Adding upstream version 1:7.0.4.upstream/1%7.0.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 354 insertions, 0 deletions

diff --git a/include/rtl/stringutils.hxx b/include/rtl/stringutils.hxx
new file mode 100644
index 000000000..b96884546
--- /dev/null
+++ b/include/rtl/stringutils.hxx
@@ -0,0 +1,354 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef INCLUDED_RTL_STRINGUTILS_HXX
+#define INCLUDED_RTL_STRINGUTILS_HXX
+
+#include "sal/config.h"
+
+#include <cassert>
+#include <cstddef>
+
+#include "sal/types.h"
+
+// The unittest uses slightly different code to help check that the proper
+// calls are made. The class is put into a different namespace to make
+// sure the compiler generates a different (if generating also non-inline)
+// copy of the function and does not merge them together. The class
+// is "brought" into the proper rtl namespace by a typedef below.
+#ifdef RTL_STRING_UNITTEST
+#define rtl rtlunittest
+#endif
+
+namespace rtl
+{
+
+#ifdef RTL_STRING_UNITTEST
+#undef rtl
+#endif
+
+#if defined LIBO_INTERNAL_ONLY
+/// @cond INTERNAL
+
+// A simple wrapper around a single char.  Can be useful in string concatenation contexts, like in
+//
+//  OString s = ...;
+//  char c = ...;
+//  s += OStringChar(c);
+//
+struct SAL_WARN_UNUSED OStringChar {
+    constexpr OStringChar(char theC): c(theC) {}
+    template<typename T> OStringChar(T &&) = delete;
+    char const c;
+};
+
+/** A simple wrapper around a single sal_Unicode character.
+
+    Can be useful to pass a sal_Unicode constant into an OUString-related
+    function that is optimized for UTF-16 string literal arguments.  That is,
+    instead of
+
+      sal_Unicode const WILDCARD = '%';
+      ...
+      if (s[i] == WILDCARD) ...
+      ...
+      if (s.endsWith(OUString(WILDCARD))) ...
+
+    use
+
+      sal_Unicode const WILDCARD = '%';
+      ...
+      if (s[i] == WILDCARD) ...
+      ...
+      if (s.endsWith(OUStringChar(WILDCARD))) ...
+
+    to avoid creating a temporary OUString instance, and instead pick the
+    endsWith overload actually designed to take an argument of type
+    sal_Unicode const[N].
+
+    (Because of the above use case,
+    instances of OUStringChar need to be const, as those literal-optimized
+    functions take the literal argument by non-const lvalue reference, for
+    technical reasons.
+
+    For actual arrays, it is important to distinguish string literals from other char or sal_Unicode
+    arrays, which may contain junk after the first NUL character or may be non-ASCII in the case of
+    char arrays.  This is not so much a concern for single char and sal_Unicode values, where NUL is
+    assumed to always be meant as an actual character.)
+
+    Can also be useful in string concatenation contexts, like in
+
+      sal_Unicode const * s = ...;
+      sal_Unicode c = ...;
+      OUString t = s + OUStringChar(c);
+
+    @since LibreOffice 5.0
+*/
+struct SAL_WARN_UNUSED OUStringChar_ {
+    constexpr OUStringChar_(sal_Unicode theC): c(theC) {}
+    constexpr OUStringChar_(char theC): c(theC) { assert(c <= 0x7F); }
+    template<typename T> OUStringChar_(T &&) = delete;
+    sal_Unicode const c;
+};
+using OUStringChar = OUStringChar_ const;
+
+/// @endcond
+#endif
+
+namespace libreoffice_internal
+{
+/*
+These templates use SFINAE (Substitution failure is not an error) to help distinguish the various
+plain C string types: char*, const char*, char[N], const char[N], char[] and const char[].
+There are 2 cases:
+1) Only string literal (i.e. const char[N]) is wanted, not any of the others.
+    In this case it is necessary to distinguish between const char[N] and char[N], as the latter
+    would be automatically converted to the const variant, which is not wanted (not a string literal
+    with known size of the content). In this case ConstCharArrayDetector is used to ensure the function
+    is called only with const char[N] arguments. There's no other plain C string type overload.
