summaryrefslogtreecommitdiffstats
path: root/rbutil/rbutilqt/mspack/readhuff.h
diff options
context:
space:
mode:
Diffstat (limited to 'rbutil/rbutilqt/mspack/readhuff.h')
-rw-r--r--rbutil/rbutilqt/mspack/readhuff.h129
1 files changed, 64 insertions, 65 deletions
diff --git a/rbutil/rbutilqt/mspack/readhuff.h b/rbutil/rbutilqt/mspack/readhuff.h
index bb15c0a123..4d94225789 100644
--- a/rbutil/rbutilqt/mspack/readhuff.h
+++ b/rbutil/rbutilqt/mspack/readhuff.h
@@ -1,5 +1,5 @@
/* This file is part of libmspack.
- * (C) 2003-2010 Stuart Caie.
+ * (C) 2003-2014 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
@@ -10,8 +10,7 @@
#ifndef MSPACK_READHUFF_H
#define MSPACK_READHUFF_H 1
-/* This implements a fast Huffman tree decoding system.
- */
+/* 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"
@@ -32,32 +31,32 @@
/* 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); \
+#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)); \
+# 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)); \
+#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
@@ -77,7 +76,7 @@
* 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)
+ unsigned char *length, unsigned short *table)
{
register unsigned short sym, next_symbol;
register unsigned int leaf, fill;
@@ -91,27 +90,27 @@ static int make_decode_table(unsigned int nsyms, unsigned int nbits,
/* 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;
+ for (sym = 0; sym < nsyms; sym++) {
+ if (length[sym] != bit_num) continue;
#ifdef BITS_ORDER_MSB
- leaf = pos;
+ 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);
+ /* 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 */
+ if((pos += bit_mask) > table_mask) return 1; /* table overrun */
- /* fill all possible lookups of this symbol with the symbol itself */
+ /* fill all possible lookups of this symbol with the symbol itself */
#ifdef BITS_ORDER_MSB
- for (fill = bit_mask; fill-- > 0;) table[leaf++] = sym;
+ 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);
+ fill = bit_mask; next_symbol = 1 << bit_num;
+ do { table[leaf] = sym; leaf += next_symbol; } while (--fill);
#endif
- }
- bit_mask >>= 1;
+ }
+ bit_mask >>= 1;
}
/* exit with success if table is now complete */
@@ -120,11 +119,11 @@ static int make_decode_table(unsigned int nsyms, unsigned int nbits,
/* mark all remaining table entries as unused */
for (sym = pos; sym < table_mask; sym++) {
#ifdef BITS_ORDER_MSB
- table[sym] = 0xFFFF;
+ table[sym] = 0xFFFF;
#else
- reverse = sym; leaf = 0; fill = nbits;
- do { leaf <<= 1; leaf |= reverse & 1; reverse >>= 1; } while (--fill);
- table[leaf] = 0xFFFF;
+ reverse = sym; leaf = 0; fill = nbits;
+ do { leaf <<= 1; leaf |= reverse & 1; reverse >>= 1; } while (--fill);
+ table[leaf] = 0xFFFF;
#endif
}
@@ -138,33 +137,33 @@ static int make_decode_table(unsigned int nsyms, unsigned int nbits,
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;
+ for (sym = 0; sym < nsyms; sym++) {
+ if (length[sym] != bit_num) continue;
+ if (pos >= table_mask) return 1; /* table overflow */
#ifdef BITS_ORDER_MSB
- leaf = pos >> 16;
+ 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);
+ /* 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;
+ 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;
+ pos += bit_mask;
+ }
+ bit_mask >>= 1;
}
/* full table? */
generated by cgit v1.2.2 (git 2.25.0) at 2021-01-19 12:18:14 +0000