X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/ed93168bf9d23bdc83184039c84d263ed6f87945..dd0fba48accaa064eba35a54a65a1f0b42b5c862:/docs/latex/wx/tstring.tex diff --git a/docs/latex/wx/tstring.tex b/docs/latex/wx/tstring.tex index 59667e009e..b40d241257 100644 --- a/docs/latex/wx/tstring.tex +++ b/docs/latex/wx/tstring.tex @@ -1,6 +1,6 @@ \section{wxString overview}\label{wxstringoverview} -Classes: \helpref{wxString}{wxstring}, \helpref{wxArrayString}{wxarray}, \helpref{wxStringTokenizer}{wxstringtokenizer} +Classes: \helpref{wxString}{wxstring}, \helpref{wxArrayString}{wxarraystring}, \helpref{wxStringTokenizer}{wxstringtokenizer} \subsection{Introduction} @@ -9,11 +9,11 @@ wxString is a class which represents a character string of arbitrary length (lim arbitrary characters. The ASCII NUL character is allowed, although care should be taken when passing strings containing it to other functions. -wxString only works with ASCII (8 bit characters) strings as of this release, -but support for UNICODE (16 but characters) is planned for the next one. +wxString works with both ASCII (8 bit characters) as well as UNICODE (16 but +characters) strings. This class has all the standard operations you can expect to find in a string class: -dynamic memory management (string extends to accomodate new characters), +dynamic memory management (string extends to accommodate new characters), construction from other strings, C strings and characters, assignment operators, access to individual characters, string concatenation and comparison, substring extraction, case conversion, trimming and padding (with spaces), searching and @@ -60,8 +60,8 @@ wxString internally by wxWindows. However, there are several problems as well. The most important one is probably that there are often several functions to do exactly the same thing: for example, to get the length of the string either one of -\helpref{length()}{wxstringlength}, \helpref{Len()}{wxstringlen} or -\helpref{Length()}{wxstringLength} may be used. The first function, as almost +length(), \helpref{Len()}{wxstringlen} or +\helpref{Length()}{wxstringlength} may be used. The first function, as almost all the other functions in lowercase, is std::string compatible. The second one is "native" wxString version and the last one is wxWindows 1.xx way. So the question is: which one is better to use? And the answer is that: @@ -73,7 +73,7 @@ in both wxWindows and other programs (by just typedefing wxString as std::string when used outside wxWindows) and by staying compatible with future versions of wxWindows which will probably start using std::string sooner or later too. -In the situations where there is no correspondinw std::string function, please +In the situations where there is no corresponding std::string function, please try to use the new wxString methods and not the old wxWindows 1.xx variants which are deprecated and may disappear in future versions. @@ -131,25 +131,33 @@ variables. \subsection{Other string related functions and classes} -As most programs use character strings, the standard C library provides quite a -few functions to work with them. Unfortunately, some of them have rather -counter-intuitive behaviour (like strncpy() which doesn't always terminate the resulting -string with a NULL) and are in general not very safe (passing NULL to them will -probably lead to program crash). Moreover, some very useful functions are not -standard at all. This is why in addition to all wxString functions, there are -also a few global string functions which try to correct these problems: -\helpref{IsEmpty()}{IsEmpty} verifies whether the string is empty (returning -TRUE for NULL pointers), \helpref{Strlen()}{Strlen} also handles NULLs correctly -and returns 0 for them and \helpref{Stricmp()}{Stricmp} is just a -platform-independent version of case-insensitive string comparison function -known either as stricmp() or strcasecmp() on different platforms. +As most programs use character strings, the standard C library provides quite +a few functions to work with them. Unfortunately, some of them have rather +counter-intuitive behaviour (like strncpy() which doesn't always terminate the +resulting string with a NULL) and are in general not very safe (passing NULL +to them will probably lead to program crash). Moreover, some very useful +functions are not standard at all. This is why in addition to all wxString +functions, there are also a few global string functions which try to correct +these problems: \helpref{wxIsEmpty()}{wxisempty} verifies whether the string +is empty (returning {\tt TRUE} for {\tt NULL} pointers), +\helpref{wxStrlen()}{wxstrlen} also handles NULLs correctly and returns 0 for +them and \helpref{wxStricmp()}{wxstricmp} is just a platform-independent +version of case-insensitive string comparison function known either as +stricmp() or strcasecmp() on different platforms. + +The {\tt } header also defines \helpref{wxSnprintf}{wxsnprintf} +and \helpref{wxVsnprintf}{wxvsnprintf} functions which should be used instead +of the inherently dangerous standard {\tt sprintf()} and which use {\tt +snprintf()} instead which does buffer size checks whenever possible. Of +course, you may also use \helpref{wxString::Printf}{wxstringprintf} which is +also safe. There is another class which might be useful when working with wxString: \helpref{wxStringTokenizer}{wxstringtokenizer}. It is helpful when a string must be broken into tokens and replaces the standard C library {\it strtok()} function. -And the very last string-related class is \helpref{wxArrayString}{wxarray}: it +And the very last string-related class is \helpref{wxArrayString}{wxarraystring}: it is just a version of the "template" dynamic array class which is specialized to work with strings. Please note that this class is specially optimized (using its knowledge of the internal structure of wxString) for storing strings and so it is @@ -164,7 +172,7 @@ share the same data. But as soon as one of the two (or more) strings is modified, the data has to be copied because the changes to one of the strings shouldn't be seen in the -otheres. As data copying only happens when the string is written to, this is +others. As data copying only happens when the string is written to, this is known as COW. What is important to understand is that all this happens absolutely @@ -252,7 +260,7 @@ which tells the wxString class to collect performance statistics and to show them on stderr on program termination. This will show you the average length of strings your program manipulates, their average initial length and also the percent of times when memory wasn't reallocated when string concatenation was -done but the alread preallocated memory was used (this value should be about +done but the already preallocated memory was used (this value should be about 98\% for the default allocation policy, if it is less than 90\% you should really consider fine tuning wxString for your application).