Build: separating optional PNG filter natives from compression code

Author: Oldes

make/rebol3.nest

@@ -444,6 +444,11 @@ include-lzma-compression: [
 	core-files: %core/u-lzma.c
 ]
 
+include-png-filter-native: [
+	config: INCLUDE_PNG_FILTER
+	core-files: %core/u-png-filter.c
+]
+
 include-view: [
 	; currently only on Windows!
 	host-files: :host-files-view
@@ -500,7 +505,7 @@ include-codec-ico: [
 ]
 include-codec-json:          [mezz-lib-files:  %mezz/codec-json.reb         ]
 include-codec-xml:           [mezz-lib-files:  %mezz/codec-xml.reb          ]
-include-codec-pdf:           [mezz-lib-files:  %mezz/codec-pdf.reb config: INCLUDE_PNG_FILTER] ; pdf may use special png pre-compression
+include-codec-pdf:           [mezz-lib-files:  %mezz/codec-pdf.reb :include-png-filter-native] ; pdf may use special png pre-compression
 include-codec-swf:           [mezz-lib-files:  %mezz/codec-swf.reb          ]
 include-codec-wav:           [mezz-lib-files:  %mezz/codec-wav.reb          ]
 include-codec-unixtime:      [mezz-lib-files:  %mezz/codec-unixtime.reb     ]

src/core/u-compress.c

@@ -343,228 +343,3 @@ static const ISzAlloc g_Alloc = { SzAlloc, SzFree };
 
