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Issue #15027: Rewrite the UTF-32 encoder. It is now 1.6x to 3.5x faster.

This commit is contained in:
Serhiy Storchaka 2014-01-04 19:25:37 +02:00
parent 41adc26708
commit 583a93943c
4 changed files with 133 additions and 62 deletions
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4
Doc/whatsnew/3.4.rst
View File

@ -1213,7 +1213,9 @@ Other Improvements
Significant Optimizations
=========================
* The UTF-32 decoder is now 3x to 4x faster.
* The UTF-32 decoder is now 3x to 4x faster. The UTF-32 encoder is now 1.6x
to 3.5x faster. (Contributed by Serhiy Storchaka in :issue:`14625` and
:issue:`15027`.)
* The cost of hash collisions for sets is now reduced. Each hash table
probe now checks a series of consecutive, adjacent key/hash pairs before

2
Misc/NEWS
View File

@ -10,6 +10,8 @@ Release date: 2014-01-05
Core and Builtins
-----------------
- Issue #15027: Rewrite the UTF-32 encoder. It is now 1.6x to 3.5x faster.
- Issue #17432: Drop UCS2 from names of Unicode functions in python3.def.
- Issue #19526: Exclude all new API from the stable ABI. Exceptions can be

87
Objects/stringlib/codecs.h
View File

@ -718,6 +718,93 @@ STRINGLIB(utf16_encode)(const STRINGLIB_CHAR *in,
return len - (end - in + 1);
#endif
}
#if STRINGLIB_SIZEOF_CHAR == 1
# define SWAB4(CH, tmp) ((CH) << 24) /* high bytes are zero */
#elif STRINGLIB_SIZEOF_CHAR == 2
# define SWAB4(CH, tmp) (tmp = (CH), \
((tmp & 0x00FFu) << 24) + ((tmp & 0xFF00u) << 8))
/* high bytes are zero */
#else
# define SWAB4(CH, tmp) (tmp = (CH), \
tmp = ((tmp & 0x00FF00FFu) << 8) + ((tmp >> 8) & 0x00FF00FFu), \
((tmp & 0x0000FFFFu) << 16) + ((tmp >> 16) & 0x0000FFFFu))
#endif
Py_LOCAL_INLINE(Py_ssize_t)
STRINGLIB(utf32_encode)(const STRINGLIB_CHAR *in,
Py_ssize_t len,
PY_UINT32_T **outptr,
int native_ordering)
{
PY_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);
while (in < unrolled_end) {
#if STRINGLIB_SIZEOF_CHAR > 1
/* check if any character is a surrogate character */
if (((in[0] ^ 0xd800) &
(in[1] ^ 0xd800) &
(in[2] ^ 0xd800) &
(in[3] ^ 0xd800) & 0xf800) == 0)
break;
#endif
out[0] = in[0];
out[1] = in[1];
out[2] = in[2];
out[3] = in[3];
in += 4; out += 4;
}
while (in < end) {
Py_UCS4 ch;
ch = *in++;
#if STRINGLIB_SIZEOF_CHAR > 1
if (Py_UNICODE_IS_SURROGATE(ch)) {
/* reject surrogate characters (U+DC800-U+DFFF) */
goto fail;
}
#endif
*out++ = ch;
}
} else {
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) &
(in[2] ^ 0xd800) &
(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);
in += 4; out += 4;
}
while (in < end) {
Py_UCS4 ch = *in++;
#if STRINGLIB_SIZEOF_CHAR > 1
if (Py_UNICODE_IS_SURROGATE(ch)) {
/* reject surrogate characters (U+DC800-U+DFFF) */
goto fail;
}
#endif
*out++ = SWAB4(ch, ch);
}
}
*outptr = out;
return len;
#if STRINGLIB_SIZEOF_CHAR > 1
fail:
*outptr = out;
return len - (end - in + 1);
#endif
}
#undef SWAB4
#endif
#endif /* STRINGLIB_IS_UNICODE */

