commands/look/look.c

   1 /*      look 1.3 - Find lines in a sorted list.         Author: Kees J. Bot
   2  */
   3 #define nil 0
   4 #include <sys/types.h>
   5 #include <stdio.h>
   6 #include <ctype.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9
  10 char DEFAULT[] = "/usr/lib/dict/words";
  11
  12 char *string, *wordlist= DEFAULT;
  13
  14 #define MAXLEN  1024    /* Maximum word length. */
  15
  16 int dflg= 0, fflg= 0;
  17
  18 void nonascii(char *what)
  19 {
  20         fprintf(stderr, "look: %s contains non-ASCII characters.\n", what);
  21         exit(1);
  22 }
  23
  24 int compare(char *prefix, char *word)
  25 {
  26         char *p= prefix, *w= word;
  27         int cp, cw;
  28
  29         do {
  30                 do {
  31                         if ((cp= *p++) == 0) return 0;
  32                         if (!isascii(cp)) nonascii("prefix string");
  33                 } while (dflg && !isspace(cp) && !isalnum(cp));
  34
  35                 if (dflg) {
  36                         if (isspace(cp)) {
  37                                 while (isspace(*p)) p++;
  38                                 cp= ' ';
  39                         }
  40                 }
  41                 if (fflg && isupper(cp)) cp= tolower(cp);
  42
  43                 do {
  44                         if ((cw= *w++) == 0) return 1;
  45                         if (!isascii(cw)) nonascii(wordlist);
  46                 } while (dflg && !isspace(cw) && !isalnum(cw));
  47
  48                 if (dflg) {
  49                         if (isspace(cw)) {
  50                                 while (isspace(*w)) w++;
  51                                 cw= ' ';
  52                         }
  53                 }
  54                 if (fflg && isupper(cw)) cw= tolower(cw);
  55         } while (cp == cw);
  56
  57         return cp - cw;
  58 }
  59
  60 char *readword(FILE *f)
  61 {
  62         static char word[MAXLEN + 2];
  63         int n;
  64
  65         if (fgets(word, sizeof(word), f) == nil) {
  66                 if (ferror(f)) {
  67                         fprintf(stderr, "look: read error on %s",
  68                                 wordlist);
  69                         exit(1);
  70                 }
  71                 return nil;
  72         }
  73
  74         n= strlen(word);
  75
  76         if (word[n-1] != '\n') {
  77                 fprintf(stderr, "look: word from %s is too long\n", wordlist);
  78                 exit(1);
  79         }
  80         word[n-1] = 0;
  81
  82         return word;
  83 }
  84
  85 void look(void)
  86 {
  87         off_t low, mid, high;
  88         FILE *f;
  89         char *word;
  90         int c;
  91
  92         if ((f= fopen(wordlist, "r")) == nil) {
  93                 fprintf(stderr, "look: Can't open %s\n", wordlist);
  94                 exit(1);
  95         }
  96
  97         low= 0;
  98
  99         fseek(f, (off_t) 0, 2);
 100
 101         high= ftell(f);
 102
 103         while (low <= high) {
 104                 mid= (low + high) / 2;
 105
 106                 fseek(f, mid, 0);
 107
 108                 if (mid != 0) readword(f);
 109
 110                 if ((word= readword(f)) == nil)
 111                         c= -1;
 112                 else
 113                         c= compare(string, word);
 114
 115                 if (c <= 0) high= mid - 1; else low= mid + 1;
 116         }
 117         fseek(f, low, 0);
 118         if (low != 0) readword(f);
 119
 120         c=0;
 121         while (c >= 0 && (word= readword(f)) != nil) {
 122                 c= compare(string, word);
 123
 124                 if (c == 0) puts(word);
 125         }
 126 }
 127
 128 int main(int argc, char **argv)
 129 {
 130         if (argc == 2) dflg= fflg= 1;
 131
 132         while (argc > 1 && argv[1][0] == '-') {
 133                 char *p= argv[1] + 1;
 134
 135                 while (*p != 0) {
 136                         switch (*p++) {
 137                         case 'd':       dflg= 1; break;
 138                         case 'f':       fflg= 1; break;
 139                         default:
 140                                 fprintf(stderr, "look: Bad flag: %c\n", p[-1]);
 141                                 exit(1);
 142                         }
 143                 }
 144                 argc--;
 145                 argv++;
 146         }
 147         if (argc == 3)
 148                 wordlist= argv[2];
 149         else
 150         if (argc != 2) {
 151                 fprintf(stderr, "Usage: look [-df] string [file]\n");
 152                 exit(1);
 153         }
 154         string= argv[1];
 155         look();
 156         exit(0);
 157 }
 158 /* Kees J. Bot 24-5-89. */