1 files changed, 87 insertions, 0 deletions
diff --git a/lzss_extract.c b/lzss_extract.c
new file mode 100644
index 0000000..b8f9d93
--- /dev/null
+++ b/lzss_extract.c
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2009      Luc Verhaegen <libv@skynet.be>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+
+#include "lzss_extract.h"
+
+static inline int
+LZSSBufferWrite(int fd, unsigned char *Buffer, int *BufferCount, unsigned char value)
+{
+    Buffer[*BufferCount] = value;
+    *BufferCount += 1;
+
+    if (*BufferCount == 0x1000) {
+	if (write(fd, Buffer, 0x1000) != 0x1000) {
+	    fprintf(stderr, "Error writing to output file: %s",
+		    strerror(errno));
+	    return 1;
+	}
+	*BufferCount = 0;
+    }
+
+    return 0;
+}
+
+int
+LZSSExtract(unsigned char *Input, int InputSize, int fd)
+{
+    unsigned char Buffer[0x1000];
+    unsigned short BitBuffer = 0;
+    int i = 0, k, BitCount = 8, BufferCount = 0;
+
+    while (i < InputSize) {
+
+	if (BitCount == 8) {
+	    BitBuffer = Input[i];
+	    BitCount = -1;
+	} else if ((BitBuffer >> BitCount) & 0x01) {
+	    if (LZSSBufferWrite(fd, Buffer, &BufferCount, Input[i]))
+		return 1;
+	} else if ((i + 1) < InputSize) {
+	    int offset = ((Input[i] | ((Input[i + 1] & 0xF0) << 4)) - 0xFEE) & 0xFFF;
+	    int length = (Input[i + 1] & 0x0F) + 3;
+
+	    for (k = 0; k < length; k++) {
+		if (LZSSBufferWrite(fd, Buffer, &BufferCount, Buffer[(offset + k) & 0xFFF]))
+		    return 1;
+	    }
+	    i++;
+	} else {
+	    fprintf(stderr, "Error: requesting data beyond end of input file.\n");
+	    return 1;
+	}
+
+	i++;
+	BitCount++;
+    }
+
+    if (BufferCount) {
+	if (write(fd, Buffer, BufferCount) != BufferCount) {
+	    fprintf(stderr, "Error writing to output file: %s",
+		    strerror(errno));
+	    return 1;
+	}
+    }
+
+    return 0;
+}