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Re: [Patch] Speed up parsing of ints and floats (in the "C" locale)
- From: Paolo Carlini <pcarlini at suse dot de>
- To: Benjamin Kosnik <bkoz at redhat dot com>
- Cc: libstdc++ at gcc dot gnu dot org
- Date: Sat, 29 Apr 2006 20:19:13 +0200
- Subject: Re: [Patch] Speed up parsing of ints and floats (in the "C" locale)
- References: <4451F497.7010202@suse.de> <20060428111737.a55bd41a.bkoz@redhat.com>
Benjamin Kosnik wrote:
+ template<typename _CharT2>
+ typename __enable_if<int, __is_char<_CharT2>::__value>::__type
+ _M_find(const _CharT2*, size_t __len, _CharT2 __c) const
very nice!
Thanks Benjamin ;) The below slight variant is going in... Tested
x86/ia64-linux.
Paolo.
///////////////
2006-04-29 Paolo Carlini <pcarlini@suse.de>
* include/bits/locale_facets.tcc (num_get<>::_M_extract_float):
Special case main parsing loop for !_M_allocated (i.e., "C" locale).
(num_get<>::_M_extract_int): Likewise.
* include/bits/locale_facets.h (num_get<>::_M_find): New.
Index: include/bits/locale_facets.tcc
===================================================================
--- include/bits/locale_facets.tcc (revision 113192)
+++ include/bits/locale_facets.tcc (working copy)
@@ -340,94 +340,147 @@
string __found_grouping;
if (__lc->_M_use_grouping)
__found_grouping.reserve(32);
- const char_type* __q;
const char_type* __lit_zero = __lit + __num_base::_S_izero;
- while (!__testeof)
- {
- // According to 22.2.2.1.2, p8-9, first look for thousands_sep
- // and decimal_point.
- if (__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
- {
- if (!__found_dec && !__found_sci)
- {
- // NB: Thousands separator at the beginning of a string
- // is a no-no, as is two consecutive thousands separators.
- if (__sep_pos)
- {
- __found_grouping += static_cast<char>(__sep_pos);
- __sep_pos = 0;
- }
- else
- {
- // NB: __convert_to_v will not assign __v and will
- // set the failbit.
- __xtrc.clear();
- break;
- }
- }
- else
- break;
- }
- else if (__c == __lc->_M_decimal_point)
- {
- if (!__found_dec && !__found_sci)
- {
- // If no grouping chars are seen, no grouping check
- // is applied. Therefore __found_grouping is adjusted
- // only if decimal_point comes after some thousands_sep.
- if (__found_grouping.size())
- __found_grouping += static_cast<char>(__sep_pos);
- __xtrc += '.';
- __found_dec = true;
- }
- else
- break;
- }
- else if ((__q = __traits_type::find(__lit_zero, 10, __c)))
- {
- __xtrc += __num_base::_S_atoms_in[__q - __lit];
- __found_mantissa = true;
- ++__sep_pos;
- }
- else if ((__c == __lit[__num_base::_S_ie]
- || __c == __lit[__num_base::_S_iE])
- && !__found_sci && __found_mantissa)
- {
- // Scientific notation.
- if (__found_grouping.size() && !__found_dec)
- __found_grouping += static_cast<char>(__sep_pos);
- __xtrc += 'e';
- __found_sci = true;
- // Remove optional plus or minus sign, if they exist.
- if (++__beg != __end)
- {
- __c = *__beg;
- const bool __plus = __c == __lit[__num_base::_S_iplus];
- if ((__plus || __c == __lit[__num_base::_S_iminus])
- && !(__lc->_M_use_grouping
- && __c == __lc->_M_thousands_sep)
- && !(__c == __lc->_M_decimal_point))
- __xtrc += __plus ? '+' : '-';
- else
- continue;
- }
- else
- {
- __testeof = true;
+ if (!__lc->_M_allocated)
+ // "C" locale
+ while (!__testeof)
+ {
+ const int __digit = _M_find(__lit_zero, 10, __c);
+ if (__digit != -1)
+ {
+ __xtrc += '0' + __digit;
+ __found_mantissa = true;
+ }
+ else if (__c == __lc->_M_decimal_point
+ && !__found_dec && !__found_sci)
+ {
+ __xtrc += '.';
+ __found_dec = true;
+ }
+ else if ((__c == __lit[__num_base::_S_ie]
+ || __c == __lit[__num_base::_S_iE])
+ && !__found_sci && __found_mantissa)
+ {
+ // Scientific notation.
+ __xtrc += 'e';
+ __found_sci = true;
+
+ // Remove optional plus or minus sign, if they exist.
+ if (++__beg != __end)
+ {
+ __c = *__beg;
+ const bool __plus = __c == __lit[__num_base::_S_iplus];
+ if (__plus || __c == __lit[__num_base::_S_iminus])
+ __xtrc += __plus ? '+' : '-';
+ else
+ continue;
+ }
+ else
+ {
+ __testeof = true;
+ break;
+ }
+ }
+ else
+ break;
+
+ if (++__beg != __end)
+ __c = *__beg;
+ else
+ __testeof = true;
+ }
+ else
+ while (!__testeof)
+ {
+ // According to 22.2.2.1.2, p8-9, first look for thousands_sep
+ // and decimal_point.
+ if (__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
+ {
+ if (!__found_dec && !__found_sci)
+ {
+ // NB: Thousands separator at the beginning of a string
+ // is a no-no, as is two consecutive thousands separators.
+ if (__sep_pos)
+ {
+ __found_grouping += static_cast<char>(__sep_pos);
+ __sep_pos = 0;
+ }
+ else
+ {
+ // NB: __convert_to_v will not assign __v and will
+ // set the failbit.
+ __xtrc.clear();
+ break;
+ }
+ }
+ else
break;
- }
- }
- else
- // Not a valid input item.
- break;
+ }
+ else if (__c == __lc->_M_decimal_point)
+ {
+ if (!__found_dec && !__found_sci)
+ {
+ // If no grouping chars are seen, no grouping check
+ // is applied. Therefore __found_grouping is adjusted
+ // only if decimal_point comes after some thousands_sep.
+ if (__found_grouping.size())
+ __found_grouping += static_cast<char>(__sep_pos);
+ __xtrc += '.';
+ __found_dec = true;
+ }
+ else
+ break;
+ }
+ else
+ {
+ const char_type* __q =
+ __traits_type::find(__lit_zero, 10, __c);
+ if (__q)
+ {
+ __xtrc += '0' + (__q - __lit_zero);
+ __found_mantissa = true;
+ ++__sep_pos;
+ }
+ else if ((__c == __lit[__num_base::_S_ie]
+ || __c == __lit[__num_base::_S_iE])
+ && !__found_sci && __found_mantissa)
+ {
+ // Scientific notation.
+ if (__found_grouping.size() && !__found_dec)
+ __found_grouping += static_cast<char>(__sep_pos);
+ __xtrc += 'e';
+ __found_sci = true;
+
+ // Remove optional plus or minus sign, if they exist.
+ if (++__beg != __end)
+ {
+ __c = *__beg;
+ const bool __plus = __c == __lit[__num_base::_S_iplus];
+ if ((__plus || __c == __lit[__num_base::_S_iminus])
+ && !(__lc->_M_use_grouping
+ && __c == __lc->_M_thousands_sep)
+ && !(__c == __lc->_M_decimal_point))
+ __xtrc += __plus ? '+' : '-';
+ else
+ continue;
+ }
+ else
+ {
+ __testeof = true;
+ break;
+ }
+ }
+ else
+ break;
+ }
+
+ if (++__beg != __end)
+ __c = *__beg;
+ else
+ __testeof = true;
+ }
- if (++__beg != __end)
- __c = *__beg;
- else
- __testeof = true;
- }
-
// Digit grouping is checked. If grouping and found_grouping don't
// match, then get very very upset, and set failbit.
if (__found_grouping.size())
@@ -569,54 +622,81 @@
-numeric_limits<_ValueT>::min() : numeric_limits<_ValueT>::max();
const __unsigned_type __smax = __max / __base;
__unsigned_type __result = 0;
- const char_type* __q;
+ int __digit = 0;
const char_type* __lit_zero = __lit + __num_base::_S_izero;
- while (!__testeof)
- {
- // According to 22.2.2.1.2, p8-9, first look for thousands_sep
- // and decimal_point.
- if (__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
- {
- // NB: Thousands separator at the beginning of a string
- // is a no-no, as is two consecutive thousands separators.
