portability and compression cleanups

[wimlib] / src / decompress_common.c

diff --git a/src/decompress_common.c b/src/decompress_common.c
index 66440efe203acaed25f56d6a45ddf07d12c25ab7..4ab9ccbe1c34fdb0519fa7cb0fe72e8e22bfc7ec 100644 (file)
--- a/src/decompress_common.c
+++ b/src/decompress_common.c
@@ -15,16 +15,16 @@
 #endif
 
 #include "wimlib/decompress_common.h"
-#include "wimlib/util.h" /* for BUILD_BUG_ON()  */
 
 #include <string.h>
 
+#define USE_WORD_FILL
+
 #ifdef __GNUC__
 #  ifdef __SSE2__
+#    undef USE_WORD_FILL
 #    define USE_SSE2_FILL
 #    include <emmintrin.h>
-#  else
-#    define USE_LONG_FILL
 #  endif
 #endif
 
@@ -142,8 +142,8 @@ make_huffman_decode_table(u16 decode_table[const restrict],
        unsigned stores_per_loop;
        unsigned decode_table_pos;
 
-#ifdef USE_LONG_FILL
-       const unsigned entries_per_long = sizeof(unsigned long) / sizeof(decode_table[0]);
+#ifdef USE_WORD_FILL
+       const unsigned entries_per_word = WORDSIZE / sizeof(decode_table[0]);
 #endif
 
 #ifdef USE_SSE2_FILL
@@ -230,7 +230,7 @@ make_huffman_decode_table(u16 decode_table[const restrict],
         * have the most entries.  From there, the number of entries per
         * codeword will decrease.  As an optimization, we may begin filling
         * entries with SSE2 vector accesses (8 entries/store), then change to
-        * 'unsigned long' accesses (2 or 4 entries/store), then change to
+        * 'machine_word_t' accesses (2 or 4 entries/store), then change to
         * 16-bit accesses (1 entry/store).  */
        decode_table_ptr = decode_table;
        sym_idx = 0;
@@ -242,11 +242,11 @@ make_huffman_decode_table(u16 decode_table[const restrict],
        for (; stores_per_loop != 0; codeword_len++, stores_per_loop >>= 1) {
                unsigned end_sym_idx = sym_idx + len_counts[codeword_len];
                for (; sym_idx < end_sym_idx; sym_idx++) {
-                       /* Note: unlike in the 'long' version below, the __m128i
-                        * type already has __attribute__((may_alias)), so using
-                        * it to access the decode table, which is an array of
-                        * unsigned shorts, will not violate strict aliasing.
-                        */
+                       /* Note: unlike in the machine_word_t version below, the
+                        * __m128i type already has __attribute__((may_alias)),
+                        * so using it to access the decode table, which is an
+                        * array of unsigned shorts, will not violate strict
+                        * aliasing.  */
                        u16 entry;
                        __m128i v;
                        __m128i *p;
@@ -265,36 +265,33 @@ make_huffman_decode_table(u16 decode_table[const restrict],
        }
 #endif /* USE_SSE2_FILL */
 
-#ifdef USE_LONG_FILL
-       /* Fill the entries one 'unsigned long' at a time.
+#ifdef USE_WORD_FILL
+       /* Fill the entries one machine word at a time.
         * On 32-bit systems this is 2 entries per store, while on 64-bit
         * systems this is 4 entries per store.  */
-       stores_per_loop = (1 << (table_bits - codeword_len)) / entries_per_long;
+       stores_per_loop = (1 << (table_bits - codeword_len)) / entries_per_word;
        for (; stores_per_loop != 0; codeword_len++, stores_per_loop >>= 1) {
                unsigned end_sym_idx = sym_idx + len_counts[codeword_len];
                for (; sym_idx < end_sym_idx; sym_idx++) {
 
-                       /* Accessing the array of unsigned shorts as unsigned
-                        * longs would violate strict aliasing and would require
-                        * compiling the code with -fno-strict-aliasing to
-                        * guarantee correctness.  To work around this problem,
-                        * use the gcc 'may_alias' extension to define a special
-                        * unsigned long type that may alias any other in-memory
-                        * variable.  */
-                       typedef unsigned long __attribute__((may_alias)) aliased_long_t;
-
-                       unsigned long v;
-                       aliased_long_t *p;
+                       /* Accessing the array of u16 as u32 or u64 would
+                        * violate strict aliasing and would require compiling
+                        * the code with -fno-strict-aliasing to guarantee
+                        * correctness.  To work around this problem, use the
+                        * gcc 'may_alias' extension.  */
+                       typedef machine_word_t _may_alias_attribute aliased_word_t;
+
+                       machine_word_t v;
+                       aliased_word_t *p;
                        unsigned n;
 
-                       BUILD_BUG_ON(sizeof(unsigned long) != 4 &&
-                                    sizeof(unsigned long) != 8);
+                       BUILD_BUG_ON(WORDSIZE != 4 && WORDSIZE != 8);
 
                        v = MAKE_DIRECT_ENTRY(sorted_syms[sym_idx], codeword_len);
                        v |= v << 16;
-                       v |= v << (sizeof(unsigned long) == 8 ? 32 : 0);
+                       v |= v << (WORDSIZE == 8 ? 32 : 0);
 
-                       p = (aliased_long_t *)decode_table_ptr;
+                       p = (aliased_word_t *)decode_table_ptr;
                        n = stores_per_loop;
 
                        do {
@@ -303,7 +300,7 @@ make_huffman_decode_table(u16 decode_table[const restrict],
                        decode_table_ptr = p;
                }
        }
-#endif /* USE_LONG_FILL */
+#endif /* USE_WORD_FILL */
 
        /* Fill the entries one 16-bit integer at a time.  */
        stores_per_loop = (1 << (table_bits - codeword_len));