From 7e6e491907b97162d98b731b5a5f3cab1a80b0e9 Mon Sep 17 00:00:00 2001
From: augustin64 <me.git@augustin64.fr>
Date: Wed, 12 Mar 2025 10:21:04 +0100
Subject: [PATCH] oops overflow

---
 .../c++/equalization.cpp                      | 58 ++++++++++++++++---
 1 file changed, 50 insertions(+), 8 deletions(-)

diff --git a/image-processing/1-SlicedOptimalTransport/c++/equalization.cpp b/image-processing/1-SlicedOptimalTransport/c++/equalization.cpp
index 57d3403..9a74203 100644
--- a/image-processing/1-SlicedOptimalTransport/c++/equalization.cpp
+++ b/image-processing/1-SlicedOptimalTransport/c++/equalization.cpp
@@ -37,6 +37,7 @@
 #include <stb_image.h>
 #define STB_IMAGE_WRITE_IMPLEMENTATION
 #include <stb_image_write.h>
+#define DEBUG (0)
 
 unsigned char min(unsigned char a, unsigned char b) {
   return a < b ? a : b;
@@ -81,10 +82,10 @@ int main(int argc, char **argv)
   
   //As an example, we just scan the pixels of the source image
   //and swap the color channels.
-  unsigned int cum_r[255];
-  unsigned int cum_g[255];
-  unsigned int cum_b[255];
-  for (auto i=0; i < 255; i++) {
+  unsigned int cum_r[256];
+  unsigned int cum_g[256];
+  unsigned int cum_b[256];
+  for (auto i=0; i < 256; i++) {
     cum_r[i] = cum_g[i] = cum_b[i] = 0;
   }
 
@@ -97,20 +98,61 @@ int main(int argc, char **argv)
     }
   }
 
-  unsigned int distrib_r[255];
-  unsigned int distrib_g[255];
-  unsigned int distrib_b[255];
+  if DEBUG {
+    bool seenB, seenR, seenG;
+    seenB = seenR = seenG = false;
+    int i=256;
+    while (i>0 && (!seenR || !seenG || !seenB)) {
+      if (!seenR && cum_r[i] != 0) {
+        printf("maxR: %d\n", i);
+        seenR=true;
+      }
+      if (!seenG && cum_g[i] != 0) {
+        printf("maxG: %d\n", i);
+        seenG=true;
+      }
+      if (!seenB && cum_b[i] != 0) {
+        printf("maxB: %d\n", i);
+        seenB=true;
+      }
+      i--;
+    }
+
+    seenB = seenR = seenG = false;
+    i=0;
+    while (i<=256 && (!seenR || !seenG || !seenB)) {
+      if (!seenR && cum_r[i] != 0) {
+        printf("minR: %d\n", i);
+        seenR=true;
+      }
+      if (!seenG && cum_g[i] != 0) {
+        printf("minG: %d\n", i);
+        seenG=true;
+      }
+      if (!seenB && cum_b[i] != 0) {
+        printf("minB: %d\n", i);
+        seenB=true;
+      }
+      i++;
+    }
+  }
+
+  unsigned int distrib_r[256];
+  unsigned int distrib_g[256];
+  unsigned int distrib_b[256];
 
   int total_px = width*height;
   float cur_cum_r, cur_cum_g, cur_cum_b;
   cur_cum_r, cur_cum_g, cur_cum_b = 0;
-  for (auto i=0; i < 255; i++) {
+  if DEBUG printf("Distrib: R G B\n");
+  for (auto i=0; i < 256; i++) {
     cur_cum_r += cum_r[i]/(float)total_px;
     cur_cum_g += cum_g[i]/(float)total_px;
     cur_cum_b += cum_b[i]/(float)total_px;
     distrib_r[i] = 255*cur_cum_r;
     distrib_g[i] = 255*cur_cum_g;
     distrib_b[i] = 255*cur_cum_b;
+    if DEBUG printf("%d\t%3d %3d %3d\n", i,distrib_r[i], distrib_g[i], distrib_b[i]);
   }
 
   for(auto i = 0 ; i < width ; ++i)