8 files changed, 134 insertions, 17 deletions
diff --git a/src/ClientMessage.cxx b/src/ClientMessage.cxx
index f98dc70ce..4b124c6ca 100644
--- a/src/ClientMessage.cxx
+++ b/src/ClientMessage.cxx
@@ -18,15 +18,14 @@
  */
 
 #include "ClientMessage.hxx"
+#include "util/CharUtil.hxx"
 #include "Compiler.h"
 
-#include <glib.h>
-
 gcc_const
 static bool
 valid_channel_char(const char ch)
 {
-	return g_ascii_isalnum(ch) ||
+	return IsAlphaNumericASCII(ch) ||
 		ch == '_' || ch == '-' || ch == '.' || ch == ':';
 }
 
diff --git a/src/LogInit.cxx b/src/LogInit.cxx
index e07c3e947..1b393fc3f 100644
--- a/src/LogInit.cxx
+++ b/src/LogInit.cxx
@@ -29,6 +29,7 @@
 #include "fs/FileSystem.hxx"
 #include "util/Error.hxx"
 #include "util/Domain.hxx"
+#include "util/CharUtil.hxx"
 #include "system/FatalError.hxx"
 
 #include <assert.h>
@@ -89,7 +90,7 @@ chomp_length(const char *p)
 {
 	size_t length = strlen(p);
 
-	while (length > 0 && g_ascii_isspace(p[length - 1]))
+	while (length > 0 && IsWhitespaceOrNull(p[length - 1]))
 		--length;
 
 	return (int)length;
diff --git a/src/TextInputStream.cxx b/src/TextInputStream.cxx
index a69e1d513..f3664018a 100644
--- a/src/TextInputStream.cxx
+++ b/src/TextInputStream.cxx
@@ -20,12 +20,11 @@
 #include "config.h"
 #include "TextInputStream.hxx"
 #include "InputStream.hxx"
+#include "util/CharUtil.hxx"
 #include "util/fifo_buffer.h"
 #include "util/Error.hxx"
 #include "Log.hxx"
 
-#include <glib.h>
-
 #include <assert.h>
 #include <string.h>
 
@@ -71,7 +70,7 @@ bool TextInputStream::ReadLine(std::string &line)
 	} while (p == nullptr);
 
 	size_t length = p - src + 1;
-	while (p > src && g_ascii_isspace(p[-1]))
+	while (p > src && IsWhitespaceOrNull(p[-1]))
 		--p;
 
 	line = std::string(src, p - src);
diff --git a/src/cue/CueParser.cxx b/src/cue/CueParser.cxx
index 89f450bae..f52f8526f 100644
--- a/src/cue/CueParser.cxx
+++ b/src/cue/CueParser.cxx
@@ -20,6 +20,7 @@
 #include "config.h"
 #include "CueParser.hxx"
 #include "util/StringUtil.hxx"
+#include "util/CharUtil.hxx"
 #include "Song.hxx"
 #include "tag/Tag.hxx"
 
@@ -54,10 +55,10 @@ static const char *
 cue_next_word(char *p, char **pp)
 {
 	assert(p >= *pp);
-	assert(!g_ascii_isspace(*p));
+	assert(!IsWhitespaceNotNull(*p));
 
 	const char *word = p;
-	while (*p != 0 && !g_ascii_isspace(*p))
+	while (!IsWhitespaceOrNull(*p))
 		++p;
 
 	*p = 0;
diff --git a/src/input/CurlInputPlugin.cxx b/src/input/CurlInputPlugin.cxx
index 8f54898fc..de3e83a86 100644
--- a/src/input/CurlInputPlugin.cxx
+++ b/src/input/CurlInputPlugin.cxx
@@ -29,6 +29,7 @@
 #include "event/MultiSocketMonitor.hxx"
 #include "event/Call.hxx"
 #include "IOThread.hxx"
+#include "util/CharUtil.hxx"
 #include "util/Error.hxx"
 #include "util/Domain.hxx"
 #include "Log.hxx"
@@ -839,10 +840,10 @@ input_curl_headerfunction(void *ptr, size_t size, size_t nmemb, void *stream)
 
 	/* strip the value */
 
-	while (value < end && g_ascii_isspace(*value))
+	while (value < end && IsWhitespaceOrNull(*value))
 		++value;
 
