string: add is7bit

Signed-off-by: Simon Rozman <simon@rozman.si>

include/stdex/sgml.hpp

@@ -478,7 +478,7 @@ namespace stdex
 		for (size_t i = 0; i < count_src;) {
 			size_t n = glyphlen(src + i, count_src - i);
 			if (n == 1 &&
-				do_ascii && (unsigned int)src[i] < 128 &&
+				do_ascii && is7bit(src[i]) &&
 				src[i] != L'&' &&
 				(do_quot || (src[i] != L'"')) &&
 				(do_apos || (src[i] != L'\'')) &&
@@ -505,7 +505,7 @@ namespace stdex
 				}
 				else if (n == 1) {
 					// Trivial character (1 code unit, 1 glyph), no entity available.
-					if ((unsigned int)src[i] < 128)
+					if (is7bit(src[i]))
 						dst.append(1, static_cast<char>(src[i++]));
 					else {
 						char tmp[3 + 8 + 1 + 1];
@@ -523,7 +523,7 @@ namespace stdex
 							dst.append(1, ';');
 							i++;
 						}
-						else if ((unsigned int)src[i] < 128)
+						else if (is7bit(src[i]))
 							dst.append(1, static_cast<char>(src[i++]));
 						else {
 							uint32_t unicode;
@@ -602,7 +602,7 @@ namespace stdex
 		for (size_t i = 0; i < count_src;) {
 			size_t n = glyphlen(src + i, count_src - i);
 			if (n == 1 &&
-				do_ascii && (unsigned int)src[i] < 128 &&
+				do_ascii && is7bit(src[i]) &&
 				src[i] != L'&' &&
 				(do_quot || (src[i] != L'"')) &&
 				(do_apos || (src[i] != L'\'')) &&
@@ -634,7 +634,7 @@ namespace stdex
 				}
 				else if (n == 1) {
 					// Trivial character (1 code unit, 1 glyph), no entity available.
-					if ((unsigned int)src[i] < 128) {
+					if (is7bit(src[i])) {
 						if (j + 1 >= count_dst)
 							throw buffer_overrun;
 						dst[j++] = static_cast<char>(src[i++]);
@@ -661,7 +661,7 @@ namespace stdex
 							dst[j++] = ';';
 							i++;
 						}
-						else if ((unsigned int)src[i] < 128) {
+						else if (is7bit(src[i])) {
 							if (j + 1 >= count_dst)
 								throw buffer_overrun;
 							dst[j++] = static_cast<char>(src[i++]);

include/stdex/string.hpp

@@ -188,6 +188,17 @@ namespace stdex
 		return islower(chr) || isupper(chr);
 	}
 
+	///
+	/// Test if the given code unit is ASCII
+	///
+	/// \param[in] chr  Code unit
+	///
+	template <class T>
+	inline bool is7bit(_In_ T chr)
+	{
+		return '\x00' <= chr && chr <= '\x7f';
+	}
+
 	///
 	/// Return number of code units the glyph represents
 	///
@@ -737,8 +748,7 @@ namespace stdex
 	///
 	template <class T>
 	inline bool isblank(
-		_In_reads_or_z_opt_(count) const T* str,
+		_In_reads_or_z_opt_(count) const T* str, _In_ size_t count,
-		_In_ size_t count,
 		_In_ const std::locale& locale)
 	{
 		_Assume_(str || !count);
@@ -778,6 +788,54 @@ namespace stdex
 		return isblank(str, N, locale);
 	}
 
+	// ///
+	// /// Checks if string contains all-ASCII characters
+	// ///
+	// /// \param[in] str  String
+	// ///
+	// /// \return `true` if all characters are ASCII or `false` when any non-ASCII character is found in string.
+	// ///
+	// template <class T>
+	// inline bool is7bit(_In_z_ const T* str)
+	// {
+	// 	_Assume_(str);
+	// 	for (size_t i = 0; str[i]; i++)
+	// 		if (!is7bit(str[i]))
+	// 			return false;
+	// 	return true;
+	// }
+
+	///
+	/// Checks if string contains all-ASCII characters
+	///
+	/// \param[in] str    String
+	/// \param[in] count  Code unit count limit
+	///
+	/// \return `true` if all characters are ASCII or `false` when any non-ASCII character is found in string.
+	///
+	template <class T>
+	inline bool is7bit(_In_reads_or_z_opt_(count) const T* str, _In_ size_t count)
+	{
+		_Assume_(str || !count);
+		for (size_t i = 0; i < count && str[i]; i++)
+			if (!is7bit(str[i]))
+				return false;
+		return true;
+	}
+
+	///
+	/// Checks if string contains all-ASCII characters
+	///
+	/// \param[in] str    String
+	///
+	/// \return `true` if all characters are ASCII or `false` when any non-ASCII character is found in string.
+	///
+	template <class T, size_t N>
+	inline bool is7bit(_In_ const T (&str)[N])
+	{
+		return is7bit(str, N);
+	}
+
 	///
 	/// Binary compare two strings
 	///
@@ -1465,7 +1523,7 @@ namespace stdex
 		_Assume_(dst);
 		_Assume_(src);
 		for (size_t i = 0; ; ++i) {
-			if ((dst[i] = src[i]) == 0)
+			if ((dst[i] = static_cast<T1>(src[i])) == 0)
 				return i;
 		}
 	}
@@ -1489,7 +1547,7 @@ namespace stdex
 		for (size_t i = 0; ; ++i) {
 			if (i >= count)
 				return i;
-			if ((dst[i] = src[i]) == 0)
+			if ((dst[i] = static_cast<T1>(src[i])) == 0)
 				return i;
 		}
 	}
@@ -1519,7 +1577,7 @@ namespace stdex
 				dst[i] = 0;
 				return i;
 			}
-			if ((dst[i] = src[i]) == 0)
+			if ((dst[i] = static_cast<T1>(src[i])) == 0)
 				return i;
 		}
 	}
@@ -1556,7 +1614,7 @@ namespace stdex
 		_Assume_(dst);
 		_Assume_(src);
 		for (size_t i = 0, j = stdex::strlen<T1>(dst); ; ++i, ++j) {
-			if ((dst[j] = src[i]) == 0)
+			if ((dst[j] = static_cast<T1>(src[i])) == 0)
 				return j;
 		}
 	}
@@ -1580,7 +1638,7 @@ namespace stdex
 		for (size_t i = 0, j = stdex::strlen<T1>(dst); ; ++i, ++j) {
 			if (i >= count)
 				return j;
-			if ((dst[j] = src[i]) == 0)
+			if ((dst[j] = static_cast<T1>(src[i])) == 0)
 				return j;
 		}
 	}
@@ -1610,7 +1668,7 @@ namespace stdex
 				dst[j] = 0;
 				return j;
 			}
-			if ((dst[j] = src[i]) == 0)
+			if ((dst[j] = static_cast<T1>(src[i])) == 0)
 				return j;
 		}
 	}