X-Git-Url: https://hackdaworld.org/gitweb/?p=physik%2Fnlsop.git;a=blobdiff_plain;f=random.c;h=a664fa70de54f7cb1d14e39fd438751e2231ef1f;hp=17cbd73c887e1d5a9656431c5b7465b7f98b9c2a;hb=21bb2d2c6e2d1de0e1c4a75d114a87a94b39ba8c;hpb=5d5a9a58e9ecb4221b1c41e536b9648500b9b41d

diff --git a/random.c b/random.c
index 17cbd73..a664fa7 100644
--- a/random.c
+++ b/random.c
@@ -9,6 +9,12 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <stdlib.h>
+#include <math.h>
+
+#ifdef USE_LIBC_RAND
+#include <time.h>
+#endif
 
 #include "random.h"
 
@@ -19,11 +25,13 @@ int rand_init(char *rf)
 {
  if(rf==NULL)
  {
+#ifndef USE_LIBC_RAND
   if((rand_fd=open("/dev/urandom",O_RDONLY))<0)
   {
    puts("cannot open /dev/urandom");
    return -1;
   }
+#endif
  } else
  {
   if((rand_fd=open(rf,O_RDONLY))<0)
@@ -44,7 +52,9 @@ int rand_init(char *rf)
 
 int rand_close(void)
 {
+#ifndef USE_LIBC_RAND
  close(rand_fd);
+#endif
  
  return 1;
 }
@@ -53,6 +63,15 @@ u32 get_rand(u32 max)
 {
  if(c_ptr>=b_ptr+BUFSIZE)
  {
+#ifdef MORE_PRINTF
+  printf("getting another %d bytes of random data ...\n",BUFSIZE);
+#endif
+#ifdef USE_LIBC_RAND
+  c_ptr=b_ptr;
+  srand((int)time(NULL));
+  while(c_ptr<b_ptr+BUFSIZE) *(c_ptr++)=(u32)rand();
+  c_ptr=b_ptr;
+#else
   if(read(rand_fd,b_ptr,BUFSIZE*sizeof(u32))<BUFSIZE*sizeof(u32))
   {
    /* -> assume random file, end reached */
@@ -61,9 +80,17 @@ u32 get_rand(u32 max)
    read(rand_fd,b_ptr,BUFSIZE*sizeof(u32));
   }
   c_ptr=b_ptr;
+#endif
+#ifdef MORE_PRINTF
+  printf("got it!\n");
+#endif
  }
- 
+
+#ifdef USE_LIBC_RAND
+ return((u32)(*(c_ptr++)*(max*1.0/((long long unsigned int)RAND_MAX+1))));
+#else
  return((u32)(*(c_ptr++)*(max*1.0/((long long unsigned int)URAND_MAX+1))));
+#endif
 }
 
 u32 get_rand_lgp(u32 max,double a,double b)
@@ -71,3 +98,18 @@ u32 get_rand_lgp(u32 max,double a,double b)
  return((u32)(1.0*max*(-1.0*b+sqrt(b*b+2*a*((b+a/2)*get_rand(URAND_MAX)/((long long unsigned int)URAND_MAX+1))))/a));
 }
 
+u32 get_rand_reject(u32 max_x,u32 max_y,u32 *graph)
+{
+ u32 x,y;
+ unsigned char ok;
+
+ ok=0;
+ while(!ok)
+ {
+  x=get_rand(max_x);
+  y=get_rand(max_y);
+  if(y<=graph[x]) ok=1;
+ }
+
+ return x;
+}