From: Gerhard Sittig <redacted>
Date: Sat, 17 Dec 2022 13:26:09 +0000 (+0100)
Subject: bindings/cxx: implement std::stoul() fallback when C++11 is missing
X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=f806de1864167feed30952f1ab65497b8ee4152a;p=libsigrok.git

bindings/cxx: implement std::stoul() fallback when C++11 is missing

Provide an implementation of stoul(3) when the targetted platform does
not provide it. This is modelled after the stoi() and stod() routines.
---

diff --git a/bindings/cxx/ConfigKey_methods.cpp b/bindings/cxx/ConfigKey_methods.cpp
index 7f8c201e..7381c922 100644
--- a/bindings/cxx/ConfigKey_methods.cpp
+++ b/bindings/cxx/ConfigKey_methods.cpp
@@ -70,6 +70,36 @@ static inline double stod( const std::string& str )
 }
 #endif
 
+#ifndef HAVE_STOUL
+
+/* Fallback implementation of stoul. */
+
+#include <cerrno>
+#include <cstdlib>
+#include <limits>
+#include <stdexcept>
+
+static inline unsigned long stoul(const std::string &str)
+{
+	char *endptr;
+	unsigned long ret;
+	errno = 0;
+	ret = std::strtoul(str.c_str(), &endptr, 10);
+	if (endptr == str.c_str())
+		throw std::invalid_argument("stoul");
+	/*
+	 * TODO Convert to a larger/wider intermediate data type?
+	 * Because after conversion into the very target type, the
+	 * range check is assumed to be ineffective.
+	 */
+	if (errno == ERANGE ||
+		ret < std::numeric_limits<unsigned long>::min() ||
+		ret > std::numeric_limits<unsigned long>::max())
+		throw std::out_of_range("stoul");
+	return ret;
+}
+#endif
+
 Glib::VariantBase ConfigKey::parse_string(std::string value, enum sr_datatype dt)
 {
 	GVariant *variant;
diff --git a/configure.ac b/configure.ac
index c98c55a4..3ba6c8c5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -465,6 +465,16 @@ AM_COND_IF([BINDINGS_CXX], [
 	AS_IF([test "x$sr_cv_have_stoi_stod" = xyes],
 		[AC_DEFINE([HAVE_STOI_STOD], [1],
 			[Specifies whether we have the stoi and stod functions.])])
+	# In theory std::stoul() should have identical availability
+	# as std::stoi() and std::stod() have. All of them are C++11.
+	# But we play it safe here, and check support individually.
+	AC_CACHE_CHECK([for stoul], [sr_cv_have_stoul],
+		[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <string>]],
+				[[(void) std::stoul("1");]])],
+			[sr_cv_have_stoul=yes], [sr_cv_have_stoul=no])])
+	AS_IF([test "x$sr_cv_have_stoul" = xyes],
+		[AC_DEFINE([HAVE_STOUL], [1],
+			[Specifies whether we have the std::stoul function.])])
 ])
 
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