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bpo-40302: Add pycore_byteswap.h header file (GH-19552)

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Add a new internal pycore_byteswap.h header file with the following
functions:

* _Py_bswap16()
* _Py_bswap32()
* _Py_bswap64()

Use these functions in _ctypes, sha256 and sha512 modules,
and also use in the UTF-32 encoder.

sha256, sha512 and _ctypes modules are now built with the internal
C API.
This commit is contained in:
Victor Stinner 2020-04-17 17:47:20 +02:00 • committed by GitHub
parent 485e715cb1
commit 1ae035b7e8
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GPG key ID: 4AEE18F83AFDEB23
13 changed files with 219 additions and 112 deletions
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36
Objects/stringlib/codecs.h
View file

@ -4,6 +4,8 @@
# error "codecs.h is specific to Unicode"
#endif
#include "pycore_byteswap.h" // _Py_bswap32()
/* Mask to quickly check whether a C 'long' contains a
non-ASCII, UTF8-encoded char. */
#if (SIZEOF_LONG == 8)
@ -732,24 +734,28 @@ STRINGLIB(utf16_encode)(const STRINGLIB_CHAR *in,
#endif
}
static inline uint32_t
STRINGLIB(SWAB4)(STRINGLIB_CHAR ch)
{
uint32_t word = ch;
#if STRINGLIB_SIZEOF_CHAR == 1
# define SWAB4(CH, tmp) ((CH) << 24) /* high bytes are zero */
/* high bytes are zero */
return (word << 24);
#elif STRINGLIB_SIZEOF_CHAR == 2
# define SWAB4(CH, tmp) (tmp = (CH), \
((tmp & 0x00FFu) << 24) + ((tmp & 0xFF00u) << 8))
/* high bytes are zero */
/* high bytes are zero */
return ((word & 0x00FFu) << 24) + ((word & 0xFF00u) << 8);
#else
# define SWAB4(CH, tmp) (tmp = (CH), \
tmp = ((tmp & 0x00FF00FFu) << 8) + ((tmp >> 8) & 0x00FF00FFu), \
((tmp & 0x0000FFFFu) << 16) + ((tmp >> 16) & 0x0000FFFFu))
return _Py_bswap32(word);
#endif
}
Py_LOCAL_INLINE(Py_ssize_t)
STRINGLIB(utf32_encode)(const STRINGLIB_CHAR *in,
Py_ssize_t len,
PY_UINT32_T **outptr,
uint32_t **outptr,
int native_ordering)
{
PY_UINT32_T *out = *outptr;
uint32_t *out = *outptr;
const STRINGLIB_CHAR *end = in + len;
if (native_ordering) {
const STRINGLIB_CHAR *unrolled_end = in + _Py_SIZE_ROUND_DOWN(len, 4);
@ -783,7 +789,6 @@ STRINGLIB(utf32_encode)(const STRINGLIB_CHAR *in,
const STRINGLIB_CHAR *unrolled_end = in + _Py_SIZE_ROUND_DOWN(len, 4);
while (in < unrolled_end) {
#if STRINGLIB_SIZEOF_CHAR > 1
Py_UCS4 ch1, ch2, ch3, ch4;
/* check if any character is a surrogate character */
if (((in[0] ^ 0xd800) &
(in[1] ^ 0xd800) &
@ -791,10 +796,10 @@ STRINGLIB(utf32_encode)(const STRINGLIB_CHAR *in,
(in[3] ^ 0xd800) & 0xf800) == 0)
break;
#endif
out[0] = SWAB4(in[0], ch1);
out[1] = SWAB4(in[1], ch2);
out[2] = SWAB4(in[2], ch3);
out[3] = SWAB4(in[3], ch4);
out[0] = STRINGLIB(SWAB4)(in[0]);
out[1] = STRINGLIB(SWAB4)(in[1]);
out[2] = STRINGLIB(SWAB4)(in[2]);
out[3] = STRINGLIB(SWAB4)(in[3]);
in += 4; out += 4;
}
while (in < end) {
@ -805,7 +810,7 @@ STRINGLIB(utf32_encode)(const STRINGLIB_CHAR *in,
goto fail;
}
#endif
*out++ = SWAB4(ch, ch);
*out++ = STRINGLIB(SWAB4)(ch);
}
}
*outptr = out;
@ -816,6 +821,5 @@ STRINGLIB(utf32_encode)(const STRINGLIB_CHAR *in,
return len - (end - in + 1);
#endif
}
#undef SWAB4
#endif