X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Flanguage%2Fexpressions%2Fhelpers.c;h=c69e440e4bde0f9c8747296884c0cf83e9ce2b45;hb=f23b29294fe11981eca39360e9479ff25050b556;hp=5aad13eb160b5f3f160481fcdaefa30a92b05354;hpb=0df9cdd3df66caf4353128feff3008289cda8115;p=pspp

diff --git a/src/language/expressions/helpers.c b/src/language/expressions/helpers.c
index 5aad13eb16..c69e440e4b 100644
--- a/src/language/expressions/helpers.c
+++ b/src/language/expressions/helpers.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2008, 2010, 2011, 2015 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2010, 2011, 2015, 2016 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -25,6 +25,8 @@
 #include "libpspp/assertion.h"
 #include "libpspp/pool.h"
 
+#include "gl/minmax.h"
+
 const struct substring empty_string = {NULL, 0};
 
 double
@@ -662,16 +664,95 @@ npdf_beta (double x, double a, double b, double lambda)
     }
 }
 
-double
-round_nearest (double x, double mult, double fuzzbits)
+static double
+round__ (double x, double mult, double fuzzbits, double adjustment)
 {
-  double adjustment;
-
   if (fuzzbits <= 0)
     fuzzbits = settings_get_fuzzbits ();
-  adjustment = .5 + exp2 (fuzzbits - DBL_MANT_DIG);
+  adjustment += exp2 (fuzzbits - DBL_MANT_DIG);
 
   x /= mult;
   x = x >= 0. ? floor (x + adjustment) : -floor (-x + adjustment);
   return x * mult;
 }
+
+double
+round_nearest (double x, double mult, double fuzzbits)
+{
+  return round__ (x, mult, fuzzbits, .5);
+}
+
+double
+round_zero (double x, double mult, double fuzzbits)
+{
+  return round__ (x, mult, fuzzbits, 0);
+}
+
+struct substring
+replace_string (struct expression *e,
+                struct substring haystack,
+                struct substring needle,
+                struct substring replacement,
+                double n)
+{
+  if (!needle.length
+      || haystack.length < needle.length
+      || n <= 0
+      || n == SYSMIS)
+    return haystack;
+
+  struct substring result = alloc_string (e, MAX_STRING);
+  result.length = 0;
+
+  size_t i = 0;
+  while (i <= haystack.length - needle.length)
+    if (!memcmp (&haystack.string[i], needle.string, needle.length))
+      {
+        size_t copy_len = MIN (replacement.length, MAX_STRING - result.length);
+        memcpy (&result.string[result.length], replacement.string, copy_len);
+        result.length += copy_len;
+        i += needle.length;
+
+        if (--n < 1)
+          break;
+      }
+    else
+      {
+        if (result.length < MAX_STRING)
+          result.string[result.length++] = haystack.string[i];
+        i++;
+      }
+  while (i < haystack.length && result.length < MAX_STRING)
+    result.string[result.length++] = haystack.string[i++];
+
+  return result;
+}
+
+static int
+compare_doubles (const void *a_, const void *b_)
+{
+  const double *ap = a_;
+  const double *bp = b_;
+  double a = *ap;
+  double b = *bp;
+
+  /* Sort SYSMIS to the end. */
+  return (a == b ? 0
+          : a == SYSMIS ? 1
+          : b == SYSMIS ? -1
+          : a > b ? 1 : -1);
+}
+
+double
+median (double *a, size_t n)
+{
+  /* Sort the array in-place, sorting SYSMIS to the end. */
+  qsort (a, n, sizeof *a, compare_doubles);
+
+  /* Drop SYSMIS. */
+  n = count_valid (a, n);
+
+  return (!n ? SYSMIS
+          : n % 2 ? a[n / 2]
+          : (a[n / 2 - 1] + a[n / 2]) / 2.0);
+}