[freetype2] master 6eb5f2be4: Update 2 files

[Werner Lemberg]

branch: master
commit 6eb5f2be40b1c780dab3fbff3c9f19a7339bcab3
Author: Alexei Podtelezhnikov <apodtele@gmail.com>
Commit: Alexei Podtelezhnikov <apodtele@gmail.com>

    Update 2 files
    
    - /src/base/ftcalc.c
    - /include/freetype/internal/ftcalc.h
---
 include/freetype/internal/ftcalc.h |  4 ++--
 src/base/ftcalc.c                  | 37 +++++++++++++++----------------------
 2 files changed, 17 insertions(+), 24 deletions(-)

diff --git a/include/freetype/internal/ftcalc.h 
b/include/freetype/internal/ftcalc.h
index d9aea2360..fa5e4050f 100644
--- a/include/freetype/internal/ftcalc.h
+++ b/include/freetype/internal/ftcalc.h
@@ -509,8 +509,8 @@ FT_BEGIN_HEADER
    * @note:
    *   This function is not very fast.
    */
-  FT_BASE( FT_Int32 )
-  FT_SqrtFixed( FT_Int32  x );
+  FT_BASE( FT_UInt32 )
+  FT_SqrtFixed( FT_UInt32  x );
 
 #endif /* 0 */
 
diff --git a/src/base/ftcalc.c b/src/base/ftcalc.c
index c5bc7e3b1..ba4d5e3fd 100644
--- a/src/base/ftcalc.c
+++ b/src/base/ftcalc.c
@@ -917,36 +917,29 @@
 
   /* documentation is in ftcalc.h */
 
-  FT_BASE_DEF( FT_Int32 )
-  FT_SqrtFixed( FT_Int32  x )
+  /* Algorithm and code by Christophe Meessen (1993). */
+  FT_BASE_DEF( FT_UInt32 )
+  FT_SqrtFixed( FT_UInt32  r )
   {
-    FT_UInt32  root, rem_hi, rem_lo, test_div;
-    FT_Int     count;
+    FT_UInt32  t, q, b;
 
 
-    root = 0;
+    q = 0;
 
-    if ( x > 0 )
+    b = 0x40000000;
+    while ( b > 0x40 )
     {
-      rem_hi = 0;
-      rem_lo = (FT_UInt32)x;
-      count  = 24;
-      do
+      t = q + b;
+      if ( r >= t )
       {
-        rem_hi   = ( rem_hi << 2 ) | ( rem_lo >> 30 );
-        rem_lo <<= 2;
-        root   <<= 1;
-        test_div = ( root << 1 ) + 1;
-
-        if ( rem_hi >= test_div )
-        {
-          rem_hi -= test_div;
-          root   += 1;
-        }
-      } while ( --count );
+        r -= t;
+        q  = t + b;  /* equivalent to q += 2*b */
+      }
+      r <<= 1;
+      b >>= 1;
     }
 
-    return (FT_Int32)root;
+    return q >> 8;
   }
 
 #endif /* 0 */