X-Git-Url: https://git.dogcows.com/gitweb?a=blobdiff_plain;ds=sidebyside;f=lib%2Fhuman.c;h=0665b3f7bf25499505b2d03a99def4b2ee676f6f;hb=1589ca47d0448f87b9a492bf5a527e53f7f1cc77;hp=5cfbce9df4ddef46b66ab67d8b1216f759344985;hpb=a9d7ae22a881292a32293688c10513bddcedd225;p=chaz%2Ftar

diff --git a/lib/human.c b/lib/human.c
index 5cfbce9..0665b3f 100644
--- a/lib/human.c
+++ b/lib/human.c
@@ -26,19 +26,12 @@
 #include <sys/types.h>
 #include <stdio.h>
 
-#if HAVE_LIMITS_H
-# include <limits.h>
-#endif
-
 #if HAVE_STRING_H
 # include <string.h>
 #else
 # include <strings.h>
 #endif
 
-#ifndef CHAR_BIT
-# define CHAR_BIT 8
-#endif
 #if HAVE_STDLIB_H
 # include <stdlib.h>
 #endif
@@ -76,6 +69,23 @@ static const char suffixes[] =
   'Y'	/* Yotta */
 };
 
+/* If INEXACT_STYLE is not human_round_to_even, and if easily
+   possible, adjust VALUE according to the style.  */
+static double
+adjust_value (enum human_inexact_style inexact_style, double value)
+{
+  /* Do not use the floor or ceil functions, as that would mean
+     linking with the standard math library, which is a porting pain.
+     So leave the value alone if it is too large to easily round.  */
+  if (inexact_style != human_round_to_even && value < (uintmax_t) -1)
+    {
+      uintmax_t u = value;
+      value = u + (inexact_style == human_ceiling && u != value);
+    }
+
+  return value;
+}
+
 /* Like human_readable_inexact, except always round to even.  */
 char *
 human_readable (uintmax_t n, char *buf,
@@ -90,9 +100,8 @@ human_readable (uintmax_t n, char *buf,
    N is expressed in units of FROM_BLOCK_SIZE.  FROM_BLOCK_SIZE must
    be nonnegative.
 
-   If OUTPUT_BLOCK_SIZE is positive, use units of OUTPUT_BLOCK_SIZE in
-   the output number.  OUTPUT_BLOCK_SIZE must be a multiple of
-   FROM_BLOCK_SIZE or vice versa.
+   OUTPUT_BLOCK_SIZE must be nonzero.  If it is positive, use units of
+   OUTPUT_BLOCK_SIZE in the output number.
 
    Use INEXACT_STYLE to determine whether to take the ceiling or floor
    of any result that cannot be expressed exactly.
@@ -148,57 +157,58 @@ human_readable_inexact (uintmax_t n, char *buf,
 
   /* Adjust AMT out of FROM_BLOCK_SIZE units and into TO_BLOCK_SIZE units.  */
 
-  if (to_block_size <= from_block_size)
-    {
-      int multiplier = from_block_size / to_block_size;
-      amt = n * multiplier;
-
-      if (amt / multiplier != n)
-	{
-	  /* Overflow occurred during multiplication.  We should use
-	     multiple precision arithmetic here, but we'll be lazy and
-	     resort to floating point.  This can yield answers that
-	     are slightly off.  In practice it is quite rare to
-	     overflow uintmax_t, so this is good enough for now.  */
-
-	  double damt = n * (double) multiplier;
-
-	  if (! base)
-	    sprintf (buf, "%.0f", damt);
-	  else
-	    {
-	      double e = 1;
-	      power = 0;
-
-	      do
-		{
-		  e *= base;
-		  power++;
-		}
-	      while (e * base <= damt && power < sizeof suffixes - 1);
-
-	      damt /= e;
-
-	      sprintf (buf, "%.1f%c", damt, suffixes[power]);
-	      if (4 < strlen (buf))
-		sprintf (buf, "%.0f%c", damt, suffixes[power]);
-	    }
-
-	  return buf;
-	}
-    }
-  else if (from_block_size == 0)
-    amt = 0;
-  else
-    {
-      int divisor = to_block_size / from_block_size;
-      int r10 = (n % divisor) * 10;
-      int r2 = (r10 % divisor) * 2;
-      amt = n / divisor;
-      tenths = r10 / divisor;
-      rounding = r2 < divisor ? 0 < r2 : 2 + (divisor < r2);
-    }
-
+  {
+    int multiplier;
+    int divisor;
+    int r2;
+    int r10;
+    if (to_block_size <= from_block_size
+	? (from_block_size % to_block_size != 0
+	   || (multiplier = from_block_size / to_block_size,
+	       (amt = n * multiplier) / multiplier != n))
+	: (from_block_size == 0
+	   || to_block_size % from_block_size != 0
+	   || (divisor = to_block_size / from_block_size,
+	       r10 = (n % divisor) * 10,
+	       r2 = (r10 % divisor) * 2,
+	       amt = n / divisor,
+	       tenths = r10 / divisor,
+	       rounding = r2 < divisor ? 0 < r2 : 2 + (divisor < r2),
+	       0)))
+      {
+	/* Either the result cannot be computed easily using uintmax_t,
+	   or from_block_size is zero.  Fall back on floating point.
+	   FIXME: This can yield answers that are slightly off.  */
+
+	double damt = n * (from_block_size / (double) to_block_size);
+
+	if (! base)
+	  sprintf (buf, "%.0f", adjust_value (inexact_style, damt));
+	else
+	  {
+	    double e = 1;
+	    power = 0;
+
+	    do
+	      {
+		e *= base;
+		power++;
+	      }
+	    while (e * base <= damt && power < sizeof suffixes - 1);
+
+	    damt /= e;
+
+	    sprintf (buf, "%.1f%c", adjust_value (inexact_style, damt),
+		     suffixes[power]);
+	    if (4 < strlen (buf))
+	      sprintf (buf, "%.0f%c",
+		       adjust_value (inexact_style, damt * 10) / 10,
+		       suffixes[power]);
+	  }
+
+	return buf;
+      }
+  }
 
   /* Use power of BASE notation if adjusted AMT is large enough.  */