From 7a3a9b8eb542196ed8e18e36b830396f54a3f63d Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@kdab.com>
Date: Wed, 13 May 2020 21:07:31 +0200
Subject: [PATCH] QStringMatcher: port internals to QStringView and char16_t

Change-Id: If540b094d003ad373d3c581e1de8c526ad4c7d73
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
---
 src/corelib/text/qstringmatcher.cpp | 50 ++++++++++++++++-------------
 src/corelib/text/qstringmatcher.h   |  4 +--
 2 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/src/corelib/text/qstringmatcher.cpp b/src/corelib/text/qstringmatcher.cpp
index 167a467480..8694255052 100644
--- a/src/corelib/text/qstringmatcher.cpp
+++ b/src/corelib/text/qstringmatcher.cpp
@@ -42,8 +42,10 @@
 
 QT_BEGIN_NAMESPACE
 
-static void bm_init_skiptable(const ushort *uc, qsizetype len, uchar *skiptable, Qt::CaseSensitivity cs)
+static void bm_init_skiptable(QStringView needle, uchar *skiptable, Qt::CaseSensitivity cs)
 {
+    const char16_t *uc = needle.utf16();
+    const qsizetype len = needle.size();
     int l = int(qMin(len, qsizetype(255)));
     memset(skiptable, l, 256 * sizeof(uchar));
     uc += len - l;
@@ -53,7 +55,7 @@ static void bm_init_skiptable(const ushort *uc, qsizetype len, uchar *skiptable,
             ++uc;
         }
     } else {
-        const ushort *start = uc;
+        const char16_t *start = uc;
         while (l--) {
             skiptable[foldCase(uc, start) & 0xff] = l;
             ++uc;
@@ -61,15 +63,20 @@ static void bm_init_skiptable(const ushort *uc, qsizetype len, uchar *skiptable,
     }
 }
 
-static inline qsizetype bm_find(const ushort *uc, qsizetype l, qsizetype index, const ushort *puc, qsizetype pl,
+static inline qsizetype bm_find(QStringView haystack, qsizetype index, QStringView needle,
                           const uchar *skiptable, Qt::CaseSensitivity cs)
 {
+    const char16_t *uc = haystack.utf16();
+    const qsizetype l = haystack.size();
+    const char16_t *puc = needle.utf16();
+    const qsizetype pl = needle.size();
+
     if (pl == 0)
         return index > l ? -1 : index;
     const qsizetype pl_minus_one = pl - 1;
 
-    const ushort *current = uc + index + pl_minus_one;
-    const ushort *end = uc + l;
+    const char16_t *current = uc + index + pl_minus_one;
+    const char16_t *end = uc + l;
     if (cs == Qt::CaseSensitive) {
         while (current < end) {
             qsizetype skip = skiptable[*current & 0xff];
@@ -121,6 +128,11 @@ static inline qsizetype bm_find(const ushort *uc, qsizetype l, qsizetype index,
     return -1; // not found
 }
 
+void QStringMatcher::updateSkipTable()
+{
+    bm_init_skiptable(p.sv, p.q_skiptable, q_cs);
+}
+
 /*!
     \class QStringMatcher
     \inmodule QtCore
@@ -163,9 +175,8 @@ QStringMatcher::QStringMatcher()
 QStringMatcher::QStringMatcher(const QString &pattern, Qt::CaseSensitivity cs)
     : d_ptr(nullptr), q_pattern(pattern), q_cs(cs)
 {
-    p.uc = pattern.unicode();
-    p.len = pattern.size();
-    bm_init_skiptable((const ushort *)p.uc, p.len, p.q_skiptable, cs);
+    p.sv = q_pattern;
+    updateSkipTable();
 }
 
 /*!
@@ -192,9 +203,8 @@ QStringMatcher::QStringMatcher(const QChar *uc, int len, Qt::CaseSensitivity cs)
 QStringMatcher::QStringMatcher(QStringView str, Qt::CaseSensitivity cs)
     : d_ptr(nullptr), q_cs(cs)
 {
-    p.uc = str.data();
-    p.len = int(str.size());
-    bm_init_skiptable((const ushort *)p.uc, p.len, p.q_skiptable, cs);
+    p.sv = str;
+    updateSkipTable();
 }
 /*!
     Copies the \a other string matcher to this string matcher.
@@ -235,9 +245,8 @@ QStringMatcher &QStringMatcher::operator=(const QStringMatcher &other)
 void QStringMatcher::setPattern(const QString &pattern)
 {
     q_pattern = pattern;
-    p.uc = pattern.unicode();
-    p.len = pattern.size();
-    bm_init_skiptable((const ushort *)pattern.unicode(), pattern.size(), p.q_skiptable, q_cs);
+    p.sv = q_pattern;
+    updateSkipTable();
 }
 
 /*!
@@ -253,7 +262,7 @@ QString QStringMatcher::pattern() const
 {
     if (!q_pattern.isEmpty())
         return q_pattern;
-    return QString(p.uc, p.len);
+    return p.sv.toString();
 }
 
 /*!
@@ -266,8 +275,8 @@ void QStringMatcher::setCaseSensitivity(Qt::CaseSensitivity cs)
 {
     if (cs == q_cs)
         return;
-    bm_init_skiptable((const ushort *)p.uc, p.len, p.q_skiptable, cs);
     q_cs = cs;
+    updateSkipTable();
 }
 
 /*!
@@ -316,9 +325,7 @@ qsizetype QStringMatcher::indexIn(QStringView str, qsizetype from) const
 {
     if (from < 0)
         from = 0;
-    return bm_find((const ushort *)str.data(), str.size(), from,
-                   (const ushort *)p.uc, p.len,
-                   p.q_skiptable, q_cs);
+    return bm_find(str, from, p.sv, p.q_skiptable, q_cs);
 }
 
 /*!
@@ -338,11 +345,10 @@ qsizetype qFindStringBoyerMoore(
     QStringView needle, Qt::CaseSensitivity cs)
 {
     uchar skiptable[256];
-    bm_init_skiptable((const ushort *)needle.data(), needle.size(), skiptable, cs);
+    bm_init_skiptable(needle, skiptable, cs);
     if (haystackOffset < 0)
         haystackOffset = 0;
-    return bm_find((const ushort *)haystack.data(), haystack.size(), haystackOffset,
-                   (const ushort *)needle.data(), needle.size(), skiptable, cs);
+    return bm_find(haystack, haystackOffset, needle, skiptable, cs);
 }
 
 QT_END_NAMESPACE
diff --git a/src/corelib/text/qstringmatcher.h b/src/corelib/text/qstringmatcher.h
index 6de4353930..c731efcc97 100644
--- a/src/corelib/text/qstringmatcher.h
+++ b/src/corelib/text/qstringmatcher.h
@@ -51,6 +51,7 @@ class QStringMatcherPrivate;
 
 class Q_CORE_EXPORT QStringMatcher
 {
+    void updateSkipTable();
 public:
     QStringMatcher();
     explicit QStringMatcher(const QString &pattern,
@@ -79,8 +80,7 @@ private:
     Qt::CaseSensitivity q_cs;
     struct Data {
         uchar q_skiptable[256];
-        const QChar *uc;
-        int len;
+        QStringView sv;
     };
     union {
         uint q_data[256];