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author | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:24:06 +0300 |
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committer | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:41:34 +0300 |
commit | e0e3e1717e3d33762ce61950504f9637a6e669ed (patch) | |
tree | bca3ff6939b10ed60c3d5c12439963a1146b9711 /contrib/tools/python3/src/Objects/stringlib/find_max_char.h | |
parent | 38f2c5852db84c7b4d83adfcb009eb61541d1ccd (diff) | |
download | ydb-e0e3e1717e3d33762ce61950504f9637a6e669ed.tar.gz |
add ydb deps
Diffstat (limited to 'contrib/tools/python3/src/Objects/stringlib/find_max_char.h')
-rw-r--r-- | contrib/tools/python3/src/Objects/stringlib/find_max_char.h | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/contrib/tools/python3/src/Objects/stringlib/find_max_char.h b/contrib/tools/python3/src/Objects/stringlib/find_max_char.h new file mode 100644 index 0000000000..b9ffdfc2e3 --- /dev/null +++ b/contrib/tools/python3/src/Objects/stringlib/find_max_char.h @@ -0,0 +1,132 @@ +/* Finding the optimal width of unicode characters in a buffer */ + +#if !STRINGLIB_IS_UNICODE +# error "find_max_char.h is specific to Unicode" +#endif + +/* Mask to quickly check whether a C 'size_t' contains a + non-ASCII, UTF8-encoded char. */ +#if (SIZEOF_SIZE_T == 8) +# define UCS1_ASCII_CHAR_MASK 0x8080808080808080ULL +#elif (SIZEOF_SIZE_T == 4) +# define UCS1_ASCII_CHAR_MASK 0x80808080U +#else +# error C 'size_t' size should be either 4 or 8! +#endif + +#if STRINGLIB_SIZEOF_CHAR == 1 + +Py_LOCAL_INLINE(Py_UCS4) +STRINGLIB(find_max_char)(const STRINGLIB_CHAR *begin, const STRINGLIB_CHAR *end) +{ + const unsigned char *p = (const unsigned char *) begin; + + while (p < end) { + if (_Py_IS_ALIGNED(p, ALIGNOF_SIZE_T)) { + /* Help register allocation */ + const unsigned char *_p = p; + while (_p + SIZEOF_SIZE_T <= end) { + size_t value = *(const size_t *) _p; + if (value & UCS1_ASCII_CHAR_MASK) + return 255; + _p += SIZEOF_SIZE_T; + } + p = _p; + if (p == end) + break; + } + if (*p++ & 0x80) + return 255; + } + return 127; +} + +#undef ASCII_CHAR_MASK + +#else /* STRINGLIB_SIZEOF_CHAR == 1 */ + +#define MASK_ASCII 0xFFFFFF80 +#define MASK_UCS1 0xFFFFFF00 +#define MASK_UCS2 0xFFFF0000 + +#define MAX_CHAR_ASCII 0x7f +#define MAX_CHAR_UCS1 0xff +#define MAX_CHAR_UCS2 0xffff +#define MAX_CHAR_UCS4 0x10ffff + +Py_LOCAL_INLINE(Py_UCS4) +STRINGLIB(find_max_char)(const STRINGLIB_CHAR *begin, const STRINGLIB_CHAR *end) +{ +#if STRINGLIB_SIZEOF_CHAR == 2 + const Py_UCS4 mask_limit = MASK_UCS1; + const Py_UCS4 max_char_limit = MAX_CHAR_UCS2; +#elif STRINGLIB_SIZEOF_CHAR == 4 + const Py_UCS4 mask_limit = MASK_UCS2; + const Py_UCS4 max_char_limit = MAX_CHAR_UCS4; +#else +#error Invalid STRINGLIB_SIZEOF_CHAR (must be 1, 2 or 4) +#endif + Py_UCS4 mask; + Py_ssize_t n = end - begin; + const STRINGLIB_CHAR *p = begin; + const STRINGLIB_CHAR *unrolled_end = begin + _Py_SIZE_ROUND_DOWN(n, 4); + Py_UCS4 max_char; + + max_char = MAX_CHAR_ASCII; + mask = MASK_ASCII; + while (p < unrolled_end) { + STRINGLIB_CHAR bits = p[0] | p[1] | p[2] | p[3]; + if (bits & mask) { + if (mask == mask_limit) { + /* Limit reached */ + return max_char_limit; + } + if (mask == MASK_ASCII) { + max_char = MAX_CHAR_UCS1; + mask = MASK_UCS1; + } + else { + /* mask can't be MASK_UCS2 because of mask_limit above */ + assert(mask == MASK_UCS1); + max_char = MAX_CHAR_UCS2; + mask = MASK_UCS2; + } + /* We check the new mask on the same chars in the next iteration */ + continue; + } + p += 4; + } + while (p < end) { + if (p[0] & mask) { + if (mask == mask_limit) { + /* Limit reached */ + return max_char_limit; + } + if (mask == MASK_ASCII) { + max_char = MAX_CHAR_UCS1; + mask = MASK_UCS1; + } + else { + /* mask can't be MASK_UCS2 because of mask_limit above */ + assert(mask == MASK_UCS1); + max_char = MAX_CHAR_UCS2; + mask = MASK_UCS2; + } + /* We check the new mask on the same chars in the next iteration */ + continue; + } + p++; + } + return max_char; +} + +#undef MASK_ASCII +#undef MASK_UCS1 +#undef MASK_UCS2 +#undef MAX_CHAR_ASCII +#undef MAX_CHAR_UCS1 +#undef MAX_CHAR_UCS2 +#undef MAX_CHAR_UCS4 + +#endif /* STRINGLIB_SIZEOF_CHAR == 1 */ + |