+2) All plain C string types are wanted, and const char[N] needs to be handled differently.
+    In this case const char[N] would match const char* argument type (not exactly sure why, but it's
+    consistent in all of gcc, clang and msvc). Using a template with a reference to const of the type
+    avoids this problem, and CharPtrDetector ensures that the function is called only with char pointer
+    arguments. The const in the argument is necessary to handle the case when something is explicitly
+    cast to const char*. Additionally (non-const) char[N] needs to be handled, but with the reference
+    being const, it would also match const char[N], so another overload with a reference to non-const
+    and NonConstCharArrayDetector are used to ensure the function is called only with (non-const) char[N].
+Additionally, char[] and const char[] (i.e. size unknown) are rather tricky. Their usage with 'T&' would
+mean it would be 'char(&)[]', which seems to be invalid. But gcc and clang somehow manage when it is
+a template. while msvc complains about no conversion from char[] to char[1]. And the reference cannot
+be avoided, because 'const char[]' as argument type would match also 'const char[N]'
+So char[] and const char[] should always be used with their contents specified (which automatically
+turns them into char[N] or const char[N]), or char* and const char* should be used.
+*/
+struct Dummy {};
+template< typename T1, typename T2 = void >
+struct CharPtrDetector
+{
+    static const bool ok = false;
+};
+template< typename T >
+struct CharPtrDetector< const char*, T >
+{
+    typedef T Type;
+    static const bool ok = true;
+};
+template< typename T >
+struct CharPtrDetector< char*, T >
+{
+    typedef T Type;
+    static const bool ok = true;
+};
+#if defined LIBO_INTERNAL_ONLY
+template<typename T> struct CharPtrDetector<sal_Unicode *, T> { using TypeUtf16 = T; };
+template<typename T> struct CharPtrDetector<sal_Unicode const *, T> { using TypeUtf16 = T; };
+template<typename T> struct CharPtrDetector<sal_Unicode[], T> { using TypeUtf16 = T; };
+template<typename T> struct CharPtrDetector<sal_Unicode const[], T> { using TypeUtf16 = T; };
+#endif
+
+template< typename T1, typename T2 >
+struct NonConstCharArrayDetector
+{
+};
+template< typename T, int N >
+struct NonConstCharArrayDetector< char[ N ], T >
+{
+    typedef T Type;
+};
+#ifdef RTL_STRING_UNITTEST
+// never use, until all compilers handle this
+template< typename T >
+struct NonConstCharArrayDetector< char[], T >
+{
+    typedef T Type;
+};
+template< typename T >
+struct NonConstCharArrayDetector< const char[], T >
+{
+    typedef T Type;
+};
+#endif
+#if defined LIBO_INTERNAL_ONLY
+template<typename T, std::size_t N> struct NonConstCharArrayDetector<sal_Unicode[N], T> {
+    using TypeUtf16 = T;
+};
+#endif
+
+template< typename T1, typename T2 = void >
+struct ConstCharArrayDetector
+{
+    static const bool ok = false;
+};
+template< std::size_t N, typename T >
+struct ConstCharArrayDetector< const char[ N ], T >
+{
+    typedef T Type;
+    static const std::size_t length = N - 1;
+    static const bool ok = true;
+#if defined LIBO_INTERNAL_ONLY
+    constexpr
+#endif
+    static bool isValid(char const (& literal)[N]) {
+        for (std::size_t i = 0; i != N - 1; ++i) {
+            if (literal[i] == '\0') {
+                return false;
+            }
+        }
+        return literal[N - 1] == '\0';
+    }
+#if defined LIBO_INTERNAL_ONLY
+    constexpr
+#endif
+    static char const * toPointer(char const (& literal)[N]) { return literal; }
+};
+
+#if defined(__COVERITY__)
+//to silence over zealous warnings that the loop is logically dead
+//for the single char case
