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12
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1 #include <stdio.h>
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2 #include <stdlib.h>
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3 #include <sys/mman.h>
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4 #include <sys/types.h>
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5 #include <sys/stat.h>
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6 #include <fcntl.h>
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7 #include <unistd.h>
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8 #include <string.h>
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9
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10 typedef unsigned char UCHAR;
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11 typedef unsigned char* UCHARP;
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12
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13 typedef enum BOOL {
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14 FALSE = 0,
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15 TRUE = 1
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16 } BOOL;
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17
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18 typedef struct ENV {
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19 BOOL print_count;
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20 BOOL print_filename;
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21 int count;
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22 char *filename;
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23 } *ENVP;
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24
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25 void filter(UCHARP beg, UCHARP buf, UCHARP end, ENVP env);
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26 void predict(UCHARP beg, UCHARP buf, UCHARP end, ENVP env);
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27 void reject(UCHARP beg, UCHARP buf, UCHARP end, ENVP env);
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28 void accept(UCHARP beg, UCHARP buf, UCHARP end, ENVP env);
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29 void s0(UCHARP beg, UCHARP buf, UCHARP end, ENVP env);
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30 #define __REGEX__ "h.s"
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31
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32 UCHARP get_line_beg(UCHARP p, UCHARP beg) {
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33 while(p > beg) {
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34 if ((*--p) == '\n') return p+1;
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35 }
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36 return beg;
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37 }
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38
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39 void print_line(UCHARP beg, UCHARP end) {
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40 fwrite(beg, sizeof(char), (end - beg + 1), stdout);
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41 }
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42
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43 void grep(int fd, ENVP env) {
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44 caddr_t file_mmap;
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45 UCHARP buf, end, beg;
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46 off_t size;
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47 struct stat sb;
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48
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49 if (fstat(fd, &sb)) {
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50 fprintf(stderr, "can't fstat %s\n", env->filename);
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51 exit(0);
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52 }
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53
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54 size = sb.st_size;
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55 file_mmap = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, (off_t)0);
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56
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57 if (file_mmap == (caddr_t)-1) {
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58 fprintf(stderr, "can't mmap %s\n", env->filename);
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59 exit(0);
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60 }
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61
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62 beg = buf = (UCHARP) file_mmap;
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63 end = beg + size - 1;
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64 env->count = 0;
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65
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66 s0(beg, beg, end, env);
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67
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68 munmap(file_mmap, size);
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69 return;
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70 }
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71
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72 void stdingrep(ENVP env) {
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73 char buf_[BUFSIZ];
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74 UCHARP buf, beg, end;
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75 buf = beg = (UCHARP) buf_;
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76
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77 while (fgets(buf_, BUFSIZ, stdin) != NULL) {
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78 env->count = 0;
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79 end = buf + strlen(buf_) - 1;
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80 s0(beg, buf, end, env);
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81 }
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82 }
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83
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84 int main(int argc, char* argv[]) {
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85 int i, fd, opt, with_filename = 0;
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86
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87 ENVP env = (ENVP)calloc(sizeof(ENVP), 1);
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88
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89 while ((opt=getopt(argc, argv, "chH")) != -1) {
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90 switch (opt) {
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91 case 'c':
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92 env->print_count = 1;
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93 break;
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94 case 'h':
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95 with_filename = -1;
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96 break;
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97 case 'H':
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98 with_filename = 1;
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99 break;
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100 default:
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101 fprintf(stderr, "invalid option.");
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102 exit(0);
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103 }
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104 }
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105
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106 if (optind == argc) {
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107 if (with_filename) {
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108 /* handle -h/-H as help */
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109 printf("grep pattern: %s\n", __REGEX__);
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110 exit(1);
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111 } else {
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112 stdingrep(env);
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113 }
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114 } else {
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115 switch (with_filename) {
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116 case 0: //default
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117 if (argc == optind + 1) {
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118 /* just grep 1 file. */
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119 env->print_filename = FALSE;
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120 } else {
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121 /* grep 1 more files. */
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122 env->print_filename = TRUE;
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123 }
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124 break;
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125 // option
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126 case -1:
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127 env->print_filename = FALSE;
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128 break;
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129 case 1:
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130 env->print_filename = TRUE;
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131 break;
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132 default: break;
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133 }
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134 for (i = optind; i < argc; i++) {
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135 fd = open(argv[i], O_RDONLY, 0666);
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136 if (fd == 0) {
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137 printf("%d, %s\n", i, argv[i]);
