Feature: drop ICU-lx in favour of directly interfacing with harfbuzz

This means we have RTL support again with ICU 58+. It makes use of:
- ICU for bidi-itemization
- ICU for script-itemization
- OpenTTD for style-itemization
- harfbuzz for shaping

src/3rdparty/icu/scriptrun.cpp

@@ -0,0 +1,208 @@
+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+ *******************************************************************************
+ *
+ *   Copyright (C) 1999-2016, International Business Machines
+ *   Corporation and others.  All Rights Reserved.
+ *
+ *******************************************************************************
+ *   file name:  scrptrun.cpp
+ *
+ *   created on: 10/17/2001
+ *   created by: Eric R. Mader
+ */
+
+#include <unicode/utypes.h>
+#include <unicode/uscript.h>
+
+#include "scriptrun.h"
+
+// Copied from cmemory.h
+#define UPRV_LENGTHOF(array) (int32_t)(sizeof(array)/sizeof((array)[0]))
+
+U_NAMESPACE_BEGIN
+
+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 = UPRV_LENGTHOF(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) {
+        char16_t   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)
+        {
+            char16_t 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;
+}
+
+U_NAMESPACE_END