commit 885a2fe3b5e79918d4e4fe9d5c675b3d1d724e02
author John Grossman <johngro@google.com> Wed Jun 27 15:34:43 2012 -0700
committer Alex Ray <aray@google.com> Tue Jul 30 13:56:59 2013 -0700
tree 273eec5b2d3411b2dc260664a6c1144c101527ea
parent dd1b0378cec939e7c90f8e8d8216b481f9f2035a

Utils: Fix a bug in the linear transformation code.

Hand merge from ics-aah

> Utils: Fix a bug in the linear transformation code.
>
> Fix a bug where an incorrect result would be computed if you used the
> linear transformation code to do a reverse transformation (from B's
> domain into A's domain) when the scaler fraction was negative.
>
> Change-Id: I8e5f109314d235a177ab41f65d3c4cd08cff78be
> Signed-off-by: John Grossman <johngro@google.com>

Change-Id: Id90e18f685c61c1a89fd91c32adcf01363b3e8f3
Signed-off-by: John Grossman <johngro@google.com>

libs/utils/LinearTransform.cpp

diff --git a/libs/utils/LinearTransform.cpp b/libs/utils/LinearTransform.cpp
index d752415..b7d28d4 100644
--- a/libs/utils/LinearTransform.cpp
+++ b/libs/utils/LinearTransform.cpp
@@ -114,6 +114,7 @@
         int64_t  basis1,
         int32_t  N,
         uint32_t D,
+        bool     invert_frac,
         int64_t  basis2,
         int64_t* out) {
     uint64_t scaled, res;
@@ -137,8 +138,8 @@
         is_neg = !is_neg;
 
     if (!scale_u64_to_u64(abs_val,
-                          ABS(N),
-                          D,
+                          invert_frac ? D : ABS(N),
+                          invert_frac ? ABS(N) : D,
                           &scaled,
                           is_neg))
         return false; // overflow/undeflow
@@ -191,6 +192,7 @@
                                        a_zero,
                                        a_to_b_numer,
                                        a_to_b_denom,
+                                       false,
                                        b_zero,
                                        b_out);
 }
@@ -201,8 +203,9 @@
 
     return linear_transform_s64_to_s64(b_in,
                                        b_zero,
-                                       a_to_b_denom,
                                        a_to_b_numer,
+                                       a_to_b_denom,
+                                       true,
                                        a_zero,
                                        a_out);
 }