Implement support for '0b' prefix in toInt() etc

[ChangeLog][QtCore][QByteArray/QByteArrayView/QLatin1String/QString/QStringView]
The string-to-integer conversion functions (toInt() etc) now support
the 0b prefix for binary literals. That means that base = 0 will
recognize 0b to mean base = 2 and an explicit base = 2 argument will
make toInt() (etc) skip an optional 0b.

[ChangeLog][QtCore][Important Behavior Changes] Due to the
newly-introduced support for 0b (binary) prefixes in integer parsing,
some strings that were previously rejected as invalid now parse as
valid. E.g., Qt 6.3 with autodetected bases would have tried to parse
"0b1" as an octal value and fail, whereas 6.4 will parse it as the
binary literal and return 1.

Fixes: QTBUG-85002
Change-Id: Id4eff72d63619080e5afece4d059b6ffd52f28c8
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

1 files changed, 26 insertions, 14 deletions

diff --git a/src/corelib/text/qlocale_tools.cpp b/src/corelib/text/qlocale_tools.cpp
index 8259878448..7a2cce6f2c 100644
--- a/src/corelib/text/qlocale_tools.cpp
+++ b/src/corelib/text/qlocale_tools.cpp
@@ -401,30 +401,42 @@ double qt_asciiToDouble(const char *num, qsizetype numLen, bool &ok, int &proces
     return d;
 }
 
-/* Detect base if 0 and, if base is hex, skip over 0x prefix */
+/* Detect base if 0 and, if base is hex or bin, skip over 0x/0b prefixes */
 static auto scanPrefix(const char *p, const char *stop, int base)
 {
+    struct R
+    {
+        const char *next;
+        int base;
+    };
     if (p < stop && *p >= '0' && *p <= '9') {
         if (*p == '0') {
-            const char *x = p + 1;
-            if (x < stop && (*x == 'x' || *x == 'X')) {
-                if (base == 0)
-                    base = 16;
-                if (base == 16)
-                    p += 2;
-            } else if (base == 0) {
-                base = 8;
+            const char *x_or_b = p + 1;
+            if (x_or_b < stop) {
+                switch (*x_or_b) {
+                case 'b':
+                case 'B':
+                    if (base == 0)
+                        base = 2;
+                    if (base == 2)
+                        p += 2;
+                    return R{p, base};
+                case 'x':
+                case 'X':
+                    if (base == 0)
+                        base = 16;
+                    if (base == 16)
+                        p += 2;
+                    return R{p, base};
+                }
             }
+            if (base == 0)
+                base = 8;
         } else if (base == 0) {
             base = 10;
         }
         Q_ASSERT(base);
     }
-    struct R
-    {
-        const char *next;
-        int base;
-    };
     return R{p, base};
 }