introduce a new example "downscaler", no real stuff for the moment

examples/Makefile.am

@@ -58,7 +58,7 @@ SPU_CC ?= spu-gcc
 SPU_LD ?= spu-ld
 
 SPULDFLAGS = 
-SPULIBS = -lblas
+SPULIBS = -lblas #-lc -lgloss -lc
 
 .c.spuo:
 	$(SPU_CC) -c -fpic $< -o $@
@@ -102,6 +102,16 @@ examplebin_PROGRAMS +=				\
 basic_examples_hello_world_SOURCES =		\
 	basic-examples/hello-world.c
 
+###################
+# PPM downscaling #
+###################
+
+examplebin_PROGRAMS +=				\
+	ppm-downscaler/ppm-downscaler
+
+ppm_downscaler_ppm_downscaler_SOURCES =		\
+	ppm-downscaler/ppm-downscaler.c
+
 ################
 # Mult example #
 ################

examples/ppm-downscaler/ppm-downscaler.c

@@ -0,0 +1,165 @@
+/*
+ * StarPU
+ * Copyright (C) INRIA 2008-2009 (see AUTHORS file)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * See the GNU Lesser General Public License in COPYING.LGPL for more details.
+ */
+
+#include "ppm-downscaler.h"
+
+#include <starpu.h>
+
+#include <malloc.h>
+#include <assert.h>
+#include <stdio.h>
+
+struct ppm_image *allocate_new_ppm(int ncols, int nlines, int coldepth)
+{
+	struct ppm_image *ppm = malloc(sizeof(struct ppm_image));
+	assert(ppm);
+
+	ppm->ncols = ncols;
+	ppm->nlines = nlines;
+	ppm->coldepth = coldepth;
+
+	ppm->data = memalign(16384, ncols*nlines*sizeof(struct ppm_color));
+	assert(ppm->data);
+
+	return ppm;
+}
+
+struct ppm_image *file_to_ppm(char *filename)
+{
+	int ret;
+
+	struct ppm_image *ppm = malloc(sizeof(struct ppm_image));
+	assert(ppm);
+	
+	FILE *file = fopen(filename, "r");
+
+	/* read the file's dimensions */
+	ret = fscanf(file, "P6\n%d %d\n%d\n", &ppm->ncols, &ppm->nlines, &ppm->coldepth);
+	if (ret != 3) {
+		fclose(file);
+		fprintf(stderr, "file %s is not valid\n", filename);
+		exit(-1);
+	}
+	
+	/* allocate a buffer for the image */
+	ppm->data = memalign(16384, ppm->ncols*ppm->nlines*sizeof(struct ppm_color));
+	assert(ppm->data);
+
+	fread(ppm->data, sizeof(struct ppm_color), ppm->ncols*ppm->nlines, file);
+
+	unsigned i;
+	for (i = 0; i < ppm->ncols*ppm->nlines; i++)
+	{
+//		fprintf(stderr, "READ (index %d) -> r %d g %d b %d\n", i, ppm->data[i].r, ppm->data[i].g, ppm->data[i].b);
+	}
+
+	fclose(file);
+
+	return ppm;
+}
+
+void ppm_to_file(struct ppm_image *ppm, char *filename)
+{
+	FILE *file = fopen(filename, "w+");
+	assert(file);
+
+	/* read the file's dimensions */
+	fprintf(file, "P6\n%d %d\n%d\n", ppm->ncols, ppm->nlines, ppm->coldepth);
+
+	fwrite(&ppm->data[0], sizeof(struct ppm_color), ppm->ncols*ppm->nlines, file);
+	
+	fclose(file);
+}
+
+
+
+char *filename_in = "serpents.ppm";
+char *filename_out = "serpents.small.ppm";
+
+void parse_args(int argc, char **argv)
+{
+	if (argc == 3) {
+		filename_in = argv[1];
+		filename_out = argv[2];
+	}
+}
+
+/* what is the downscaling factor ? */
+#define FACTOR	2
+
+void dummy_downscale(struct ppm_image *input_ppm, struct ppm_image *output_ppm)
+{
+	struct ppm_color *in = input_ppm->data;
+	struct ppm_color *out = output_ppm->data;
+
+	unsigned line, col;
+	for (line = 0; line < output_ppm->nlines; line++)
+	{
+		for (col = 0; col < output_ppm->ncols; col++)
+		{
+			unsigned sum_r = 0, sum_g = 0, sum_b = 0;
+
+			unsigned big_col = col*FACTOR;
+			unsigned big_line = line*FACTOR;
+			
+			/* compute the average value of all components */
+			unsigned i, j;
+			for (i = 0; i < FACTOR; i++)
+			{
+				for (j = 0; j < FACTOR; j++)
+				{
+					unsigned index = (big_col + i)+(big_line + j)*input_ppm->ncols;
+
+//					fprintf(stderr, "(col %d, line %d) i %d j %d index %d -> r %d g %d b %d\n", col, line, i, j, index, in[index].r, in[index].g, in[index].b);
+
+					sum_r += (unsigned)in[index].r;
+					sum_g += (unsigned)in[index].g;
+					sum_b += (unsigned)in[index].b;
+				}
+			}
+
+			out[col + line*output_ppm->ncols].r = (unsigned char)(sum_r/(FACTOR*FACTOR));
+			out[col + line*output_ppm->ncols].g = (unsigned char)(sum_g/(FACTOR*FACTOR));
+			out[col + line*output_ppm->ncols].b = (unsigned char)(sum_b/(FACTOR*FACTOR));
+
+//			fprintf(stderr, "col %d line %d -> sum_r = %d out -> %d\n", col, line, sum_r, out[col + line*FACTOR].r);
+	
+		}
+	}
+}
+
+int main(int argc, char **argv)
+{
+	struct ppm_image *input_ppm, *output_ppm;
+
+	parse_args(argc, argv);
+
+	input_ppm = file_to_ppm(filename_in);
+
+	fprintf(stderr, "Read input ppm file : ncols = %d, nlines = %d, coldept = %d\n",
+		input_ppm->nlines, input_ppm->ncols, input_ppm->coldepth);
+
+	assert(input_ppm->nlines % FACTOR == 0);
+	assert(input_ppm->ncols % FACTOR == 0);
+
+	output_ppm = allocate_new_ppm(input_ppm->ncols/FACTOR, input_ppm->nlines/FACTOR, input_ppm->coldepth);
+
+	dummy_downscale(input_ppm, output_ppm);
+
+	ppm_to_file(output_ppm, filename_out);
+
+	return 0;
+}

examples/ppm-downscaler/ppm-downscaler.h

@@ -0,0 +1,29 @@
+/*
+ * StarPU
+ * Copyright (C) INRIA 2008-2009 (see AUTHORS file)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * See the GNU Lesser General Public License in COPYING.LGPL for more details.
+ */
+
+/* we make the asumption that there are 256 color levels at most */
+struct ppm_color {
+	unsigned char r;
+	unsigned char g;
+	unsigned char b;
+};
+
+struct ppm_image {
+	int nlines;
+	int ncols;
+	int coldepth;
+	struct ppm_color *data;
+};