Do proper script itemization with HarfBuzz

This implements http://www.unicode.org/reports/tr24/ by using ICU’s
implementation of it, but since the code in question is private API, I
simply copied the two self-contained files.

This commit is best viewed with --ignore-space-change.

Change-Id: I38c385d4fb6f8a2edc804d48f0aa14df9f0a8b3b

vcl/Library_vcl.mk

@@ -464,6 +464,7 @@ vcl_generic_code= \
     vcl/generic/glyphs/gcach_layout \
     vcl/generic/glyphs/gcach_rbmp \
     vcl/generic/glyphs/glyphcache \
+    vcl/generic/glyphs/scrptrun \
     vcl/generic/fontmanager/fontcache \
     vcl/generic/fontmanager/fontconfig \
     vcl/generic/fontmanager/fontmanager \

vcl/generic/glyphs/scrptrun.cxx

+/*
+ *******************************************************************************
+ *
+ *   Copyright (c) 1995-2013 International Business Machines Corporation and others
+ *
+ *   All rights reserved.
+ *
+ *   Permission is hereby granted, free of charge, to any person obtaining a copy of
+ *   this software and associated documentation files (the "Software"), to deal in
+ *   the Software without restriction, including without limitation the rights to
+ *   use, copy, modify, merge, publish, distribute, and/or sell copies of the
+ *   Software, and to permit persons to whom the Software is furnished to do so,
+ *   provided that the above copyright notice(s) and this permission notice appear
+ *   in all copies of the Software and that both the above copyright notice(s) and
+ *   this permission notice appear in supporting documentation.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN
+ *   NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE BE
+ *   LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY
+ *   DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ *   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ *   Except as contained in this notice, the name of a copyright holder shall not be
+ *   used in advertising or otherwise to promote the sale, use or other dealings in
+ *   this Software without prior written authorization of the copyright holder.
+ *
+ *******************************************************************************
+ *   file name:  scrptrun.cpp
+ *
+ *   created on: 10/17/2001
+ *   created by: Eric R. Mader
+ */
+
+#include "unicode/utypes.h"
+#include "unicode/uscript.h"
+
+#include "scrptrun.h"
+
+#define ARRAY_SIZE(array) (sizeof array  / sizeof array[0])
+
+const char ScriptRun::fgClassID=0;
+
+UChar32 ScriptRun::pairedChars[] = {
+    0x0028, 0x0029, // ascii paired punctuation
+    0x003c, 0x003e,
+    0x005b, 0x005d,
+    0x007b, 0x007d,
+    0x00ab, 0x00bb, // guillemets
+    0x2018, 0x2019, // general punctuation
+    0x201c, 0x201d,
+    0x2039, 0x203a,
+    0x3008, 0x3009, // chinese paired punctuation
+    0x300a, 0x300b,
+    0x300c, 0x300d,
+    0x300e, 0x300f,
+    0x3010, 0x3011,
+    0x3014, 0x3015,
+    0x3016, 0x3017,
+    0x3018, 0x3019,
+    0x301a, 0x301b
+};
+
+const int32_t ScriptRun::pairedCharCount = ARRAY_SIZE(pairedChars);
+const int32_t ScriptRun::pairedCharPower = 1 << highBit(pairedCharCount);
+const int32_t ScriptRun::pairedCharExtra = pairedCharCount - pairedCharPower;
+
+int8_t ScriptRun::highBit(int32_t value)
+{
+    if (value <= 0) {
+        return -32;
+    }
+
+    int8_t bit = 0;
+
+    if (value >= 1 << 16) {
+        value >>= 16;
+        bit += 16;
+    }
+
+    if (value >= 1 << 8) {
+        value >>= 8;
+        bit += 8;
+    }
+
+    if (value >= 1 << 4) {
+        value >>= 4;
+        bit += 4;
+    }
+
+    if (value >= 1 << 2) {
+        value >>= 2;
+        bit += 2;
+    }
+
+    if (value >= 1 << 1) {
+        value >>= 1;
+        bit += 1;
+    }
+
