From: Antonio Ospite <ospite@studenti.unina.it>
Date: Sat, 23 Mar 2013 18:58:29 +0000 (+0100)
Subject: Initial import
X-Git-Url: https://git.ao2.it/experiments/libjpeg8.git/commitdiff_plain/HEAD

Initial import
---

54800635387fbe226255359e3a78e2884deb162d
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..38c11ad
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+*.o
+*.jpg
+libjpeg8-mem-dest
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..5307b1e
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,39 @@
+CFLAGS = -std=c99 -pedantic -pedantic-errors -Wall -g3 -O2 -D_ANSI_SOURCE_
+CFLAGS += -fno-common \
+	  -Wall \
+	  -Wdeclaration-after-statement \
+	  -Wextra \
+	  -Wformat=2 \
+	  -Winit-self \
+	  -Winline \
+	  -Wpacked \
+	  -Wp,-D_FORTIFY_SOURCE=2 \
+	  -Wpointer-arith \
+	  -Wlarger-than-65500 \
+	  -Wmissing-declarations \
+	  -Wmissing-format-attribute \
+	  -Wmissing-noreturn \
+	  -Wmissing-prototypes \
+	  -Wnested-externs \
+	  -Wold-style-definition \
+	  -Wredundant-decls \
+	  -Wsign-compare \
+	  -Wstrict-aliasing=2 \
+	  -Wstrict-prototypes \
+	  -Wswitch-enum \
+	  -Wundef \
+	  -Wunreachable-code \
+	  -Wunsafe-loop-optimizations \
+	  -Wunused-but-set-variable \
+	  -Wwrite-strings
+
+
+LDLIBS += -ljpeg
+
+libjpeg8-mem-dest: libjpeg8-mem-dest.o
+
+clean:
+	rm -rf *~ *.o *.jpg libjpeg8-mem-dest
+
+test:
+	valgrind --leak-check=full --show-reachable=yes ./libjpeg8-mem-dest
diff --git a/libjpeg8-mem-dest.c b/libjpeg8-mem-dest.c
new file mode 100644
index 0000000..95e1c36
--- /dev/null
+++ b/libjpeg8-mem-dest.c
@@ -0,0 +1,127 @@
+/*
+ * libjpeg8-mem-dest - an example about reusing the memory buffer with libjpeg8
+ *
+ * Copyright (C) 2013  Antonio Ospite <ospite@studenti.unina.it>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <jpeglib.h>
+
+#define WIDTH 800
+#define HEIGHT 480
+
+static unsigned char *new_image(void)
+{
+	unsigned char *image;
+	int i;
+
+	image = malloc(WIDTH * HEIGHT * 3 * sizeof(*image));
+	if (image == NULL) {
+		perror("malloc");
+		exit(EXIT_FAILURE);
+	}
+
+	for (i = 0; i < WIDTH * HEIGHT * 3; i++)
+		image[i] = rand() % 0xff;
+
+	return image;
+}
+
+int main(void)
+{
+	int i;
+	struct jpeg_compress_struct cinfo;
+	struct jpeg_error_mgr jerr;
+	JSAMPROW row_pointer[1];
+	int row_stride;
+
+	unsigned char *out_buf;
+	unsigned long out_buf_size;
+
+	unsigned char *input_image;
+
+	cinfo.err = jpeg_std_error(&jerr);
+	jpeg_create_compress(&cinfo);
+
+	out_buf = NULL;
+	out_buf_size = 0;
+	jpeg_mem_dest(&cinfo, &out_buf, &out_buf_size);
+
+	cinfo.image_width = WIDTH;
+	cinfo.image_height = HEIGHT;
+	cinfo.input_components = 3;
+	cinfo.in_color_space = JCS_RGB;
+
+	jpeg_set_defaults(&cinfo);
+	jpeg_set_quality(&cinfo, 80, TRUE);
+
+	row_stride = WIDTH * 3;
+
+	srand(time(NULL));
+
+	i = 0;
+	while(i++ < 10) {
+		input_image = new_image();
+
+		jpeg_start_compress(&cinfo, TRUE);
+		while(cinfo.next_scanline < cinfo.image_height) {
+			row_pointer[0] = &input_image[cinfo.next_scanline * row_stride];
+			(void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
+		}
+		jpeg_finish_compress(&cinfo);
+
+		free(input_image);
+
+		/* Is out_buf_size the number of bytes of the jpeg image, or the
+		 * size of the allocated buffer? */
+		fprintf(stderr, "out_buf: %p out_buf_size: %ld\n", out_buf, out_buf_size);
+		{
+			char filename[256] = { 0 };
+			FILE *out_file;
+
+			snprintf(filename, sizeof(filename), "out%03d.jpg", i);
+			out_file = fopen(filename, "wb");
+			fwrite(out_buf, out_buf_size, 1, out_file);
+			fclose(out_file);
+		}
+
+#if 1
+		/*
+		 * Rewind the buffer, taken from:
+		 * http://sourceforge.net/p/libjpeg-turbo/discussion/1086868/thread/b797ffaf/
+		 */
+		cinfo.dest->free_in_buffer += cinfo.dest->next_output_byte - out_buf;
+		cinfo.dest->next_output_byte = out_buf;
+#else
+		/* The code above avoids freeing and allocating a NEW buffer
+		 * Isn't there a more straightforward way to recycle the old
+		 * buffer after we consumed its content?
+		 */
+		free(out_buf);
+		out_buf = NULL;
+		out_buf_size = 0;
+		jpeg_mem_dest(&cinfo, &out_buf, &out_buf_size);
+#endif
+	}
+
+	jpeg_destroy_compress(&cinfo);
+
+	free(out_buf);
+
+	return 0;
+}