X-Git-Url: https://wimlib.net/git/?a=blobdiff_plain;f=src%2Fdecompress.c;h=f149b48c7bcf06f9172d48d9e7da0568b26f80fb;hb=b8df27e5fdd4dae472ababcec11d04eafea8830b;hp=e97aab5c5c2f72cbf407ccacc65f8a750fb62f01;hpb=908adfc82c98c531ca847f183489ccf57e190e16;p=wimlib

diff --git a/src/decompress.c b/src/decompress.c
index e97aab5c..f149b48c 100644
--- a/src/decompress.c
+++ b/src/decompress.c
@@ -5,7 +5,7 @@
  */
 
 /*
- * Copyright (C) 2012 Eric Biggers
+ * Copyright (C) 2012, 2013 Eric Biggers
  *
  * This file is part of wimlib, a library for working with WIM files.
  *
@@ -23,15 +23,21 @@
  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  */
 
-#include "decompress.h"
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include "wimlib/decompress.h"
+#include "wimlib/util.h"
+
 #include <string.h>
 
 /*
- * Builds a fast huffman decoding table from an array that gives the length of
- * the codeword for each symbol in the alphabet.  Originally based on code
- * written by David Tritscher (taken the original LZX decompression code); also
- * heavily modified to add some optimizations used in the zlib code, as well as
- * more comments.
+ * make_huffman_decode_table: - Builds a fast huffman decoding table from an
+ * array that gives the length of the codeword for each symbol in the alphabet.
+ * Originally based on code written by David Tritscher (taken the original LZX
+ * decompression code); also heavily modified to add some optimizations used in
+ * the zlib code, as well as more comments.
  *
  * @decode_table:	The array in which to create the fast huffman decoding
  * 			table.  It must have a length of at least
@@ -89,9 +95,10 @@
  * indices into the decoding table, and symbol entries are distinguished from
  * pointers by the fact that values less than @num_syms must be symbol values.
  */
-int make_huffman_decode_table(u16 decode_table[],  unsigned num_syms,
-			      unsigned table_bits, const u8 lens[],
-			      unsigned max_codeword_len)
+int
+make_huffman_decode_table(u16 * restrict decode_table,  unsigned num_syms,
+			  unsigned table_bits, const u8 * restrict lens,
+			  unsigned max_codeword_len)
 {
 	unsigned len_counts[max_codeword_len + 1];
 	u16 sorted_syms[num_syms];
@@ -164,30 +171,13 @@ int make_huffman_decode_table(u16 decode_table[],  unsigned num_syms,
 			break;
 
 		unsigned num_entries = 1 << (table_bits - codeword_len);
-		const unsigned entries_per_long = sizeof(unsigned long) /
-						  sizeof(decode_table[0]);
-		if (num_entries >= entries_per_long) {
-			wimlib_assert2(decode_table_pos % entries_per_long == 0);
-			BUILD_BUG_ON(sizeof(unsigned long) != 4 &&
-				     sizeof(unsigned long) != 8);
-
-			unsigned long *p = (unsigned long *)&decode_table[decode_table_pos];
-			unsigned n = num_entries / entries_per_long;
-			unsigned long v = sym;
-			if (sizeof(unsigned long) >= 4)
-				v |= v << 16;
-			if (sizeof(unsigned long) >= 8)
-				v |= v << 32;
-			do {
-				*p++ = v;
-			} while (--n);
-
-			decode_table_pos += num_entries;
-		} else {
-			do {
-				decode_table[decode_table_pos++] = sym;
-			} while (--num_entries);
-		}
+
+		/* Fill in the Huffman decode table entries one 16-bit
+		 * integer at a time. */
+		do {
+			decode_table[decode_table_pos++] = sym;
+		} while (--num_entries);
+
 		wimlib_assert2(decode_table_pos <= table_num_entries);
 		if (++i == num_used_syms) {
 			wimlib_assert2(decode_table_pos == table_num_entries);
@@ -234,7 +224,6 @@ int make_huffman_decode_table(u16 decode_table[],  unsigned num_syms,
 		unsigned sym = sorted_syms[i];
 		unsigned codeword_len = lens[sym];
 		unsigned extra_bits = codeword_len - table_bits;
-		unsigned extra_mask;
 
 		cur_codeword <<= (codeword_len - prev_codeword_len);
 		prev_codeword_len = codeword_len;
@@ -282,14 +271,15 @@ int make_huffman_decode_table(u16 decode_table[],  unsigned num_syms,
 	return 0;
 }
 
-/* Reads a Huffman-encoded symbol when it is known there are less than
- * MAX_CODE_LEN bits remaining in the bitstream. */
-int read_huffsym_near_end_of_input(struct input_bitstream *istream,
-				   const u16 decode_table[],
-				   const u8 lens[],
-				   unsigned num_syms,
-				   unsigned table_bits,
-				   unsigned *n)
+/* Reads a Huffman-encoded symbol from the bistream when the number of remaining
+ * bits is less than the maximum codeword length. */
+int
+read_huffsym_near_end_of_input(struct input_bitstream *istream,
+			       const u16 decode_table[],
+			       const u8 lens[],
+			       unsigned num_syms,
+			       unsigned table_bits,
+			       unsigned *n)
 {
 	unsigned bitsleft = istream->bitsleft;
 	unsigned key_size;