blind

commit 2741eab8fcbe01af3972557e2df6e765a9450093
parent 94de8e2bd18743949bbb82d9e8cac109da4a15f3
Author: Mattias Andrée <maandree@kth.se>
Date:   Mon,  8 May 2017 22:08:36 +0200

Improve performance and memory usage of blind-transpose

Signed-off-by: Mattias Andrée <maandree@kth.se>

Diffstat:
M
man/blind-transpose.1
 | 
5
+++--
M
src/blind-transpose.c
 | 
45
++++++++++++++++++++++++++++++---------------

2 files changed, 33 insertions(+), 17 deletions(-)
diff --git a/man/blind-transpose.1 b/man/blind-transpose.1
@@ -12,8 +12,9 @@ To transpose a videos means to swap the
 X and Y coordinates.
 .SH REQUIREMENTS
 .B blind-transpose
-requires enough free memory to load two full frames into
-memory. A frame requires 32 bytes per pixel it contains.
+requires enough free memory to load one full frames and
+one input column into memory. A frame requires 32 bytes
+per pixel it contains.
 .B blind-transpose
 has not been optimised for memory usage, but instead
 for code simplicity.
diff --git a/src/blind-transpose.c b/src/blind-transpose.c
@@ -9,12 +9,31 @@
 
 USAGE("")
 
+static size_t srcw, srch, srcwps, srchps, ps;
+
+#define PROCESS(TYPE)\
+	do {\
+		size_t x, i, n = ps / sizeof(TYPE);\
+		char *src, *img;\
+		for (x = 0; x < srchps; x += ps) {\
+			img = row + x;\
+			src = col + x * srcw;\
+			for (i = 0; i < n; i++)\
+				((TYPE *)img)[i] = ((TYPE *)src)[i];\
+		}\
+	} while (0)
+
+static void process_double(char *row, char *col) {PROCESS(double);}
+static void process_float (char *row, char *col) {PROCESS(float);}
+static void process_char  (char *row, char *col) {PROCESS(char);}
+
 int
 main(int argc, char *argv[])
 {
 	struct stream stream;
-	char *buf, *row, *pix, *image, *imag, *img;
-	size_t n, srcw, srch, srcwps, srchps, ps, x, y, i;
+	char *buf, *image;
+	size_t n, y;
+	void (*process)(char *col, char *row);
 
 	UNOFLAGS(argc);
 
@@ -27,23 +46,19 @@ main(int argc, char *argv[])
 
 	echeck_frame_size(stream.width, stream.height, stream.pixel_size, 0, stream.file);
 	n = stream.height * stream.width * (ps = stream.pixel_size);
-	buf   = emalloc(n);
-	image = emalloc(n);
-
 	srchps = srch * ps;
 	srcwps = srcw * ps;
+	buf   = emalloc(n);
+	image = emalloc(srchps);
+
+	process = !(ps % sizeof(double)) ? process_double :
+		  !(ps % sizeof(float))  ? process_float  : process_char;
+
 	while (eread_frame(&stream, buf, n)) {
-		for (y = 0; y < srchps; y += ps) {
-			imag = image + y;
-			row  = buf + y * srcw;
-			for (x = 0; x < srcwps; x += ps) {
-				img = imag + x * srch;
-				pix = row + x;
-				for (i = 0; i < ps; i++)
-					img[i] = pix[i];
-			}
+		for (y = 0; y < srcwps; y += ps) {
+			process(image, buf + y);
+			ewriteall(STDOUT_FILENO, image, srchps, "<stdout>");
 		}
-		ewriteall(STDOUT_FILENO, image, n, "<stdout>");
 	}
 
 	free(buf);