110 lines
3.2 KiB
C++
110 lines
3.2 KiB
C++
// 25 may 2016
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#include "uipriv_windows.hpp"
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// We could use CharNext() to generate grapheme cluster boundaries, but it doesn't handle surrogate pairs properly (see http://archives.miloush.net/michkap/archive/2008/12/16/9223301.html).
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// So let's use Uniscribe (see http://archives.miloush.net/michkap/archive/2005/01/14/352802.html)
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// See also http://www.catch22.net/tuts/uniscribe-mysteries, http://www.catch22.net/tuts/keyboard-navigation, and https://maxradi.us/documents/uniscribe/ for more details.
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// TODO the DirectWrite equivalent appears to be https://msdn.microsoft.com/en-us/library/windows/desktop/dd316625(v=vs.85).aspx but is somehow somewhat more complicated to use than Uniscribe is! maybe the PadWrite sample uses it? or should we just keep using Uniscribe?
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int graphemesTakesUTF16(void)
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{
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return 1;
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}
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static HRESULT itemize(WCHAR *s, size_t len, SCRIPT_ITEM **out, int *outn)
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{
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SCRIPT_CONTROL sc;
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SCRIPT_STATE ss;
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SCRIPT_ITEM *items;
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size_t maxItems;
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int n;
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HRESULT hr;
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// make sure these are zero-initialized to avoid mangling the text
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ZeroMemory(&sc, sizeof (SCRIPT_CONTROL));
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ZeroMemory(&ss, sizeof (SCRIPT_STATE));
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maxItems = len + 2;
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for (;;) {
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items = new SCRIPT_ITEM[maxItems + 1];
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hr = ScriptItemize(s, len,
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maxItems,
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&sc, &ss,
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items, &n);
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if (hr == S_OK)
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break;
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// otherwise either an error or not enough room
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delete[] items;
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if (hr != E_OUTOFMEMORY)
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return hr;
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maxItems *= 2; // add some more and try again
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}
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*out = items;
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*outn = n;
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return S_OK;
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}
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struct graphemes *graphemes(void *s, size_t len)
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{
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struct graphemes *g;
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WCHAR *str = (WCHAR *) s;
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SCRIPT_ITEM *items;
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int nItems;
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int curItemIndex;
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int nCharsInCurItem;
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size_t *pPTG, *pGTP;
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HRESULT hr;
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g = uiNew(struct graphemes);
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hr = itemize(str, len, &items, &nItems);
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if (hr != S_OK)
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logHRESULT(L"error itemizing string for finding grapheme cluster boundaries", hr);
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g->len = nItems;
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g->pointsToGraphemes = (size_t *) uiAlloc((len + 1) * sizeof (size_t), "size_t[] (graphemes)");
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// note that there are actually nItems + 1 elements in items
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// items[nItems] is the grapheme one past the end
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g->graphemesToPoints = (size_t *) uiAlloc((g->len + 1) * sizeof (size_t), "size_t[] (graphemes)");
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pPTG = g->pointsToGraphemes;
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pGTP = g->graphemesToPoints;
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for (curItemIndex = 0; curItemIndex < nItems; curItemIndex++) {
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SCRIPT_ITEM *curItem, *nextItem;
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SCRIPT_LOGATTR *logattr;
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size_t *curGTP;
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int i;
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curItem = items + curItemIndex;
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nextItem = curItem + 1;
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nCharsInCurItem = nextItem->iCharPos - curItem->iCharPos;
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logattr = new SCRIPT_LOGATTR[nCharsInCurItem];
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hr = ScriptBreak(str + curItem->iCharPos, nCharsInCurItem,
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&(curItem->a), logattr);
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if (hr != S_OK)
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logHRESULT(L"error breaking string for finding grapheme cluster boundaries", hr);
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// TODO can we merge these loops somehow?
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curGTP = pGTP;
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for (i = 0; i < nCharsInCurItem; i++)
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if (logattr[i].fCharStop != 0)
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*pGTP++ = curItem->iCharPos + i;
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for (i = 0; i < nCharsInCurItem; i++) {
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*pPTG++ = curGTP - g->graphemesToPoints;
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if (logattr[i].fCharStop != 0)
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curGTP++;
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}
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delete[] logattr;
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}
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// and handle the last item for the end of the string
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*pGTP++ = items[nItems].iCharPos;
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*pPTG++ = pGTP - g->graphemesToPoints;
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delete[] items;
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return g;
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}
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