external/ibm-public/postfix/dist/src/util/mvect.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      mvect 3
   6 /* SUMMARY
   7 /*      memory vector management
   8 /* SYNOPSIS
   9 /*      #include <mvect.h>
  10 /*
  11 /*      char    *mvect_alloc(vector, elsize, nelm, init_fn, wipe_fn)
  12 /*      MVECT   *vector;
  13 /*      int     elsize;
  14 /*      int     nelm;
  15 /*      void    (*init_fn)(char *ptr, int count);
  16 /*      void    (*wipe_fn)(char *ptr, int count);
  17 /*
  18 /*      char    *mvect_realloc(vector, nelm)
  19 /*      MVECT   *vector;
  20 /*      int     nelm;
  21 /*
  22 /*      char    *mvect_free(vector)
  23 /*      MVECT   *vector;
  24 /* DESCRIPTION
  25 /*      This module supports memory management for arrays of arbitrary
  26 /*      objects.  It is up to the application to provide specific code
  27 /*      that initializes and uses object memory.
  28 /*
  29 /*      mvect_alloc() initializes memory for a vector with elements
  30 /*      of \fIelsize\fR bytes, and with at least \fInelm\fR elements.
  31 /*      \fIinit_fn\fR is a null pointer, or a pointer to a function
  32 /*      that initializes \fIcount\fR vector elements.
  33 /*      \fIwipe_fn\fR is a null pointer, or a pointer to a function
  34 /*      that is complementary to \fIinit_fn\fR. This routine is called
  35 /*      by mvect_free(). The result of mvect_alloc() is a pointer to
  36 /*      the allocated vector.
  37 /*
  38 /*      mvect_realloc() guarantees that the specified vector has space
  39 /*      for at least \fInelm\fR elements. The result is a pointer to the
  40 /*      allocated vector, which may change across calls.
  41 /*
  42 /*      mvect_free() releases storage for the named vector. The result
  43 /*      is a convenient null pointer.
  44 /* SEE ALSO
  45 /*      mymalloc(3) memory management
  46 /* DIAGNOSTICS
  47 /*      Problems are reported via the msg(3) diagnostics routines:
  48 /*      the requested amount of memory is not available; improper use
  49 /*      is detected; other fatal errors.
  50 /* LICENSE
  51 /* .ad
  52 /* .fi
  53 /*      The Secure Mailer license must be distributed with this software.
  54 /* AUTHOR(S)
  55 /*      Wietse Venema
  56 /*      IBM T.J. Watson Research
  57 /*      P.O. Box 704
  58 /*      Yorktown Heights, NY 10598, USA
  59 /*--*/
  60
  61 /* System library. */
  62
  63 #include <sys_defs.h>
  64
  65 /* Utility library. */
  66
  67 #include "mymalloc.h"
  68 #include "mvect.h"
  69
  70 /* mvect_alloc - allocate memory vector */
  71
  72 char   *mvect_alloc(MVECT *vect, int elsize, int nelm,
  73                void (*init_fn) (char *, int), void (*wipe_fn) (char *, int))
  74 {
  75     vect->init_fn = init_fn;
  76     vect->wipe_fn = wipe_fn;
  77     vect->nelm = 0;
  78     vect->ptr = mymalloc(elsize * nelm);
  79     vect->nelm = nelm;
  80     vect->elsize = elsize;
  81     if (vect->init_fn)
  82         vect->init_fn(vect->ptr, vect->nelm);
  83     return (vect->ptr);
  84 }
  85
  86 /* mvect_realloc - adjust memory vector allocation */
  87
  88 char   *mvect_realloc(MVECT *vect, int nelm)
  89 {
  90     int     old_len = vect->nelm;
  91     int     incr = nelm - old_len;
  92     int     new_nelm;
  93
  94     if (incr > 0) {
  95         if (incr < old_len)
  96             incr = old_len;
  97         new_nelm = vect->nelm + incr;
  98         vect->ptr = myrealloc(vect->ptr, vect->elsize * new_nelm);
  99         vect->nelm = new_nelm;
 100         if (vect->init_fn)
 101             vect->init_fn(vect->ptr + old_len * vect->elsize, incr);
 102     }
 103     return (vect->ptr);
 104 }
 105
 106 /* mvect_free - release memory vector storage */
 107
 108 char   *mvect_free(MVECT *vect)
 109 {
 110     if (vect->wipe_fn)
 111         vect->wipe_fn(vect->ptr, vect->nelm);
 112     myfree(vect->ptr);
 113     myfree((char *) vect);
 114     return (0);
 115 }