wrlib: Renamed image format related files for clarity

This patch makes all files appear together when listing files and
it is more clear about their function.

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>

wrlib/load_jpeg.c

@@ -0,0 +1,190 @@
+/* jpeg.c - load JPEG image from file
+ *
+ * Raster graphics library
+ *
+ * Copyright (c) 1997-2003 Alfredo K. Kojima
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Library General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2 of the License, or (at your option) any later version.
+ *
+ *  This library 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
+ *  Library General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Library General Public
+ *  License along with this library; if not, write to the Free
+ *  Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ *  MA 02110-1301, USA.
+ */
+
+#include <config.h>
+
+/* Avoid a compiler warning */
+#undef HAVE_STDLIB_H
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <jpeglib.h>
+
+#include "wraster.h"
+#include "imgformat.h"
+
+/*
+ * <setjmp.h> is used for the optional error recovery mechanism shown in
+ * the second part of the example.
+ */
+
+#include <setjmp.h>
+
+/*
+ * ERROR HANDLING:
+ *
+ * The JPEG library's standard error handler (jerror.c) is divided into
+ * several "methods" which you can override individually.  This lets you
+ * adjust the behavior without duplicating a lot of code, which you might
+ * have to update with each future release.
+ *
+ * Our example here shows how to override the "error_exit" method so that
+ * control is returned to the library's caller when a fatal error occurs,
+ * rather than calling exit() as the standard error_exit method does.
+ *
+ * We use C's setjmp/longjmp facility to return control.  This means that the
+ * routine which calls the JPEG library must first execute a setjmp() call to
+ * establish the return point.  We want the replacement error_exit to do a
+ * longjmp().  But we need to make the setjmp buffer accessible to the
+ * error_exit routine.  To do this, we make a private extension of the
+ * standard JPEG error handler object.  (If we were using C++, we'd say we
+ * were making a subclass of the regular error handler.)
+ *
+ * Here's the extended error handler struct:
+ */
+
+struct my_error_mgr {
+	struct jpeg_error_mgr pub;	/* "public" fields */
+
+	jmp_buf setjmp_buffer;	/* for return to caller */
+};
+
+typedef struct my_error_mgr *my_error_ptr;
+
+/*
+ * Here's the routine that will replace the standard error_exit method:
+ */
+
+static void my_error_exit(j_common_ptr cinfo)
+{
+	/* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
+	my_error_ptr myerr = (my_error_ptr) cinfo->err;
+
+	/* Always display the message. */
+	/* We could postpone this until after returning, if we chose. */
+	(*cinfo->err->output_message) (cinfo);
+
+	/* Return control to the setjmp point */
+	longjmp(myerr->setjmp_buffer, 1);
+}
+
+RImage *RLoadJPEG(const char *file_name)
+{
+	RImage *image = NULL;
+	struct jpeg_decompress_struct cinfo;
+	int i;
+	unsigned char *ptr;
+	JSAMPROW buffer[1], bptr;
+	FILE *file;
+	/* We use our private extension JPEG error handler.
+	 * Note that this struct must live as long as the main JPEG parameter
+	 * struct, to avoid dangling-pointer problems.
+	 */
+	struct my_error_mgr jerr;
+
+	file = fopen(file_name, "rb");
+	if (!file) {
+		RErrorCode = RERR_OPEN;
+		return NULL;
+	}
+
+	cinfo.err = jpeg_std_error(&jerr.pub);
+	jerr.pub.error_exit = my_error_exit;
+	/* Establish the setjmp return context for my_error_exit to use. */
+	if (setjmp(jerr.setjmp_buffer)) {
+		/* If we get here, the JPEG code has signaled an error.
+		 * We need to clean up the JPEG object, close the input file, and return.
+		 */
+		jpeg_destroy_decompress(&cinfo);
+		fclose(file);
+		return NULL;
+	}
+
+	jpeg_create_decompress(&cinfo);
+
+	jpeg_stdio_src(&cinfo, file);
+
+	jpeg_read_header(&cinfo, TRUE);
+
+	if (cinfo.image_width < 1 || cinfo.image_height < 1) {
+		RErrorCode = RERR_BADIMAGEFILE;
+		goto bye;
+	}
+
+	bptr = buffer[0] = (JSAMPROW) malloc(cinfo.image_width * cinfo.num_components);
+	if (!buffer[0]) {
+		RErrorCode = RERR_NOMEMORY;
+		goto bye;
+	}
+
+	if (cinfo.jpeg_color_space == JCS_GRAYSCALE) {
+		cinfo.out_color_space = JCS_GRAYSCALE;
+	} else
+		cinfo.out_color_space = JCS_RGB;
+	cinfo.quantize_colors = FALSE;
+	cinfo.do_fancy_upsampling = FALSE;
+	cinfo.do_block_smoothing = FALSE;
+	jpeg_calc_output_dimensions(&cinfo);
+
+	image = RCreateImage(cinfo.image_width, cinfo.image_height, False);
+
+	if (!image) {
+		RErrorCode = RERR_NOMEMORY;
+		goto bye;
+	}
+	jpeg_start_decompress(&cinfo);
+
+	ptr = image->data;
+
+	if (cinfo.out_color_space == JCS_RGB) {
+		while (cinfo.output_scanline < cinfo.output_height) {
+			jpeg_read_scanlines(&cinfo, buffer, (JDIMENSION) 1);
+			bptr = buffer[0];
+			memcpy(ptr, bptr, cinfo.image_width * 3);
+			ptr += cinfo.image_width * 3;
+		}
+	} else {
+		while (cinfo.output_scanline < cinfo.output_height) {
+			jpeg_read_scanlines(&cinfo, buffer, (JDIMENSION) 1);
+			bptr = buffer[0];
+			for (i = 0; i < cinfo.image_width; i++) {
+				*ptr++ = *bptr;
+				*ptr++ = *bptr;
+				*ptr++ = *bptr++;
+			}
+		}
+	}
+
+	jpeg_finish_decompress(&cinfo);
+
+ bye:
+	jpeg_destroy_decompress(&cinfo);
+
+	fclose(file);
+
+	if (buffer[0])
+		free(buffer[0]);
+
+	return image;
+}