FEAT: extend PNG codec with size? function (returning image size of the binary)

Author: Oldes

src/mezz/codec-image-ext.reb

@@ -0,0 +1,41 @@
+REBOL [
+	title:  "REBOL 3 image codecs extensions"
+	name:   'codec-image-ext
+	author: "Oldes"
+	version: 0.1.0
+	date:    10-Nov-2020
+	history: [
+		0.1.0 10-Nov-2020 "Oldes" {Extend native PNG codec with `size?` function}
+	]
+]
+
+if find codecs 'png [
+	extend codecs/png 'size2? func ["Return PNG image size or none" bin [binary!]][
+		if all [
+			parse bin [
+				#{89504E470D0A1A0A} ;- PNG magic number
+				thru #{49484452}    ;- IHDR chunk
+				bin: to end
+			]
+			8 <= length? bin
+		][
+			to pair! binary/read bin [UI32 UI32]
+		]
+	]
+]
+
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src/tests/units/codecs-test.r3

@@ -283,6 +283,14 @@ if find codecs 'JSON [
 	===end-group===
 ]
 
+if find codecs 'PNG [
+	===start-group=== "PNG codec"
+	--test-- "png/size?"
+		--assert 24x24 = codecs/png/size? read %units/files/r3.png
+		--assert none?   codecs/png/size? read %units/files/test.aar
+	===end-group===
+]
+
 if find codecs 'XML [
 	===start-group=== "XML codec"
 	--test-- "XML decode test1"

src/tools/make-boot.reb

@@ -993,6 +993,7 @@ if product = 'view [
 		]
 	]
 ]
+append mezz-files/3 %codec-image-ext.reb
 
 foreach section [boot-base boot-sys boot-mezz] [
 	set section make block! 200