60 lines
1.7 KiB
Objective-C
60 lines
1.7 KiB
Objective-C
// 3 december 2016
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#import "uipriv_darwin.h"
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#import "attrstr.h"
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// CFStringGetRangeOfComposedCharactersAtIndex() is the function for grapheme clusters
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// https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/Strings/Articles/stringsClusters.html says that this does work on all multi-codepoint graphemes (despite the name), and that this is the preferred function for this particular job anyway
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int uiprivGraphemesTakesUTF16(void)
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{
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return 1;
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}
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uiprivGraphemes *uiprivNewGraphemes(void *s, size_t len)
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{
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uiprivGraphemes *g;
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UniChar *str = (UniChar *) s;
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CFStringRef cfstr;
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size_t ppos, gpos;
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CFRange range;
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size_t i;
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g = uiprivNew(uiprivGraphemes);
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cfstr = CFStringCreateWithCharactersNoCopy(NULL, str, len, kCFAllocatorNull);
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if (cfstr == NULL) {
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// TODO
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}
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// first figure out how many graphemes there are
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g->len = 0;
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ppos = 0;
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while (ppos < len) {
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range = CFStringGetRangeOfComposedCharactersAtIndex(cfstr, ppos);
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g->len++;
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ppos = range.location + range.length;
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}
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g->pointsToGraphemes = (size_t *) uiprivAlloc((len + 1) * sizeof (size_t), "size_t[] (graphemes)");
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g->graphemesToPoints = (size_t *) uiprivAlloc((g->len + 1) * sizeof (size_t), "size_t[] (graphemes)");
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// now calculate everything
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// fortunately due to the use of CFRange we can do this in one loop trivially!
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ppos = 0;
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gpos = 0;
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while (ppos < len) {
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range = CFStringGetRangeOfComposedCharactersAtIndex(cfstr, ppos);
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for (i = 0; i < range.length; i++)
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g->pointsToGraphemes[range.location + i] = gpos;
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g->graphemesToPoints[gpos] = range.location;
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gpos++;
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ppos = range.location + range.length;
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}
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// and set the last one
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g->pointsToGraphemes[ppos] = gpos;
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g->graphemesToPoints[gpos] = ppos;
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CFRelease(cfstr);
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return g;
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}
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