2.5.7: fix bisection

Author: zvezdochiot

CHANGELOG

@@ -1,6 +1,10 @@
 JPEG Recompress
 https://github.com/ImageProcessing-ElectronicPublications/jpeg-recompress
 
+2.5.7 "bisection"
+
+    Fix bisection
+
 2.5.6 "subsample"
 
     Fix IPEP/#1: ignores subsampling option

src/jmetrics.h

@@ -21,7 +21,7 @@
 #define JMETRICS_H
 
 #ifndef JMVERSION
-#define JMVERSION "2.5.6"
+#define JMVERSION "2.5.7"
 #endif
 
 #define MIN(a, b) ((a) < (b) ? (a) : (b))

src/jpeg-recompress.c

@@ -300,7 +300,7 @@ int main (int argc, char **argv)
     max = jpegMax;
     for (attempt = attempts - 1; attempt >= 0; --attempt)
     {
-        quality = min + (max - min) / 2;
+        quality = (max + min + 1) / 2;
 
         /* Terminate early once bisection interval is a singleton. */
         if (min == max)
@@ -365,11 +365,11 @@ int main (int argc, char **argv)
                     return 1;
                 }
             }
-            min = MIN(quality + 1, max);
+            min = MIN(quality, max);
         }
         else
         {
-            max = MAX(quality - 1, min);
+            max = MAX(quality, min);
         }
 
         // If we aren't done yet, then free the image data

src/jpeg-zfpoint.c

@@ -281,7 +281,7 @@ int main (int argc, char **argv)
     cmpMin = qmetric * (float)min - metric;
     for (attempt = attempts - 1; attempt >= 0; --attempt)
     {
-        quality = min + (max - min) / 2;
+        quality = (max + min + 1) / 2;
         progressive = attempt ? 0 : !noProgressive;
         optimize = accurate ? 1 : (attempt ? 0 : 1);
 
@@ -315,12 +315,12 @@ int main (int argc, char **argv)
 
         if (cmpMin < cmpMax)
         {
-            min = MIN(quality + 1, max);
+            min = MIN(quality, max);
             cmpMin = cmpQ;
         }
         else
         {
-            max = MAX(quality - 1, min);
+            max = MAX(quality, min);
             cmpMax = cmpQ;
         }
 

src/webp-compress.c

@@ -254,7 +254,7 @@ int main (int argc, char **argv)
     max = qMax;
     for (attempt = attempts - 1; attempt >= 0; --attempt)
     {
-         quality = min + (max - min) / 2;
+         quality = (max + min + 1) / 2;
 
         /* Terminate early once bisection interval is a singleton. */
         if (min == max)
@@ -354,11 +354,11 @@ int main (int argc, char **argv)
                     return 1;
                 }
             }
-            min = MIN(quality + 1, max);
+            min = MIN(quality, max);
         }
         else
         {
-            max = MAX(quality - 1, min);
+            max = MAX(quality, min);
         }
 
         // If we aren't done yet, then free the image data