2.11BSD#431 - /usr/src/new/PORT/perl.1.0.0/hash.c

   1: /* $Header: hash.c,v 1.0 87/12/18 13:05:17 root Exp $
   2:  *
   3:  * $Log:	hash.c,v $
   4:  * Revision 1.0  87/12/18  13:05:17  root
   5:  * Initial revision
   6:  *
   7:  */
   8: 
   9: #include <stdio.h>
  10: #include "EXTERN.h"
  11: #include "handy.h"
  12: #include "util.h"
  13: #include "search.h"
  14: #include "perl.h"
  15: 
  16: STR *
  17: hfetch(tb,key)
  18: register HASH *tb;
  19: char *key;
  20: {
  21:     register char *s;
  22:     register int i;
  23:     register int hash;
  24:     register HENT *entry;
  25: 
  26:     if (!tb)
  27:     return Nullstr;
  28:     for (s=key,     i=0,    hash = 0;
  29:       /* while */ *s;
  30:      s++,       i++,    hash *= 5) {
  31:     hash += *s * coeff[i];
  32:     }
  33:     entry = tb->tbl_array[hash & tb->tbl_max];
  34:     for (; entry; entry = entry->hent_next) {
  35:     if (entry->hent_hash != hash)       /* strings can't be equal */
  36:         continue;
  37:     if (strNE(entry->hent_key,key)) /* is this it? */
  38:         continue;
  39:     return entry->hent_val;
  40:     }
  41:     return Nullstr;
  42: }
  43: 
  44: bool
  45: hstore(tb,key,val)
  46: register HASH *tb;
  47: char *key;
  48: STR *val;
  49: {
  50:     register char *s;
  51:     register int i;
  52:     register int hash;
  53:     register HENT *entry;
  54:     register HENT **oentry;
  55: 
  56:     if (!tb)
  57:     return FALSE;
  58:     for (s=key,     i=0,    hash = 0;
  59:       /* while */ *s;
  60:      s++,       i++,    hash *= 5) {
  61:     hash += *s * coeff[i];
  62:     }
  63: 
  64:     oentry = &(tb->tbl_array[hash & tb->tbl_max]);
  65:     i = 1;
  66: 
  67:     for (entry = *oentry; entry; i=0, entry = entry->hent_next) {
  68:     if (entry->hent_hash != hash)       /* strings can't be equal */
  69:         continue;
  70:     if (strNE(entry->hent_key,key)) /* is this it? */
  71:         continue;
  72:     safefree((char*)entry->hent_val);
  73:     entry->hent_val = val;
  74:     return TRUE;
  75:     }
  76:     entry = (HENT*) safemalloc(sizeof(HENT));
  77: 
  78:     entry->hent_key = savestr(key);
  79:     entry->hent_val = val;
  80:     entry->hent_hash = hash;
  81:     entry->hent_next = *oentry;
  82:     *oentry = entry;
  83: 
  84:     if (i) {                /* initial entry? */
  85:     tb->tbl_fill++;
  86:     if ((tb->tbl_fill * 100 / (tb->tbl_max + 1)) > FILLPCT)
  87:         hsplit(tb);
  88:     }
  89: 
  90:     return FALSE;
  91: }
  92: 
  93: #ifdef NOTUSED
  94: bool
  95: hdelete(tb,key)
  96: register HASH *tb;
  97: char *key;
  98: {
  99:     register char *s;
 100:     register int i;
 101:     register int hash;
 102:     register HENT *entry;
 103:     register HENT **oentry;
 104: 
 105:     if (!tb)
 106:     return FALSE;
 107:     for (s=key,     i=0,    hash = 0;
 108:       /* while */ *s;
 109:      s++,       i++,    hash *= 5) {
 110:     hash += *s * coeff[i];
 111:     }
 112: 
 113:     oentry = &(tb->tbl_array[hash & tb->tbl_max]);
 114:     entry = *oentry;
 115:     i = 1;
 116:     for (; entry; i=0, oentry = &entry->hent_next, entry = entry->hent_next) {
