Add libmspack to rbutil

Change-Id: I520c14131ec1e12013f106c13cba00aac058ad83
Reviewed-on: http://gerrit.rockbox.org/391
Reviewed-by: Dominik Riebeling <Dominik.Riebeling@gmail.com>

1 files changed, 173 insertions, 0 deletions

diff --git a/rbutil/rbutilqt/mspack/readhuff.h b/rbutil/rbutilqt/mspack/readhuff.h
new file mode 100644
index 0000000000..bb15c0a123
--- /dev/null
+++ b/rbutil/rbutilqt/mspack/readhuff.h
@@ -0,0 +1,173 @@
+/* This file is part of libmspack.
+ * (C) 2003-2010 Stuart Caie.
+ *
+ * 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
+ */
+
+#ifndef MSPACK_READHUFF_H
+#define MSPACK_READHUFF_H 1
+
+/* This implements a fast Huffman tree decoding system.
+ */
+
+#if !(defined(BITS_ORDER_MSB) || defined(BITS_ORDER_LSB))
+# error "readhuff.h is used in conjunction with readbits.h, include that first"
+#endif
+#if !(defined(TABLEBITS) && defined(MAXSYMBOLS))
+# error "define TABLEBITS(tbl) and MAXSYMBOLS(tbl) before using readhuff.h"
+#endif
+#if !(defined(HUFF_TABLE) && defined(HUFF_LEN))
+# error "define HUFF_TABLE(tbl) and HUFF_LEN(tbl) before using readhuff.h"
+#endif
+#ifndef HUFF_ERROR
+# error "define HUFF_ERROR before using readhuff.h"
+#endif
+#ifndef HUFF_MAXBITS
+# define HUFF_MAXBITS 16
+#endif
+
+/* Decodes the next huffman symbol from the input bitstream into var.
+ * Do not use this macro on a table unless build_decode_table() succeeded.
+ */
+#define READ_HUFFSYM(tbl, var) do {                     \
+    ENSURE_BITS(HUFF_MAXBITS);                          \
+    sym = HUFF_TABLE(tbl, PEEK_BITS(TABLEBITS(tbl)));   \
+    if (sym >= MAXSYMBOLS(tbl)) HUFF_TRAVERSE(tbl);     \
+    (var) = sym;                                        \
+    i = HUFF_LEN(tbl, sym);                             \
+    REMOVE_BITS(i);                                     \
+} while (0)
+
+#ifdef BITS_ORDER_LSB
+# define HUFF_TRAVERSE(tbl) do {                        \
+    i = TABLEBITS(tbl) - 1;                             \
+    do {                                                \
+        if (i++ > HUFF_MAXBITS) HUFF_ERROR;             \
+        sym = HUFF_TABLE(tbl,                           \
+            (sym << 1) | ((bit_buffer >> i) & 1));      \
+    } while (sym >= MAXSYMBOLS(tbl));                   \
+} while (0)
+#else
+#define HUFF_TRAVERSE(tbl) do {                         \
+    i = 1 << (BITBUF_WIDTH - TABLEBITS(tbl));           \
+    do {                                                \
+        if ((i >>= 1) == 0) HUFF_ERROR;                 \
+        sym = HUFF_TABLE(tbl,                           \
+            (sym << 1) | ((bit_buffer & i) ? 1 : 0));   \
+    } while (sym >= MAXSYMBOLS(tbl));                   \
+} while (0)
+#endif
+
+/* make_decode_table(nsyms, nbits, length[], table[])
+ *
+ * This function was originally coded by David Tritscher.
+ * It builds a fast huffman decoding table from
+ * a canonical huffman code lengths table.
+ *
+ * nsyms  = total number of symbols in this huffman tree.
+ * nbits  = any symbols with a code length of nbits or less can be decoded
+ *          in one lookup of the table.
+ * length = A table to get code lengths from [0 to nsyms-1]
+ * table  = The table to fill up with decoded symbols and pointers.
+ *          Should be ((1<<nbits) + (nsyms*2)) in length.
+ *
+ * Returns 0 for OK or 1 for error
+ */
+static int make_decode_table(unsigned int nsyms, unsigned int nbits,
