VIDEO: Minor updates to SVQ1 decoder, mainly return flags to bool.

Since the returned int values from the decoding functions are just
0 for good or -1 for error, have changed these into an errorFlag
bool. This improves readability and cleans up some of the error
checking code. In addition, have fixed some oversights in formatting
spacing for readability.

1 files changed, 75 insertions, 83 deletions

diff --git a/video/codecs/svq1.cpp b/video/codecs/svq1.cpp
index 72fb299d8c..9d2faaa243 100644
--- a/video/codecs/svq1.cpp
+++ b/video/codecs/svq1.cpp
@@ -297,8 +297,8 @@ const Graphics::Surface *SVQ1Decoder::decodeImage(Common::SeekableReadStream *st
 			byte *currentP = current[i];
 			for (uint16 y = 0; y < height; y += 16) {
 				for (uint16 x = 0; x < width; x += 16) {
-					if (int result = svq1DecodeBlockIntra(&frameData, &currentP[x], linesize) != 0) {
-						warning("Error in svq1DecodeBlock %i (keyframe)", result);
+					if (svq1DecodeBlockIntra(&frameData, &currentP[x], linesize)) {
+						warning("svq1DecodeBlockIntra decode failure");
 						return _surface;
 					}
 				}
@@ -320,8 +320,8 @@ const Graphics::Surface *SVQ1Decoder::decodeImage(Common::SeekableReadStream *st
 			byte *currentP = current[i];
 			for (uint16 y = 0; y < height; y += 16) {
 				for (uint16 x = 0; x < width; x += 16) {
-					if (int result = svq1DecodeDeltaBlock(&frameData, &currentP[x], previous, linesize, pmv, x, y) != 0) {
-						warning("Error in svq1DecodeDeltaBlock %i", result);
+					if (svq1DecodeDeltaBlock(&frameData, &currentP[x], previous, linesize, pmv, x, y)) {
+						warning("svq1DecodeDeltaBlock decode failure");
 						return _surface;
 					}
 				}
@@ -344,7 +344,7 @@ const Graphics::Surface *SVQ1Decoder::decodeImage(Common::SeekableReadStream *st
 	return _surface;
 }
 
-int SVQ1Decoder::svq1DecodeBlockIntra(Common::BitStream *s, uint8 *pixels, int pitch) {
+bool SVQ1Decoder::svq1DecodeBlockIntra(Common::BitStream *s, uint8 *pixels, int pitch) {
 	uint8 *list[63];
 	uint32 *dst;
 	int entries[6];
@@ -357,7 +357,7 @@ int SVQ1Decoder::svq1DecodeBlockIntra(Common::BitStream *s, uint8 *pixels, int p
 	list[0] = pixels;
 
 	// recursively process vector
-	for (i=0, m=1, n=1, level=5; i < n; i++) {
+	for (i = 0, m = 1, n = 1, level = 5; i < n; i++) {
 		// SVQ1_PROCESS_VECTOR()
 		for (; level > 0; i++) {
 			// process next depth
@@ -383,7 +383,7 @@ int SVQ1Decoder::svq1DecodeBlockIntra(Common::BitStream *s, uint8 *pixels, int p
 		stages = _intraMultistage[level]->getSymbol(*s) - 1;
 
 		if (stages == -1) {
-			for (y=0; y < height; y++) {
+			for (y = 0; y < height; y++) {
 				memset (&dst[y*(pitch / 4)], 0, width);
 			}
 		continue; // skip vector
@@ -391,13 +391,13 @@ int SVQ1Decoder::svq1DecodeBlockIntra(Common::BitStream *s, uint8 *pixels, int p
 
 		if ((stages > 0) && (level >= 4)) {
 			warning("Error (svq1_decode_block_intra): invalid vector: stages=%i level=%i", stages, level);
-		return -1; // invalid vector
+			return true; // error - invalid vector
 		}
 
 		mean = _intraMean->getSymbol(*s);
 
 		if (stages == 0) {
-			for (y=0; y < height; y++) {
+			for (y = 0; y < height; y++) {
 				memset (&dst[y*(pitch / 4)], mean, width);
 			}
 		} else {
@@ -405,15 +405,15 @@ int SVQ1Decoder::svq1DecodeBlockIntra(Common::BitStream *s, uint8 *pixels, int p
 			const uint32 *codebook = s_svq1IntraCodebooks[level];
 			uint32 bit_cache = s->getBits(4*stages);
 			// calculate codebook entries for this vector
-			for (j=0; j < stages; j++) {
+			for (j = 0; j < stages; j++) {
 				entries[j] = (((bit_cache >> (4*(stages - j - 1))) & 0xF) + 16*j) << (level + 1);
 			}
 			mean -= (stages * 128);
-			n4    = ((mean + (mean >> 31)) << 16) | (mean & 0xFFFF);
+			n4 = ((mean + (mean >> 31)) << 16) | (mean & 0xFFFF);
 
