1 files changed, 128 insertions, 0 deletions

diff --git a/utils/jztool/src/ucl_unpack.c b/utils/jztool/src/ucl_unpack.c
new file mode 100644
index 0000000000..3b199c7008
--- /dev/null
+++ b/utils/jztool/src/ucl_unpack.c
@@ -0,0 +1,128 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2021 Aidan MacDonald
+ *
+ * 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include "jztool.h"
+#include "ucl/ucl.h"
+
+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;
+}
+
+/* adapted from firmware/common/ucl_decompress.c */
+jz_buffer* jz_ucl_unpack(const uint8_t* src, uint32_t src_len, uint32_t* dst_len)
+{
+    static const uint8_t magic[8] =
+        {0x00, 0xe9, 0x55, 0x43, 0x4c, 0xff, 0x01, 0x1a};
+
+    jz_buffer* buffer = NULL;
+
+    /* make sure there are enough bytes for the header */
+    if(src_len < 18)
+        goto error;
+
+    /* avoid memcmp for reasons of code size */
+    for(size_t i = 0; i < sizeof(magic); ++i)
+        if(src[i] != magic[i])
+            goto error;
+
+    /* 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)
+        goto error;
+
+    /* validate */
+    if(block_size < 1024 || block_size > 8*1024*1024)
+        goto error;
+
+    src += 18;
+    src_len -= 18;
+
+    /* Calculate amount of space that we might need & allocate a buffer:
+     * - subtract 4 to account for end of file marker
+     * - each block is block_size bytes + 8 bytes of header
+     * - add one to nr_blocks to account for case where file size < block size
+     * - total size =  max uncompressed size of block * nr_blocks
+     */
+    uint32_t nr_blocks = (src_len - 4) / (8 + block_size) + 1;
+    uint32_t max_size = nr_blocks * (block_size + block_size/8 + 256);
+    buffer = jz_buffer_alloc(max_size, NULL);
+    if(!buffer)
+        goto error;
+
+    /* perform the decompression */
+    uint32_t dst_ilen = buffer->size;
+    uint8_t* dst = buffer->data;
+    while(1) {
+        if(src_len < 4)
+            goto error;
+
+        uint32_t out_len = xread32(src); src += 4, src_len -= 4;
+        if(out_len == 0)
+            break;
+
+        if(src_len < 4)
+            goto error;
+
+        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)
+            goto error;
+
+        if(src_len < in_len)
+            goto error;
+
+        if(in_len < out_len) {
+            uint32_t actual_out_len = dst_ilen;
+            int rc = ucl_nrv2e_decompress_safe_8(src, in_len, dst, &actual_out_len, NULL);
+            if(rc != UCL_E_OK)
+                goto error;
+            if(actual_out_len != out_len)
+                goto error;
+        } 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 = buffer->size - dst_ilen;
+    return buffer;
+
+  error:
+    jz_buffer_free(buffer);
+    return NULL;
+}