2 files changed, 224 insertions, 0 deletions

diff --git a/firmware/common/ucl_decompress.c b/firmware/common/ucl_decompress.c
new file mode 100644
index 0000000000..3b43d76f9d
--- /dev/null
+++ b/firmware/common/ucl_decompress.c
@@ -0,0 +1,192 @@
+/* Standalone version of ucl_nrv2e_decompress_8 from UCL library
+ * Original copyright notice:
+ */
+/* n2e_d.c -- implementation of the NRV2E decompression algorithm
+
+   This file is part of the UCL data compression library.
+
+   Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
+   All Rights Reserved.
+
+   The UCL library 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.
+
+   The UCL library 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 the UCL library; see the file COPYING.
+   If not, write to the Free Software Foundation, Inc.,
+   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+   Markus F.X.J. Oberhumer
+   <markus@oberhumer.com>
+   http://www.oberhumer.com/opensource/ucl/
+ */
+
+#include "ucl_decompress.h"
+
+#define UCL_UINT32_C(c) c ## U
+#define fail(x, r) do if(x) { *dst_len = olen; return r; } while(0)
+
+#define getbit(bb) \
+    (((bb = bb & 0x7f ? bb*2 : ((unsigned)src[ilen++]*2+1)) >> 8) & 1)
+
+int ucl_nrv2e_decompress_8(const uint8_t* src, uint32_t src_len,
+                           uint8_t* dst, uint32_t* dst_len)
+{
+    uint32_t bb = 0;
+    uint32_t ilen = 0, olen = 0, last_m_off = 1;
+    uint32_t oend = *dst_len;
+
+    for (;;)
+    {
+        uint32_t m_off, m_len;
+
+        while (getbit(bb))
+        {
+            fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
+            fail(olen >= oend, UCL_E_OUTPUT_OVERRUN);
+            dst[olen++] = src[ilen++];
+        }
+        m_off = 1;
+        for (;;)
+        {
+            m_off = m_off*2 + getbit(bb);
+            fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
+            fail(m_off > UCL_UINT32_C(0xffffff) + 3, UCL_E_LOOKBEHIND_OVERRUN);
+            if (getbit(bb)) break;
+            m_off = (m_off-1)*2 + getbit(bb);
+        }
+        if (m_off == 2)
+        {
+            m_off = last_m_off;
+            m_len = getbit(bb);
+        }
+        else
+        {
+            fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
+            m_off = (m_off-3)*256 + src[ilen++];
+            if (m_off == UCL_UINT32_C(0xffffffff))
+                break;
+            m_len = (m_off ^ UCL_UINT32_C(0xffffffff)) & 1;
+            m_off >>= 1;
+            last_m_off = ++m_off;
+        }
+        if (m_len)
+            m_len = 1 + getbit(bb);
+        else if (getbit(bb))
+            m_len = 3 + getbit(bb);
+        else
+        {
+            m_len++;
+            do {
+                m_len = m_len*2 + getbit(bb);
+                fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
+                fail(m_len >= oend, UCL_E_OUTPUT_OVERRUN);
+            } while (!getbit(bb));
+            m_len += 3;
+        }
+        m_len += (m_off > 0x500);
+        fail(olen + m_len > oend, UCL_E_OUTPUT_OVERRUN);
+        fail(m_off > olen, UCL_E_LOOKBEHIND_OVERRUN);
+        {
+            const uint8_t *m_pos;
+            m_pos = dst + olen - m_off;
+            dst[olen++] = *m_pos++;
+            do dst[olen++] = *m_pos++; while (--m_len > 0);
+        }
+    }
+    *dst_len = olen;
+    return ilen == src_len ? UCL_E_OK : (ilen < src_len ? UCL_E_INPUT_NOT_CONSUMED : UCL_E_INPUT_OVERRUN);
+}
+
+static uint32_t xread32(const uint8_t* d)
+{
+    uint32_t r = 0;
+    r |= d[0] << 24;
+    r |= d[1] << 16;