 			// SVQ1_DO_CODEBOOK_INTRA()
-			for (y=0; y < height; y++) {
-				for (x=0; x < (width / 4); x++, codebook++) {
+			for (y = 0; y < height; y++) {
+				for (x = 0; x < (width / 4); x++, codebook++) {
 					n1 = n4;
 					n2 = n4;
 					// SVQ1_ADD_CODEBOOK()
@@ -447,10 +447,10 @@ int SVQ1Decoder::svq1DecodeBlockIntra(Common::BitStream *s, uint8 *pixels, int p
 		}
 	}
 
-	return 0;
+	return false;
 }
 
-int SVQ1Decoder::svq1DecodeBlockNonIntra(Common::BitStream *s, uint8 *pixels, int pitch) {
+bool SVQ1Decoder::svq1DecodeBlockNonIntra(Common::BitStream *s, uint8 *pixels, int pitch) {
 	uint8 *list[63];
 	uint32 *dst;
 	int entries[6];
@@ -463,7 +463,7 @@ int SVQ1Decoder::svq1DecodeBlockNonIntra(Common::BitStream *s, uint8 *pixels, in
 	list[0] = pixels;
 
 	// recursively process vector
-	for (i=0, m=1, n=1, level=5; i < n; i++) {
+	for (i = 0, m = 1, n = 1, level = 5; i < n; i++) {
 		// SVQ1_PROCESS_VECTOR()
 		for (; level > 0; i++) {
 			// process next depth
@@ -492,7 +492,7 @@ int SVQ1Decoder::svq1DecodeBlockNonIntra(Common::BitStream *s, uint8 *pixels, in
 
 		if ((stages > 0) && (level >= 4)) {
 			warning("Error (svq1_decode_block_non_intra): invalid vector: stages=%i level=%i", stages, level);
-			return -1;        // invalid vector
+			return true; // error - invalid vector
 		}
 
 		mean = _interMean->getSymbol(*s) - 256;
@@ -508,8 +508,8 @@ int SVQ1Decoder::svq1DecodeBlockNonIntra(Common::BitStream *s, uint8 *pixels, in
 		n4 = ((mean + (mean >> 31)) << 16) | (mean & 0xFFFF);
 
 		// SVQ1_DO_CODEBOOK_NONINTRA()
-		for (y=0; y < height; y++) {
-			for (x=0; x < (width / 4); x++, codebook++) {
+		for (y = 0; y < height; y++) {
+			for (x = 0; x < (width / 4); x++, codebook++) {
 				n3 = dst[x];
 				// add mean value to vector
 				n1 = ((n3 & 0xFF00FF00) >> 8) + n4;
@@ -543,7 +543,7 @@ int SVQ1Decoder::svq1DecodeBlockNonIntra(Common::BitStream *s, uint8 *pixels, in
 			dst += (pitch / 4);
 		}
 	}
-	return 0;
+	return false;
 }
 
 // median of 3
@@ -562,14 +562,14 @@ static inline int mid_pred(int a, int b, int c) {
 	return b;
 }
 
-int SVQ1Decoder::svq1DecodeMotionVector(Common::BitStream *s, Common::Point *mv, Common::Point **pmv) {
-	for (int i=0; i < 2; i++) {
+bool SVQ1Decoder::svq1DecodeMotionVector(Common::BitStream *s, Common::Point *mv, Common::Point **pmv) {
+	for (int i = 0; i < 2; i++) {
 		// get motion code
 		int diff = _motionComponent->getSymbol(*s);
 		if (diff < 0)
-			return -1;
+			return true; // error - invalid motion code
 		else if (diff) {
-			if (s->getBit()) diff= -diff;
+			if (s->getBit()) diff = -diff;
 		}
 
 		// add median of motion vector predictors and clip result
@@ -579,7 +579,7 @@ int SVQ1Decoder::svq1DecodeMotionVector(Common::BitStream *s, Common::Point *mv,
 			mv->x = ((diff + mid_pred(pmv[0]->x, pmv[1]->x, pmv[2]->x)) << 26) >> 26;
 	}
 
-	return 0;
+	return false;
 }
 
 void SVQ1Decoder::svq1SkipBlock(uint8 *current, uint8 *previous, int pitch, int x, int y) {
@@ -680,14 +680,14 @@ static void put_pixels16_xy2_c(uint8 *block, const uint8 *pixels, int line_size,
 	put_pixels8_xy2_c(block+8, pixels+8, line_size, h);
 }
 