+                             unsigned char *length, unsigned short *table)
+{
+    register unsigned short sym, next_symbol;
+    register unsigned int leaf, fill;
+#ifdef BITS_ORDER_LSB
+    register unsigned int reverse;
+#endif
+    register unsigned char bit_num;
+    unsigned int pos         = 0; /* the current position in the decode table */
+    unsigned int table_mask  = 1 << nbits;
+    unsigned int bit_mask    = table_mask >> 1; /* don't do 0 length codes */
+
+    /* fill entries for codes short enough for a direct mapping */
+    for (bit_num = 1; bit_num <= nbits; bit_num++) {
+        for (sym = 0; sym < nsyms; sym++) {
+            if (length[sym] != bit_num) continue;
+#ifdef BITS_ORDER_MSB
+            leaf = pos;
+#else
+            /* reverse the significant bits */
+            fill = length[sym]; reverse = pos >> (nbits - fill); leaf = 0;
+            do {leaf <<= 1; leaf |= reverse & 1; reverse >>= 1;} while (--fill);
+#endif
+
+            if((pos += bit_mask) > table_mask) return 1; /* table overrun */
+
+            /* fill all possible lookups of this symbol with the symbol itself */
+#ifdef BITS_ORDER_MSB
+            for (fill = bit_mask; fill-- > 0;) table[leaf++] = sym;
+#else
+            fill = bit_mask; next_symbol = 1 << bit_num;
+            do { table[leaf] = sym; leaf += next_symbol; } while (--fill);
+#endif
+        }
+        bit_mask >>= 1;
+    }
+
+    /* exit with success if table is now complete */
+    if (pos == table_mask) return 0;
+
+    /* mark all remaining table entries as unused */
+    for (sym = pos; sym < table_mask; sym++) {
+#ifdef BITS_ORDER_MSB
+        table[sym] = 0xFFFF;
+#else
+        reverse = sym; leaf = 0; fill = nbits;
+        do { leaf <<= 1; leaf |= reverse & 1; reverse >>= 1; } while (--fill);
+        table[leaf] = 0xFFFF;
+#endif
+    }
+
+    /* next_symbol = base of allocation for long codes */
+    next_symbol = ((table_mask >> 1) < nsyms) ? nsyms : (table_mask >> 1);
+
+    /* give ourselves room for codes to grow by up to 16 more bits.
+     * codes now start at bit nbits+16 and end at (nbits+16-codelength) */
+    pos <<= 16;
+    table_mask <<= 16;
+    bit_mask = 1 << 15;
+
+    for (bit_num = nbits+1; bit_num <= HUFF_MAXBITS; bit_num++) {
+        for (sym = 0; sym < nsyms; sym++) {
+            if (length[sym] != bit_num) continue;
+
+#ifdef BITS_ORDER_MSB
+            leaf = pos >> 16;
+#else
+            /* leaf = the first nbits of the code, reversed */
+            reverse = pos >> 16; leaf = 0; fill = nbits;
+            do {leaf <<= 1; leaf |= reverse & 1; reverse >>= 1;} while (--fill);
+#endif
+            for (fill = 0; fill < (bit_num - nbits); fill++) {
+                /* if this path hasn't been taken yet, 'allocate' two entries */
+                if (table[leaf] == 0xFFFF) {
+                    table[(next_symbol << 1)     ] = 0xFFFF;
+                    table[(next_symbol << 1) + 1 ] = 0xFFFF;
+                    table[leaf] = next_symbol++;
+                }
+
+                /* follow the path and select either left or right for next bit */
+                leaf = table[leaf] << 1;
+                if ((pos >> (15-fill)) & 1) leaf++;
+            }
+            table[leaf] = sym;
+
+            if ((pos += bit_mask) > table_mask) return 1; /* table overflow */
+        }
+        bit_mask >>= 1;
+    }
+
+    /* full table? */
+    return (pos == table_mask) ? 0 : 1;
+}
+#endif