Address PR comments

src/util/MemorySize/MemorySize.cpp

@@ -8,6 +8,7 @@
 #include <absl/strings/charconv.h>
 #include <absl/strings/str_cat.h>
 
+#include <cctype>
 #include <charconv>
 #include <ctre-unicode.hpp>
 #include <string_view>
@@ -59,30 +60,31 @@ std::string MemorySize::asString() const {
 
 // _____________________________________________________________________________
 MemorySize MemorySize::parse(std::string_view str) {
-  if (auto matcher = ctre::match<
-          "(?<amount>\\d+(?:\\.\\d+)?) ?(?<unit>[kKmMgGtT][bB]?|[bB])">(str)) {
+  constexpr ctll::fixed_string regex =
+      "(?<amount>\\d+(?:\\.\\d+)?)\\s*(?<unit>[kKmMgGtT][bB]?|[bB])";
+  if (auto matcher = ctre::match<regex>(str)) {
     auto amountString = matcher.get<"amount">().to_view();
+    // Versions after CTRE v3.8.1 should support to_number()
+    // with double values if the compilers support it.
     double amount;
     absl::from_chars(amountString.begin(), amountString.end(), amount);
     auto unitString = matcher.get<"unit">().to_view();
-    switch (unitString.at(0)) {
+    switch (std::tolower(unitString.at(0))) {
       case 'b':
-      case 'B':
         if (ad_utility::contains(amountString, '.')) {
-          break;
+          throw std::runtime_error(absl::StrCat(
+              "'", str,
+              "' could not be parsed as a memory size. When using bytes as "
+              "units only unsigned integers are allowed."));
         }
         return MemorySize::bytes(static_cast<size_t>(amount));
       case 'k':
-      case 'K':
         return MemorySize::kilobytes(amount);
       case 'm':
-      case 'M':
         return MemorySize::megabytes(amount);
       case 'g':
-      case 'G':
         return MemorySize::gigabytes(amount);
       case 't':
-      case 'T':
         return MemorySize::terabytes(amount);
       default:
         // Whatever this is, it is false.

test/MemorySizeTest.cpp

@@ -239,7 +239,7 @@ TEST(MemorySize, Parse) {
   doExceptionTest("4.2 B");
   doExceptionTest("-4.2 B");
 
-  // Nothing should work with negativ numbers.
+  // Nothing should work with negative numbers.
   std::ranges::for_each(generalAsStringTestCases(), doExceptionTest,
                         [](const MemorySizeAndStringRepresentation& testCase) {
                           return absl::StrCat("-",
@@ -288,7 +288,7 @@ TEST(MemorySize, Parse) {
                                                      {42_TB, "42 t"}},
       doTest);
 
-  // Check if string is truly optional
+  // Check if whitespace between unit and amount is truly optional
   std::ranges::for_each(
       std::vector<MemorySizeAndStringRepresentation>{{42_B, "42B"},
                                                      {42_B, "42b"},
@@ -321,6 +321,12 @@ TEST(MemorySize, Parse) {
                                                      {42_TB, "42t"}},
       doTest);
 
+  // Test if multiple spaces are fine too
+  std::ranges::for_each(
+      std::vector<MemorySizeAndStringRepresentation>{{42_kB, "42    K"},
+                                                     {42_kB, "42  k"}},
+      doTest);
+
   // We only take memory units up to `TB`. Not further.
   std::ranges::for_each(std::vector{"42 P", "42 PB"}, doExceptionTest);
 }