From c5cda03125a6d34c179d968011083bceb87976bd Mon Sep 17 00:00:00 2001
From: Michele Calgaro <michele.calgaro@yahoo.it>
Date: Wed, 29 Jan 2025 18:05:37 +0900
Subject: Add support for surrogate pairs to TQChar API.

This relates to issue #162.
The new code is partially taken from Qt4 but with some local rework.

Signed-off-by: Michele Calgaro <michele.calgaro@yahoo.it>
---
 src/codecs/tqgb18030codec.cpp | 30 ++++++++++++------------------
 1 file changed, 12 insertions(+), 18 deletions(-)

(limited to 'src/codecs/tqgb18030codec.cpp')

diff --git a/src/codecs/tqgb18030codec.cpp b/src/codecs/tqgb18030codec.cpp
index 0ae2fb4ff..d2578dc8e 100644
--- a/src/codecs/tqgb18030codec.cpp
+++ b/src/codecs/tqgb18030codec.cpp
@@ -184,18 +184,16 @@ TQCString TQGb18030Codec::fromUnicode(const TQString& uc, int& lenInOut) const
 	if ( ch.row() == 0x00 && ch.cell() < 0x80 ) {
 	    // ASCII
 	    *cursor++ = ch.cell();
-	} else if ((ch.unicode() & 0xf800) == 0xd800) {
-	    unsigned short high = ch.unicode();
+	} else if (ch.isHighSurrogate()) {
 	    // surrogates area. check for correct encoding
 	    // we need at least one more character, first the high surrogate, then the low one
-	    if (i == l-1 || high >= 0xdc00)
+	    if (i == l-1)
 		*cursor++ = '?';
 	    else {
-		unsigned short low = uc[i+1].unicode();
-		if (low >= 0xdc00 && low <= 0xdfff) {
+		if (uc[i+1].isLowSurrogate()) {
 		    // valid surrogate pair
+		    uint u = TQChar::surrogateToUcs4(uc[i], uc[i + 1]);
 		    ++i;
-		    uint u = (high-0xd800)*0x400+(low-0xdc00)+0x10000;
 		    len = qt_UnicodeToGb18030(u, buf);
 		    if (len >= 2) {
 			for (int j=0; j<len; j++)
@@ -241,15 +239,13 @@ TQString TQGb18030Codec::toUnicode(const char* chars, int len) const
 	    uint u = qt_Gb18030ToUnicode( (const uchar*)(chars + i), clen );
 
 	    if (clen == 2 || clen == 4) {
-		if (u < 0x10000)
+		if (!TQChar::requiresSurrogates(u)) {
 		    result += TQValidChar(u);
+		}
 		else {
 		    // encode into surrogate pair
-		    u -= 0x10000;
-		    unsigned short high = u/0x400 + 0xd800;
-		    unsigned short low = u%0x400 + 0xdc00;
-		    result += TQChar(high);
-		    result += TQChar(low);
+		    result += TQChar(TQChar::highSurrogate(u));
+		    result += TQChar(TQChar::lowSurrogate(u));
 		}
 		i += clen;
 	    } else if (i < len) {
@@ -402,15 +398,13 @@ public:
 		    int clen = 4;
 		    uint u = qt_Gb18030ToUnicode(buf, clen);
 		    if (clen == 4) {
-			if (u < 0x10000)
+			if (!TQChar::requiresSurrogates(u)) {
 			    result += TQValidChar(u);
+			}
 			else {
 			    // encode into surrogate pair
-			    u -= 0x10000;
-			    unsigned short high = u/0x400 + 0xd800;
-			    unsigned short low = u%0x400 + 0xdc00;
-			    result += TQChar(high);
-			    result += TQChar(low);
+			    result += TQChar(TQChar::highSurrogate(u));
+			    result += TQChar(TQChar::lowSurrogate(u));
 			}
 		    } else {
 			result += TQChar::replacement;
-- 
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