-int SVQ1Decoder::svq1MotionInterBlock(Common::BitStream *ss,
+bool SVQ1Decoder::svq1MotionInterBlock(Common::BitStream *ss,
                                 uint8 *current, uint8 *previous, int pitch,
                                 Common::Point *motion, int x, int y) {
 	uint8 *src;
 	uint8 *dst;
 	Common::Point mv;
 	Common::Point *pmv[3];
-	int result;
+	bool errorFlag;
 
 	// predict and decode motion vector
 	pmv[0] = &motion[0];
@@ -698,27 +698,22 @@ int SVQ1Decoder::svq1MotionInterBlock(Common::BitStream *ss,
 		pmv[2] = &motion[(x / 8) + 4];
 	}
 
-	result = svq1DecodeMotionVector(ss, &mv, pmv);
+	errorFlag = svq1DecodeMotionVector(ss, &mv, pmv);
+	if (errorFlag)
+		return true;
 
-	if (result != 0)
-		return result;
+	motion[0].x = motion[(x / 8) + 2].x = motion[(x / 8) + 3].x = mv.x;
+	motion[0].y = motion[(x / 8) + 2].y = motion[(x / 8) + 3].y = mv.y;
 
-	motion[0].x                =
-	motion[(x / 8) + 2].x      =
-	motion[(x / 8) + 3].x      = mv.x;
-	motion[0].y                =
-	motion[(x / 8) + 2].y      =
-	motion[(x / 8) + 3].y      = mv.y;
-
-	if(y + (mv.y >> 1)<0)
-		mv.y= 0;
-	if(x + (mv.x >> 1)<0)
-		mv.x= 0;
+	if(y + (mv.y >> 1) < 0)
+		mv.y = 0;
+	if(x + (mv.x >> 1) < 0)
+		mv.x = 0;
 
 #if 0
-	int w = (s->width+15)&~15;
-	int h = (s->height+15)&~15;
-	if(x + (mv.x >> 1)<0 || y + (mv.y >> 1)<0 || x + (mv.x >> 1) + 16 > w || y + (mv.y >> 1) + 16> h)
+	int w = (s->width + 15) & ~15;
+	int h = (s->height + 15) & ~15;
+	if(x + (mv.x >> 1) < 0 || y + (mv.y >> 1) < 0 || x + (mv.x >> 1) + 16 > w || y + (mv.y >> 1) + 16 > h)
 		debug(1, "%d %d %d %d", x, y, x + (mv.x >> 1), y + (mv.y >> 1));
 #endif
 
@@ -746,17 +741,17 @@ int SVQ1Decoder::svq1MotionInterBlock(Common::BitStream *ss,
 		break;
 	}
 
-	return 0;
+	return false;
 }
 
-int SVQ1Decoder::svq1MotionInter4vBlock(Common::BitStream *ss,
+bool SVQ1Decoder::svq1MotionInter4vBlock(Common::BitStream *ss,
                                   uint8 *current, uint8 *previous, int pitch,
                                   Common::Point *motion, int x, int y) {
 	uint8 *src;
 	uint8 *dst;
 	Common::Point mv;
 	Common::Point *pmv[4];
-	int i, result;
+	bool errorFlag;
 
 	// predict and decode motion vector (0)
 	pmv[0] = &motion[0];
@@ -767,10 +762,9 @@ int SVQ1Decoder::svq1MotionInter4vBlock(Common::BitStream *ss,
 		pmv[2] = &motion[(x / 8) + 4];
 	}
 
-	result = svq1DecodeMotionVector(ss, &mv, pmv);
-
-	if (result != 0)
-		return result;
+	errorFlag = svq1DecodeMotionVector(ss, &mv, pmv);
+	if (errorFlag)
+		return true;
 
 	// predict and decode motion vector (1)
 	pmv[0] = &mv;
@@ -779,44 +773,42 @@ int SVQ1Decoder::svq1MotionInter4vBlock(Common::BitStream *ss,
 	} else {
 		pmv[1] = &motion[(x / 8) + 3];
 	}
-	result = svq1DecodeMotionVector(ss, &motion[0], pmv);
 
-	if (result != 0)
-		return result;
+	errorFlag = svq1DecodeMotionVector(ss, &motion[0], pmv);
+	if (errorFlag)
+		return true;
 
 	// predict and decode motion vector (2)
 	pmv[1] = &motion[0];
 	pmv[2] = &motion[(x / 8) + 1];
 
