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| author | Victor Stinner <victor.stinner@gmail.com> | 2012-04-05 11:44:34 (GMT) |
|---|---|---|
| committer | Victor Stinner <victor.stinner@gmail.com> | 2012-04-05 11:44:34 (GMT) |
| commit | e7eee01f3697835d168f82357a6a97d7ca40d99a (patch) | |
| tree | c4b8154a67af64071f766cc50dd75b1a4bed8c92 /Objects | |
| parent | 20bbf54f5ee53b20fa22d0eb2e957f88ac927331 (diff) | |
| download | cpython-e7eee01f3697835d168f82357a6a97d7ca40d99a.zip cpython-e7eee01f3697835d168f82357a6a97d7ca40d99a.tar.gz cpython-e7eee01f3697835d168f82357a6a97d7ca40d99a.tar.bz2 | |
Close #14249: Use an union instead of a long to short pointer to avoid aliasing
issue. Speed up UTF-16 by 20%.
Diffstat (limited to 'Objects')
| -rw-r--r-- | Objects/unicodeobject.c | 44 |
1 files changed, 25 insertions, 19 deletions
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c index 1d8a176..8522a74 100644 --- a/Objects/unicodeobject.c +++ b/Objects/unicodeobject.c @@ -5496,33 +5496,39 @@ PyUnicode_DecodeUTF16Stateful(const char *s, int kind = PyUnicode_KIND(unicode); void *data = PyUnicode_DATA(unicode); while (_q < aligned_end) { - unsigned long block = * (unsigned long *) _q; - unsigned short *pblock = (unsigned short*)█ + union { + unsigned long as_long; + unsigned short units[sizeof(long) / sizeof(short)]; + unsigned char bytes[sizeof(long)]; + } block, block_copy; Py_UCS4 maxch; + + block.as_long = *(unsigned long *) _q; if (native_ordering) { /* Can use buffer directly */ - if (block & FAST_CHAR_MASK) + if (block.as_long & FAST_CHAR_MASK) break; } else { /* Need to byte-swap */ - unsigned char *_p = (unsigned char*)pblock; - if (block & SWAPPED_FAST_CHAR_MASK) + block_copy = block; + + if (block.as_long & SWAPPED_FAST_CHAR_MASK) break; - _p[0] = _q[1]; - _p[1] = _q[0]; - _p[2] = _q[3]; - _p[3] = _q[2]; + block.bytes[0] = block_copy.bytes[1]; + block.bytes[1] = block_copy.bytes[0]; + block.bytes[2] = block_copy.bytes[3]; + block.bytes[3] = block_copy.bytes[2]; #if (SIZEOF_LONG == 8) - _p[4] = _q[5]; - _p[5] = _q[4]; - _p[6] = _q[7]; - _p[7] = _q[6]; + block.bytes[4] = block_copy.bytes[5]; + block.bytes[5] = block_copy.bytes[4]; + block.bytes[6] = block_copy.bytes[7]; + block.bytes[7] = block_copy.bytes[6]; #endif } - maxch = Py_MAX(pblock[0], pblock[1]); + maxch = Py_MAX(block.units[0], block.units[1]); #if SIZEOF_LONG == 8 - maxch = Py_MAX(maxch, Py_MAX(pblock[2], pblock[3])); + maxch = Py_MAX(maxch, Py_MAX(block.units[2], block.units[3])); #endif if (maxch > PyUnicode_MAX_CHAR_VALUE(unicode)) { if (unicode_widen(&unicode, maxch) < 0) @@ -5530,11 +5536,11 @@ PyUnicode_DecodeUTF16Stateful(const char *s, kind = PyUnicode_KIND(unicode); data = PyUnicode_DATA(unicode); } - PyUnicode_WRITE(kind, data, outpos++, pblock[0]); - PyUnicode_WRITE(kind, data, outpos++, pblock[1]); + PyUnicode_WRITE(kind, data, outpos++, block.units[0]); + PyUnicode_WRITE(kind, data, outpos++, block.units[1]); #if SIZEOF_LONG == 8 - PyUnicode_WRITE(kind, data, outpos++, pblock[2]); - PyUnicode_WRITE(kind, data, outpos++, pblock[3]); + PyUnicode_WRITE(kind, data, outpos++, block.units[2]); + PyUnicode_WRITE(kind, data, outpos++, block.units[3]); #endif _q += SIZEOF_LONG; } |