {
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246 int s1, s2;
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247 s1 = peek(stack1, stack1pos);
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248 s2 = peek(stack2, stack2pos);
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249 if (s2 < s1)
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250 {
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251 push(acc, &stack2,
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252 &stack2pos, &stack2size);
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253 LEFT45(dir);
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254 movefwd(&codex, &codey, dir, 1);
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255 break;
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256 }
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257 push(acc, &stack1, &stack1pos, &stack1size);
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258 if (s2 == s1)
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259 {
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260 RIGHT45(dir);
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261 movefwd(&codex, &codey, dir, 1);
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262 break;
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263 }
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264 if (acc)
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265 LEFT90(dir);
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266 else
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267 RIGHT135(dir);
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268 movefwd(&codex, &codey, dir, 1);
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269 break;
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270 }
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271 case 5:
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272 {
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273 if (acc & 1)
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274 acc--;
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275 else
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276 acc++;
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277 break;
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278 }
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279 case 7:
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280 {
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281 movefwd(&codex, &codey, dir,
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282 bitsset[(size_t) acc]);
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283 break;
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284 }
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285 case 11:
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286 {
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287 int s1, s2;
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288 s1 = peek(stack1, stack1pos);
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289 s2 = peek(stack2, stack2pos);
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290 if (s1 > s2)
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291 acc = pop(stack1, &stack1pos);
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292 else if (s2 == -1)
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293 acc = 0;
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294 else
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295 acc = pop(stack2, &stack2pos);
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296 break;
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297 }
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298 case 13:
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299 {
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300 int s2;
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301 s2 = pop(stack2, &stack2pos);
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302 if (s2 != -1)
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303 putchar(s2);
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304 break;
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305 }
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306 case 17:
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307 case 19:
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308 {
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309 int ch;
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310 if (gpf[(size_t) c] == 17)
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311 ch = getchar();
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312 else
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313 ch = pop(stack2, &stack2pos);
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314 if (ch < 0 || ch > 255) /* empty stack/EOF */
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315 {
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316 int steps = 0;
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317 if (acc & (1<<2))
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318 RIGHT90(dir);
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319 steps += (acc & (1<<3));
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320 steps += (acc & (1<<4));
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321 steps += (acc & (1<<7));
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322 movefwd(&codex, &codey, dir, steps);
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323 break;
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324 }
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325 push(ch, &stack1, &stack1pos, &stack1size);
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326 break;
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327 }
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328 case 23:
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329 {
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330 acc <<= 5;
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331 break;
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332 }
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333 case 29:
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334 {
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335 int s1, s2, steps = 2;
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336 if (acc != 0)
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337 break;
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338 LEFT45(dir);
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339 s1 = peek(stack1, stack1pos);
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340 s2 = peek(stack2, stack2pos);
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341 if (s2 < s1)
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342 steps++;
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343 movefwd(&codex, &codey, dir, steps);
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344 RIGHT45(dir);
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345 break;
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346 }
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347 case 31:
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348 {
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349 movefwd(&codex, &codey, dir, 1);
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350 break;
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351 }
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352 case 37:
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353 {
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354 int s1, s2;
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355 s1 = peek(stack1, stack1pos);
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356 s2 = peek(stack2, stack2pos);
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357 if (s1 == s2)
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358 break;
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359 if (s1 < s2)
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360 push(s1, &stack2, &stack2pos,
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361 &stack2size);
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362 else
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363 push(s2, &stack1, &stack1pos,
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364 &stack1size);
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365 break;
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366 }
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367 case 41:
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368 {
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369 int s1, s2;
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370 s1 = peek(stack1, stack1pos);
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371 s2 = peek(stack2, stack2pos);
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372 if (s1 == s2)
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373 break;
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374 if (s1 > s2)
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375 pop(stack1, &stack1pos);
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376 else
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377 pop(stack2, &stack2pos);
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378 break;
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379 }
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380 case 43:
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381 {
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382 acc >>= 1;
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383 if (!acc)
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384 {
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385 movefwd(&codex, &codey, dir, 1);
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386 LEFT90(dir);
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387 }
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388 break;
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389 }
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390 case 47:
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391 {
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392 int s1, s2;
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393 s1 = peek(stack1, stack1pos);
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394 s2 = peek(stack2, stack2pos);
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395 if (s1 == s2)
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396 break;
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397 if (s1 < s2)
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398 acc = pop(stack1, &stack1pos);
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399 else
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400 acc = pop(stack2, &stack2pos);
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401 break;
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402 }
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403 case 53:
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404 {
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405 int s1, s2;
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406 s1 = peek(stack1, stack1pos);
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407 s2 = peek(stack2, stack2pos);
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408 if (s1 < s2)
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409 {
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410 cell tmp;
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411 tmp = acc & 0xf0;
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412 if (acc & 1)
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413 tmp |= 8;
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414 if (acc & 2)
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415 tmp |= 4;
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416 if (acc & 4)
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417 tmp |= 2;
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418 if (acc & 8)
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419 tmp |= 1;
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420 acc = tmp;
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421 }
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422 else
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423 {
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424 cell tmp;
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425 tmp = acc & 0x0f;
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426 if (acc & 16)
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427 tmp |= 128;
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428 if (acc & 32)
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429 tmp |= 64;
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430 if (acc & 64)
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431 tmp |= 32;
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432 if (acc & 128)
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433 tmp |= 16;
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434 acc = tmp;
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435 }
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436 break;
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437 }
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438 case 59:
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439 {
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440 int n;
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441 n = bitsset[(size_t) acc] % 8;
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442 while(n--)
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443 RIGHT45(dir);
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444 break;
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445 }
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446 case 61:
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447 {
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448 cell *tmps;
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449 int tmp;
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450 tmps = stack1;
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451 stack1 = stack2;
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452 stack2 = tmps;
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453 tmp = stack1size;
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454 stack1size = stack2size;
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455 stack2size = tmp;
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456 tmp = stack1pos;
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457 stack1pos = stack2pos;
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458 stack2pos = tmp;
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459 break;
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460 }
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461 case 67:
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462 goto quit;
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463 default:
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464 acc = gpf[(size_t) c];
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465 }
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466
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467 movefwd(&codex, &codey, dir, 1);
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468 checkmove(codex, codey, maxline, lines);
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469 }
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470
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471 quit:
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472 free(lengths);
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473 free(stack1);
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474 free(stack2);
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475 }
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476
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477 cell *read_arbitrary_length_string(FILE *fp)
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478 {
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479 cell *p = NULL, *q;
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480 int size = 50;
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481
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482 if ((p = malloc(size)) == NULL)
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483 return NULL;
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484 if (fgets(p, size, fp) == NULL)
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485 return NULL;
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486
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487 while ((q = strchr(p, '\n')) == NULL)
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488 {
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489 size *= 2;
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490 if ((p = realloc(p, size)) == NULL)
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491 return NULL;
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492 if (fgets(&p[size/2-1], size/2+1, fp) == NULL)
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493 return NULL; /* invalid; file must end with newline */
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494 }
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495
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496 *q = '\0';
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497 return p;
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498 }
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