1 files changed, 56 insertions, 0 deletions
diff --git a/grub-core/loader/lzss.c b/grub-core/loader/lzss.c
new file mode 100644
index 0000000..532d8e4
--- /dev/null
+++ b/grub-core/loader/lzss.c
@@ -0,0 +1,56 @@
+/**************************************************************
+	LZSS.C -- A Data Compression Program
+	(tab = 4 spaces)
+***************************************************************
+	4/6/1989 Haruhiko Okumura
+	Use, distribute, and modify this program freely.
+	Please send me your improved versions.
+		PC-VAN		SCIENCE
+		NIFTY-Serve	PAF01022
+		CompuServe	74050,1022
+**************************************************************/
+
+#include <grub/types.h>
+#include <grub/macho.h>
+
+#define N		 4096	/* size of ring buffer */
+#define F		   18	/* upper limit for match_length */
+#define THRESHOLD	2   /* encode string into position and length
+						   if match_length is greater than this */
+#define NIL			N	/* index for root of binary search trees */
+
+#define EOF -1
+#define getc(file) ((src < srcend) ? *src++ : EOF)
+#define putc(c, file) (dst < dstend) ? (*dst++ = (c)) : 0;
+
+grub_size_t
+grub_decompress_lzss (grub_uint8_t *dst, grub_uint8_t *dstend,
+		      grub_uint8_t *src, grub_uint8_t *srcend)
+{
+	int  i, j, k, r, c;
+	unsigned int  flags;
+	static unsigned char text_buf[N + F - 1];
+	grub_uint8_t *dst0 = dst;
+	
+	for (i = 0; i < N - F; i++) text_buf[i] = ' ';
+	r = N - F;  flags = 0;
+	for ( ; ; ) {
+		if (((flags >>= 1) & 256) == 0) {
+			if ((c = getc(infile)) == EOF) break;
+			flags = c | 0xff00;		/* uses higher byte cleverly */
+		}							/* to count eight */
+		if (flags & 1) {
+			if ((c = getc(infile)) == EOF) break;
+			putc(c, outfile);  text_buf[r++] = c;  r &= (N - 1);
+		} else {
+			if ((i = getc(infile)) == EOF) break;
+			if ((j = getc(infile)) == EOF) break;
+			i |= ((j & 0xf0) << 4);  j = (j & 0x0f) + THRESHOLD;
+			for (k = 0; k <= j; k++) {
+				c = text_buf[(i + k) & (N - 1)];
+				putc(c, outfile);  text_buf[r++] = c;  r &= (N - 1);
+			}
+		}
+	}
+    return dst - dst0;
+}