+    r |= d[2] <<  8;
+    r |= d[3] <<  0;
+    return r;
+}
+
+/* From uclpack.c */
+int ucl_unpack(const uint8_t* src, uint32_t src_len,
+               uint8_t* dst, uint32_t* dst_len)
+{
+    static const uint8_t magic[8] =
+        {0x00, 0xe9, 0x55, 0x43, 0x4c, 0xff, 0x01, 0x1a};
+
+    /* make sure there are enough bytes for the header */
+    if(src_len < 18)
+        return UCL_E_BAD_MAGIC;
+
+    /* avoid memcmp for reasons of code size */
+    for(size_t i = 0; i < sizeof(magic); ++i)
+        if(src[i] != magic[i])
+            return UCL_E_BAD_MAGIC;
+
+    /* read the other header fields */
+    /* uint32_t flags = xread32(&src[8]); */
+    uint8_t method = src[12];
+    /* uint8_t level = src[13]; */
+    uint32_t block_size = xread32(&src[14]);
+
+    /* check supported compression method */
+    if(method != 0x2e)
+        return UCL_E_UNSUPPORTED_METHOD;
+
+    /* validate */
+    if(block_size < 1024 || block_size > 8*1024*1024)
+        return UCL_E_BAD_BLOCK_SIZE;
+
+    /* process the blocks */
+    src += 18;
+    src_len -= 18;
+    uint32_t dst_ilen = *dst_len;
+    while(1) {
+        if(src_len < 4)
+            return UCL_E_TRUNCATED;
+
+        uint32_t out_len = xread32(src); src += 4, src_len -= 4;
+        if(out_len == 0)
+            break;
+
+        if(src_len < 4)
+            return UCL_E_TRUNCATED;
+
+        uint32_t in_len = xread32(src); src += 4, src_len -= 4;
+        if(in_len > block_size || out_len > block_size ||
+           in_len == 0 || in_len > out_len)
+            return UCL_E_CORRUPTED;
+
+        if(src_len < in_len)
+            return UCL_E_TRUNCATED;
+
+        if(in_len < out_len) {
+            uint32_t actual_out_len = dst_ilen;
+            int rc = ucl_nrv2e_decompress_8(src, in_len, dst, &actual_out_len);
+            if(rc != UCL_E_OK)
+                return rc;
+            if(actual_out_len != out_len)
+                return UCL_E_CORRUPTED;
+        } else {
+            for(size_t i = 0; i < in_len; ++i)
+                dst[i] = src[i];
+        }
+
+        src += in_len;
+        src_len -= in_len;
+        dst += out_len;
+        dst_ilen -= out_len;
+    }
+
+    /* subtract leftover number of bytes to get size of compressed output */
+    *dst_len -= dst_ilen;
+    return UCL_E_OK;
+}
diff --git a/firmware/export/ucl_decompress.h b/firmware/export/ucl_decompress.h
new file mode 100644
index 0000000000..bea7564a94
--- /dev/null
+++ b/firmware/export/ucl_decompress.h
@@ -0,0 +1,32 @@
+/* Standalone UCL decompressor and uclpack-compatible unpacker,
+ * adapted for Rockbox from the libucl code.
+ *
+ * Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
+ * All Rights Reserved.
+ *
+ * See firmware/common/ucl_decompress.c for full copyright notice
+ */
+#ifndef UCL_DECOMPRESS_H
+#define UCL_DECOMPRESS_H
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#define UCL_E_OK                 0
+#define UCL_E_INPUT_OVERRUN      1
+#define UCL_E_OUTPUT_OVERRUN     2
+#define UCL_E_LOOKBEHIND_OVERRUN 3
+#define UCL_E_INPUT_NOT_CONSUMED 4
+#define UCL_E_BAD_MAGIC          5
+#define UCL_E_BAD_BLOCK_SIZE     6
+#define UCL_E_UNSUPPORTED_METHOD 7
+#define UCL_E_TRUNCATED          8
+#define UCL_E_CORRUPTED          9
+
+extern int ucl_nrv2e_decompress_8(const uint8_t* src, uint32_t src_len,
+                                  uint8_t* dst, uint32_t* dst_len);
+
+extern int ucl_unpack(const uint8_t* src, uint32_t src_len,
+                      uint8_t* dst, uint32_t* dst_len);
+
+#endif /* UCL_DECOMPRESS_H */