QtMiscUtils: add isAsciiPrintable() helper

- isAsciiPrintable: borrowed the logic from isPrintable(uchar) in
  qdebug.cpp, now isPrintable(uchar) calls isAsciiPrintable

- Replace ::isspace() with ascii_isspace() from qlocale_p.h

Functions from ctype.h have a couple of issues:
- they're locale-dependent, which isn't what's required here, the code
  is only interested in ASCII
- their args should be representable as uchar or EOF otherwise it's
  undefined behavior

An Early-Warning could use something like:
grep -rP "\b(isalnum|isalpha|isblank|iscntrl|isdigit|islower|isgraph|\
         "isprint|ispunct|isspace|isupper|isxdigit|tolower|toupper)\b"

Pick-to: 6.5
Task-number: QTBUG-111262
Change-Id: I1f47f41bd56735297078ff0d0ddc2ebf999abf8b
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qdebug.cpp

@@ -14,13 +14,10 @@
 #include "qmetaobject.h"
 #include <private/qtextstream_p.h>
 #include <private/qtools_p.h>
-#include <ctype.h>
 
 QT_BEGIN_NAMESPACE
 
-using QtMiscUtils::toHexUpper;
+using namespace QtMiscUtils;
-using QtMiscUtils::toHexLower;
-using QtMiscUtils::fromHex;
 
 /*
     Returns a human readable representation of the first \a maxSize
@@ -35,7 +32,7 @@ QByteArray QtDebugUtils::toPrintable(const char *data, qint64 len, qsizetype max
     QByteArray out;
     for (qsizetype i = 0; i < qMin(len, maxSize); ++i) {
         char c = data[i];
-        if (isprint(c)) {
+        if (isAsciiPrintable(c)) {
             out += c;
         } else {
             switch (c) {
@@ -198,7 +195,7 @@ void QDebug::putUcs4(uint ucs4)
 static inline bool isPrintable(char32_t ucs4) { return QChar::isPrint(ucs4); }
 static inline bool isPrintable(char16_t uc) { return QChar::isPrint(uc); }
 static inline bool isPrintable(uchar c)
-{ return c >= ' ' && c < 0x7f; }
+{ return isAsciiPrintable(c); }
 
 template <typename Char>
 static inline void putEscapedString(QTextStreamPrivate *d, const Char *begin, size_t length, bool isUnicode = true)

src/corelib/io/qiodevice.cpp

@@ -10,16 +10,14 @@
 #include "qstringlist.h"
 #include "qdir.h"
 #include "private/qbytearray_p.h"
+#include "private/qtools_p.h"
 
 #include <algorithm>
 
-#ifdef QIODEVICE_DEBUG
-#  include <ctype.h>
-#endif
-
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
+using namespace QtMiscUtils;
 
 [[maybe_unused]]
 static void debugBinaryString(const char *input, qint64 maxlen)
@@ -38,7 +36,7 @@ static void debugBinaryString(const char *input, qint64 maxlen)
             for (qsizetype j = tmp.size(); j < 16 + 1; ++j)
                 printf("   ");
             for (qsizetype j = 0; j < tmp.size(); ++j)
-                printf("%c", isprint(int(uchar(tmp[j]))) ? tmp[j] : '.');
+                printf("%c", isAsciiPrintable(tmp[j]) ? tmp[j] : '.');
             tmp.clear();
         }
     }
@@ -1011,7 +1009,7 @@ qint64 QIODevice::read(char *data, qint64 maxSize)
             *data = c;
 #if defined QIODEVICE_DEBUG
             printf("%p \tread 0x%hhx (%c) returning 1 (shortcut)\n", this,
-                   int(c), isprint(c) ? c : '?');
+                   int(c), isAsciiPrintable(c) ? c : '?');
 #endif
             if (d->buffer.isEmpty())
                 readData(data, 0);
@@ -1792,7 +1790,7 @@ void QIODevice::ungetChar(char c)
     }
 
 #if defined QIODEVICE_DEBUG
-    printf("%p QIODevice::ungetChar(0x%hhx '%c')\n", this, c, isprint(c) ? c : '?');
+    printf("%p QIODevice::ungetChar(0x%hhx '%c')\n", this, c, isAsciiPrintable(c) ? c : '?');
 #endif
 
     d->buffer.ungetChar(c);

src/corelib/tools/qtools_p.h

@@ -101,6 +101,11 @@ constexpr inline int caseCompareAscii(char lhs, char rhs) noexcept
     return int(uchar(lhsLower)) - int(uchar(rhsLower));
 }
 
