1 files changed, 51 insertions, 0 deletions
diff --git a/uncompress.c b/uncompress.c
new file mode 100644
index 0000000..3ef83ec
--- /dev/null
+++ b/uncompress.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
+#include <stdio.h>
+#include <stdint.h>
+
+int main() {
+	FILE *in = stdin;
+	FILE *out = stdout;
+
+	int c;
+	uint8_t out_i = 0;
+	char outbuf[256];
+	while(1) {
+		c = fgetc_unlocked(in);
+		if(c < 0) goto end;
+		uint8_t cmd = c;
+		for(size_t i = 0; i < 8; i++) {
+			if(cmd & 1) {
+				c = fgetc_unlocked(in);
+				if(c < 0) goto fail;
+				uint8_t offset = c;
+				offset += 1;
+				c = fgetc_unlocked(in);
+				if(c < 0) goto fail;
+				uint8_t len = c;
+				do {
+					c = outbuf[(uint8_t)(out_i - offset)];
+					outbuf[out_i++] = c;
+					c = fputc_unlocked(c, out);
+					if(c < 0) goto writefail;
+				} while(len--);
+			} else {
+				c = fgetc_unlocked(in);
+				if(c < 0) goto end;
+				outbuf[out_i++] = c;
+				c = fputc_unlocked(c, out);
+				if(c < 0) goto writefail;
+			}
+			cmd >>= 1;
+		}
+	}
+
+end:
+	if(feof_unlocked(in)) return 0;
+fail:
+	fprintf(stderr, ferror_unlocked(in) ? "Read Error: %m\n" : "Unexpected EOF\n");
+	return 1;
+writefail:
+	fprintf(stderr, "Write Error: %m\n");
+	return 1;
+}