Pipeline: City rename, add address/postal-code generation, add xeger generation (#232)

tooling/pipeline/includes/services/xeger/xeger.h

@@ -0,0 +1,38 @@
+#ifndef BIERGARTEN_PIPELINE_INCLUDES_SERVICES_XEGER_XEGER_H_
+#define BIERGARTEN_PIPELINE_INCLUDES_SERVICES_XEGER_XEGER_H_
+
+#include <random>
+#include <string>
+#include <string_view>
+
+/**
+ * @brief Generates a random string matching @p pattern.
+ *
+ * Supported syntax:
+ * - literals
+ * - `.`
+ * - alternation `|`
+ * - groups `(...)` and non-capturing groups `(?:...)`
+ * - quantifiers `*` `+` `?` `{n}` `{n,}` `{n,m}`
+ * - character classes `[...]` / `[^...]`
+ * - shorthand escapes `\d \D \w \W \s \S \n \t \r`
+ *
+ * Not supported: lookaround, backreferences, and lazy quantifiers.
+ *
+ * @param pattern              Regular expression to generate a matching
+ *                             string for.
+ * @param rng                  Random source driving alternation/quantifier/
+ *                             class choices.
+ * @param unbounded_repeat_cap Extra repeats allowed on top of the declared
+ *                             minimum for unbounded quantifiers
+ *                             (`*`, `+`, `{n,}`).
+ *
+ * @return A string satisfying `std::regex_match(result, std::regex(pattern))`
+ *         for any @p pattern within the supported syntax subset.
+ *
+ * @throws std::runtime_error if @p pattern cannot be parsed.
+ */
+std::string GenerateStringFromRegex(std::string_view pattern, std::mt19937& rng,
+                                    int unbounded_repeat_cap = 8);
+
+#endif  // BIERGARTEN_PIPELINE_INCLUDES_SERVICES_XEGER_XEGER_H_