Fix T44541 aka gigapixel image render support in blender.

Moral of the story: Make sure that size_t is used whenever pointer
arithmetic is involved. For images, that basically means whenever any
squared dimensions are involved. Casting an operand to size_t early in
the operation is usually sufficient to force the entire operation to
size_t.

There might still be places lurking where we don't support this
correctly. This has been tested with render pipeline, quite a few image
functions (meaning we can paint on such images now, albeit somewhat
slowly ;) ) and export to jpeg. Too many places in code to check so I
guess we'll be handling cases as they come.

Don't try this at home unless you have an immense ammount of RAM.
First GPixel render of suzanne in the multiverse can be found here:

http://download.blender.org/demo/test/suzanne-billion-pixel.jpg

Can be viewed from blender (takes about 3.3 GB after loading but may
take more during loading so 8GB might be more safe to try this).

1 files changed, 41 insertions, 41 deletions

diff --git a/source/blender/imbuf/intern/divers.c b/source/blender/imbuf/intern/divers.c
index 3417fe2fc1d..455b78bce4d 100644
--- a/source/blender/imbuf/intern/divers.c
+++ b/source/blender/imbuf/intern/divers.c
@@ -184,16 +184,16 @@ void IMB_buffer_byte_from_float(uchar *rect_to, const float *rect_from,
 
 		if (channels_from == 1) {
 			/* single channel input */
-			const float *from = rect_from + stride_from * y;
-			uchar *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y;
+			uchar *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			for (x = 0; x < width; x++, from++, to += 4)
 				to[0] = to[1] = to[2] = to[3] = FTOCHAR(from[0]);
 		}
 		else if (channels_from == 3) {
 			/* RGB input */
-			const float *from = rect_from + stride_from * y * 3;
-			uchar *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y * 3;
+			uchar *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			if (profile_to == profile_from) {
 				/* no color space conversion */
@@ -221,8 +221,8 @@ void IMB_buffer_byte_from_float(uchar *rect_to, const float *rect_from,
 		}
 		else if (channels_from == 4) {
 			/* RGBA input */
-			const float *from = rect_from + stride_from * y * 4;
-			uchar *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y * 4;
+			uchar *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			if (profile_to == profile_from) {
 				float straight[4];
@@ -334,8 +334,8 @@ void IMB_buffer_byte_from_float_mask(uchar *rect_to, const float *rect_from,
 
 		if (channels_from == 1) {
 			/* single channel input */
-			const float *from = rect_from + stride_from * y;
-			uchar *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y;
+			uchar *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			for (x = 0; x < width; x++, from++, to += 4)
 				if (*mask++ == FILTER_MASK_USED)
@@ -343,8 +343,8 @@ void IMB_buffer_byte_from_float_mask(uchar *rect_to, const float *rect_from,
 		}
 		else if (channels_from == 3) {
 			/* RGB input */
-			const float *from = rect_from + stride_from * y * 3;
-			uchar *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y * 3;
+			uchar *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			for (x = 0; x < width; x++, from += 3, to += 4) {
 				if (*mask++ == FILTER_MASK_USED) {
@@ -355,8 +355,8 @@ void IMB_buffer_byte_from_float_mask(uchar *rect_to, const float *rect_from,
 		}
 		else if (channels_from == 4) {
 			/* RGBA input */
-			const float *from = rect_from + stride_from * y * 4;
-			uchar *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y * 4;
+			uchar *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			float straight[4];
 
@@ -408,7 +408,7 @@ void IMB_buffer_float_from_byte(float *rect_to, const uchar *rect_from,
 	/* RGBA input */
 	for (y = 0; y < height; y++) {
 		const uchar *from = rect_from + stride_from * y * 4;
-		float *to = rect_to + stride_to * y * 4;
+		float *to = rect_to + ((size_t)stride_to) * y * 4;
 
