1 files changed, 93 insertions, 0 deletions

diff --git a/utils/rbutilqt/mspack/lzssd.c b/utils/rbutilqt/mspack/lzssd.c
new file mode 100644
index 0000000000..63716d414a
--- /dev/null
+++ b/utils/rbutilqt/mspack/lzssd.c
@@ -0,0 +1,93 @@
+/* This file is part of libmspack.
+ * (C) 2003-2010 Stuart Caie.
+ *
+ * LZSS is a derivative of LZ77 and was created by James Storer and
+ * Thomas Szymanski in 1982. Haruhiko Okumura wrote a very popular C
+ * implementation.
+ *
+ * libmspack is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License (LGPL) version 2.1
+ *
+ * For further details, see the file COPYING.LIB distributed with libmspack
+ */
+
+#include "system-mspack.h"
+#include "lzss.h"
+
+#define ENSURE_BYTES do {                               \
+    if (i_ptr >= i_end) {                               \
+        read = system->read(input, &inbuf[0],           \
+                            input_buffer_size);         \
+        if (read <= 0) {                                \
+            system->free(window);                       \
+            return (read < 0) ? MSPACK_ERR_READ         \
+                              : MSPACK_ERR_OK;          \
+        }                                               \
+        i_ptr = &inbuf[0]; i_end = &inbuf[read];        \
+    }                                                   \
+} while (0)
+
+#define WRITE_BYTE do {                                 \
+    if (system->write(output, &window[pos], 1) != 1) {  \
+        system->free(window);                           \
+        return MSPACK_ERR_WRITE;                        \
+    }                                                   \
+} while (0)
+
+int lzss_decompress(struct mspack_system *system,
+                    struct mspack_file *input,
+                    struct mspack_file *output,
+                    int input_buffer_size,
+                    int mode)
+{
+    unsigned char *window, *inbuf, *i_ptr, *i_end;
+    unsigned int pos, i, c, invert, mpos, len;
+    int read;
+
+    /* check parameters */
+    if (!system || input_buffer_size < 1 || (mode != LZSS_MODE_EXPAND &&
+        mode != LZSS_MODE_MSHELP && mode != LZSS_MODE_QBASIC))
+    {
+        return MSPACK_ERR_ARGS;
+    }
+
+    /* allocate memory */
+    window = (unsigned char *) system->alloc(system, LZSS_WINDOW_SIZE + input_buffer_size);
+    if (!window) return MSPACK_ERR_NOMEMORY;
+
+    /* initialise decompression */
+    inbuf = &window[LZSS_WINDOW_SIZE];
+    memset(window, LZSS_WINDOW_FILL, (size_t) LZSS_WINDOW_SIZE);
+    pos = LZSS_WINDOW_SIZE - ((mode == LZSS_MODE_QBASIC) ? 18 : 16);
+    invert = (mode == LZSS_MODE_MSHELP) ? ~0 : 0;
+    i_ptr = i_end = &inbuf[0];
+
+    /* loop forever; exit condition is in ENSURE_BYTES macro */
+    for (;;) {
+        ENSURE_BYTES; c = *i_ptr++ ^ invert;
+        for (i = 0x01; i & 0xFF; i <<= 1) {
+            if (c & i) {
+                /* literal */
+                ENSURE_BYTES; window[pos] = *i_ptr++;
+                WRITE_BYTE;
+                pos++; pos &= LZSS_WINDOW_SIZE - 1;
+            }
+            else {
+                /* match */
+                ENSURE_BYTES; mpos = *i_ptr++;
+                ENSURE_BYTES; mpos |= (*i_ptr & 0xF0) << 4;
+                len = (*i_ptr++ & 0x0F) + 3;
+                while (len--) {
+                    window[pos] = window[mpos];
+                    WRITE_BYTE;
+                    pos++;  pos  &= LZSS_WINDOW_SIZE - 1;
+                    mpos++; mpos &= LZSS_WINDOW_SIZE - 1;
+                }
+            }
+        }
+    }
+
+    /* not reached */
+    system->free(window);
+    return MSPACK_ERR_OK;
+}