+    return bit;
+}
+
+int32_t ScriptRun::getPairIndex(UChar32 ch)
+{
+    int32_t probe = pairedCharPower;
+    int32_t index = 0;
+
+    if (ch >= pairedChars[pairedCharExtra]) {
+        index = pairedCharExtra;
+    }
+
+    while (probe > (1 << 0)) {
+        probe >>= 1;
+
+        if (ch >= pairedChars[index + probe]) {
+            index += probe;
+        }
+    }
+
+    if (pairedChars[index] != ch) {
+        index = -1;
+    }
+
+    return index;
+}
+
+UBool ScriptRun::sameScript(int32_t scriptOne, int32_t scriptTwo)
+{
+    return scriptOne <= USCRIPT_INHERITED || scriptTwo <= USCRIPT_INHERITED || scriptOne == scriptTwo;
+}
+
+UBool ScriptRun::next()
+{
+    int32_t startSP  = parenSP;  // used to find the first new open character
+    UErrorCode error = U_ZERO_ERROR;
+
+    // if we've fallen off the end of the text, we're done
+    if (scriptEnd >= charLimit) {
+        return false;
+    }
+
+    scriptCode = USCRIPT_COMMON;
+
+    for (scriptStart = scriptEnd; scriptEnd < charLimit; scriptEnd += 1) {
+        UChar   high = charArray[scriptEnd];
+        UChar32 ch   = high;
+
+        // if the character is a high surrogate and it's not the last one
+        // in the text, see if it's followed by a low surrogate
+        if (high >= 0xD800 && high <= 0xDBFF && scriptEnd < charLimit - 1)
+        {
+            UChar low = charArray[scriptEnd + 1];
+
+            // if it is followed by a low surrogate,
+            // consume it and form the full character
+            if (low >= 0xDC00 && low <= 0xDFFF) {
+                ch = (high - 0xD800) * 0x0400 + low - 0xDC00 + 0x10000;
+                scriptEnd += 1;
+            }
+        }
+
+        UScriptCode sc = uscript_getScript(ch, &error);
+        int32_t pairIndex = getPairIndex(ch);
+
+        // Paired character handling:
+        //
+        // if it's an open character, push it onto the stack.
+        // if it's a close character, find the matching open on the
+        // stack, and use that script code. Any non-matching open
+        // characters above it on the stack will be poped.
+        if (pairIndex >= 0) {
+            if ((pairIndex & 1) == 0) {
+                parenStack[++parenSP].pairIndex = pairIndex;
+                parenStack[parenSP].scriptCode  = scriptCode;
+            } else if (parenSP >= 0) {
+                int32_t pi = pairIndex & ~1;
+
+                while (parenSP >= 0 && parenStack[parenSP].pairIndex != pi) {
+                    parenSP -= 1;
+                }
+
+                if (parenSP < startSP) {
+                    startSP = parenSP;
+                }
+
+                if (parenSP >= 0) {
+                    sc = parenStack[parenSP].scriptCode;
+                }
+            }
+        }
+
+        if (sameScript(scriptCode, sc)) {
+            if (scriptCode <= USCRIPT_INHERITED && sc > USCRIPT_INHERITED) {
+                scriptCode = sc;
+
+                // now that we have a final script code, fix any open
+                // characters we pushed before we knew the script code.
+                while (startSP < parenSP) {
+                    parenStack[++startSP].scriptCode = scriptCode;
+                }
+            }
+
+            // if this character is a close paired character,
+            // pop it from the stack
+            if (pairIndex >= 0 && (pairIndex & 1) != 0 && parenSP >= 0) {
+                parenSP -= 1;
+                startSP -= 1;
+            }
+        } else {
+            // if the run broke on a surrogate pair,
+            // end it before the high surrogate
+            if (ch >= 0x10000) {
+                scriptEnd -= 1;
+            }
+
+            break;
+        }
+    }
+
+    return true;
+}
+