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138 fprintf(stderr, "can't open %s:", argv[i]);
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139 continue;
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140 }
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141 env->filename = argv[i];
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142 grep(fd, env);
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143 close(fd);
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144 }
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145 }
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146
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147 return 0;
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148 }
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149 void s1(UCHARP beg, UCHARP buf, UCHARP end, ENVP env);
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150 void s2(UCHARP beg, UCHARP buf, UCHARP end, ENVP env);
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151 void s3(UCHARP beg, UCHARP buf, UCHARP end, ENVP env);
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152 void s4(UCHARP beg, UCHARP buf, UCHARP end, ENVP env);
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153 void s5(UCHARP beg, UCHARP buf, UCHARP end, ENVP env);
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154 void s6(UCHARP beg, UCHARP buf, UCHARP end, ENVP env);
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155
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156 void s0(UCHARP beg, UCHARP buf, UCHARP end, ENVP env) {
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157 return filter(beg, buf, end, env);
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158 }
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159
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160 void filter(UCHARP beg, UCHARP buf, UCHARP end, ENVP env) {
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161 static const UCHARP const key = (UCHARP)"h";
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162 int i, len = 1;
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163 loop:
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164 while ((buf = memchr(buf, key[0], end-buf))) {
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165 for (i = 1; i < len; i++) {
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166 if (buf[i] != key[i]) {
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167 buf++;
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168 goto loop;
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169 }
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170 }
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171 goto next;
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172 }
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173 return reject(beg, end, end, env);
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174 next:
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175 return s1(beg, buf, end, env);
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176 }
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177
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178 void s1(UCHARP beg, UCHARP buf, UCHARP end, ENVP env) {
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179 static void (*tbl[256])(UCHARP, UCHARP, UCHARP, ENVP) = {[0 ... 255] = (void*)s1, /* NL */ [10] = (void*)reject, /* h */ [104] = (void*)s2};
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180 if (buf > end) return tbl['\n'](beg, buf, end, env);
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181 return tbl[*buf++](beg, buf, end, env);
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182 }
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183
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184 void s2(UCHARP beg, UCHARP buf, UCHARP end, ENVP env) {
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185 static void (*tbl[256])(UCHARP, UCHARP, UCHARP, ENVP) = {[0 ... 255] = (void*)s3, /* NL */ [10] = (void*)reject, /* h */ [104] = (void*)s4};
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186 if (buf > end) return tbl['\n'](beg, buf, end, env);
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187 return tbl[*buf++](beg, buf, end, env);
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188 }
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189
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190 void s3(UCHARP beg, UCHARP buf, UCHARP end, ENVP env) {
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191 static void (*tbl[256])(UCHARP, UCHARP, UCHARP, ENVP) = {[0 ... 255] = (void*)s1, /* NL */ [10] = (void*)reject, /* h */ [104] = (void*)s2, /* s */ [115] = (void*)s5};
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192 if (buf > end) return tbl['\n'](beg, buf, end, env);
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193 return tbl[*buf++](beg, buf, end, env);
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194 }
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195
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196 void s4(UCHARP beg, UCHARP buf, UCHARP end, ENVP env) {
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197 static void (*tbl[256])(UCHARP, UCHARP, UCHARP, ENVP) = {[0 ... 255] = (void*)s3, /* NL */ [10] = (void*)reject, /* h */ [104] = (void*)s4, /* s */ [115] = (void*)s6};
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198 if (buf > end) return tbl['\n'](beg, buf, end, env);
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199 return tbl[*buf++](beg, buf, end, env);
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200 }
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201
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202 void s5(UCHARP beg, UCHARP buf, UCHARP end, ENVP env) {
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203 return accept(beg, buf - 1, end, env);}
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204
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205 void s6(UCHARP beg, UCHARP buf, UCHARP end, ENVP env) {
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206 return accept(beg, buf - 1, end, env);}
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207
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208 void
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209 accept(UCHARP beg, UCHARP buf, UCHARP end, ENVP env)
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210 {
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211 if (buf < beg) buf = beg;
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212 UCHARP ret = (buf < end) ? (UCHARP) memchr(buf, '\n', (end - buf)) : NULL;
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213 if (env->print_count) {
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214 env->count++;
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215 if (ret == NULL) {
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216 if (env->print_filename) {
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217 printf("%s:", env->filename);
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218 }
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219 printf("%d\n", env->count);
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220 return;
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221 }
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222 beg = buf = ret + 1;
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223 } else {
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224 beg = get_line_beg(buf, beg);
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225 if (env->print_filename) {
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226 printf("%s:", env->filename);
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227 }
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228 if (ret == NULL) {
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229 print_line(beg, end);
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230 return;
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231 }
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232 print_line(beg, ret);
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233 beg = buf = ret + 1;
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234 }
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235 return s0(beg, buf, end, env);
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236 }
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237
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238 void
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239 reject(UCHARP beg, UCHARP buf, UCHARP end, ENVP env) {
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240 UCHARP ret;
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241 if (buf >= end) {
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242 ret = NULL;
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243 } else {
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244 if (*(buf-1) == '\n') {
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245 ret = buf-1;
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246 } else {
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247 ret = (UCHARP)memchr(buf, '\n', (end - buf));
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248 }
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249 }
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250 if (ret == NULL) {
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251 if (env->print_count) {
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252 if (env->print_filename) {
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253 printf("%s:", env->filename);
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254 }
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255 printf("%d\n", env->count);
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256 }
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257 return;
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258 }
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259 beg = buf = ret + 1;
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260 return s0(beg, buf, end, env);
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261 }
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