From 34e9cba51f5149da0670b32101e23b4d76e20d61 Mon Sep 17 00:00:00 2001
From: Hiltjo Posthuma <hiltjo@codemadness.org>
Date: Thu, 24 Mar 2016 19:17:48 +0100
Subject: add ff2jpg tool, convert farbfeld images to RGB JPEG

---
 ff2jpg.c | 151 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)
 create mode 100644 ff2jpg.c

(limited to 'ff2jpg.c')

diff --git a/ff2jpg.c b/ff2jpg.c
new file mode 100644
index 0000000..d489774
--- /dev/null
+++ b/ff2jpg.c
@@ -0,0 +1,151 @@
+/* See LICENSE file for copyright and license details. */
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <jpeglib.h>
+
+#include "arg.h"
+
+char *argv0;
+
+METHODDEF(void)
+jpeg_error(j_common_ptr js)
+{
+	fprintf(stderr, "%s: libjpeg: ", argv0);
+	(*js->err->output_message)(js);
+	exit(1);
+}
+
+static void
+usage(void)
+{
+	fprintf(stderr, "usage: %s [-b #rrggbb] [-o] [-q quality]\n", argv0);
+	exit(1);
+}
+
+int
+main(int argc, char *argv[])
+{
+	JSAMPROW row_pointer[1]; /* pointer to a single row */
+	struct jpeg_compress_struct cinfo;
+	struct jpeg_error_mgr jerr;
+	size_t rowlen;
+	uint64_t a;
+	uint32_t hdr[4], width, height, i, j, k, l;
+	uint16_t *row, mask[3] = { 0xffff, 0xffff, 0xffff };
+	uint8_t *rowout;
+	char *color, colfmt[] = "%#x%#x%#x";
+	unsigned int collen, col[3], colfac, quality = 85, optimize = 0;
+
+	argv0 = argv[0];
+	ARGBEGIN {
+	case 'b':
+		color = EARGF(usage());
+		if (color[0] == '#') {
+			color++;
+		}
+		collen = strlen(color);
+		if (collen != 3 && collen != 6 && collen != 12) {
+			usage();
+		}
+		colfmt[1] = colfmt[4] = colfmt[7] = ((collen / 3) + '0');
+		if (sscanf(color, colfmt, col, col + 1, col + 2) != 3) {
+			usage();
+		}
+		/* UINT16_MAX / 255 = 257; UINT16_MAX / 15 = 4369 */
+		colfac = (collen == 3) ? 4369 : (collen == 6) ? 257 : 1;
+		for (i = 0; i < 3; i++) {
+			mask[i] = col[i] * colfac;
+		}
+		break;
+	case 'o':
+		optimize = 1;
+		break;
+	case 'q':
+		if ((quality = atoi(EARGF(usage()))) > 100)
+			usage();
+		break;
+	default:
+		usage();
+	} ARGEND
+
+	if (argc)
+		usage();
+
+	/* header */
+	if (fread(hdr, sizeof(*hdr), 4, stdin) != 4) {
+		fprintf(stderr, "%s: fread: %s\n", argv0, strerror(errno));
+		return 1;
+	}
+	if (memcmp("farbfeld", hdr, sizeof("farbfeld") - 1)) {
+		fprintf(stderr, "%s: invalid magic value\n", argv0);
+		return 1;
+	}
+	if (!(width = ntohl(hdr[2]))) {
+		fprintf(stderr, "%s: invalid width: zero\n", argv0);
+		return 1;
+	}
+	if (!(height = ntohl(hdr[3]))) {
+		fprintf(stderr, "%s: invalid height: zero\n", argv0);
+		return 1;
+	}
+
+	if (width > SIZE_MAX / ((sizeof("RGBA") - 1) * sizeof(uint16_t))) {
+		fprintf(stderr, "%s: row length integer overflow\n", argv0);
+		return 1;
+	}
+	rowlen = width * (sizeof("RGBA") - 1);
+	if (!(row = malloc(rowlen * sizeof(uint16_t)))) {
+		fprintf(stderr, "%s: malloc: %s\n", argv0, strerror(errno));
+		return 1;
+	}
+	if (!(rowout = malloc(width * (sizeof("RGB") - 1) * sizeof(uint8_t)))) {
+		fprintf(stderr, "%s: malloc: %s\n", argv0, strerror(errno));
+		return 1;
+	}
+	row_pointer[0] = rowout;
+
+	jerr.error_exit = jpeg_error;
+
+	jpeg_create_compress(&cinfo);
+	cinfo.err = jpeg_std_error(&jerr);
+	jpeg_stdio_dest(&cinfo, stdout);
+	cinfo.image_width = width;
+	cinfo.image_height = height;
+	cinfo.input_components = 3;  /* color components per pixel */
+	cinfo.in_color_space = JCS_RGB; /* output color space */
+	jpeg_set_defaults(&cinfo);
+	if (optimize)
+		cinfo.optimize_coding = TRUE;
+	jpeg_set_quality(&cinfo, quality, TRUE);
+
+	jpeg_start_compress(&cinfo, TRUE);
+
+	/* write rows */
+	for (i = 0; i < height; ++i) {
+		if (fread(row, sizeof(uint16_t), rowlen, stdin) != rowlen) {
+			fprintf(stderr, "%s: fread: %s\n", argv0, strerror(errno));
+			return 1;
+		}
+		for (j = 0, k = 0; j < rowlen; j += 4, k += 3) {
+			a = ntohs(row[j + 3]);
+			for (l = 0; l < 3; l++) {
+				rowout[k + l] = (a * ntohs(row[j + l]) +
+				                 (65535 - a) * mask[l]) /
+				                (257 * 65535);
+			}
+		}
+		jpeg_write_scanlines(&cinfo, row_pointer, 1);
+	}
+
+	jpeg_finish_compress(&cinfo);
+	jpeg_destroy_compress(&cinfo);
+
+	return 0;
+}
-- 
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