From c0a7b53baf2a6e7bf9bc1fbec7ac05e43ac59154 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Wed, 8 Sep 2021 15:51:40 -0700
Subject: checkin

---
 sys/libn/error.c  |  5 ++---
 sys/libn/memory.c | 22 +++++++++++-----------
 sys/libn/random.c | 35 ++++++++++++++++++++++++++++++++++-
 3 files changed, 47 insertions(+), 15 deletions(-)

(limited to 'sys/libn')

diff --git a/sys/libn/error.c b/sys/libn/error.c
index a9d684c..508136c 100644
--- a/sys/libn/error.c
+++ b/sys/libn/error.c
@@ -17,9 +17,8 @@ errorf(byte* fmt, ...)
     va_list args;
     va_start(args, fmt);
 
-    printf("error: ");
-    vprintf(fmt, args);
-    printf("\n");
+    fprintf(stderr, "error: ");
+    vfprintf(stderr, fmt, args);
 
     va_end(args);
 }
diff --git a/sys/libn/memory.c b/sys/libn/memory.c
index d7df8e3..1c7ab07 100644
--- a/sys/libn/memory.c
+++ b/sys/libn/memory.c
@@ -36,23 +36,23 @@ mem·Allocator sys·Memory = {
 
 /* Grow to particular size */
 void*
-bufgrow(void* buf, vlong newLen, vlong eltsize)
+·bufgrow(void* buf, vlong newLen, vlong eltsize)
 {
     assert(bufcap(buf) <= (SIZE_MAX - 1) / 2);
 
     vlong newCap = MAX(16, MAX(1 + 2 * bufcap(buf), newLen));
 
     assert(newLen <= newCap);
-    assert(newCap <= (SIZE_MAX - offsetof(bufHdr, buf)) / eltsize);
+    assert(newCap <= (SIZE_MAX - offsetof(BufHdr, buf)) / eltsize);
 
-    vlong newSize = offsetof(bufHdr, buf) + newCap * eltsize;
+    vlong newSize = offsetof(BufHdr, buf) + newCap * eltsize;
 
-    bufHdr* newHdr;
+    BufHdr* newHdr;
     if (buf) {
-        newHdr = _bufHdr(buf);
-        newHdr = (bufHdr*)realloc((void*)newHdr, newSize);
+        newHdr = bufhdr(buf);
+        newHdr = (BufHdr*)realloc((void*)newHdr, newSize);
     } else {
-        newHdr      = (bufHdr*)malloc(newSize);
+        newHdr      = (BufHdr*)malloc(newSize);
         newHdr->len = 0;
     }
 
@@ -62,20 +62,20 @@ bufgrow(void* buf, vlong newLen, vlong eltsize)
 
 /* Pop out a value */
 void
-_bufpop(void *buf, int i, vlong eltsize)
+·bufdel(void *buf, int i, vlong eltsize)
 {
     int n;
     byte *b;
     byte stk[1024];
     assert(eltsize < sizeof(stk));
 
-    b = (byte*) buf;
-    if (n = buflen(buf), i < n) {
+    b = (byte*)buf;
+    if(n = buflen(buf), i < n) {
         memcpy(stk, b+eltsize*i, eltsize);
         memcpy(b+eltsize*i, b+eltsize*(i+1), eltsize*(n-i-1));
         memcpy(b+eltsize*(n-1), stk, eltsize);
     } 
-    _bufHdr(buf)->len--;
+    bufhdr(buf)->len--;
 }
 
 // -------------------------------------------------------------------------
diff --git a/sys/libn/random.c b/sys/libn/random.c
index 558641e..551d1e9 100644
--- a/sys/libn/random.c
+++ b/sys/libn/random.c
@@ -1,4 +1,5 @@
 #include <u.h>
+#include <libn.h>
 
 // ----------------------------------------------------------------------------
 // Internal structure
@@ -66,12 +67,29 @@ rng·init(uint64 seed)
 
 /* Returns a random float64 between 0 and 1 */
 double
-rng·random()
+rng·random(void)
 {
     uint64 r = xoshiro256ss(&RNG); 
     return (double)r / (double)UINT64_MAX;
 }
 
+double
+rng·exponential(double lambda)
+{
+    double f;
+
+    f = rng·random();
+    return -log(1 - f)/lambda;
+}
+
+double
+rng·normal(void)
+{
+    double f;
+    f = rng·random();
+
+}
+
 /* Returns true or false on success of trial */
 bool
 rng·bernoulli(double f)
@@ -88,3 +106,18 @@ rng·randi(int max)
     uint64 r = xoshiro256ss(&RNG); 
     return r % max;
 }
+
+uint64
+rng·poisson(double mean)
+{
+    uint64 n;
+    double c;
+
+    if(mean<10.0) {
+        for(n=0, c=rng·exponential(1.0); c<mean; ++n, c+=rng·exponential(1.0))
+            ;
+        return n;
+    }
+
+    return 0;
+}
-- 
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