diff --git a/src/common/string.cpp b/src/common/string.cpp index bb02779aee..c2246e4991 100644 --- a/src/common/string.cpp +++ b/src/common/string.cpp @@ -44,6 +44,10 @@ IMPLEMENT_DYNAMIC_CLASS(wxString, wxObject) #endif //WXSTRING_IS_WXOBJECT +// allocating extra space for each string consumes more memory but speeds up +// the concatenation operations (nLen is the current string's length) +#define EXTRA_ALLOC 16 + // --------------------------------------------------------------------------- // static class variables definition // --------------------------------------------------------------------------- @@ -52,9 +56,9 @@ const size_t wxString::npos = STRING_MAXLEN; #endif -// =========================================================================== -// static class data, special inlines -// =========================================================================== +// ---------------------------------------------------------------------------- +// static data +// ---------------------------------------------------------------------------- // for an empty string, GetStringData() will return this address static int g_strEmpty[] = { -1, // ref count (locked) @@ -64,9 +68,9 @@ static int g_strEmpty[] = { -1, // ref count (locked) // empty C style string: points to 'string data' byte of g_strEmpty extern const char *g_szNul = (const char *)(&g_strEmpty[3]); -// =========================================================================== +// ---------------------------------------------------------------------------- // global functions -// =========================================================================== +// ---------------------------------------------------------------------------- #ifdef STD_STRING_COMPATIBILITY @@ -115,6 +119,35 @@ NAMESPACE istream& operator>>(NAMESPACE istream& is, wxString& WXUNUSED(str)) #endif //std::string compatibility +// ---------------------------------------------------------------------------- +// private classes +// ---------------------------------------------------------------------------- + +// this small class is used to gather statistics for performance tuning +//#define WXSTRING_STATISTICS +#ifdef WXSTRING_STATISTICS + class Averager + { + public: + Averager(const char *sz) { m_sz = sz; m_nTotal = m_nCount = 0; } + ~Averager() + { printf("wxString: average %s = %f\n", m_sz, ((float)m_nTotal)/m_nCount); } + + void Add(uint n) { m_nTotal += n; m_nCount++; } + + private: + uint m_nCount, m_nTotal; + const char *m_sz; + } g_averageLength("allocation size"), + g_averageSummandLength("summand length"), + g_averageConcatHit("hit probability in concat"), + g_averageInitialLength("initial string length"); + + #define STATISTICS_ADD(av, val) g_average##av.Add(val) +#else + #define STATISTICS_ADD(av, val) +#endif // WXSTRING_STATISTICS + // =========================================================================== // wxString class core // =========================================================================== @@ -123,27 +156,6 @@ NAMESPACE istream& operator>>(NAMESPACE istream& is, wxString& WXUNUSED(str)) // construction // --------------------------------------------------------------------------- -// construct an empty string -wxString::wxString() -{ - Init(); -} - -// copy constructor -wxString::wxString(const wxString& stringSrc) -{ - wxASSERT( stringSrc.GetStringData()->IsValid() ); - - if ( stringSrc.IsEmpty() ) { - // nothing to do for an empty string - Init(); - } - else { - m_pchData = stringSrc.m_pchData; // share same data - GetStringData()->Lock(); // => one more copy - } -} - // constructs string of copies of character wxString::wxString(char ch, size_t nLength) { @@ -168,6 +180,8 @@ void wxString::InitWith(const char *psz, size_t nPos, size_t nLength) if ( nLength == STRING_MAXLEN ) nLength = Strlen(psz + nPos); + STATISTICS_ADD(InitialLength, nLength); + if ( nLength > 0 ) { // trailing '\0' is written in AllocBuffer() AllocBuffer(nLength); @@ -175,13 +189,6 @@ void wxString::InitWith(const char *psz, size_t nPos, size_t nLength) } } -// take first nLength characters of C string psz -// (default value of STRING_MAXLEN means take all the string) -wxString::wxString(const char *psz, size_t nLength) -{ - InitWith(psz, 0, nLength); -} - // the same as previous constructor, but for compilers using unsigned char wxString::wxString(const unsigned char* psz, size_t nLength) { @@ -190,14 +197,6 @@ wxString::wxString(const unsigned char* psz, size_t nLength) #ifdef STD_STRING_COMPATIBILITY -// ctor from a substring -wxString::wxString(const wxString& str, size_t nPos, size_t nLen) -{ - wxASSERT( str.GetStringData()->IsValid() ); - - InitWith(str.c_str(), nPos, nLen == npos ? 