- if (__sep_pos)
- {
- __found_grouping += static_cast<char>(__sep_pos);
- __sep_pos = 0;
- }
- else
- {
+
+ if (!__lc->_M_allocated)
+ // "C" locale
+ while (!__testeof)
+ {
+ __digit = _M_find(__lit_zero, __len, __c);
+ if (__digit == -1)
+ break;
+
+ if (__result > __smax)
+ __testfail = true;
+ else
+ {
+ __result *= __base;
+ __testfail |= __result > __max - __digit;
+ __result += __digit;
+ ++__sep_pos;
+ }
+
+ if (++__beg != __end)
+ __c = *__beg;
+ else
+ __testeof = true;
+ }
+ else
+ while (!__testeof)
+ {
+ // According to 22.2.2.1.2, p8-9, first look for thousands_sep
+ // and decimal_point.
+ if (__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
+ {
+ // NB: Thousands separator at the beginning of a string
+ // is a no-no, as is two consecutive thousands separators.
+ if (__sep_pos)
+ {
+ __found_grouping += static_cast<char>(__sep_pos);
+ __sep_pos = 0;
+ }
+ else
+ {
+ __testfail = true;
+ break;
+ }
+ }
+ else if (__c == __lc->_M_decimal_point)
+ break;
+ else
+ {
+ const char_type* __q =
+ __traits_type::find(__lit_zero, __len, __c);
+ if (!__q)
+ break;
+
+ __digit = __q - __lit_zero;
+ if (__digit > 15)
+ __digit -= 6;
+ if (__result > __smax)
__testfail = true;
- break;
- }
- }
- else if (__c == __lc->_M_decimal_point)
- break;
- else if ((__q = __traits_type::find(__lit_zero, __len, __c)))
- {
- int __digit = __q - __lit_zero;
- if (__digit > 15)
- __digit -= 6;
- if (__result > __smax)
- __testfail = true;
- else
- {
- __result *= __base;
- __testfail |= __result > __max - __digit;
- __result += __digit;
- ++__sep_pos;
- }
- }
- else
- // Not a valid input item.
- break;
-
- if (++__beg != __end)
- __c = *__beg;
- else
- __testeof = true;
- }
-
+ else
+ {
+ __result *= __base;
+ __testfail |= __result > __max - __digit;
+ __result += __digit;
+ ++__sep_pos;
+ }
+ }
+
+ if (++__beg != __end)
+ __c = *__beg;
+ else
+ __testeof = true;
+ }
+
// Digit grouping is checked. If grouping and found_grouping don't
// match, then get very very upset, and set failbit.
if (__found_grouping.size())
Index: include/bits/locale_facets.h
===================================================================
--- include/bits/locale_facets.h (revision 113192)
+++ include/bits/locale_facets.h (working copy)
@@ -47,6 +47,7 @@
#include <iosfwd>
#include <bits/ios_base.h> // For ios_base, ios_base::iostate
#include <streambuf>
+#include <bits/cpp_type_traits.h>
_GLIBCXX_BEGIN_NAMESPACE(std)
@@ -2125,6 +2126,43 @@
_M_extract_int(iter_type, iter_type, ios_base&, ios_base::iostate&,
_ValueT& __v) const;
+ template<typename _CharT2>
+ typename __enable_if<int, __is_char<_CharT2>::__value>::__type
+ _M_find(const _CharT2*, size_t __len, _CharT2 __c) const
+ {
+ int __ret = -1;
+ if (__len <= 10)
+ {
+ if (__c >= _CharT2('0') && __c < _CharT2(_CharT2('0') + __len))
+ __ret = __c - _CharT2('0');
+ }
+ else
+ {
+ if (__c >= _CharT2('0') && __c <= _CharT2('9'))
+ __ret = __c - _CharT2('0');
+ else if (__c >= _CharT2('a') && __c <= _CharT2('f'))
+ __ret = 10 + (__c - _CharT2('a'));
+ else if (__c >= _CharT2('A') && __c <= _CharT2('F'))
+ __ret = 10 + (__c - _CharT2('A'));
+ }
+ return __ret;
+ }
+
+ template<typename _CharT2>
+ typename __enable_if<int, !__is_char<_CharT2>::__value>::__type
+ _M_find(const _CharT2* __zero, size_t __len, _CharT2 __c) const
+ {
+ int __ret = -1;
+ const char_type* __q = char_traits<_CharT2>::find(__zero, __len, __c);
+ if (__q)
+ {
+ __ret = __q - __zero;
+ if (__ret > 15)
+ __ret -= 6;
+ }
+ return __ret;
+ }
+
//@{
/**
* @brief Numeric parsing.