src/nws_portability/Forecast/fbuff.c

   1 /* $Id$ */
   2
   3 #include <unistd.h>
   4 #include <stdlib.h>
   5 #include <stdio.h>
   6 #include <math.h>
   7
   8 #include "fbuff.h"
   9
  10 fbuff
  11 InitFBuff(int size)
  12 {
  13         fbuff lb;
  14
  15         lb = (fbuff)malloc(FBUFF_SIZE);
  16
  17         if(lb == NULL)
  18         {
  19                 fprintf(stderr,"InitFBuff: couldn't get space for fbuff\n");
  20                 fflush(stderr);
  21                 return(NULL);
  22         }
  23
  24         /*
  25          * count from bottom to top
  26          *
  27          * head is the next available space
  28          * tail is the last valid data item
  29          */
  30         lb->size = size;
  31         lb->head = size - 1;
  32         lb->tail = 0;
  33
  34         lb->vals = (double *)malloc(size*sizeof(double));
  35         if(lb->vals == NULL)
  36         {
  37                 fprintf(stderr,"InitFBuff: couldn't get space for vals\n");
  38                 fflush(stderr);
  39                 free(lb);
  40                 return(NULL);
  41         }
  42
  43         return(lb);
  44
  45 }
  46
  47 void
  48 FreeFBuff(fbuff fb)
  49 {
  50         free(fb->vals);
  51         free(fb);
  52
  53         return;
  54 }
  55
  56 void
  57 UpdateFBuff(fbuff fb, double val)
  58 {
  59         F_HEAD(fb) = val;
  60         fb->head = MODMINUS(fb->head,1,fb->size);
  61
  62         /*
  63          * if we have moved the head over the tail, bump the tail around too
  64          */
  65         if(fb->head == fb->tail)
  66         {
  67                 fb->tail = MODMINUS(fb->tail,1,fb->size);
  68         }
  69
  70         return;
  71 }
  72