102
Objects/unicodeobject.c
View File

@ -5085,32 +5085,22 @@ _PyUnicode_EncodeUTF32(PyObject *str,
const char *errors,
int byteorder)
{
int kind;
void *data;
enum PyUnicode_Kind kind;
const void *data;
Py_ssize_t len;
PyObject *v;
unsigned char *p;
Py_ssize_t nsize, i;
/* Offsets from p for storing byte pairs in the right order. */
PY_UINT32_T *out;
#if PY_LITTLE_ENDIAN
int iorder[] = {0, 1, 2, 3};
int native_ordering = byteorder <= 0;
#else
int iorder[] = {3, 2, 1, 0};
int native_ordering = byteorder >= 0;
#endif
const char *encoding;
Py_ssize_t nsize, pos;
PyObject *errorHandler = NULL;
PyObject *exc = NULL;
PyObject *rep = NULL;
#define STORECHAR(CH) \
do { \
p[iorder[3]] = ((CH) >> 24) & 0xff; \
p[iorder[2]] = ((CH) >> 16) & 0xff; \
p[iorder[1]] = ((CH) >> 8) & 0xff; \
p[iorder[0]] = (CH) & 0xff; \
p += 4; \
} while(0)
if (!PyUnicode_Check(str)) {
PyErr_BadArgument();
return NULL;
@ -5121,59 +5111,53 @@ _PyUnicode_EncodeUTF32(PyObject *str,
data = PyUnicode_DATA(str);
len = PyUnicode_GET_LENGTH(str);
nsize = len + (byteorder == 0);
if (nsize > PY_SSIZE_T_MAX / 4)
if (len > PY_SSIZE_T_MAX / 4 - (byteorder == 0))
return PyErr_NoMemory();
nsize = len + (byteorder == 0);
v = PyBytes_FromStringAndSize(NULL, nsize * 4);
if (v == NULL)
return NULL;
p = (unsigned char *)PyBytes_AS_STRING(v);
/* output buffer is 4-bytes aligned */
assert(_Py_IS_ALIGNED(PyBytes_AS_STRING(v), 4));
out = (PY_UINT32_T *)PyBytes_AS_STRING(v);
if (byteorder == 0)
STORECHAR(0xFEFF);
*out++ = 0xFEFF;
if (len == 0)
return v;
goto done;
if (byteorder == -1) {
/* force LE */
iorder[0] = 0;
iorder[1] = 1;
iorder[2] = 2;
iorder[3] = 3;
if (byteorder == -1)
encoding = "utf-32-le";
}
else if (byteorder == 1) {
/* force BE */
iorder[0] = 3;
iorder[1] = 2;
iorder[2] = 1;
iorder[3] = 0;
else if (byteorder == 1)
encoding = "utf-32-be";
}
else
encoding = "utf-32";
if (kind == PyUnicode_1BYTE_KIND) {
for (i = 0; i < len; i++)
STORECHAR(PyUnicode_READ(kind, data, i));
return v;
ucs1lib_utf32_encode((const Py_UCS1 *)data, len, &out, native_ordering);
goto done;
}
for (i = 0; i < len;) {
pos = 0;
while (pos < len) {
Py_ssize_t repsize, moreunits;
Py_UCS4 ch = PyUnicode_READ(kind, data, i);
i++;
assert(ch <= MAX_UNICODE);
if (!Py_UNICODE_IS_SURROGATE(ch)) {
STORECHAR(ch);
continue;
if (kind == PyUnicode_2BYTE_KIND) {
pos += ucs2lib_utf32_encode((const Py_UCS2 *)data + pos, len - pos,
&out, native_ordering);
}
else {
assert(kind == PyUnicode_4BYTE_KIND);
pos += ucs4lib_utf32_encode((const Py_UCS4 *)data + pos, len - pos,
&out, native_ordering);
}
if (pos == len)
break;
rep = unicode_encode_call_errorhandler(
errors, &errorHandler,
encoding, "surrogates not allowed",
str, &exc, i-1, i, &i);
str, &exc, pos, pos + 1, &pos);
if (!rep)
goto error;
@ -5181,7 +5165,7 @@ _PyUnicode_EncodeUTF32(PyObject *str,
repsize = PyBytes_GET_SIZE(rep);
if (repsize & 3) {
raise_encode_exception(&exc, encoding,
str, i - 1, i,
str, pos - 1, pos,
"surrogates not allowed");
goto error;
}
@ -5194,7 +5178,7 @@ _PyUnicode_EncodeUTF32(PyObject *str,
moreunits = repsize = PyUnicode_GET_LENGTH(rep);
if (!PyUnicode_IS_ASCII(rep)) {
raise_encode_exception(&exc, encoding,
str, i - 1, i,
str, pos - 1, pos,
"surrogates not allowed");
goto error;
}
@ -5202,7 +5186,7 @@ _PyUnicode_EncodeUTF32(PyObject *str,
/* four bytes are reserved for each surrogate */
if (moreunits > 1) {
Py_ssize_t outpos = p - (unsigned char*) PyBytes_AS_STRING(v);
Py_ssize_t outpos = out - (PY_UINT32_T*) PyBytes_AS_STRING(v);
Py_ssize_t morebytes = 4 * (moreunits - 1);
if (PyBytes_GET_SIZE(v) > PY_SSIZE_T_MAX - morebytes) {
/* integer overflow */
@ -5211,20 +5195,16 @@ _PyUnicode_EncodeUTF32(PyObject *str,
}
if (_PyBytes_Resize(&v, PyBytes_GET_SIZE(v) + morebytes) < 0)
goto error;
p = (unsigned char*) PyBytes_AS_STRING(v) + outpos;
out = (PY_UINT32_T*) PyBytes_AS_STRING(v) + outpos;
}
if (PyBytes_Check(rep)) {
Py_MEMCPY(p, PyBytes_AS_STRING(rep), repsize);
p += repsize;
Py_MEMCPY(out, PyBytes_AS_STRING(rep), repsize);
out += moreunits;
} else /* rep is unicode */ {
const Py_UCS1 *repdata;
assert(PyUnicode_KIND(rep) == PyUnicode_1BYTE_KIND);
repdata = PyUnicode_1BYTE_DATA(rep);
while (repsize--) {
Py_UCS4 ch = *repdata++;
STORECHAR(ch);
}
ucs1lib_utf32_encode(PyUnicode_1BYTE_DATA(rep), repsize,
&out, native_ordering);
}
Py_CLEAR(rep);
@ -5233,11 +5213,12 @@ _PyUnicode_EncodeUTF32(PyObject *str,
/* Cut back to size actually needed. This is necessary for, for example,
encoding of a string containing isolated surrogates and the 'ignore'
handler is used. */
nsize = p - (unsigned char*) PyBytes_AS_STRING(v);
nsize = (unsigned char*) out - (unsigned char*) PyBytes_AS_STRING(v);
if (nsize != PyBytes_GET_SIZE(v))
_PyBytes_Resize(&v, nsize);
Py_XDECREF(errorHandler);
Py_XDECREF(exc);
done:
return v;
error:
Py_XDECREF(rep);
@ -5245,7 +5226,6 @@ _PyUnicode_EncodeUTF32(PyObject *str,
Py_XDECREF(exc);
Py_XDECREF(v);
return NULL;
#undef STORECHAR
}
PyObject *