Add utility to compress game image files.

.gitignore

@@ -96,5 +96,6 @@ doc/main.fdb_latexmk
 doc/main.fls
 doc/main.ilg
 doc/main.ind
-tools/genfont
 tools/bmpicn
+tools/genfont
+tools/icnpack

tools/icnpack.c

@@ -0,0 +1,126 @@
+/*
+ * Seven Kingdoms: Ancient Adversaries
+ *
+ * Copyright 2018-2022 Jesse Allen
+ * Copyright 1997,1998 Enlight Software Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+/*
+ * To compile:
+ * gcc -g -I../include icnpack.c -o icnpack
+ *
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <COLCODE.h>
+
+//-------------------------------------------------
+//
+// Format of the compressed data
+// compressed	decompressed
+// FF		FF
+// FE (-2)	FF FF
+// FD (-3)	FF FF FF
+// FC (-4)	FF FF FF FF
+// FB (-5)	FF FF FF FF FF
+// FA (-6)	FF FF FF FF FF FF
+// F9 (-7)	FF FF FF FF FF FF FF
+// F8 B		FF ... <B times>
+//
+// Header COLCODE.H provides some helpers macros.
+//
+//-------------------------------------------------
+//
+// Format of the bitmap data :
+//
+// <short>  width
+// <short>  height
+// <char..> bitmap image
+//
+//-------------------------------------------------
+
+
+int main(int argc, char **argv)
+{
+	short w, h;
+	unsigned char *pixels;
+	FILE *fh;
+
+	if( argc<2 )
+	{
+		printf("Usage: icnbmp input.icn\n");
+		return 1;
+	}
+
+	fh = fopen(argv[1], "r");
+	if( !fh )
+		return 1;
+	fread(&w, sizeof(short), 1, fh);
+	fread(&h, sizeof(short), 1, fh);
+
+	pixels = malloc(w*h);
+	fread(pixels, 1, w*h, fh);
+	fclose(fh);
+
+	fh = fopen("OUT.ICN", "w");
+	if( !fh )
+		return 1;
+	fwrite(&w, sizeof(short), 1, fh);
+	fwrite(&h, sizeof(short), 1, fh);
+
+	unsigned char run = 0;
+	for( int i = 0; i < w*h; i++ )
+	{
+		if( run && pixels[i] != TRANSPARENT_CODE )
+		{
+			unsigned char code;
+			if( run == 1 )
+			{
+				code = TRANSPARENT_CODE;
+			}
+			if( run <= UNIQUE_REPEAT_CODE_NUM )
+			{
+				code = FEW_TRANSPARENT_CODE(run);
+			}
+			else
+			{
+				code = MANY_TRANSPARENT_CODE;
+				fwrite(&code, sizeof(unsigned char), 1, fh);
+				code = run;
+			}
+			fwrite(&code, sizeof(unsigned char), 1, fh);
+			run = 0;
+		}
+		if( pixels[i] == TRANSPARENT_CODE )
+		{
+			unsigned char code;
+			if( ++run < TRANSPARENT_CODE )
+				continue;
+			code = MANY_TRANSPARENT_CODE;
+			fwrite(&code, sizeof(unsigned char), 1, fh);
+			code = 0xff;
+			fwrite(&code, sizeof(unsigned char), 1, fh);
+			run = 0;
+			continue;
+		}
+		fwrite(&pixels[i], sizeof(unsigned char), 1, fh);
+	}
+
+	fclose(fh);
+	return 0;
+}