 117:     if (entry->hent_hash != hash)       /* strings can't be equal */
 118:         continue;
 119:     if (strNE(entry->hent_key,key)) /* is this it? */
 120:         continue;
 121:     safefree((char*)entry->hent_val);
 122:     safefree(entry->hent_key);
 123:     *oentry = entry->hent_next;
 124:     safefree((char*)entry);
 125:     if (i)
 126:         tb->tbl_fill--;
 127:     return TRUE;
 128:     }
 129:     return FALSE;
 130: }
 131: #endif
 132: 
 133: hsplit(tb)
 134: HASH *tb;
 135: {
 136:     int oldsize = tb->tbl_max + 1;
 137:     register int newsize = oldsize * 2;
 138:     register int i;
 139:     register HENT **a;
 140:     register HENT **b;
 141:     register HENT *entry;
 142:     register HENT **oentry;
 143: 
 144:     a = (HENT**) saferealloc((char*)tb->tbl_array, newsize * sizeof(HENT*));
 145:     bzero((char*)&a[oldsize], oldsize * sizeof(HENT*)); /* zero second half */
 146:     tb->tbl_max = --newsize;
 147:     tb->tbl_array = a;
 148: 
 149:     for (i=0; i<oldsize; i++,a++) {
 150:     if (!*a)                /* non-existent */
 151:         continue;
 152:     b = a+oldsize;
 153:     for (oentry = a, entry = *a; entry; entry = *oentry) {
 154:         if ((entry->hent_hash & newsize) != i) {
 155:         *oentry = entry->hent_next;
 156:         entry->hent_next = *b;
 157:         if (!*b)
 158:             tb->tbl_fill++;
 159:         *b = entry;
 160:         continue;
 161:         }
 162:         else
 163:         oentry = &entry->hent_next;
 164:     }
 165:     if (!*a)                /* everything moved */
 166:         tb->tbl_fill--;
 167:     }
 168: }
 169: 
 170: HASH *
 171: hnew()
 172: {
 173:     register HASH *tb = (HASH*)safemalloc(sizeof(HASH));
 174: 
 175:     tb->tbl_array = (HENT**) safemalloc(8 * sizeof(HENT*));
 176:     tb->tbl_fill = 0;
 177:     tb->tbl_max = 7;
 178:     hiterinit(tb);  /* so each() will start off right */
 179:     bzero((char*)tb->tbl_array, 8 * sizeof(HENT*));
 180:     return tb;
 181: }
 182: 
 183: #ifdef NOTUSED
 184: hshow(tb)
 185: register HASH *tb;
 186: {
 187:     fprintf(stderr,"%5d %4d (%2d%%)\n",
 188:     tb->tbl_max+1,
 189:     tb->tbl_fill,
 190:     tb->tbl_fill * 100 / (tb->tbl_max+1));
 191: }
 192: #endif
 193: 
 194: hiterinit(tb)
 195: register HASH *tb;
 196: {
 197:     tb->tbl_riter = -1;
 198:     tb->tbl_eiter = Null(HENT*);
 199:     return tb->tbl_fill;
 200: }
 201: 
 202: HENT *
 203: hiternext(tb)
 204: register HASH *tb;
 205: {
 206:     register HENT *entry;
 207: 
 208:     entry = tb->tbl_eiter;
 209:     do {
 210:     if (entry)
 211:         entry = entry->hent_next;
 212:     if (!entry) {
 213:         tb->tbl_riter++;
 214:         if (tb->tbl_riter > tb->tbl_max) {
 215:         tb->tbl_riter = -1;
 216:         break;
 217:         }
 218:         entry = tb->tbl_array[tb->tbl_riter];
 219:     }
 220:     } while (!entry);
 221: 
 222:     tb->tbl_eiter = entry;
 223:     return entry;
 224: }
 225: 
 226: char *
 227: hiterkey(entry)
 228: register HENT *entry;
 229: {
 230:     return entry->hent_key;
 231: }
 232: 
 233: STR *
 234: hiterval(entry)
 235: register HENT *entry;
 236: {
 237:     return entry->hent_val;
 238: }

Defined functions