From de15e1036fb7c6f117576b6f465db23284d4e681 Mon Sep 17 00:00:00 2001
From: Thomas Bernard <miniupnp@free.fr>
Date: Sat, 16 Nov 2019 00:32:58 +0100
Subject: [PATCH] packbits optimization #1

---
 src/fileformats.c | 12 +++++++++++-
 src/tests/tests.c |  7 ++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/fileformats.c b/src/fileformats.c
index b4eda9e0..5cfc4efc 100644
--- a/src/fileformats.c
+++ b/src/fileformats.c
@@ -2247,7 +2247,17 @@ void Load_IFF(T_IO_Context * context)
         second_last_color=IFF_color_list[IFF_list_size-2];
         if (last_color==color)  // On a une répétition de couleur
         {
-          if ( (IFF_repetition_mode) || (second_last_color!=color) )
+          if ( !IFF_repetition_mode && IFF_list_size >= 127)
+          {
+            // mode <> avec 126 octets <> puis 2 identiques
+            IFF_list_size--;
+            Transfer_colors(file);
+            IFF_color_list[0]=color;
+            IFF_color_list[1]=color;
+            IFF_list_size=2;
+            IFF_repetition_mode=1;
+          }
+          else if ( (IFF_repetition_mode) || (second_last_color!=color) )
           // On conserve le mode...
           {
             IFF_color_list[IFF_list_size]=color;
diff --git a/src/tests/tests.c b/src/tests/tests.c
index fd696fdf..7f4223d7 100644
--- a/src/tests/tests.c
+++ b/src/tests/tests.c
@@ -158,9 +158,14 @@ int Test_Packbits(void)
     "AABBCCDDDDDDD12345@@@54321", // best : -1(ff) 'A' -1(ff) 'B' -1(ff) 'C' -6(fa) 'D' 12(0c) "12345@@@54321" => 22 bytes
                                   //                                            or 04 "12345" -2(fe) '@' 04 "54321"
     "123AA123BBB123CCCC123DDDDD", // best : 07 "123AA123" -2 'B' 02 "123" -3(fd) 'C' 02 "123" -4(fc) 'D' => 23 bytes
+    "12345678123456781234567812345678" // 32
+    "12345678123456781234567812345678" // 64
+    "12345678123456781234567812345678" // 96
+    "123456781234567812345678123456@@" // 128
+    "@@12345678", // best : 125(7d) "123..." -3 '@' 08 "12345678" => 138
     NULL
   };
-  const long best_packed = 7 + 22 + 23;
+  const long best_packed = 7 + 22 + 23 + (138/*+2*/);
   byte buffer[1024];
 
   snprintf(tempfilename, sizeof(tempfilename), "/tmp/gfx2test-packbits-%lx", random());