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Fix crc32.c to compile local functions only if used.

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This commit is contained in:
Mark Adler 2022-03-27 13:48:19 -07:00
parent e9a52aa129
commit 296967c7b7
1 changed files with 64 additions and 62 deletions
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126
crc32.c
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@ -101,11 +101,41 @@
/* Local functions. */
local z_crc_t multmodp OF((z_crc_t a, z_crc_t b));
local z_crc_t x2nmodp OF((z_off64_t n, unsigned k));
#ifdef W
local z_word_t byte_swap OF((z_word_t word));
local z_crc_t crc_word OF((z_word_t data));
local z_word_t crc_word_big OF((z_word_t data));
#endif /* W */
/* If available, use the ARM processor CRC32 instruction. */
#if defined(__aarch64__) && defined(__ARM_FEATURE_CRC32) && W == 8
# define ARMCRC32
#endif
#if defined(W) && (!defined(ARMCRC32) || defined(DYNAMIC_CRC_TABLE))
/*
Swap the bytes in a z_word_t to convert between little and big endian. Any
self-respecting compiler will optimize this to a single machine byte-swap
instruction, if one is available. This assumes that word_t is either 32 bits
or 64 bits.
*/
local z_word_t byte_swap(word)
z_word_t word;
{
# if W == 8
return
(word & 0xff00000000000000) >> 56 |
(word & 0xff000000000000) >> 40 |
(word & 0xff0000000000) >> 24 |
(word & 0xff00000000) >> 8 |
(word & 0xff000000) << 8 |
(word & 0xff0000) << 24 |
(word & 0xff00) << 40 |
(word & 0xff) << 56;
# else /* W == 4 */
return
(word & 0xff000000) >> 24 |
(word & 0xff0000) >> 8 |
(word & 0xff00) << 8 |
(word & 0xff) << 24;
# endif
}
#endif
/* CRC polynomial. */
#define POLY 0xedb88320 /* p(x) reflected, with x^32 implied */
@ -549,62 +579,6 @@ local z_crc_t x2nmodp(n, k)
return p;
}
#ifdef W
/*
Swap the bytes in a z_word_t to convert between little and big endian. Any
self-respecting compiler will optimize this to a single machine byte-swap
instruction, if one is available. This assumes that word_t is either 32 bits
or 64 bits.
*/
local z_word_t byte_swap(word)
z_word_t word;
{
#if W == 8
return
(word & 0xff00000000000000) >> 56 |
(word & 0xff000000000000) >> 40 |
(word & 0xff0000000000) >> 24 |
(word & 0xff00000000) >> 8 |
(word & 0xff000000) << 8 |
(word & 0xff0000) << 24 |
(word & 0xff00) << 40 |
(word & 0xff) << 56;
#else /* W == 4 */
return
(word & 0xff000000) >> 24 |
(word & 0xff0000) >> 8 |
(word & 0xff00) << 8 |
(word & 0xff) << 24;
#endif
}
/*
Return the CRC of the W bytes in the word_t data, taking the
least-significant byte of the word as the first byte of data, without any pre
or post conditioning. This is used to combine the CRCs of each braid.
*/
local z_crc_t crc_word(data)
z_word_t data;
{
int k;
for (k = 0; k < W; k++)
data = (data >> 8) ^ crc_table[data & 0xff];
return (z_crc_t)data;
}
local z_word_t crc_word_big(data)
z_word_t data;
{
int k;
for (k = 0; k < W; k++)
data = (data << 8) ^
crc_big_table[(data >> ((W - 1) << 3)) & 0xff];
return data;
}
#endif /* W */
/* =========================================================================
* This function can be used by asm versions of crc32(), and to force the
* generation of the CRC tables in a threaded application.
@ -626,7 +600,7 @@ const z_crc_t FAR * ZEXPORT get_crc_table()
* -march=armv8-a+crc, or -march=native if the compile machine has the crc32
* instructions.
*/
#if defined(__aarch64__) && defined(__ARM_FEATURE_CRC32) && W == 8
#ifdef ARMCRC32
/*
Constants empirically determined to maximize speed. These values are from
@ -733,6 +707,34 @@ unsigned long ZEXPORT crc32_z(crc, buf, len)
#else
#ifdef W
/*
Return the CRC of the W bytes in the word_t data, taking the
least-significant byte of the word as the first byte of data, without any pre
or post conditioning. This is used to combine the CRCs of each braid.
*/
local z_crc_t crc_word(data)
z_word_t data;
{
int k;
for (k = 0; k < W; k++)
data = (data >> 8) ^ crc_table[data & 0xff];
return (z_crc_t)data;
}
local z_word_t crc_word_big(data)
z_word_t data;
{
int k;
for (k = 0; k < W; k++)
data = (data << 8) ^
crc_big_table[(data >> ((W - 1) << 3)) & 0xff];
return data;
}
#endif
/* ========================================================================= */
unsigned long ZEXPORT crc32_z(crc, buf, len)
unsigned long crc;