2 files changed, 47 insertions, 0 deletions
diff --git a/src/util/string.cpp b/src/util/string.cpp
index 914f1f74..4ad3decd 100644
--- a/src/util/string.cpp
+++ b/src/util/string.cpp
@@ -114,6 +114,48 @@ parse_signed(std::string_view value,
   }
 }
 
+nonstd::expected<uint64_t, std::string>
+parse_size(const std::string& value)
+{
+  errno = 0;
+
+  char* p;
+  double result = strtod(value.c_str(), &p);
+  if (errno != 0 || result < 0 || p == value.c_str() || value.empty()) {
+    return nonstd::make_unexpected(FMT("invalid size: \"{}\"", value));
+  }
+
+  while (isspace(*p)) {
+    ++p;
+  }
+
+  if (*p != '\0') {
+    unsigned multiplier = *(p + 1) == 'i' ? 1024 : 1000;
+    switch (*p) {
+    case 'T':
+      result *= multiplier;
+      [[fallthrough]];
+    case 'G':
+      result *= multiplier;
+      [[fallthrough]];
+    case 'M':
+      result *= multiplier;
+      [[fallthrough]];
+    case 'K':
+    case 'k':
+      result *= multiplier;
+      break;
+    default:
+      return nonstd::make_unexpected(FMT("invalid size: \"{}\"", value));
+    }
+  } else {
+    // Default suffix: G.
+    result *= 1000 * 1000 * 1000;
+  }
+
+  return static_cast<uint64_t>(result);
+}
+
 nonstd::expected<mode_t, std::string>
 parse_umask(std::string_view value)
 {
diff --git a/src/util/string.hpp b/src/util/string.hpp
index 5154915d..7df40aad 100644
--- a/src/util/string.hpp
+++ b/src/util/string.hpp
@@ -77,6 +77,11 @@ parse_signed(std::string_view value,
              std::optional<int64_t> max_value = std::nullopt,
              std::string_view description = "integer");
 
+// Parse a "size value", i.e. a string that can end in k, M, G, T (10-based
+// suffixes) or Ki, Mi, Gi, Ti (2-based suffixes). For backward compatibility, K
+// is also recognized as a synonym of k.
+nonstd::expected<uint64_t, std::string> parse_size(const std::string& value);
+
 // Parse `value` (an octal integer).
 nonstd::expected<mode_t, std::string> parse_umask(std::string_view value);