Add portable lrand48 (etc) implementation

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@61350 15284696-431f-4ddb-bdfa-cd5b030d7da7

include/defs/gis.h

@@ -396,6 +396,13 @@ int G_llres_scan(const char *, double *);
 const char *G_location(void);
 char *G_location_path(void);
 
+/* lrand48.c */
+void G_srand48(long);
+long G_srand48_auto(void);
+long G_lrand48(void);
+long G_mrand48(void);
+double G_drand48(void);
+
 /* ls.c */
 void G_set_ls_filter(int (*)(const char *, void *), void *);
 void G_set_ls_exclude_filter(int (*)(const char *, void *), void *);

lib/gis/lrand48.c

@@ -0,0 +1,134 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <grass/gis.h>
+#include <grass/glocale.h>
+
+#ifdef HAVE_GETTIMEOFDAY
+#include <sys/time.h>
+#else
+#include <time.h>
+#endif
+
+#include <sys/types.h>
+#include <unistd.h>
+
+typedef unsigned short uint16;
+typedef unsigned int uint32;
+typedef signed int int32;
+
+static uint16 x0, x1, x2;
+static const uint32 a0 = 0xE66D;
+static const uint32 a1 = 0xDEEC;
+static const uint32 a2 = 0x5;
+
+static const uint32 b0 = 0xB;
+
+#define LO(x) ((x) & 0xFFFFU)
+#define HI(x) ((x) >> 16)
+
+void G_srand48(long seedval)
+{
+    uint32 x = (uint32) *(unsigned long *)&seedval;
+    x2 = (uint16) HI(x);
+    x1 = (uint16) LO(x);
+    x0 = (uint16) 0x330E;
+}
+
+long G_srand48_auto(void)
+{
+    unsigned long seed = (unsigned long) getpid();
+
+#ifdef HAVE_GETTIMEOFDAY
+    {
+	struct timeval tv;
+	if (gettimeofday(&tv, NULL) < 0)
+	    G_fatal_error(_("gettimeofday failed: %s"), strerror(errno));
+	seed += (unsigned long) tv.tv_sec;
+	seed += (unsigned long) tv.tv_usec;
+    }
+#else
+    {
+	time_t t = time(NULL);
+	seed += (unsigned long) t;
+    }
+#endif
+
+    G_srand48((long) seed);
+    return (long) seed;
+}
+
+static void G__next(void)
+{
+    uint32 a0x0 = a0 * x0;
+    uint32 a0x1 = a0 * x1;
+    uint32 a0x2 = a0 * x2;
+    uint32 a1x0 = a1 * x0;
+    uint32 a1x1 = a1 * x1;
+    uint32 a2x0 = a2 * x0;
+
+    uint32 y0 = LO(a0x0) + b0;
+    uint32 y1 = LO(a0x1) + LO(a1x0) + HI(a0x0);
+    uint32 y2 = LO(a0x2) + LO(a1x1) + LO(a2x0) + HI(a0x1) + HI(a1x0);
+
+    x0 = (uint16) LO(y0);
+    y1 += HI(y0);
+    x1 = (uint16) LO(y1);
+    y2 += HI(y1);
+    x2 = (uint16) LO(y2);
+}
+
+long G_lrand48(void)
+{
+    uint32 r;
+    G__next();
+    r = ((uint32) x2 << 15) | ((uint32) x1 >> 1);
+    return (long) r;
+}
+
+long G_mrand48(void)
+{
+    uint32 r;
+    G__next();
+    r = ((uint32) x2 << 16) | ((uint32) x1);
+    return (long) (int32) r;
+}
+
+double G_drand48(void)
+{
+    double r = 0.0;
+    G__next();
+    r += x2;
+    r *= 0x10000;
+    r += x1;
+    r *= 0x10000;
+    r += x0;
+    r /= 281474976710656.0; /* 2^48 */
+    return r;
+}
+
+/*
+
+Test program
+
+int main(int argc, char **argv)
+{
+    long s = (argc > 1) ? atol(argv[1]) : 0;
+    int i;
+
+    srand48(s);
+    G_srand48(s);
+
+    for (i = 0; i < 100; i++) {
+	printf("%.50f %.50f\n", drand48(), G_drand48());
+	printf("%lu %lu\n", lrand48(), G_lrand48());
+	printf("%ld %ld\n", mrand48(), G_mrand48());
+    }
+
+    return 0;
+}
+
+*/