4.3BSD - /usr/src/new/spms/src/lib/libslist/src/slsort.c

   1: /* $Header$ */
   2: 
   3: /*
   4:  * Author: Peter J. Nicklin
   5:  */
   6: 
   7: /*
   8:  * slsort() sorts list slist according to comparison function compar().
   9:  * compar() is to be called with two arguments and must return an integer
  10:  * greater than, equal to, or less than 0, depending on the lexicographic
  11:  * relationship between the two arguments. Returns integer YES if
  12:  * successful, otherwise NO if out of memory.
  13:  */
  14: #include "null.h"
  15: #include "slist.h"
  16: #include "yesno.h"
  17: 
  18: static int (*sscmp)();          /* string compare function */
  19: 
  20: slsort(compar, slist)
  21:     int (*compar)();        /* compare two strings */
  22:     SLIST *slist;           /* pointer to list head block */
  23: {
  24:     char **kp;          /* pointer to key pointer array */
  25:     char *malloc();         /* memory allocator */
  26:     char **skp;         /* ptr to start of key ptr array */
  27:     int comparb();          /* compare 2 list blocks */
  28:     SLBLK *curblk;          /* current list block */
  29: 
  30:     if (slist->nk <= 0)
  31:         return(YES);
  32:     else if ((skp = (char **) malloc((unsigned)slist->nk*sizeof(char *))) == NULL)
  33:         {
  34:         warn("out of memory");
  35:         return(NO);
  36:         }
  37:     for (kp = skp, curblk = slist->head; curblk != NULL; kp++, curblk = curblk->next)
  38:         *kp = curblk->key;
  39: 
  40:     sscmp = compar;
  41:     qsort((char *) skp, slist->nk, sizeof(char *), comparb);
  42: 
  43:     for (kp = skp, curblk = slist->head; curblk != NULL; kp++, curblk = curblk->next)
  44:         curblk->key = *kp;
  45: 
  46:     free((char *) skp);
  47:     return(YES);
  48: }
  49: 
  50: 
  51: 
  52: /*
  53:  * comparb() compares key strings in 2 list blocks. Returns whatever
  54:  * sscmp() returns. sscmp() is a string compare function.
  55:  */
  56: static int
  57: comparb(s1, s2)
  58:     char **s1;          /* string pointer */
  59:     char **s2;          /* string pointer */
  60: {
  61:     return(sscmp(*s1, *s2));
  62: }

Defined functions