WebCore/rendering/break_lines.cpp
changeset 0 4f2f89ce4247
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/rendering/break_lines.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2005, 2007, 2010 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "break_lines.h"
+
+#include "CharacterNames.h"
+#include "TextBreakIterator.h"
+
+#if PLATFORM(MAC)
+#include <CoreServices/CoreServices.h>
+#endif
+
+namespace WebCore {
+
+static inline bool isBreakableSpace(UChar ch, bool treatNoBreakSpaceAsBreak)
+{
+    switch (ch) {
+        case ' ':
+        case '\n':
+        case '\t':
+            return true;
+        case noBreakSpace:
+            return treatNoBreakSpaceAsBreak;
+        default:
+            return false;
+    }
+}
+
+// This differs from the Unicode algorithm only in that Unicode does not break
+// between a question mark and a vertical line (U+007C).
+static const unsigned char internetExplorerLineBreaksAfterQuestionMarkTable[0x80] = {
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, // \t
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+    1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, // ! " ' ) , . /
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, // : ; ?
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, // ]
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1  // }
+};
+
+static const size_t internetExplorerLineBreaksAfterQuestionMarkTableSize = sizeof(internetExplorerLineBreaksAfterQuestionMarkTable) / sizeof(*internetExplorerLineBreaksAfterQuestionMarkTable);
+
+static inline bool shouldBreakAfter(UChar ch, UChar nextCh)
+{
+    switch (ch) {
+        // For a question mark preceding a non-ASCII characters, defer to the Unicode algorithm by returning false.
+        // For ASCII characters, use a lookup table for enhanced speed and for compatibility with Internet Explorer. 
+        case '?':
+            return nextCh < internetExplorerLineBreaksAfterQuestionMarkTableSize && internetExplorerLineBreaksAfterQuestionMarkTable[nextCh];
+        // Internet Explorer always allows breaking after a hyphen.
+        case '-':
+        case softHyphen:
+        // FIXME: cases for ideographicComma and ideographicFullStop are a workaround for an issue in Unicode 5.0
+        // which is likely to be resolved in Unicode 5.1 <http://bugs.webkit.org/show_bug.cgi?id=17411>.
+        // We may want to remove or conditionalize this workaround at some point.
+        case ideographicComma:
+        case ideographicFullStop:
+            return true;
+        default:
+            return false;
+    }
+}
+
+static inline bool needsLineBreakIterator(UChar ch)
+{
+    return ch > 0x7F && ch != noBreakSpace;
+}
+
+#if PLATFORM(MAC) && defined(BUILDING_ON_TIGER)
+static inline TextBreakLocatorRef lineBreakLocator()
+{
+    TextBreakLocatorRef locator = 0;
+    UCCreateTextBreakLocator(0, 0, kUCTextBreakLineMask, &locator);
+    return locator;
+}
+#endif
+
+int nextBreakablePosition(const UChar* str, int pos, int len, bool treatNoBreakSpaceAsBreak)
+{
+#if !PLATFORM(MAC) || !defined(BUILDING_ON_TIGER)
+    TextBreakIterator* breakIterator = 0;
+#endif
+    int nextBreak = -1;
+
+    UChar lastCh = pos > 0 ? str[pos - 1] : 0;
+    for (int i = pos; i < len; i++) {
+        UChar ch = str[i];
+
+        if (isBreakableSpace(ch, treatNoBreakSpaceAsBreak) || shouldBreakAfter(lastCh, ch))
+            return i;
+
+        if (needsLineBreakIterator(ch) || needsLineBreakIterator(lastCh)) {
+            if (nextBreak < i && i) {
+#if !PLATFORM(MAC) || !defined(BUILDING_ON_TIGER)
+                if (!breakIterator)
+                    breakIterator = lineBreakIterator(str, len);
+                if (breakIterator)
+                    nextBreak = textBreakFollowing(breakIterator, i - 1);
+#else
+                static TextBreakLocatorRef breakLocator = lineBreakLocator();
+                if (breakLocator) {
+                    UniCharArrayOffset nextUCBreak;
+                    if (UCFindTextBreak(breakLocator, kUCTextBreakLineMask, 0, str, len, i, &nextUCBreak) == 0)
+                        nextBreak = nextUCBreak;
+                }
+#endif
+            }
+            if (i == nextBreak && !isBreakableSpace(lastCh, treatNoBreakSpaceAsBreak))
+                return i;
+        }
+
+        lastCh = ch;
+    }
+
+    return len;
+}
+
+} // namespace WebCore