1 files changed, 61 insertions, 0 deletions
diff --git a/reader/src/formats/chm/E8Decoder.cpp b/reader/src/formats/chm/E8Decoder.cpp
new file mode 100644
index 0000000..53b9335
--- /dev/null
+++ b/reader/src/formats/chm/E8Decoder.cpp
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2004-2012 Geometer Plus <[email protected]>
+ *
+ * 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 of the License, 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; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include "LZXDecompressor.h"
+
+void LZXDecompressor::E8Decoder::reset(unsigned int fileSize) {
+	myFileSize = fileSize;
+	myFramesCounter = 0;
+	myPosition = 0;
+}
+
+void LZXDecompressor::E8Decoder::decode(unsigned char *buffer, const std::size_t size) {
+	if (myFramesCounter >= 32768) {
+		return;
+	}
+	++myFramesCounter;
+	if (myFileSize == 0) {
+		return;
+	}
+
+	myPosition += size;
+
+	if (size <= 10) {
+		return;
+	}
+	
+	const unsigned char *end = buffer + size - 10;
+
+	for (unsigned char *ptr = buffer; ptr < end; ) {
+		if (*ptr == 0xE8) {
+			int absoluteOffset =
+				ptr[1] + (ptr[2] << 8) + (ptr[3] << 16) + (ptr[4] << 24);
+			int relativeOffset =
+				(absoluteOffset >= 0) ?
+					absoluteOffset - (ptr - buffer) : absoluteOffset + myFileSize;
+			ptr[1] = (unsigned char)relativeOffset;
+			ptr[2] = (unsigned char)(relativeOffset >> 8);
+			ptr[3] = (unsigned char)(relativeOffset >> 16);
+			ptr[4] = (unsigned char)(relativeOffset >> 24);
+			ptr += 5;
+		} else {
+			++ptr;
+		}
+	}
+}