1 files changed, 131 insertions, 0 deletions
diff --git a/xps/xps_jpeg.c b/xps/xps_jpeg.c
new file mode 100644
index 00000000..a8ea40f5
--- /dev/null
+++ b/xps/xps_jpeg.c
@@ -0,0 +1,131 @@
+#include "fitz.h"
+#include "muxps.h"
+
+#include <jpeglib.h>
+#include <setjmp.h>
+
+struct jpeg_error_mgr_jmp
+{
+	struct jpeg_error_mgr super;
+	jmp_buf env;
+	char msg[JMSG_LENGTH_MAX];
+};
+
+static void error_exit(j_common_ptr cinfo)
+{
+	struct jpeg_error_mgr_jmp *err = (struct jpeg_error_mgr_jmp *)cinfo->err;
+	cinfo->err->format_message(cinfo, err->msg);
+	longjmp(err->env, 1);
+}
+
+static void init_source(j_decompress_ptr cinfo)
+{
+	/* nothing to do */
+}
+
+static void term_source(j_decompress_ptr cinfo)
+{
+	/* nothing to do */
+}
+
+static boolean fill_input_buffer(j_decompress_ptr cinfo)
+{
+	static unsigned char eoi[2] = { 0xFF, JPEG_EOI };
+	struct jpeg_source_mgr *src = cinfo->src;
+	src->next_input_byte = eoi;
+	src->bytes_in_buffer = 2;
+	return 1;
+}
+
+static void skip_input_data(j_decompress_ptr cinfo, long num_bytes)
+{
+	struct jpeg_source_mgr *src = cinfo->src;
+	if (num_bytes > 0)
+	{
+		src->next_input_byte += num_bytes;
+		src->bytes_in_buffer -= num_bytes;
+	}
+}
+
+int
+xps_decode_jpeg(fz_pixmap **imagep, byte *rbuf, int rlen)
+{
+	struct jpeg_decompress_struct cinfo;
+	struct jpeg_error_mgr_jmp err;
+	struct jpeg_source_mgr src;
+	unsigned char *row[1], *sp, *dp;
+	fz_colorspace *colorspace;
+	int x, k;
+
+	fz_pixmap *image = NULL;
+
+	if (setjmp(err.env))
+	{
+		if (image)
+			fz_droppixmap(image);
+		return fz_throw("jpeg error: %s", err.msg);
+	}
+
+	cinfo.err = jpeg_std_error(&err.super);
+	err.super.error_exit = error_exit;
+
+	jpeg_create_decompress(&cinfo);
+
+	cinfo.src = &src;
+	src.init_source = init_source;
+	src.fill_input_buffer = fill_input_buffer;
+	src.skip_input_data = skip_input_data;
+	src.resync_to_restart = jpeg_resync_to_restart;
+	src.term_source = term_source;
+	src.next_input_byte = rbuf;
+	src.bytes_in_buffer = rlen;
+
+	jpeg_read_header(&cinfo, 1);
+
+	jpeg_start_decompress(&cinfo);
+
+	if (cinfo.output_components == 1)
+		colorspace = fz_devicegray;
+	else if (cinfo.output_components == 3)
+		colorspace = fz_devicergb;
+	else if (cinfo.output_components == 4)
+		colorspace = fz_devicecmyk;
+	else
+		return fz_throw("bad number of components in jpeg: %d", cinfo.output_components);
+
+	image = fz_newpixmap(colorspace, 0, 0, cinfo.output_width, cinfo.output_height);
+
+	if (cinfo.density_unit == 1)
+	{
+		image->xres = cinfo.X_density;
+		image->yres = cinfo.Y_density;
+	}
+	else if (cinfo.density_unit == 2)
+	{
+		image->xres = cinfo.X_density * 2.54;
+		image->yres = cinfo.Y_density * 2.54;
+	}
+
+	fz_clearpixmap(image);
+
+	row[0] = fz_malloc(cinfo.output_components * cinfo.output_width);
+	dp = image->samples;
+	while (cinfo.output_scanline < cinfo.output_height)
+	{
+		jpeg_read_scanlines(&cinfo, row, 1);
+		sp = row[0];
+		for (x = 0; x < cinfo.output_width; x++)
+		{
+			for (k = 0; k < cinfo.output_components; k++)
+				*dp++ = *sp++;
+			*dp++ = 255;
+		}
+	}
+	fz_free(row[0]);
+
+	jpeg_finish_decompress(&cinfo);
+	jpeg_destroy_decompress(&cinfo);
+
+	*imagep = image;
+	return fz_okay;
+}