Initial import

diff --git a/.gitignore b/.gitignore
new file mode 100644 (file)
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--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+*.o
+*.jpg
+libjpeg8-mem-dest

diff --git a/Makefile b/Makefile
new file mode 100644 (file)
index 0000000..5307b1e
--- /dev/null
+++ b/Makefile
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+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 (file)
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;
+}