1 files changed, 73 insertions, 0 deletions
diff --git a/src/util/parse-int-range.h b/src/util/parse-int-range.h
new file mode 100644
index 0000000..aac18d9
--- /dev/null
+++ b/src/util/parse-int-range.h
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Parse a string containing number ranges.
+ *
+ * Copyright (C) 2022 Martin Owens
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+#ifndef INKSCAPE_UTIL_PARSE_INT_RANGE_H
+#define INKSCAPE_UTIL_PARSE_INT_RANGE_H
+
+#include <regex>
+#include <string>
+#include <set>
+
+namespace Inkscape {
+
+/**
+ * Parse integer ranges out of a string using regex.
+ *
+ * @param input - A string containing number ranges that can either be comma
+ *                separated or dash separated for non and continuous ranges.
+ * @param start - Optional first number in the acceptable range.
+ * @param end - The last number in the acceptable range.
+ *
+ * @returns a sorted set of unique numbers.
+ */
+inline std::set<unsigned int> parseIntRange(const std::string &input, unsigned int start=1, unsigned int end=0)
+{
+    // Special word based translations go here:
+    if (input == "all") {
+        return parseIntRange("-", start, end);
+    }
+
+    std::set<unsigned int> out;
+    auto add = [=](std::set<unsigned int> &to, unsigned int val) {
+        if (start <= val && (!end || val <= end))
+            to.insert(val);
+    };
+
+    std::regex re("((\\d+|)\\s?(-)\\s?(\\d+|)|,?(\\d+)([^-]|$))");
+
+    std::string::const_iterator sit = input.cbegin(), fit = input.cend();
+    for (std::smatch match; std::regex_search(sit, fit, match, re); sit = match[0].second)
+    {
+        if (match.str(3) == "") {
+            add(out, std::stoul(match.str(5)));
+        } else {
+            auto r1 = match.str(2).empty() ? start : std::stoul(match.str(2));
+            auto r2 = match.str(4).empty() ? (end ? end : r1) : std::stoul(match.str(4));
+            for (auto i = std::min(r1, r2); i <= std::max(r1, r2); i++) {
+                add(out, i);
+            }
+        }
+    }
+
+   return out;
+}
+
+} // namespace Inkscape
+
+#endif
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :