feat: godot-engine-source-4.3-stable

engine/thirdparty/graphite/src/Decompressor.cpp

@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: MIT OR MPL-2.0 OR LGPL-2.1-or-later OR GPL-2.0-or-later
+// Copyright 2015, SIL International, All rights reserved.
+
+#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;
+
+    // Normal exit for end of stream, wrap arround check and parital match check.
+    if (src > end - sizeof(u16) || src < literal)
+        return false;
+
+    match_dist  = *src++;
+    match_dist |= *src++ << 8;
+    match_len = read_literal(src, end, token & 0xf) + MINMATCH;
+
+    // Malformed stream check.
+    return src <= end-MINCODA;
+}
+
+}
+
+int lz4::decompress(void const *in, size_t in_size, void *out, size_t out_size)
+{
+    if (out_size <= in_size || in_size < MINSRCSIZE)
+        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;
+
+    // Check the in and out size hasn't wrapped around.
+    if (src >= src_end || dst >= dst_end)
+        return -1;
+
+    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 a minimal literal + minminal
+            // match plus the coda (1 + 2 + 5) must be 8 bytes or more allowing
+            // us to remain within the src buffer for an overrun_copy on
+            // machines upto 64 bits.
+            if (align(literal_len) > out_size)
+                return -1;
+            dst = overrun_copy(dst, literal, literal_len);
+            out_size -= 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)
+              || match_len > unsigned(out_size - LASTLITERALS)
+              // Wrap around checks:
+              || out_size < LASTLITERALS || pcpy >= dst)
+            return -1;
+        if (dst > pcpy+sizeof(unsigned long)
+            && align(match_len) <= out_size)
+            dst = overrun_copy(dst, pcpy, match_len);
+        else
+            dst = safe_copy(dst, pcpy, match_len);
+        out_size -= match_len;
+    }
+
+    if (literal > src_end - literal_len || literal_len > out_size)
+        return -1;
+    dst = fast_copy(dst, literal, literal_len);
+
+    return int(dst - (u8*)out);
+}