1 files changed, 111 insertions, 0 deletions
diff --git a/src/common/Format.cpp b/src/common/Format.cpp
new file mode 100644
index 00000000..2d3b50eb
--- /dev/null
+++ b/src/common/Format.cpp
@@ -0,0 +1,111 @@
+#include "cru/common/Format.hpp"
+
+namespace cru {
+namespace details {
+FormatToken ParsePlaceHolder(String place_holder_string) {
+  if (place_holder_string.empty()) {
+    return FormatToken::NonePlaceHolder({});
+  }
+
+  if (place_holder_string.StartWith(u":")) {
+    if (place_holder_string.Find(u':', 1) != -1) {
+      throw Exception(u"Two ':' inside placeholder.");
+    }
+
+    return FormatToken::NonePlaceHolder(place_holder_string.substr(1));
+  }
+  if (IsDigit(place_holder_string[0])) {
+    int position = 0;
+    int index = 0;
+    while (index < place_holder_string.size() &&
+           IsDigit(place_holder_string[index])) {
+      position = position * 10 + place_holder_string[index] - '0';
+      index++;
+    }
+
+    String option;
+
+    if (index != place_holder_string.size()) {
+      if (place_holder_string[index] != ':') {
+        throw Exception(u"Invalid placeholder in format.");
+      }
+
+      option = place_holder_string.substr(index + 1);
+    }
+
+    return FormatToken::PositionedPlaceHolder(position, std::move(option));
+  }
+
+  auto separator_index = place_holder_string.Find(':');
+  if (separator_index == -1) {
+    return FormatToken::NamedPlaceHolder(place_holder_string, {});
+  } else {
+    return FormatToken::NamedPlaceHolder(
+        place_holder_string.substr(0, separator_index),
+        place_holder_string.substr(separator_index + 1));
+  }
+}
+
+std::vector<FormatToken> ParseToFormatTokenList(const String& str) {
+  std::vector<FormatToken> result;
+
+  auto push_char = [&result](char16_t c) {
+    if (result.empty() || result.back().type == FormatTokenType::PlaceHolder) {
+      result.push_back(FormatToken::Text());
+    }
+    result.back().data.append(c);
+  };
+
+  bool try_to_escape = false;
+  bool is_in_place_holder = false;
+  String place_holder_string;
+
+  for (auto c : str) {
+    if (c == u'{') {
+      if (try_to_escape) {
+        push_char(u'{');
+        try_to_escape = false;
+        is_in_place_holder = false;
+      } else {
+        if (is_in_place_holder) {
+          throw Exception(u"Invalid format string: '{' inside placeholder.");
+        }
+
+        try_to_escape = true;
+        is_in_place_holder = true;
+      }
+    } else if (c == u'}') {
+      if (is_in_place_holder) {
+        is_in_place_holder = false;
+        result.push_back(ParsePlaceHolder(std::move(place_holder_string)));
+        place_holder_string.clear();
+      } else {
+        push_char(u'}');
+      }
+      try_to_escape = false;
+    } else {
+      if (is_in_place_holder) {
+        place_holder_string.push_back(c);
+      } else {
+        push_char(c);
+      }
+      try_to_escape = false;
+    }
+  }
+  return result;
+}
+
+void FormatAppendFromFormatTokenList(
+    String& current, const std::vector<FormatToken>& format_token_list,
+    Index index) {
+  for (Index i = index; i < static_cast<Index>(format_token_list.size()); i++) {
+    const auto& token = format_token_list[i];
+    if (token.type == FormatTokenType::PlaceHolder) {
+      throw Exception(u"More placeholder than args.");
+    } else {
+      current += token.data;
+    }
+  }
+}
+}  // namespace details
+}  // namespace cru