1: /*	@(#)spell.h	4.1	12/18/82	*/
   2: 
   3: #include <sys/localopts.h>  /* for computer type (NONSEPARATE?) */
   4: #include <stdio.h>
   5: #include <ctype.h>
   6: 
   7: #ifndef unix
   8: #define SHIFT   5
   9: #define TABSIZE (int)(400000/(1<<SHIFT))
  10: int *tab;   /*honeywell loader deficiency*/
  11: #else
  12: #define Tolower(c)  (isupper(c)?tolower(c):c) /* ugh!!! */
  13: #define SHIFT   4
  14:     /* The following modifications cut hash table to 300,000
  15: 	 * bits if NONSEPARATE is defined.
  16: 	 * mjk 9/19/80
  17: 	 * Eight hashing functions are used.
  18: 	 * This will run on non-separate I/D machine.
  19: 	 */
  20: #ifdef NONSEPARATE
  21: #define TABSIZE 18750   /*(int)(300000/(1<<SHIFT)) */
  22: #else
  23: #define TABSIZE 25000   /*(int)(400000/(1<<SHIFT)) */
  24: #endif
  25: short   tab[TABSIZE];
  26: #endif
  27: 
  28: #ifdef NONSEPARATE
  29: long    p[] = {
  30:     299909,
  31:     299933,
  32:     299941,
  33:     299951,
  34:     299969,
  35:     299977,
  36:     299983,
  37:     299993
  38: };
  39: #else
  40: long    p[] = {
  41:     399871,
  42:     399887,
  43:     399899,
  44:     399911,
  45:     399913,
  46:     399937,
  47:     399941,
  48:     399953,
  49:     399979,
  50:     399983,
  51:     399989,
  52: };
  53: #endif
  54: #define NP  (sizeof(p)/sizeof(p[0]))
  55: #define NW  30
  56: 
  57: /*
  58: * Hash table for spelling checker has n bits.
  59: * Each word w is hashed by k different (modular) hash functions, hi.
  60: * The bits hi(w), i=1..k, are set for words in the dictionary.
  61: * Assuming independence, the probability that no word of a d-word
  62: * dictionary sets a particular bit is given by the Poisson formula
  63: * P = exp(-y)*y**0/0!, where y=d*k/n.
  64: * The probability that a random string is recognized as a word is then
  65: * (1-P)**k.  For given n and d this is minimum when y=log(2), P=1/2,
  66: * whence one finds, for example, that a 25000-word dictionary in a
  67: * 400000-bit table works best with k=11.
  68: *	(For 300000-bit table use k=8; mjk.)
  69: */
  70: 
  71: long    pow2[NP][NW];
  72: 
  73: prime(argc, argv) register char **argv;
  74: {
  75:     int i, j;
  76:     long h;
  77:     register long *lp;
  78: 
  79: #ifndef unix
  80:     if ((tab = (int *)calloc(sizeof(*tab), TABSIZE)) == NULL)
  81:         return(0);
  82: #endif
  83:     if (argc > 1) {
  84:         FILE *f;
  85:         if ((f = fopen(argv[1], "ri")) == NULL)
  86:             return(0);
  87:         if (fread((char *)tab, sizeof(*tab), TABSIZE, f) != TABSIZE)
  88:             return(0);
  89:         fclose(f);
  90:     }
  91:     for (i=0; i<NP; i++) {
  92:         h = *(lp = pow2[i]) = 1<<14;
  93:         for (j=1; j<NW; j++)
  94:             h = *++lp = (h<<7) % p[i];
  95:     }
  96:     return(1);
  97: }
  98: 
  99: #define get(h)  (tab[h>>SHIFT]&(1<<((int)h&((1<<SHIFT)-1))))
 100: #define set(h)  tab[h>>SHIFT] |= 1<<((int)h&((1<<SHIFT)-1))

Defined functions

Defined variables

p defined in line 40; used 13 times
tab defined in line 25; used 8 times

Defined macros

NW defined in line 55; used 4 times
SHIFT defined in line 13; used 5 times
TABSIZE defined in line 23; used 6 times
Tolower defined in line 12; used 5 times
get defined in line 99; used 2 times
set defined in line 100; used 1 times

Usage of this include

Last modified: 1987-02-17
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