 		if (profile_to == profile_from) {
 			/* no color space conversion */
@@ -460,8 +460,8 @@ void IMB_buffer_float_from_float(float *rect_to, const float *rect_from,
 	if (channels_from == 1) {
 		/* single channel input */
 		for (y = 0; y < height; y++) {
-			const float *from = rect_from + stride_from * y;
-			float *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y;
+			float *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			for (x = 0; x < width; x++, from++, to += 4)
 				to[0] = to[1] = to[2] = to[3] = from[0];
@@ -470,8 +470,8 @@ void IMB_buffer_float_from_float(float *rect_to, const float *rect_from,
 	else if (channels_from == 3) {
 		/* RGB input */
 		for (y = 0; y < height; y++) {
-			const float *from = rect_from + stride_from * y * 3;
-			float *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y * 3;
+			float *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			if (profile_to == profile_from) {
 				/* no color space conversion */
@@ -499,12 +499,12 @@ void IMB_buffer_float_from_float(float *rect_to, const float *rect_from,
 	else if (channels_from == 4) {
 		/* RGBA input */
 		for (y = 0; y < height; y++) {
-			const float *from = rect_from + stride_from * y * 4;
-			float *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y * 4;
+			float *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			if (profile_to == profile_from) {
 				/* same profile, copy */
-				memcpy(to, from, sizeof(float) * 4 * width);
+				memcpy(to, from, sizeof(float) * ((size_t)4) * width);
 			}
 			else if (profile_to == IB_PROFILE_LINEAR_RGB) {
 				/* convert to sRGB to linear */
@@ -541,8 +541,8 @@ void IMB_buffer_float_from_float_mask(float *rect_to, const float *rect_from, in
 	if (channels_from == 1) {
 		/* single channel input */
 		for (y = 0; y < height; y++) {
-			const float *from = rect_from + stride_from * y;
-			float *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y;
+			float *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			for (x = 0; x < width; x++, from++, to += 4)
 				if (*mask++ == FILTER_MASK_USED)
@@ -552,8 +552,8 @@ void IMB_buffer_float_from_float_mask(float *rect_to, const float *rect_from, in
 	else if (channels_from == 3) {
 		/* RGB input */
 		for (y = 0; y < height; y++) {
-			const float *from = rect_from + stride_from * y * 3;
-			float *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y * 3;
+			float *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			for (x = 0; x < width; x++, from += 3, to += 4) {
 				if (*mask++ == FILTER_MASK_USED) {
@@ -566,8 +566,8 @@ void IMB_buffer_float_from_float_mask(float *rect_to, const float *rect_from, in
 	else if (channels_from == 4) {
 		/* RGBA input */
 		for (y = 0; y < height; y++) {
-			const float *from = rect_from + stride_from * y * 4;
-			float *to = rect_to + stride_to * y * 4;
+			const float *from = rect_from + ((size_t)stride_from) * y * 4;
+			float *to = rect_to + ((size_t)stride_to) * y * 4;
 
 			for (x = 0; x < width; x++, from += 4, to += 4)
 				if (*mask++ == FILTER_MASK_USED)
@@ -590,8 +590,8 @@ void IMB_buffer_byte_from_byte(uchar *rect_to, const uchar *rect_from,
 
 	/* always RGBA input */
 	for (y = 0; y < height; y++) {
-		const uchar *from = rect_from + stride_from * y * 4;
-		uchar *to = rect_to + stride_to * y * 4;
+		const uchar *from = rect_from + ((size_t)stride_from) * y * 4;
+		uchar *to = rect_to + ((size_t)stride_to) * y * 4;
 
 		if (profile_to == profile_from) {
 			/* same profile, copy */
@@ -690,8 +690,8 @@ void IMB_partial_rect_from_float(ImBuf *ibuf, float *buffer, int x, int y, int w
 		imb_addrectImBuf(ibuf);
 
 	/* do conversion */
-	rect_float = ibuf->rect_float + (x + y * ibuf->x) * ibuf->channels;
-	rect_byte = (uchar *)ibuf->rect + (x + y * ibuf->x) * 4;
+	rect_float = ibuf->rect_float + (x + ((size_t)y) * ibuf->x) * ibuf->channels;
+	rect_byte = (uchar *)ibuf->rect + (x + ((size_t)y) * ibuf->x) * 4;
 
 	if (is_data) {
 		/* exception for non-color data, just copy float */
@@ -734,9 +734,9 @@ void IMB_float_from_rect(ImBuf *ibuf)
 	 */
 	rect_float = ibuf->rect_float;
 	if (rect_float == NULL) {
-		int size;
+		size_t size;
 
