Spreadsheet: Fix column index to number conversion

The output of Spreadsheet::convert_from_string() is now correct for
numbers larger than 26^2.

1 files changed, 5 insertions, 5 deletions

diff --git a/Userland/Applications/Spreadsheet/Spreadsheet.cpp b/Userland/Applications/Spreadsheet/Spreadsheet.cpp
index a0175e9aa2..e42cd6a2e9 100644
--- a/Userland/Applications/Spreadsheet/Spreadsheet.cpp
+++ b/Userland/Applications/Spreadsheet/Spreadsheet.cpp
@@ -98,6 +98,9 @@ static Optional<size_t> convert_from_string(StringView str, unsigned base = 26,
 
     VERIFY(base >= 2 && base <= map.length());
 
+    if (str.is_empty())
+        return {};
+
     size_t value = 0;
     auto const len = str.length();
     for (auto i = 0u; i < len; i++) {
@@ -105,13 +108,10 @@ static Optional<size_t> convert_from_string(StringView str, unsigned base = 26,
         if (!maybe_index.has_value())
             return {};
         size_t digit_value = maybe_index.value();
-        // NOTE: Refer to the note in `String::bijective_base_from()'.
-        if (i == 0 && len > 1)
-            ++digit_value;
-        value += digit_value * AK::pow<float>(base, len - 1 - i);
+        value += (digit_value + 1) * AK::pow<float>(base, len - 1 - i);
     }
 
-    return value;
+    return value - 1;
 }
 
 DeprecatedString Sheet::add_column()