+template< typename T >
+struct ConstCharArrayDetector< const char[ 1 ], T >
+{
+    typedef T Type;
+    static const std::size_t length = 0;
+    static const bool ok = true;
+#if defined LIBO_INTERNAL_ONLY
+    constexpr
+#endif
+    static bool isValid(char const (& literal)[1]) {
+        return literal[0] == '\0';
+    }
+#if defined LIBO_INTERNAL_ONLY
+    constexpr
+#endif
+    static char const * toPointer(char const (& literal)[1]) { return literal; }
+};
+#endif
+
+#if defined LIBO_INTERNAL_ONLY && defined __cpp_char8_t
+template<std::size_t N, typename T>
+struct ConstCharArrayDetector<char8_t const [N], T> {
+    using Type = T;
+    static constexpr bool const ok = true;
+    static constexpr std::size_t const length = N - 1;
+    static constexpr bool isValid(char8_t const (& literal)[N]) {
+        for (std::size_t i = 0; i != N - 1; ++i) {
+            if (literal[i] == u8'\0') {
+                return false;
+            }
+        }
+        return literal[N - 1] == u8'\0';
+    }
+    static constexpr char const * toPointer(char8_t const (& literal)[N])
+    { return reinterpret_cast<char const *>(literal); }
+};
+#endif
+
+#if defined LIBO_INTERNAL_ONLY
+template<std::size_t N, typename T>
+struct ConstCharArrayDetector<sal_Unicode const [N], T> {
+    using TypeUtf16 = T;
+    static constexpr bool const ok = true;
+    static constexpr std::size_t const length = N - 1;
+    static constexpr sal_Unicode const * toPointer(
+        sal_Unicode const (& literal)[N])
+    { return literal; }
+};
+template<typename T> struct ConstCharArrayDetector<
+    OUStringChar,
+    T>
+{
+    using TypeUtf16 = T;
+    static constexpr bool const ok = true;
+    static constexpr std::size_t const length = 1;
+    static constexpr sal_Unicode const * toPointer(
+        OUStringChar_ const & literal)
+    { return &literal.c; }
+};
+#endif
+
+// this one is used to rule out only const char[N]
+template< typename T >
+struct ExceptConstCharArrayDetector
+{
+    typedef Dummy Type;
+};
+template< int N >
+struct ExceptConstCharArrayDetector< const char[ N ] >
+{
+};
+#if defined LIBO_INTERNAL_ONLY
+template<std::size_t N>
+struct ExceptConstCharArrayDetector<sal_Unicode const[N]> {};
+template<> struct ExceptConstCharArrayDetector<
+    OUStringChar
+    >
+{};
+#endif
+
+// this one is used to rule out only const char[N]
+// (const will be brought in by 'const T&' in the function call)
+// msvc needs const char[N] here (not sure whether gcc or msvc
+// are right, it doesn't matter).
+template< typename T >
+struct ExceptCharArrayDetector
+{
+    typedef Dummy Type;
+};
+template< int N >
+struct ExceptCharArrayDetector< char[ N ] >
+{
+};
+template< int N >
+struct ExceptCharArrayDetector< const char[ N ] >
+{
+};
+#if defined LIBO_INTERNAL_ONLY
+template<std::size_t N> struct ExceptCharArrayDetector<sal_Unicode[N]> {};
+template<std::size_t N> struct ExceptCharArrayDetector<sal_Unicode const[N]> {};
+template<> struct ExceptCharArrayDetector<OUStringChar_> {};
+#endif
+
+template< typename T1, typename T2 = void >
+struct SalUnicodePtrDetector
+{
+    static const bool ok = false;
+};
+template< typename T >
+struct SalUnicodePtrDetector< const sal_Unicode*, T >
+{
+    typedef T Type;
+    static const bool ok = true;
+};
+template< typename T >
+struct SalUnicodePtrDetector< sal_Unicode*, T >
+{
+    typedef T Type;
+    static const bool ok = true;
+};
+
+// SFINAE helper class
+template< typename T, bool >
+struct Enable
+    {
+    };
+
+template< typename T >
+struct Enable< T, true >
+    {
+    typedef T Type;
+    };
+
+
+} /* Namespace */
+
+} /* Namespace */
+
+#endif // INCLUDED_RTL_STRINGUTILS_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */