[zbar-commits] push rev [278]: More fixes for issue 3131834.

[<tte...@us...>]

changeset: 278:595ae6c5159f
user:      tte...@us...
date:      Fri Dec 10 06:49:44 2010 -0800
details:   http://zbar.hg.sourceforge.net:8000/hgroot/zbar/zbarzbar/rev/595ae6c5159f
description:
More fixes for issue 3131834.

I'm not sure how my fixes managed to successfully decode the image in
 question yesterday, but they don't today.
There was also an overflow in the code to project the lower-right
 alignment pattern out to the exterior corner when fitting the
 initial homography.
When computing w for large versions, dim could use 8 bits, and the
 product of two image coordinates was using 12 each, overflowing a
 signed 32-bit number.
These calculations have been expanded to 64-bit.
This patch also fixes a potential divide-by-zero when the determinant
 in the affine transformation is small.
The new strategy for picking ires should avoid this and avoid any
 potential overflow in the unprojection calculations.

diffstat:

 configure.ac        |   4 ++--
 zbar/qrcode/qrdec.c |  40 ++++++++++++++++++++--------------------
 2 files changed, 22 insertions(+), 22 deletions(-)

diffs (117 lines):

diff -r e0d80fc5de48 -r 595ae6c5159f configure.ac
--- a/configure.ac	Thu Dec 09 12:40:16 2010 -0800
+++ b/configure.ac	Fri Dec 10 06:49:44 2010 -0800
@@ -3,7 +3,7 @@
 AC_INIT([zbar], [0.10], [sp...@us...])
 AC_CONFIG_AUX_DIR(config)
 AC_CONFIG_MACRO_DIR(config)
-AM_INIT_AUTOMAKE([1.10 -Wall -Werror foreign subdir-objects std-options dist-bzip2])
+AM_INIT_AUTOMAKE([1.10 -Wall foreign subdir-objects std-options dist-bzip2])
 AC_CONFIG_HEADERS([include/config.h])
 AC_CONFIG_SRCDIR(zbar/scanner.c)
 LT_PREREQ([2.2])
@@ -47,7 +47,7 @@
   [Library revision])
 
 AM_CPPFLAGS="-I$srcdir/include"
-AM_CFLAGS="-Wall -Wno-parentheses -Werror"
+AM_CFLAGS="-Wall -Wno-parentheses"
 AM_CXXFLAGS="$AM_CFLAGS"
 AC_SUBST([AM_CPPFLAGS])
 AC_SUBST([AM_CFLAGS])
diff -r e0d80fc5de48 -r 595ae6c5159f zbar/qrcode/qrdec.c
--- a/zbar/qrcode/qrdec.c	Thu Dec 09 12:40:16 2010 -0800
+++ b/zbar/qrcode/qrdec.c	Fri Dec 10 06:49:44 2010 -0800
@@ -635,30 +635,32 @@
 
 
 static void qr_aff_init(qr_aff *_aff,
- const qr_point _p0,const qr_point _p1,const qr_point _p2,int _res,int _ires){
+ const qr_point _p0,const qr_point _p1,const qr_point _p2,int _res){
   int det;
+  int ires;
   int dx1;
   int dy1;
   int dx2;
   int dy2;
   /*det is ensured to be positive by our caller.*/
-  det=qr_point_ccw(_p0,_p1,_p2);
   dx1=_p1[0]-_p0[0];
   dx2=_p2[0]-_p0[0];
   dy1=_p1[1]-_p0[1];
   dy2=_p2[1]-_p0[1];
+  det=dx1*dy2-dy1*dx2;
+  ires=QR_MAXI((qr_ilog(abs(det))>>1)-2,0);
   _aff->fwd[0][0]=dx1;
   _aff->fwd[0][1]=dx2;
   _aff->fwd[1][0]=dy1;
   _aff->fwd[1][1]=dy2;
-  _aff->inv[0][0]=QR_DIVROUND(dy2<<_res,det>>_ires);
-  _aff->inv[0][1]=QR_DIVROUND(-dx2<<_res,det>>_ires);
-  _aff->inv[1][0]=QR_DIVROUND(-dy1<<_res,det>>_ires);
-  _aff->inv[1][1]=QR_DIVROUND(dx1<<_res,det>>_ires);
+  _aff->inv[0][0]=QR_DIVROUND(dy2<<_res,det>>ires);
+  _aff->inv[0][1]=QR_DIVROUND(-dx2<<_res,det>>ires);
+  _aff->inv[1][0]=QR_DIVROUND(-dy1<<_res,det>>ires);
+  _aff->inv[1][1]=QR_DIVROUND(dx1<<_res,det>>ires);
   _aff->x0=_p0[0];
   _aff->y0=_p0[1];
   _aff->res=_res;
-  _aff->ires=_ires;
+  _aff->ires=ires;
 }
 
 /*Map from the image (at subpel resolution) into the square domain.*/
@@ -2222,11 +2224,11 @@
      _p[2][0],_p[2][1],_p[3][0],_p[3][1]);
     if(qr_alignment_pattern_search(p3,&cell,dim-7,dim-7,4,
      _img,_width,_height)>=0){
-      int c21;
-      int dx21;
-      int dy21;
-      int mask;
-      int w;
+      long long w;
+      long long mask;
+      int       c21;
+      int       dx21;
+      int       dy21;
       /*There's no real need to update the bounding box corner, and in fact we
          actively perform worse if we do.
         Clearly it was good enough for us to find this alignment pattern, so
@@ -2242,10 +2244,11 @@
       c21=_p[2][0]*_p[1][1]-_p[2][1]*_p[1][0];
       dx21=_p[2][0]-_p[1][0];
       dy21=_p[2][1]-_p[1][1];
-      w=(dim-7)*c21
-       +(dim-13)*(_p[0][0]*dy21-_p[0][1]*dx21)+6*(p3[0]*dy21-p3[1]*dx21);
+      w=QR_EXTMUL(dim-7,c21,
+       QR_EXTMUL(dim-13,_p[0][0]*dy21-_p[0][1]*dx21,
+       QR_EXTMUL(6,p3[0]*dy21-p3[1]*dx21,0)));
       mask=QR_SIGNMASK(w);
-      w=abs(w);
+      w=w+mask^mask;
       brx=(int)QR_DIVROUND(QR_EXTMUL((dim-7)*_p[0][0],p3[0]*dy21,
        QR_EXTMUL((dim-13)*p3[0],c21-_p[0][1]*dx21,
        QR_EXTMUL(6*_p[0][0],c21-p3[1]*dx21,0)))+mask^mask,w);
@@ -3633,7 +3636,6 @@
     qr_finder ur;
     qr_finder dl;
     int       res;
-    int       ires;
     int       ur_version;
     int       dl_version;
     int       fmt_info;
@@ -3646,10 +3648,8 @@
        estimate it there.
       Although it should be the same along both axes, we keep separate
        estimates to account for any remaining projective distortion.*/
-    ires=qr_ilog(QR_MAXI(_width,_height)-1)+QR_FINDER_SUBPREC;
-    res=QR_INT_BITS-2-ires;
-    ires-=2;
-    qr_aff_init(&aff,ul.c->pos,ur.c->pos,dl.c->pos,res,ires);
+    res=QR_INT_BITS-2-QR_FINDER_SUBPREC-qr_ilog(QR_MAXI(_width,_height)-1);
+    qr_aff_init(&aff,ul.c->pos,ur.c->pos,dl.c->pos,res);
     qr_aff_unproject(ur.o,&aff,ur.c->pos[0],ur.c->pos[1]);
     qr_finder_edge_pts_aff_classify(&ur,&aff);
     if(qr_finder_estimate_module_size_and_version(&ur,1<<res,1<<res)<0)continue;