Add blind-compress and blind-decompress

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 64 insertions, 0 deletions

diff --git a/src/blind-decompress.c b/src/blind-decompress.c
new file mode 100644
index 0000000..ea24fc6
--- /dev/null
+++ b/src/blind-decompress.c
@@ -0,0 +1,64 @@
+/* See LICENSE file for copyright and license details. */
+#include "stream.h"
+#include "util.h"
+
+#include <string.h>
+#include <unistd.h>
+
+USAGE("")
+
+int
+main(int argc, char *argv[])
+{
+	struct stream stream;
+	char *buf;
+	size_t n, m, fptr, sptr, same = 0, diff = 0;
+
+	ENOFLAGS(argc);
+
+	stream.file = "<stdin>";
+	stream.fd = STDIN_FILENO;
+	einit_stream(&stream);
+	fprint_stream_head(stdout, &stream);
+	efflush(stdout, "<stdout>");
+
+	echeck_frame_size(stream.width, stream.height, stream.pixel_size, 0, "<stdin>");
+	n = stream.width * stream.height * stream.pixel_size;
+	buf = ecalloc(1, n);
+
+	fptr = 0;
+	do {
+		sptr = 0;
+	again:
+		while (same) {
+			m = same < n - fptr ? same : n - fptr;
+			ewriteall(STDOUT_FILENO, buf + fptr, m, "<stdout>");
+			fptr = (fptr + m) % n;
+			same -= m;
+		}
+
+		while (diff && sptr < stream.ptr) {
+			m = diff < n - fptr ? diff : n - fptr;
+			m = m < stream.ptr - sptr ? m : stream.ptr - sptr;
+			memcpy(buf + fptr, stream.buf + sptr, m);
+			ewriteall(STDOUT_FILENO, buf + fptr, m, "<stdout>");
+			fptr = (fptr + m) % n;
+			diff -= m;
+			sptr += m;
+		}
+
+		if (diff || sptr + 2 * sizeof(size_t) > stream.ptr) {
+			memmove(stream.buf, stream.buf + sptr, stream.ptr -= sptr);
+		} else {
+			same = ((size_t *)(stream.buf + sptr))[0];
+			diff = ((size_t *)(stream.buf + sptr))[1];
+			sptr += 2 * sizeof(size_t);
+			goto again;
+		}
+	} while (eread_stream(&stream, SIZE_MAX));
+
+	free(buf);
+	if (same || diff)
+		eprintf("<stdin>: corrupt input\n");
+	return 0;
+}