1 files changed, 114 insertions, 0 deletions
diff --git a/.repos/farbfeld/ff2jpg.c b/.repos/farbfeld/ff2jpg.c
new file mode 100644
index 0000000..f4514b8
--- /dev/null
+++ b/.repos/farbfeld/ff2jpg.c
@@ -0,0 +1,114 @@
+/* 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"
+#include "util.h"
+
+static void
+jpeg_error(j_common_ptr js)
+{
+	fprintf(stderr, "%s: libjpeg: ", argv0);
+	(*js->err->output_message)(js);
+	exit(1);
+}
+
+static void
+jpeg_setup_writer(struct jpeg_compress_struct *s, struct jpeg_error_mgr *e,
+                  uint32_t w, uint32_t h, int quality, int opt)
+{
+	jpeg_create_compress(s);
+	e->error_exit = jpeg_error;
+	s->err = jpeg_std_error(e);
+
+	jpeg_stdio_dest(s, stdout);
+	s->image_width = w;
+	s->image_height = h;
+	s->input_components = 3;     /* color components per pixel */
+	s->in_color_space = JCS_RGB; /* output color space */
+	jpeg_set_defaults(s);
+
+	if (opt) {
+		s->optimize_coding = 1;
+	}
+	jpeg_set_quality(s, quality, 1);
+
+	jpeg_start_compress(s, 1);
+}
+
+static void
+usage(void)
+{
+	die("usage: %s [-b colour] [-o] [-q quality]", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	struct jpeg_compress_struct jcomp;
+	struct jpeg_error_mgr jerr;
+	size_t rowlen;
+	uint64_t a;
+	uint32_t width, height, i, j, k, l;
+	uint16_t *row, mask[3] = { 0xffff, 0xffff, 0xffff };
+	uint8_t *rowout;
+	int optimize = 0, quality = 85;
+
+	/* arguments */
+	ARGBEGIN {
+	case 'b':
+		if (parse_mask(EARGF(usage()), mask)) {
+			usage();
+		}
+		break;
+	case 'o':
+		optimize = 1;
+		break;
+	case 'q':
+		quality = estrtonum(EARGF(usage()), 0, 100);
+		break;
+	default:
+		usage();
+	} ARGEND
+
+	if (argc) {
+		usage();
+	}
+
+	/* prepare */
+	ff_read_header(&width, &height);
+	jpeg_setup_writer(&jcomp, &jerr, width, height, quality, optimize);
+	row = ereallocarray(NULL, width, (sizeof("RGBA") - 1) * sizeof(uint16_t));
+	rowlen = width * (sizeof("RGBA") - 1);
+	rowout = ereallocarray(NULL, width, (sizeof("RGB") - 1) * sizeof(uint8_t));
+
+	/* write data */
+	for (i = 0; i < height; ++i) {
+		efread(row, sizeof(uint16_t), rowlen, stdin);
+		for (j = 0, k = 0; j < rowlen; j += 4, k += 3) {
+			a = ntohs(row[j + 3]);
+			for (l = 0; l < 3; l++) {
+				/* alpha blending and 8-bit-reduction */
+				rowout[k + l] = (a * ntohs(row[j + l]) +
+				                 (UINT16_MAX - a) * mask[l]) /
+				                (UINT16_MAX *
+						 (UINT16_MAX / UINT8_MAX));
+			}
+		}
+		jpeg_write_scanlines(&jcomp, &rowout, 1);
+	}
+
+	/* clean up */
+	jpeg_finish_compress(&jcomp);
+	jpeg_destroy_compress(&jcomp);
+
+	return fshut(stdout, "<stdout>");
+}