 #endif //INCLUDE_LZMA
 
-
-#ifdef INCLUDE_PNG_FILTER
-#ifdef INCLUDE_PNG_CODEC
-int paeth_predictor(int a, int b, int c);
-#else
-#define int_abs(a) (((a)<0)?(-(a)):(a))
-static int paeth_predictor(int a, int b, int c) {
-	int p, pa, pb, pc;
-
-	p = a + b - c;
-	pa = int_abs(p - a);
-	pb = int_abs(p - b);
-	pc = int_abs(p - c);
-	if ((pa <= pb) && (pa <= pc))
-		return a;
-	else if (pb <= pc)
-		return b;
-	return c;
-}
-#endif
-
-enum PNG_Filter_Types {
-	PNG_FILTER_SUB = 1,
-	PNG_FILTER_UP,
-	PNG_FILTER_AVERAGE,
-	PNG_FILTER_PAETH
-};
-
-static REBYTE get_png_filter_type(REBVAL* val) {
-	if (IS_WORD(val)) {
-		switch (VAL_WORD_SYM(val)) {
-		case SYM_SUB:     return PNG_FILTER_SUB;
-		case SYM_UP:      return PNG_FILTER_UP;
-		case SYM_AVERAGE: return PNG_FILTER_AVERAGE;
-		case SYM_PAETH:   return PNG_FILTER_PAETH;
-		}
-	}
-	else if (IS_INTEGER(val)) {
-		return MIN(PNG_FILTER_PAETH, MAX(0, VAL_INT32(val)));
-	}
-	Trap1(RE_INVALID_ARG, val);
-	return 0; // to make xcode happy
-}
-
-// See: https://www.rfc-editor.org/rfc/rfc2083.html#page-31
-//      https://en.wikipedia.org/wiki/Portable_Network_Graphics#Filtering
-/***********************************************************************
-**
-*/	REBNATIVE(filter)
-/*
-//	filter: native [
-//		"PNG delta filter"
-//		data   [binary!] "Input"
-//		width  [number!] "Scanline width"
-//		type   [integer! word!] "1..4 or one of: [sub up average paeth]"
-//		/skip bpp [integer!] "Bytes per pixel"
-//	]
-***********************************************************************/
-{
-	REBVAL *val_data  = D_ARG(1);
-	REBVAL *val_width = D_ARG(2);
-	REBVAL *val_type  = D_ARG(3);
-	REBOOL  ref_skip  = D_REF(4);
-	REBVAL *val_bpp   = D_ARG(5);
-
-	REBSER *ser;
-	REBYTE *bin = VAL_BIN_DATA(val_data);
-	REBYTE *scan, *prev, *temp, *out;
-	REBCNT r, c, rows, bytes;
-	REBINT width = AS_INT32(val_width);
-	REBYTE filter = get_png_filter_type(val_type);
-	REBCNT bpp = ref_skip ? VAL_INT32(val_bpp) : 1;
-
-	bytes = VAL_LEN(val_data);
-
-	if (width <= 1 || width > bytes)
-		Trap1(RE_INVALID_ARG, val_width);
-	if (bpp < 1 || bpp > width)
-		Trap1(RE_INVALID_ARG, val_bpp);
-
-	rows = bytes / width;
-	ser  = Make_Binary(bytes);
-	out  = BIN_DATA(ser);
-
-	temp = malloc(width);
-	if (!temp) {
-		Trap0(RE_NO_MEMORY);
-		return R_NONE;
-	}
-	memset(temp, 0, width);
-
-	prev = temp;
-	for (r = 0; r < rows; r++) {
-		scan = bin + (r * width);
-		out  = BIN_SKIP(ser, r * width);
-
-		switch (filter) {
-		case PNG_FILTER_SUB:
-			for (c = 0; c < bpp; c++)
-				out[c] = scan[c];
-			for (c = bpp; c < width; c++)
-				out[c] = scan[c] - scan[c - bpp];
-			break;
-		case PNG_FILTER_UP:
-			for (c = 0; c < width; c++)
-				out[c] = scan[c] - prev[c];
-			break;
-		case PNG_FILTER_AVERAGE:
-			for (c = 0; c < bpp; c++)
-				out[c] = scan[c] - (prev[c] >> 1);
-			for (c = bpp; c < width; c++)
-				out[c] = scan[c] - ((scan[c - bpp] + prev[c]) >> 1) & 0xFF;
-			break;
-		case PNG_FILTER_PAETH:
-			for (c = 0; c < bpp; c++)
-				out[c] = scan[c] - prev[c];
-			for (c = bpp; c < width; c++)
-				out[c] = scan[c] - paeth_predictor(scan[c - bpp], prev[c], prev[c - bpp]);
-			break;
-		}
-		prev = scan;
-	}
-	free(temp);
-	SET_BINARY(D_RET, ser);
-	VAL_TAIL(D_RET) = bytes;
-	return R_RET;
-}
-
-/***********************************************************************
-**
-*/	REBNATIVE(unfilter)
-/*
-//	unfilter: native [
-//		"Reversed PNG delta filter"
-//		data  [binary!]  "Input"
-//		width [number!]  "Scanline width (not counting the type byte)"
-//		/as   "Filter type. If not used, type is decoded from first byte on each line."
-//		 type [integer! word!] "1..4 or one of: [sub up average paeth]"
-//		/skip
-//		 bpp [integer!]  "Bytes per pixel"
-//	]
-***********************************************************************/
-{
-	REBVAL *val_data  = D_ARG(1);
-	REBVAL *val_width = D_ARG(2);
-	REBOOL  ref_as    = D_REF(3);
-	REBVAL *val_type  = D_ARG(4);
-	REBOOL  ref_skip  = D_REF(5);
-	REBVAL *val_bpp   = D_ARG(6);
-
-	REBSER *ser;
-	REBYTE *bin = VAL_BIN_DATA(val_data);
-	REBINT width = AS_INT32(val_width);
-	REBCNT r, c, rows;
-	REBYTE *scan, *prev, *temp, *out;
-	REBYTE filter = 0;
-	REBCNT bytes = VAL_LEN(val_data);
-	REBCNT bpp = ref_skip ? VAL_INT32(val_bpp) : 1;
-
-	if (!ref_as) width++;
-	if (width <= 1 || width > bytes)
-		Trap1(RE_INVALID_ARG, val_width);
-	if (bpp < 1 || bpp > width)
-		Trap1(RE_INVALID_ARG, val_bpp);
-
-	rows = ceil(bytes / width);
-	ser  = Make_Binary(bytes);
-	out  = BIN_DATA(ser);
-
-	if (ref_as)
-		filter = get_png_filter_type(val_type);
-
-	temp = malloc(width);
-	if (!temp) {
-		Trap0(RE_NO_MEMORY);
-		return R_NONE;
-	}
-	memset(temp, 0, width);
-
-	if (!ref_as) width--;
-
-	prev = temp;
-	for (r = 0; r < rows; r++) {
-		if (ref_as) {
-			scan = bin + r * width;
-			out = BIN_SKIP(ser, r * width);
-		} else {
-			scan = bin + r * (width + 1);
-			out = BIN_SKIP(ser, r * (width));
-			filter = scan[0];
-			scan++;
-		}
-		
-		switch (filter) {
-		case PNG_FILTER_SUB:
-			for (c = 0; c < bpp; c++)
-				out[c] = scan[c];
-			for (c = bpp; c < width; c++)
-				out[c] = scan[c] + out[c - bpp];
-			break;
-		case PNG_FILTER_UP:
-			for (c = 0; c < width; c++)
-				out[c] = scan[c] + prev[c];
-			break;
-		case PNG_FILTER_AVERAGE:
-			for (c = 0; c < bpp; c++)
-				out[c] = scan[c] + (prev[c] >> 1) & 0xFF;
-			for (c = bpp; c < width; c++)
-				out[c] = scan[c] + ((out[c - bpp] + prev[c]) >> 1) & 0xFF;
-			break;
-		case PNG_FILTER_PAETH:
-			for (c = 0; c < bpp; c++)
-				out[c] = scan[c] + prev[c];
-			for (c = bpp; c < width; c++)
-				out[c] = scan[c] + paeth_predictor(out[c - bpp], prev[c], prev[c - bpp]);
-			break;
-		}
-		prev = out;
-	}
-	free(temp);
-	SET_BINARY(D_RET, ser);
-	VAL_TAIL(D_RET) = ref_as ? bytes : bytes - rows;
-	return R_RET;
-}
-#endif //INCLUDE_PNG_FILTER