-	result = svq1DecodeMotionVector(ss, &motion[(x / 8) + 2], pmv);
-
-	if (result != 0)
-		return result;
+	errorFlag = svq1DecodeMotionVector(ss, &motion[(x / 8) + 2], pmv);
+	if (errorFlag)
+		return true;
 
 	// predict and decode motion vector (3)
 	pmv[2] = &motion[(x / 8) + 2];
 	pmv[3] = &motion[(x / 8) + 3];
 
-	result = svq1DecodeMotionVector(ss, pmv[3], pmv);
-
-	if (result != 0)
-		return result;
+	errorFlag = svq1DecodeMotionVector(ss, pmv[3], pmv);
+	if (errorFlag)
+		return true;
 
 	// form predictions
-	for (i=0; i < 4; i++) {
-		int mvx = pmv[i]->x + (i&1)*16;
-		int mvy = pmv[i]->y + (i>>1)*16;
+	for (int i = 0; i < 4; i++) {
+		int mvx = pmv[i]->x + (i & 1)*16;
+		int mvy = pmv[i]->y + (i >> 1)*16;
 
 		///XXX /FIXME clipping or padding?
-		if(y + (mvy >> 1)<0)
+		if(y + (mvy >> 1) < 0)
 			mvy = 0;
-		if(x + (mvx >> 1)<0)
+		if(x + (mvx >> 1) < 0)
 			mvx = 0;
 
 #if 0
-		int w = (s->width+15)&~15;
-		int h = (s->height+15)&~15;
-		if(x + (mvx >> 1)<0 || y + (mvy >> 1)<0 || x + (mvx >> 1) + 8 > w || y + (mvy >> 1) + 8> h)
+		int w = (s->width + 15) & ~15;
+		int h = (s->height + 15) & ~15;
+		if(x + (mvx >> 1) < 0 || y + (mvy >> 1) < 0 || x + (mvx >> 1) + 8 > w || y + (mvy >> 1) + 8 > h)
 			debug(1, "%d %d %d %d", x, y, x + (mvx >> 1), y + (mvy >> 1));
 #endif
 		src = &previous[(x + (mvx >> 1)) + (y + (mvy >> 1))*pitch];
@@ -851,14 +843,14 @@ int SVQ1Decoder::svq1MotionInter4vBlock(Common::BitStream *ss,
 		}
 	}
 
-	return 0;
+	return false;
 }
 
-int SVQ1Decoder::svq1DecodeDeltaBlock(Common::BitStream *ss,
+bool SVQ1Decoder::svq1DecodeDeltaBlock(Common::BitStream *ss,
                         uint8 *current, uint8 *previous, int pitch,
                         Common::Point *motion, int x, int y) {
 	uint32 block_type;
-	int result = 0;
+	bool errorFlag = false;
 
 	// get block type
 	block_type = _blockType->getSymbol(*ss);
@@ -879,29 +871,29 @@ int SVQ1Decoder::svq1DecodeDeltaBlock(Common::BitStream *ss,
 		break;
 
 	case SVQ1_BLOCK_INTER:
-		result = svq1MotionInterBlock(ss, current, previous, pitch, motion, x, y);
-		if (result != 0) {
-			warning("Error in svq1MotionInterBlock %i", result);
+		errorFlag = svq1MotionInterBlock(ss, current, previous, pitch, motion, x, y);
+		if (errorFlag) {
+			warning("svq1MotionInterBlock decode failure");
 			break;
 		}
-		result = svq1DecodeBlockNonIntra(ss, current, pitch);
+		errorFlag = svq1DecodeBlockNonIntra(ss, current, pitch);
 		break;
 
 	case SVQ1_BLOCK_INTER_4V:
-		result = svq1MotionInter4vBlock(ss, current, previous, pitch, motion, x, y);
-		if (result != 0) {
-			warning("Error in svq1MotionInter4vBlock %i", result);
+		errorFlag = svq1MotionInter4vBlock(ss, current, previous, pitch, motion, x, y);
+		if (errorFlag) {
+			warning("svq1MotionInter4vBlock decode failure");
 			break;
 		}
-		result = svq1DecodeBlockNonIntra(ss, current, pitch);
+		errorFlag = svq1DecodeBlockNonIntra(ss, current, pitch);
 		break;
 
 	case SVQ1_BLOCK_INTRA:
-		result = svq1DecodeBlockIntra(ss, current, pitch);
+		errorFlag = svq1DecodeBlockIntra(ss, current, pitch);
 		break;
 	}
 
-	return result;
+	return errorFlag;
 }
 
 } // End of namespace Video