0 : nLen); -} - // poor man's iterators are "void *" pointers wxString::wxString(const void *pStart, const void *pEnd) { @@ -233,16 +232,18 @@ void wxString::AllocBuffer(size_t nLen) wxASSERT( nLen > 0 ); // wxASSERT( nLen <= INT_MAX-1 ); // max size (enough room for 1 extra) + STATISTICS_ADD(Length, nLen); + // allocate memory: // 1) one extra character for '\0' termination // 2) sizeof(wxStringData) for housekeeping info - wxStringData* pData = (wxStringData*)malloc(sizeof(wxStringData) + - (nLen + 1)*sizeof(char)); + wxStringData* pData = (wxStringData*) + malloc(sizeof(wxStringData) + (nLen + EXTRA_ALLOC + 1)*sizeof(char)); pData->nRefs = 1; - pData->data()[nLen] = '\0'; pData->nDataLength = nLen; - pData->nAllocLength = nLen; + pData->nAllocLength = nLen + EXTRA_ALLOC; m_pchData = pData->data(); // data starts after wxStringData + m_pchData[nLen] = '\0'; } // must be called before changing this string @@ -252,8 +253,9 @@ void wxString::CopyBeforeWrite() if ( pData->IsShared() ) { pData->Unlock(); // memory not freed because shared - AllocBuffer(pData->nDataLength); - memcpy(m_pchData, pData->data(), (pData->nDataLength + 1)*sizeof(char)); + uint nLen = pData->nDataLength; + AllocBuffer(nLen); + memcpy(m_pchData, pData->data(), nLen*sizeof(char)); } wxASSERT( !pData->IsShared() ); // we must be the only owner @@ -265,7 +267,7 @@ void wxString::AllocBeforeWrite(size_t nLen) wxASSERT( nLen != 0 ); // doesn't make any sense // must not share string and must have enough space - register wxStringData* pData = GetStringData(); + wxStringData* pData = GetStringData(); if ( pData->IsShared() || (nLen > pData->nAllocLength) ) { // can't work with old buffer, get new one pData->Unlock(); @@ -282,19 +284,27 @@ void wxString::Alloc(uint nLen) if ( pData->nAllocLength <= nLen ) { if ( pData->IsEmpty() ) AllocBuffer(nLen); + else if ( pData->IsShared() ) { + pData->Unlock(); // memory not freed because shared + uint nLen = pData->nDataLength; + AllocBuffer(nLen); + memcpy(m_pchData, pData->data(), nLen*sizeof(char)); + } else { + nLen += EXTRA_ALLOC; + wxStringData *p = (wxStringData *) realloc(pData, sizeof(wxStringData) + (nLen + 1)*sizeof(char)); - if ( p != NULL && p != pData ) { - // the call succeeded but the pointer changed - pData->Unlock(); - free(pData); - p->nRefs = 1; - p->nAllocLength = nLen; - m_pchData = p->data(); + if ( p == NULL ) { + // @@@ what to do on memory error? + return; } - //else: do nothing: either the call failed or the pointer is unchanged + + // it's not important if the pointer changed or not (the check for this + // is not faster than assigning to m_pchData in all cases) + p->nAllocLength = nLen; + m_pchData = p->data(); } } //else: we've already got enough @@ -306,8 +316,7 @@ void wxString::Shrink() wxStringData *pData = GetStringData(); void *p = realloc(pData, sizeof(wxStringData) + (pData->nDataLength + 1)*sizeof(char)); - if ( p == NULL ) // huh? can't unallocate memory? unlikely but possible. - return; + wxASSERT( p != NULL ); // can't free memory? wxASSERT( p == pData ); // we're decrementing the size - block shouldn't move! } @@ -329,12 +338,6 @@ void wxString::UngetWriteBuf() GetStringData()->Validate(TRUE); } -// dtor frees memory if no other strings use it -wxString::~wxString() -{ - GetStringData()->Unlock(); -} - // --------------------------------------------------------------------------- // data access // --------------------------------------------------------------------------- @@ -412,47 +415,48 @@ wxString& wxString::operator=(const wchar_t *pwz) // string concatenation // --------------------------------------------------------------------------- -// concatenate two sources -// NB: assume that 'this' is a new wxString object -void wxString::ConcatCopy(int nSrc1Len, const char *pszSrc1Data, - int nSrc2Len, const char *pszSrc2Data) -{ - int nNewLen = nSrc1Len + nSrc2Len; - if ( nNewLen != 0 ) - { - AllocBuffer(nNewLen); - memcpy(m_pchData, pszSrc1Data, nSrc1Len*sizeof(char)); - memcpy(m_pchData + nSrc1Len, pszSrc2Data, nSrc2Len*sizeof(char)); - } -} - // add something to this string void wxString::ConcatSelf(int nSrcLen, const char *pszSrcData) { - // concatenating an empty string is a NOP - if ( nSrcLen != 0 ) { - register wxStringData *pData = GetStringData(); + STATISTICS_ADD(SummandLength, nSrcLen); - // alloc new buffer if current is too small - if ( pData->IsShared() || - pData->nDataLength + nSrcLen > pData->nAllocLength ) { - // we have to grow the buffer, use