vcl/generic/glyphs/scrptrun.h

+/*
+ *******************************************************************************
+ *
+ *   Copyright (c) 1995-2013 International Business Machines Corporation and others
+ *
+ *   All rights reserved.
+ *
+ *   Permission is hereby granted, free of charge, to any person obtaining a copy of
+ *   this software and associated documentation files (the "Software"), to deal in
+ *   the Software without restriction, including without limitation the rights to
+ *   use, copy, modify, merge, publish, distribute, and/or sell copies of the
+ *   Software, and to permit persons to whom the Software is furnished to do so,
+ *   provided that the above copyright notice(s) and this permission notice appear
+ *   in all copies of the Software and that both the above copyright notice(s) and
+ *   this permission notice appear in supporting documentation.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN
+ *   NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE BE
+ *   LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY
+ *   DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ *   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ *   Except as contained in this notice, the name of a copyright holder shall not be
+ *   used in advertising or otherwise to promote the sale, use or other dealings in
+ *   this Software without prior written authorization of the copyright holder.
+ *
+ *******************************************************************************
+ *   file name:  scrptrun.h
+ *
+ *   created on: 10/17/2001
+ *   created by: Eric R. Mader
+ */
+
+#ifndef __SCRPTRUN_H
+#define __SCRPTRUN_H
+
+#include "unicode/utypes.h"
+#include "unicode/uobject.h"
+#include "unicode/uscript.h"
+
+struct ScriptRecord
+{
+    UChar32 startChar;
+    UChar32 endChar;
+    UScriptCode scriptCode;
+};
+
+struct ParenStackEntry
+{
+    int32_t pairIndex;
+    UScriptCode scriptCode;
+};
+
+class ScriptRun : public UObject {
+public:
+    ScriptRun();
+
+    ScriptRun(const UChar chars[], int32_t length);
+
+    ScriptRun(const UChar chars[], int32_t start, int32_t length);
+
+    void reset();
+
+    void reset(int32_t start, int32_t count);
+
+    void reset(const UChar chars[], int32_t start, int32_t length);
+
+    int32_t getScriptStart();
+
+    int32_t getScriptEnd();
+
+    UScriptCode getScriptCode();
+
+    UBool next();
+
+    /**
+     * ICU "poor man's RTTI", returns a UClassID for the actual class.
+     *
+     * @stable ICU 2.2
+     */
+    virtual inline UClassID getDynamicClassID() const { return getStaticClassID(); }
+
+    /**
+     * ICU "poor man's RTTI", returns a UClassID for this class.
+     *
+     * @stable ICU 2.2
+     */
+    static inline UClassID getStaticClassID() { return (UClassID)&fgClassID; }
+
+private:
+
+    static UBool sameScript(int32_t scriptOne, int32_t scriptTwo);
+
+    int32_t charStart;
+    int32_t charLimit;
+    const UChar *charArray;
+
+    int32_t scriptStart;
+    int32_t scriptEnd;
+    UScriptCode scriptCode;
+
+    ParenStackEntry parenStack[128];
+    int32_t parenSP;
+
+    static int8_t highBit(int32_t value);
+    static int32_t getPairIndex(UChar32 ch);
+
+    static UChar32 pairedChars[];
+    static const int32_t pairedCharCount;
+    static const int32_t pairedCharPower;
+    static const int32_t pairedCharExtra;
+
+    /**
+     * The address of this static class variable serves as this class's ID
+     * for ICU "poor man's RTTI".
+     */
+    static const char fgClassID;
+};
+
+inline ScriptRun::ScriptRun()
+{
+    reset(NULL, 0, 0);
+}
+
+inline ScriptRun::ScriptRun(const UChar chars[], int32_t length)
+{
+    reset(chars, 0, length);
+}
+
+inline ScriptRun::ScriptRun(const UChar chars[], int32_t start, int32_t length)
+{
+    reset(chars, start, length);
+}
+
+inline int32_t ScriptRun::getScriptStart()
+{
+    return scriptStart;
+}
+
+inline int32_t ScriptRun::getScriptEnd()
+{
+    return scriptEnd;
+}
+
+inline UScriptCode ScriptRun::getScriptCode()
+{
+    return scriptCode;
+}
+
+inline void ScriptRun::reset()
+{
+    scriptStart = charStart;
+    scriptEnd   = charStart;
+    scriptCode  = USCRIPT_INVALID_CODE;
+    parenSP     = -1;
+}
+
+inline void ScriptRun::reset(int32_t start, int32_t length)
+{
+    charStart = start;
+    charLimit = start + length;
+
+    reset();
+}
+
+inline void ScriptRun::reset(const UChar chars[], int32_t start, int32_t length)
+{
+    charArray = chars;
+
+    reset(start, length);
+}
+
+
+#endif