How to Break Text Based on Locale

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Different languages might have different rules for hyphenation, spacing, and where a line should be broken on a page. For this reason, the MLang IMLangLineBreakConsole interface provides a locale-aware line-breaking functionality for console-based applications.

To use this feature to break a Unicode string for output:

  1. Make sure the Component Object Library has been initialized.

    Before you can use any of the functionality provided by MLang, you must first initialize the Component Object Library through a call to CoInitialize. Every call to CoInitialize must be accompanied by a call to CoUninitialize when the application terminates. CoUninitialize ensures that the application does not quit until it has received all of its pending messages.

  2. Obtain a pointer to an IMLangLineBreakConsole interface.

    The IMLangLineBreakConsole interface is part of the MultiLanguage. If no such object exists, you must create one and obtain a pointer to the corresponding IMultiLanguage interface through a call to CoCreateInstance. Once this has been accomplished, call QueryInterface through IMultiLanguage for a pointer to an IMLangLineBreakConsole interface.

  3. Use the IMLangLineBreakConsole methods to break the string into the proper number of columns for output.

    For Unicode strings, use IMLangLineBreakConsole::BreakLineW. For multibyte strings, use IMLangLineBreakConsole::BreakLineA. The following code sample breaks the null-terminated Unicode string pwszStr, based on the constant NUMCOLUMNS and the given locale, and prints it to the screen.

    // pwszStr - null-terminated Unicode string of cchMax characters or less.
// locale - locale identifier of the output string.
// pMLLBC - pointer to an IMLangLineBreakConsole interface.

size_t cchMax = STRSAFE_MAX_CCH;
size_t cchLength;

WCHAR pwszSrc[cchMax] = L("some source string");
HRESULT lengthHr = StringCchLengthW(pwszSrc, cchMax, &cchLength);

long cchSize = cchLength;
    // Size of pwszStr in characters.
int MaxColumns = NUMCOLUMNS;
    // Desired number of columns for output.
long cchLine;
    // Number of characters to output in the current line.
long cchSkip;
    // Number of characters to skip before starting the next line.
long totalLine = 0;
   // Total number of characters processed.

if(SUCCEEDED(lengthHr))
{
    WCHAR wStr[NUMCOLUMNS] = "";
    HRESULT hr = S_OK;
    while((totalLine < cchSize) && SUCCEEDED(hr))
        // Process the entire string unless an error occurs.
    {    
        hr = pMLLBC->BreakLineW(locale, pwszStr + totalLine,
            cchSize - totalLine, MaxColumns, &cchLine, &cchSkip);

        HRESULT copyHr = StringCchCopyW(wStr,  cchLine + 1, pwszStr + cchSkip + totalLine);
            // Copy characters of pwszStr for output.

        if(SUCCEEDED(copyHr))
        {
            totalLine = totalLine + cchLine + cchSkip;
                // Increase the total number of characters processed. 
            wprintf(L"%s\n", wStr);
                // Output the string to the console-based application.
        }
    }
}
else
{
   //  TODO: Add error handling code here.
}

  4. Remember to release the interfaces and uninitialize the Component Object Library before your program terminates.

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