1 files changed, 115 insertions, 0 deletions
diff --git a/gfx/graphite2/src/Decompressor.cpp b/gfx/graphite2/src/Decompressor.cpp
new file mode 100644
index 000000000..4b8b1b495
--- /dev/null
+++ b/gfx/graphite2/src/Decompressor.cpp
@@ -0,0 +1,115 @@
+/*  GRAPHITE2 LICENSING
+
+    Copyright 2015, SIL International
+    All rights reserved.
+
+    This library is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published
+    by the Free Software Foundation; either version 2.1 of 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
+    Lesser General Public License for more details.
+
+    You should also have received a copy of the GNU Lesser General Public
+    License along with this library in the file named "LICENSE".
+    If not, write to the Free Software Foundation, 51 Franklin Street, 
+    Suite 500, Boston, MA 02110-1335, USA or visit their web page on the 
+    internet at http://www.fsf.org/licenses/lgpl.html.
+
+Alternatively, the contents of this file may be used under the terms of the
+Mozilla Public License (http://mozilla.org/MPL) or 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.
+*/
+#include <cassert>
+
+#include "inc/Decompressor.h"
+#include "inc/Compression.h"
+
+using namespace lz4;
+
+namespace {
+
+inline
+u32 read_literal(u8 const * &s, u8 const * const e, u32 l) {
+    if (l == 15 && s != e)
+    {
+        u8 b = 0;
+        do { l += b = *s++; } while(b==0xff && s != e);
+    }
+    return l;
+}
+
+bool read_sequence(u8 const * &src, u8 const * const end, u8 const * &literal, u32 & literal_len, u32 & match_len, u32 & match_dist)
+{
+    u8 const token = *src++;
+    
+    literal_len = read_literal(src, end, token >> 4);
+    literal = src;
+    src += literal_len;
+    
+    if (src > end - 2 || src < literal)
+        return false;
+    
+    match_dist  = *src++;
+    match_dist |= *src++ << 8;
+    match_len = read_literal(src, end, token & 0xf);
+    
+    return src <= end-5;
+}
+
+}
+
+int lz4::decompress(void const *in, size_t in_size, void *out, size_t out_size)
+{
+    if (out_size <= in_size || in_size < sizeof(unsigned long)+1)
+        return -1;
+    
+    u8 const *       src     = static_cast<u8 const *>(in),
+             *       literal = 0,
+             * const src_end = src + in_size;
+
+    u8 *       dst     = static_cast<u8*>(out),
+       * const dst_end = dst + out_size;
+    
+    u32 literal_len = 0,
+        match_len = 0,
+        match_dist = 0;
+    
+    while (read_sequence(src, src_end, literal, literal_len, match_len, match_dist))
+    {
+        if (literal_len != 0)
+        {
+            // Copy in literal. At this point the last full sequence must be at
+            // least MINMATCH + 5 from the end of the output buffer.
+            if (align(literal_len) > unsigned(dst_end - dst - (MINMATCH+5)) || dst_end - dst < MINMATCH + 5)
+                return -1;
+            dst = overrun_copy(dst, literal, literal_len);
+        }
+        
+        // Copy, possibly repeating, match from earlier in the
+        //  decoded output.
+        u8 const * const pcpy = dst - match_dist;
+        if (pcpy < static_cast<u8*>(out)
+                  || pcpy >= dst
+                  || match_len > unsigned(dst_end - dst - (MINMATCH+5))
+                  || dst_end - dst < MINMATCH + 5)
+            return -1;
+        if (dst > pcpy+sizeof(unsigned long) 
+            && dst + align(match_len + MINMATCH) <= dst_end)
+            dst = overrun_copy(dst, pcpy, match_len + MINMATCH);
+        else 
+            dst = safe_copy(dst, pcpy, match_len + MINMATCH);
+    }
+    
+    if (literal_len > src_end - literal
+              || literal_len > dst_end - dst)
+        return -1;
+    dst = fast_copy(dst, literal, literal_len);
+    
+    return dst - (u8*)out;
+}
+