Patch for libicns 0.8.1 to add 128x128 PNG extraction support

readme.md

This got libicns working well enough to extract 128x128 PNG images from a macOS resource file that just contained icons. It's not the cleanest fix, but it works to extract icons on my machine.

libicns-0.8.1-128px-png.patch

diff -ruN libicns-0.8.1/src/icns_element.c libicns-0.8.1-modified/src/icns_element.c
--- libicns-0.8.1/src/icns_element.c	2012-06-13 19:42:06.000000000 -0400
+++ libicns-0.8.1-modified/src/icns_element.c	2022-01-31 08:07:50.871844474 -0500
@@ -565,6 +565,7 @@
 	switch(iconType)
 	{
 	case ICNS_1024x1024_32BIT_ARGB_DATA:
+	case ICNS_128x128_32BIT_ARGB_DATA:
 	case ICNS_256x256_32BIT_ARGB_DATA:
 	case ICNS_512x512_32BIT_ARGB_DATA:
 		error = icns_image_to_jp2(imageIn,&newDataSize,&newDataPtr);
diff -ruN libicns-0.8.1/src/icns.h libicns-0.8.1-modified/src/icns.h
--- libicns-0.8.1/src/icns.h	2012-06-13 19:42:06.000000000 -0400
+++ libicns-0.8.1-modified/src/icns.h	2022-01-31 08:07:34.272082774 -0500
@@ -96,6 +96,7 @@
 
 #define ICNS_512x512_32BIT_ARGB_DATA  0x69633039  // "ic09"
 #define ICNS_256x256_32BIT_ARGB_DATA  0x69633038  // "ic08"
+#define ICNS_128x128_32BIT_ARGB_DATA  0x69633037  // "ic07"
 
 #define ICNS_128X128_32BIT_DATA       0x69743332  // "it32"
 #define ICNS_128X128_8BIT_MASK        0x74386D6B  // "t8mk"
diff -ruN libicns-0.8.1/src/icns_image.c libicns-0.8.1-modified/src/icns_image.c
--- libicns-0.8.1/src/icns_image.c	2012-06-13 19:42:06.000000000 -0400
+++ libicns-0.8.1-modified/src/icns_image.c	2022-01-31 08:36:18.419892020 -0500
@@ -99,7 +99,7 @@
 	}
 	
 	// We used the jp2 processor for these two, so we're done!
-	if( (iconType == ICNS_256x256_32BIT_ARGB_DATA) || (iconType == ICNS_512x512_32BIT_ARGB_DATA) || (iconType == ICNS_1024x1024_32BIT_ARGB_DATA) ) {
+	if( (iconType == ICNS_128x128_32BIT_ARGB_DATA) || (iconType == ICNS_256x256_32BIT_ARGB_DATA) || (iconType == ICNS_512x512_32BIT_ARGB_DATA) || (iconType == ICNS_1024x1024_32BIT_ARGB_DATA) ) {
 		memcpy(imageOut,&iconImage,sizeof(icns_image_t));
 		if(iconElement != NULL) {
 		free(iconElement);
@@ -413,6 +413,7 @@
 	switch(iconType)
 	{
 		// 32-Bit Icon Image Data Types ( > 256px )
+		case ICNS_128x128_32BIT_ARGB_DATA:
 		case ICNS_256x256_32BIT_ARGB_DATA:
 		case ICNS_512x512_32BIT_ARGB_DATA:
 		case ICNS_1024x1024_32BIT_ARGB_DATA:
diff -ruN libicns-0.8.1/src/icns_utils.c libicns-0.8.1-modified/src/icns_utils.c
--- libicns-0.8.1/src/icns_utils.c	2012-06-13 19:42:06.000000000 -0400
+++ libicns-0.8.1-modified/src/icns_utils.c	2022-01-31 08:09:30.897405349 -0500
@@ -51,6 +51,7 @@
 	case ICNS_512x512_32BIT_ARGB_DATA:
 		return 22;
 	case ICNS_256x256_32BIT_ARGB_DATA:
+	case ICNS_128x128_32BIT_ARGB_DATA:
 		return 21;
 	case ICNS_128X128_8BIT_MASK:
 		return 20;
@@ -120,6 +121,8 @@
 		return ICNS_NULL_MASK;			
 	case ICNS_256x256_32BIT_ARGB_DATA:
 		return ICNS_NULL_MASK;		
+	case ICNS_128x128_32BIT_ARGB_DATA:
+		return ICNS_NULL_MASK;		
 		
 	// 32-bit image types - 8-bit mask type
 	case ICNS_128X128_32BIT_DATA:
@@ -240,6 +243,15 @@
 		iconInfo.iconPixelDepth = 8;
 		iconInfo.iconBitDepth = 32;
 		break;
+	case ICNS_128x128_32BIT_ARGB_DATA:
+		iconInfo.isImage = 1;
+		iconInfo.isMask = 0;
+		iconInfo.iconWidth = 128;
+		iconInfo.iconHeight = 128;
+		iconInfo.iconChannels = 4;
+		iconInfo.iconPixelDepth = 8;
+		iconInfo.iconBitDepth = 32;
+		break;
 	case ICNS_128X128_32BIT_DATA:
 		iconInfo.isImage = 1;
 		iconInfo.isMask = 0;
@@ -610,10 +622,14 @@
 		}
 		break;
 	case 128:
+		return ICNS_256x256_32BIT_ARGB_DATA;
+
+    /*
 		if(iconInfo.isImage == 1 || iconInfo.iconBitDepth == 32)
 			return ICNS_128X128_32BIT_DATA;
 		if(iconInfo.isMask == 1 || iconInfo.iconBitDepth == 8)
 			return ICNS_128X128_8BIT_MASK;
+    */
 		break;
 	case 256:
 		return ICNS_256x256_32BIT_ARGB_DATA;