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	Refactor jpg2ff - farbfeld - suckless image format with conversion tools
	git clone git://git.suckless.org/farbfeld
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	---
	commit ff5bbfae5214d8291c8eb93670233909ded5b722
	parent 98dbe21bcb83fead026c295329ad2a55d8eff1b5
	Author: FRIGN <[email protected]>
	Date: Wed, 6 Jan 2016 12:30:17 +0100

	Refactor jpg2ff

	Remove some kitchen sink comments (the jpg boilerplate is already
	horrible enough) and flush the output buffer manually to detect write
	errors.
	Also improve error reporting.

	Diffstat:
	M jpg2ff.c \| 74 +++++++++++++++--------------…

	1 file changed, 36 insertions(+), 38 deletions(-)
	---
	diff --git a/jpg2ff.c b/jpg2ff.c
	@@ -1,34 +1,22 @@
	/* See LICENSE file for copyright and license details. */
	#include <arpa/inet.h>
	+
	#include <errno.h>
	#include <stdint.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	-
	#include <setjmp.h>
	-#include <jpeglib.h>

	-char *argv0;
	-
	-static jmp_buf setjmp_buffer;
	+#include <jpeglib.h>

	-static void
	-usage(void)
	-{
	- fprintf(stderr, "usage: %s\n", argv0);
	- exit(1);
	-}
	+static jmp_buf error_jump;

	METHODDEF(void)
	-if_jpeg_error(j_common_ptr cinfo)
	+jpeg_error(j_common_ptr cinfo)
	{
	- /* 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(setjmp_buffer, 1);
	+ (*cinfo->err->output_message)(cinfo);
	+ longjmp(error_jump, 1);
	}

	int
	@@ -42,18 +30,16 @@ main(int argc, char *argv[])
	int ret = 1;
	JSAMPARRAY buffer; /* output row buffer */

	- argv0 = argv[0];
	- if (argc > 1)
	- usage();
	+ if (argc > 1) {
	+ fprintf(stderr, "usage: %s\n", argv[0]);
	+ return 1;
	+ }

	- /* load jpeg */
	+ /* load jpg */
	cinfo.err = jpeg_std_error(&jerr);

	- jerr.error_exit = if_jpeg_error;
	- /* Establish the setjmp return context for my_error_exit to use. */
	- if (setjmp(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, a…
	+ jerr.error_exit = jpeg_error;
	+ if (setjmp(error_jump)) {
	goto cleanup;
	}

	@@ -64,23 +50,23 @@ main(int argc, char *argv[])
	width = cinfo.image_width;
	height = cinfo.image_height;

	- /* change output for farbfeld */
	- cinfo.output_components = 3; /* # of color components per pixel */
	- cinfo.out_color_space = JCS_RGB; /* colorspace of input image */
	+ /* set output format */
	+ cinfo.output_components = 3; /* color components per pixel */
	+ cinfo.out_color_space = JCS_RGB; /* input color space */

	jpeg_start_decompress(&cinfo);
	jpeg_row_len = width * cinfo.output_components;

	- /* Make a one-row-high sample array that will go away when done with i…
	- buffer = (*cinfo.mem->alloc_sarray)
	- ((j_common_ptr) &cinfo, JPOOL_IMAGE, jpeg_row_len, 1);
	- ff_row_len = strlen("RRGGBBAA") * width;
	+ /* create output buffers */
	+ buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr)&cinfo,
	+ JPOOL_IMAGE, jpeg_row_len, 1);
	+ ff_row_len = strlen("RGBA") * sizeof(uint16_t) * width;
	if(!(ff_row = malloc(ff_row_len))) {
	- fprintf(stderr, "Can't malloc\n");
	+ fprintf(stderr, "%s: malloc: out of memory\n", argv[0]);
	return 1;
	}

	- /* write header with big endian width and height-values */
	+ /* write header */
	fprintf(stdout, "farbfeld");
	val_be = htonl(width);
	fwrite(&val_be, sizeof(uint32_t), 1, stdout);
	@@ -91,7 +77,7 @@ main(int argc, char *argv[])
	/* jpeg_read_scanlines expects an array of pointers to scanlin…
	* Here the array is only one element long, but you could ask …
	* more than one scanline at a time if that's more convenient.…
	- (void)jpeg_read_scanlines(&cinfo, buffer, 1);
	+ jpeg_read_scanlines(&cinfo, buffer, 1);

	for(i = 0, dx = 0, sx = 0; i < width; i++, sx += 3, dx += 4) {
	ff_row[dx] = htons(buffer[0][sx] * 257);
	@@ -102,13 +88,25 @@ main(int argc, char *argv[])

	/* write data */
	if (fwrite(ff_row, 1, ff_row_len, stdout) != ff_row_len) {
	- fprintf(stderr, "fwrite() failed\n");
	+ fprintf(stderr, "%s: fwrite: ");
	+ perror(NULL);
	goto cleanup;
	}
	}
	jpeg_finish_decompress(&cinfo);
	ret = 0;

	+ /* flush output */
	+ if (fflush(stdout)) {
	+ fprintf(stderr, "%s: fflush stdout: ", argv[0]);
	+ perror(NULL);
	+ ret = 1;
	+ }
	+ if (fclose(stdout) && !ret) {
	+ fprintf(stderr, "%s: fclose stdout: ", argv[0]);
	+ perror(NULL);
	+ ret = 1;
	+ }
	cleanup:
	free(ff_row);
	jpeg_destroy_decompress(&cinfo);