+constexpr inline int isAsciiPrintable(char32_t ch) noexcept
+{
+    return ch >= ' ' && ch < 0x7f;
+}
+
 constexpr inline int qt_lencmp(qsizetype lhs, qsizetype rhs) noexcept
 {
     return lhs == rhs ? 0 :

src/gui/image/qppmhandler.cpp

@@ -11,8 +11,8 @@
 #include <qloggingcategory.h>
 #include <qrgba64.h>
 #include <qvariant.h>
-
+#include <private/qlocale_p.h>
-#include <ctype.h>
+#include <private/qtools_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -41,7 +41,7 @@ static int read_pbm_int(QIODevice *d, bool *ok)
     for (;;) {
         if (!d->getChar(&c))                // end of file
             break;
-        digit = isdigit((uchar) c);
+        digit = QtMiscUtils::isAsciiDigit(c);
         if (val != -1) {
             if (digit) {
                 const int cValue = c - '0';
@@ -59,7 +59,7 @@ static int read_pbm_int(QIODevice *d, bool *ok)
         }
         if (digit)                                // first digit
             val = c - '0';
-        else if (isspace((uchar) c))
+        else if (ascii_isspace(c))
             continue;
         else if (c == '#')
             discard_pbm_line(d);
@@ -77,7 +77,7 @@ static bool read_pbm_header(QIODevice *device, char& type, int& w, int& h, int&
     if (device->read(buf, 3) != 3)                        // read P[1-6]<white-space>
         return false;
 
-    if (!(buf[0] == 'P' && isdigit((uchar) buf[1]) && isspace((uchar) buf[2])))
+    if (!(buf[0] == 'P' && QtMiscUtils::isAsciiDigit(buf[1]) && ascii_isspace(buf[2])))
         return false;
 
     type = buf[1];

src/gui/kernel/qguiapplication.cpp

@@ -96,12 +96,14 @@
 
 #include <qtgui_tracepoints_p.h>
 
-#include <ctype.h>
+#include <private/qtools_p.h>
+
 #include <limits>
 
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
+using namespace QtMiscUtils;
 
 // Helper macro for static functions to check on the existence of the application class.
 #define CHECK_QAPP_INSTANCE(...) \
@@ -263,13 +265,13 @@ static inline int nextGeometryToken(const QByteArray &a, int &pos, char *op)
     *op = a.at(pos);
     if (*op == '+' || *op == '-' || *op == 'x')
         pos++;
-    else if (isdigit(*op))
+    else if (isAsciiDigit(*op))
         *op = 'x'; // If it starts with a digit, it is supposed to be a width specification.
     else
         return -1;
 
     const int numberPos = pos;
-    for ( ; pos < size && isdigit(a.at(pos)); ++pos) ;
+    for ( ; pos < size && isAsciiDigit(a.at(pos)); ++pos) ;
 
     bool ok;
     const int result = a.mid(numberPos, pos - numberPos).toInt(&ok);

src/testlib/qteamcitylogger.cpp

@@ -7,8 +7,8 @@
 #include <QtTest/private/qtestlog_p.h>
 #include <QtTest/private/qteamcitylogger_p.h>
 #include <QtCore/qbytearray.h>
+#include <private/qlocale_p.h>
 
-#include <cctype>
 #include <limits.h>
 #include <stdarg.h>
 #include <stdio.h>
@@ -235,7 +235,7 @@ void QTeamCityLogger::tcEscapedString(QTestCharBuffer *buf, const char *str) con
             swallowSpace = false;
             break;
         default:
-            if (std::isspace(ch)) {
+            if (ascii_isspace(ch)) {
                 if (swallowSpace)
                     continue;
                 swallowSpace = true;
@@ -252,7 +252,7 @@ void QTeamCityLogger::tcEscapedString(QTestCharBuffer *buf, const char *str) con
         Q_ASSERT(p[-1] == ' ');
         --p;
     }
-    Q_ASSERT(p == buf->data() || !std::isspace(p[-1]));
+    Q_ASSERT(p == buf->data() || !ascii_isspace(p[-1]));
     *p = '\0';
 }