-		size = ibuf->x * ibuf->y;
+		size = ((size_t)ibuf->x) * ibuf->y;
 		size = size * 4 * sizeof(float);
 		ibuf->channels = 4;
 
@@ -771,22 +771,22 @@ void IMB_color_to_bw(ImBuf *ibuf)
 {
 	float *rct_fl = ibuf->rect_float;
 	uchar *rct = (uchar *)ibuf->rect;
-	int i;
+	size_t i;
 
 	if (rct_fl) {
-		for (i = ibuf->x * ibuf->y; i > 0; i--, rct_fl += 4)
+		for (i = ((size_t)ibuf->x) * ibuf->y; i > 0; i--, rct_fl += 4)
 			rct_fl[0] = rct_fl[1] = rct_fl[2] = IMB_colormanagement_get_luminance(rct_fl);
 	}
 
 	if (rct) {
-		for (i = ibuf->x * ibuf->y; i > 0; i--, rct += 4)
+		for (i = ((size_t)ibuf->x * ibuf->y); i > 0; i--, rct += 4)
 			rct[0] = rct[1] = rct[2] = IMB_colormanagement_get_luminance_byte(rct);
 	}
 }
 
 void IMB_buffer_float_clamp(float *buf, int width, int height)
 {
-	int i, total = width * height * 4;
+	size_t i, total = ((size_t)width) * height * 4;
 	for (i = 0; i < total; i++) {
 		buf[i] = min_ff(1.0, buf[i]);
 	}
@@ -794,7 +794,7 @@ void IMB_buffer_float_clamp(float *buf, int width, int height)
 
 void IMB_buffer_float_unpremultiply(float *buf, int width, int height)
 {
-	int total = width * height;
+	size_t total = ((size_t)width) * height;
 	float *fp = buf;
 	while (total--) {
 		premul_to_straight_v4(fp);
@@ -804,7 +804,7 @@ void IMB_buffer_float_unpremultiply(float *buf, int width, int height)
 
 void IMB_buffer_float_premultiply(float *buf, int width, int height)
 {
-	int total = width * height;
+	size_t total = ((size_t)width) * height;
 	float *fp = buf;
 	while (total--) {
 		straight_to_premul_v4(fp);
@@ -816,14 +816,14 @@ void IMB_buffer_float_premultiply(float *buf, int width, int height)
 
 void IMB_saturation(ImBuf *ibuf, float sat)
 {
-	int i;
+	size_t i;
 	unsigned char *rct = (unsigned char *)ibuf->rect;
 	float *rct_fl = ibuf->rect_float;
 	float hsv[3];
 
 	if (rct) {
 		float rgb[3];
-		for (i = ibuf->x * ibuf->y; i > 0; i--, rct += 4) {
+		for (i = ((size_t)ibuf->x) * ibuf->y; i > 0; i--, rct += 4) {
 			rgb_uchar_to_float(rgb, rct);
 			rgb_to_hsv_v(rgb, hsv);
 			hsv_to_rgb(hsv[0], hsv[1] * sat, hsv[2], rgb, rgb + 1, rgb + 2);
@@ -832,7 +832,7 @@ void IMB_saturation(ImBuf *ibuf, float sat)
 	}
 
 	if (rct_fl) {
-		for (i = ibuf->x * ibuf->y; i > 0; i--, rct_fl += 4) {
+		for (i = ((size_t)ibuf->x) * ibuf->y; i > 0; i--, rct_fl += 4) {
 			rgb_to_hsv_v(rct_fl, hsv);
 			hsv_to_rgb(hsv[0], hsv[1] * sat, hsv[2], rct_fl, rct_fl + 1, rct_fl + 2);
 		}