1 files changed, 112 insertions, 0 deletions
diff --git a/src/common/strtol.h b/src/common/strtol.h
new file mode 100644
index 000000000..2183137b1
--- /dev/null
+++ b/src/common/strtol.h
@@ -0,0 +1,112 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2011 New Dream Network
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation.  See file COPYING.
+ *
+ */
+
+#ifndef CEPH_COMMON_STRTOL_H
+#define CEPH_COMMON_STRTOL_H
+
+#include <charconv>
+#include <cinttypes>
+#include <cstdlib>
+#include <optional>
+#include <string>
+#include <string_view>
+#include <system_error>
+#include <type_traits>
+
+
+namespace ceph {
+// Wrappers around std::from_chars.
+//
+// Why do we want this instead of strtol and friends? Because the
+// string doesn't have to be NUL-terminated! (Also, for a lot of
+// purposes, just putting a string_view in and getting an optional out
+// is friendly.)
+//
+// Returns the found number on success. Returns an empty optional on
+// failure OR on trailing characters.
+// Sadly GCC < 11 is missing the floating point versions.
+template<typename T>
+auto parse(std::string_view s, int base = 10)
+  -> std::enable_if_t<std::is_integral_v<T>, std::optional<T>>
+{
+  T t;
+  auto r = std::from_chars(s.data(), s.data() + s.size(), t, base);
+  if ((r.ec != std::errc{}) || (r.ptr != s.data() + s.size())) {
+    return std::nullopt;
+  }
+  return t;
+}
+
+// As above, but succeed on trailing characters and trim the supplied
+// string_view to remove the parsed number. Set the supplied
+// string_view to empty if it ends with the number.
+template<typename T>
+auto consume(std::string_view& s, int base = 10)
+  -> std::enable_if_t<std::is_integral_v<T>, std::optional<T>>
+{
+  T t;
+  auto r = std::from_chars(s.data(), s.data() + s.size(), t, base);
+  if (r.ec != std::errc{})
+    return std::nullopt;
+
+  if (r.ptr == s.data() + s.size()) {
+    s = std::string_view{};
+  } else {
+    s.remove_prefix(r.ptr - s.data());
+  }
+  return t;
+}
+} // namespace ceph
+
+bool strict_strtob(const char* str, std::string *err);
+
+long long strict_strtoll(std::string_view str, int base, std::string *err);
+
+int strict_strtol(std::string_view str, int base, std::string *err);
+
+double strict_strtod(std::string_view str, std::string *err);
+
+float strict_strtof(std::string_view str, std::string *err);
+
+uint64_t strict_iecstrtoll(std::string_view str, std::string *err);
+
+template<typename T>
+T strict_iec_cast(std::string_view str, std::string *err);
+
+template<typename T>
+T strict_si_cast(std::string_view str, std::string *err);
+
+/* On enter buf points to the end of the buffer, e.g. where the least
+ * significant digit of the input number will be printed. Returns pointer to
+ * where the most significant digit were printed, including zero padding.
+ * Does NOT add zero at the end of buffer, this is responsibility of the caller.
+ */
+template<typename T, const unsigned base = 10, const unsigned width = 1>
+static inline
+char* ritoa(T u, char *buf)
+{
+  static_assert(std::is_unsigned_v<T>, "signed types are not supported");
+  static_assert(base <= 16, "extend character map below to support higher bases");
+  unsigned digits = 0;
+  while (u) {
+    *--buf = "0123456789abcdef"[u % base];
+    u /= base;
+    digits++;
+  }
+  while (digits++ < width)
+    *--buf = '0';
+  return buf;
+}
+
+#endif