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optimized wxStringTokenizer: it's now slightly faster in wchar_t build and much faster in UTF-8 build

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@47707 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Václav Slavík 2007-07-24 20:00:12 +00:00
parent a2db25a143
commit f0dfc29c71
2 changed files with 98 additions and 19 deletions
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24
include/wx/tokenzr.h
View File

@ -72,12 +72,12 @@ public:
// get current tokenizer state
// returns the part of the string which remains to tokenize (*not* the
// initial string)
wxString GetString() const { return m_string.substr(m_pos); }
wxString GetString() const { return wxString(m_pos, m_string.end()); }
// returns the current position (i.e. one index after the last
// returned token or 0 if GetNextToken() has never been called) in the
// original string
size_t GetPosition() const { return m_pos; }
size_t GetPosition() const { return m_pos - m_string.begin(); }
// misc
// get the current mode - can be different from the one passed to the
@ -111,10 +111,24 @@ public:
protected:
bool IsOk() const { return m_mode != wxTOKEN_INVALID; }
wxString m_string, // the string we tokenize
m_delims; // all possible delimiters
bool DoHasMoreTokens() const;
size_t m_pos; // the current position in m_string
enum MoreTokensState
{
MoreTokens_Unknown,
MoreTokens_Yes,
MoreTokens_No
};
MoreTokensState m_hasMoreTokens;
wxString m_string; // the string we tokenize
wxString::const_iterator m_stringEnd;
// FIXME-UTF8: use wxWcharBuffer
wxWxCharBuffer m_delims; // all possible delimiters
size_t m_delimsLen;
wxString::const_iterator m_pos; // the current position in m_string
wxStringTokenizerMode m_mode; // see wxTOKEN_XXX values

93
src/common/tokenzr.cpp
View File

@ -38,6 +38,42 @@
// implementation
// ============================================================================
// ----------------------------------------------------------------------------
// helpers
// ----------------------------------------------------------------------------
static wxString::const_iterator
find_first_of(const wxChar *delims, size_t len,
const wxString::const_iterator& from,
const wxString::const_iterator& end)
{
wxASSERT_MSG( from <= end, _T("invalid index") );
for ( wxString::const_iterator i = from; i != end; ++i )
{
if ( wxTmemchr(delims, *i, len) )
return i;
}
return end;
}
static wxString::const_iterator
find_first_not_of(const wxChar *delims, size_t len,
const wxString::const_iterator& from,
const wxString::const_iterator& end)
{
wxASSERT_MSG( from <= end, _T("invalid index") );
for ( wxString::const_iterator i = from; i != end; ++i )
{
if ( !wxTmemchr(delims, *i, len) )
return i;
}
return end;
}
// ----------------------------------------------------------------------------
// wxStringTokenizer construction
// ----------------------------------------------------------------------------
@ -78,7 +114,13 @@ void wxStringTokenizer::SetString(const wxString& str,
}
}
m_delims = delims;
#if wxUSE_UNICODE // FIXME-UTF8: only wc_str()
m_delims = delims.wc_str();
#else
m_delims = delims.mb_str();
#endif
m_delimsLen = delims.length();
m_mode = mode;
Reinit(str);
@ -89,8 +131,10 @@ void wxStringTokenizer::Reinit(const wxString& str)
wxASSERT_MSG( IsOk(), _T("you should call SetString() first") );
m_string = str;
m_pos = 0;
m_stringEnd = m_string.end();
m_pos = m_string.begin();
m_lastDelim = _T('\0');
m_hasMoreTokens = MoreTokens_Unknown;
}
// ----------------------------------------------------------------------------
@ -99,10 +143,29 @@ void wxStringTokenizer::Reinit(const wxString& str)
// do we have more of them?
bool wxStringTokenizer::HasMoreTokens() const
{
// GetNextToken() calls HasMoreTokens() and so HasMoreTokens() is called
// twice in every interation in the following common usage patten:
// while ( HasMoreTokens() )
// GetNextToken();
// We optimize this case by caching HasMoreTokens() return value here:
if ( m_hasMoreTokens == MoreTokens_Unknown )
{
bool r = DoHasMoreTokens();
wxConstCast(this, wxStringTokenizer)->m_hasMoreTokens =
r ? MoreTokens_Yes : MoreTokens_No;
return r;
}
else
return m_hasMoreTokens == MoreTokens_Yes;
}
bool wxStringTokenizer::DoHasMoreTokens() const
{
wxCHECK_MSG( IsOk(), false, _T("you should call SetString() first") );
if ( m_string.find_first_not_of(m_delims, m_pos) != wxString::npos )
if ( find_first_not_of(m_delims, m_delimsLen, m_pos, m_stringEnd)
!= m_stringEnd )
{
// there are non delimiter characters left, so we do have more tokens
return true;
@ -114,7 +177,7 @@ bool wxStringTokenizer::HasMoreTokens() const
case wxTOKEN_RET_DELIMS:
// special hack for wxTOKEN_RET_EMPTY: we should return the initial
// empty token even if there are only delimiters after it
return m_pos == 0 && !m_string.empty();
return !m_string.empty() && m_pos == m_string.begin();
case wxTOKEN_RET_EMPTY_ALL:
// special hack for wxTOKEN_RET_EMPTY_ALL: we can know if we had
@ -123,7 +186,7 @@ bool wxStringTokenizer::HasMoreTokens() const
// up to the end of the string in GetNextToken(), but if it is not
// NUL yet we still have this last token to return even if m_pos is
// already at m_string.length()
return m_pos < m_string.length() || m_lastDelim != _T('\0');
return m_pos < m_stringEnd || m_lastDelim != _T('\0');
case wxTOKEN_INVALID:
case wxTOKEN_DEFAULT:
@ -147,7 +210,7 @@ size_t wxStringTokenizer::CountTokens() const
// important if its implementation here is not as efficient as it
// could be -- but OTOH like this we're sure to get the correct answer
// in all modes
wxStringTokenizer tkz(m_string.c_str() + m_pos, m_delims, m_mode);
wxStringTokenizer tkz(wxString(m_pos, m_stringEnd), m_delims, m_mode);
size_t count = 0;
while ( tkz.HasMoreTokens() )
@ -174,18 +237,21 @@ wxString wxStringTokenizer::GetNextToken()
break;
}
m_hasMoreTokens = MoreTokens_Unknown;
// find the end of this token
size_t pos = m_string.find_first_of(m_delims, m_pos);
wxString::const_iterator pos =
find_first_of(m_delims, m_delimsLen, m_pos, m_stringEnd);
// and the start of the next one
if ( pos == wxString::npos )
if ( pos == m_stringEnd )
{
// no more delimiters, the token is everything till the end of
// string
token.assign(m_string, m_pos, wxString::npos);
token.assign(m_pos, m_stringEnd);
// skip the token
m_pos = m_string.length();
m_pos = m_stringEnd;
// it wasn't terminated
m_lastDelim = _T('\0');
@ -194,16 +260,15 @@ wxString wxStringTokenizer::GetNextToken()
{
// in wxTOKEN_RET_DELIMS mode we return the delimiter character
// with token, otherwise leave it out
size_t len = pos - m_pos;
if ( m_mode == wxTOKEN_RET_DELIMS )
len++;
++pos;
token.assign(m_string, m_pos, len);
token.assign(m_pos, pos);
// skip the token and the trailing delimiter
m_pos = pos + 1;
m_lastDelim = m_string[pos];
m_lastDelim = (pos == m_stringEnd) ? _T('\0') : (wxChar)*pos;
}
}
while ( !AllowEmpty() && token.empty() );