-	while (end > value && g_ascii_isspace(end[-1]))
+	while (end > value && IsWhitespaceOrNull(end[-1]))
 		--end;
 
 	if (g_ascii_strcasecmp(name, "accept-ranges") == 0) {
diff --git a/src/util/CharUtil.hxx b/src/util/CharUtil.hxx
new file mode 100644
index 000000000..dd964f9c3
--- /dev/null
+++ b/src/util/CharUtil.hxx
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2011-2013 Max Kellermann <max@duempel.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef CHAR_UTIL_HPP
+#define CHAR_UTIL_HPP
+
+constexpr
+static inline bool
+IsASCII(const unsigned char ch)
+{
+  return ch < 0x80;
+}
+
+constexpr
+static inline bool
+IsASCII(const char ch)
+{
+  return IsASCII((unsigned char)ch);
+}
+
+static inline bool
+IsWhitespaceOrNull(const char ch)
+{
+  return (unsigned char)ch <= 0x20;
+}
+
+static inline bool
+IsWhitespaceNotNull(const char ch)
+{
+  return ch > 0 && ch <= 0x20;
+}
+
+constexpr
+static inline bool
+IsPrintableASCII(char ch)
+{
+  return (signed char)ch >= 0x20;
+}
+
+constexpr
+static inline bool
+IsDigitASCII(char ch)
+{
+  return ch >= '0' && ch <= '9';
+}
+
+constexpr
+static inline bool
+IsUpperAlphaASCII(char ch)
+{
+  return ch >= 'A' && ch <= 'Z';
+}
+
+constexpr
+static inline bool
+IsLowerAlphaASCII(char ch)
+{
+  return ch >= 'a' && ch <= 'z';
+}
+
+constexpr
+static inline bool
+IsAlphaASCII(char ch)
+{
+  return IsUpperAlphaASCII(ch) || IsLowerAlphaASCII(ch);
+}
+
+constexpr
+static inline bool
+IsAlphaNumericASCII(char ch)
+{
+  return IsAlphaASCII(ch) || IsDigitASCII(ch);
+}
+
+/**
+ * Convert the specified ASCII character (0x00..0x7f) to upper case.
+ * Unlike toupper(), it ignores the system locale.
+ */
+constexpr
+static inline char
+ToUpperASCII(char ch)
+{
+  return ch >= 'a' && ch <= 'z'
+    ? (ch - ('a' - 'A'))
+    : ch;
+}
+
+#endif
diff --git a/src/util/StringUtil.cxx b/src/util/StringUtil.cxx
index 26aa7825e..048f009f5 100644
--- a/src/util/StringUtil.cxx
+++ b/src/util/StringUtil.cxx
@@ -18,6 +18,7 @@
  */
 
 #include "StringUtil.hxx"
+#include "CharUtil.hxx"
 
 #include <glib.h>
 
@@ -26,7 +27,7 @@
 const char *
 strchug_fast(const char *p)
 {
-	while (*p != 0 && g_ascii_isspace(*p))
+	while (IsWhitespaceNotNull(*p))
 		++p;
 
 	return p;
diff --git a/src/util/Tokenizer.cxx b/src/util/Tokenizer.cxx
index 726da0dd6..1c8af23fd 100644
--- a/src/util/Tokenizer.cxx
+++ b/src/util/Tokenizer.cxx
@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "Tokenizer.hxx"
+#include "CharUtil.hxx"
 #include "StringUtil.hxx"
 #include "Error.hxx"
 #include "Domain.hxx"
@@ -33,13 +34,13 @@ static constexpr Domain tokenizer_domain("tokenizer");
 static inline bool
 valid_word_first_char(char ch)
 {
-	return g_ascii_isalpha(ch);
+	return IsAlphaASCII(ch);
 }
 
 static inline bool
 valid_word_char(char ch)
 {
-	return g_ascii_isalnum(ch) || ch == '_';
+	return IsAlphaNumericASCII(ch) || ch == '_';
 }
 
 char *
@@ -61,7 +62,7 @@ Tokenizer::NextWord(Error &error)
 	   whitespace or end-of-string */
 
 	while (*++input != 0) {
-		if (g_ascii_isspace(*input)) {
+		if (IsWhitespaceOrNull(*input)) {
 			/* a whitespace: the word ends here */
 			*input = 0;
 			/* skip all following spaces, too */
@@ -106,7 +107,7 @@ Tokenizer::NextUnquoted(Error &error)
 	   whitespace or end-of-string */
 
 	while (*++input != 0) {
-		if (g_ascii_isspace(*input)) {
+		if (IsWhitespaceOrNull(*input)) {
 			/* a whitespace: the word ends here */
 			*input = 0;
 			/* skip all following spaces, too */
@@ -170,7 +171,7 @@ Tokenizer::NextString(Error &error)
 	   line) */
 
 	++input;
-	if (*input != 0 && !g_ascii_isspace(*input)) {
+	if (!IsWhitespaceOrNull(*input)) {
 		error.Set(tokenizer_domain,
 			  "Space expected after closing '\"'");
 		return nullptr;