the ConcatCopy routine - // (which will allocate memory) - wxStringData* pOldData = GetStringData(); - ConcatCopy(pOldData->nDataLength, m_pchData, nSrcLen, pszSrcData); - pOldData->Unlock(); - } - else { - // fast concatenation when buffer big enough - memcpy(m_pchData + pData->nDataLength, pszSrcData, nSrcLen*sizeof(char)); - pData->nDataLength += nSrcLen; + // concatenating an empty string is a NOP, but it happens quite rarely, + // so we don't waste our time checking for it + // if ( nSrcLen > 0 ) + wxStringData *pData = GetStringData(); + uint nLen = pData->nDataLength; + uint nNewLen = nLen + nSrcLen; - // should be enough space - wxASSERT( pData->nDataLength <= pData->nAllocLength ); + // alloc new buffer if current is too small + if ( pData->IsShared() ) { + STATISTICS_ADD(ConcatHit, 0); - m_pchData[pData->nDataLength] = '\0'; // put terminating '\0' - } + // we have to allocate another buffer + wxStringData* pOldData = GetStringData(); + AllocBuffer(nNewLen); + memcpy(m_pchData, pOldData->data(), nLen*sizeof(char)); + pOldData->Unlock(); } + else if ( nNewLen > pData->nAllocLength ) { + STATISTICS_ADD(ConcatHit, 0); + + // we have to grow the buffer + Alloc(nNewLen); + } + else { + STATISTICS_ADD(ConcatHit, 1); + + // the buffer is already big enough + } + + // should be enough space + wxASSERT( nNewLen <= GetStringData()->nAllocLength ); + + // fast concatenation - all is done in our buffer + memcpy(m_pchData + nLen, pszSrcData, nSrcLen*sizeof(char)); + + m_pchData[nNewLen] = '\0'; // put terminating '\0' + GetStringData()->nDataLength = nNewLen; // and fix the length } /* @@ -467,18 +471,19 @@ wxString operator+(const wxString& string1, const wxString& string2) wxASSERT( string1.GetStringData()->IsValid() ); wxASSERT( string2.GetStringData()->IsValid() ); - wxString s; - s.ConcatCopy(string1.GetStringData()->nDataLength, string1.m_pchData, - string2.GetStringData()->nDataLength, string2.m_pchData); + wxString s = string1; + s += string2; + return s; } -wxString operator+(const wxString& string1, char ch) +wxString operator+(const wxString& string, char ch) { - wxASSERT( string1.GetStringData()->IsValid() ); + wxASSERT( string.GetStringData()->IsValid() ); + + wxString s = string; + s += ch; - wxString s; - s.ConcatCopy(string1.GetStringData()->nDataLength, string1.m_pchData, 1, &ch); return s; } @@ -486,8 +491,9 @@ wxString operator+(char ch, const wxString& string) { wxASSERT( string.GetStringData()->IsValid() ); - wxString s; - s.ConcatCopy(1, &ch, string.GetStringData()->nDataLength, string.m_pchData); + wxString s = ch; + s += string; + return s; } @@ -496,8 +502,10 @@ wxString operator+(const wxString& string, const char *psz) wxASSERT( string.GetStringData()->IsValid() ); wxString s; - s.ConcatCopy(string.GetStringData()->nDataLength, string.m_pchData, - Strlen(psz), psz); + s.Alloc(Strlen(psz) + string.Len()); + s = string; + s += psz; + return s; } @@ -506,8 +514,10 @@ wxString operator+(const char *psz, const wxString& string) wxASSERT( string.GetStringData()->IsValid() ); wxString s; - s.ConcatCopy(Strlen(psz), psz, - string.GetStringData()->nDataLength, string.m_pchData); + s.Alloc(Strlen(psz) + string.Len()); + s = psz; + s += string; + return s; } @@ -522,12 +532,10 @@ wxString operator+(const char *psz, const wxString& string) // helper function: clone the data attached to this string void wxString::AllocCopy(wxString& dest, int nCopyLen, int nCopyIndex) const { - if ( nCopyLen == 0 ) - { + if ( nCopyLen == 0 ) { dest.Init(); } - else - { + else { dest.AllocBuffer(nCopyLen); memcpy(dest.m_pchData, m_pchData + nCopyIndex, nCopyLen*sizeof(char)); } @@ -833,30 +841,6 @@ int wxString::PrintfV(const char* pszFormat, va_list argptr) return iLen; } -#if 0 -int wxString::Scanf(const char *pszFormat, ...) const -{ - va_list argptr; - va_start(argptr, pszFormat); - - int iLen = ScanfV(pszFormat, argptr); - - va_end(argptr); - - return iLen; -} - -int wxString::ScanfV(const char *pszFormat, va_list argptr) const -{ -#ifdef __WXMSW__ - wxMessageBox("ScanfV not implemented"); - return 0; -#else - return vsscanf(c_str(), pszFormat, argptr); -#endif -} -#endif - // ---------------------------------------------------------------------------- // misc other operations // ---------------------------------------------------------------------------- @@ -1192,9 +1176,6 @@ void wxArrayString::Alloc(size_t nSize) } // searches the array for an item (forward or backwards) - -// Robert Roebling (changed to bool from bool) - int wxArrayString::Index(const char *sz, bool bCase, bool bFromEnd) const { if ( bFromEnd ) {