From 5cc7cbc3704ec255eb5d0ac53b2cc0fcb1221d63 Mon Sep 17 00:00:00 2001
From: Dominick Allen <djallen@librehumanitas.org>
Date: Wed, 23 Oct 2024 13:21:10 -0500
Subject: String conversion and parsing format spec.

---
 source/fud_string_convert.cpp | 110 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 source/fud_string_convert.cpp

(limited to 'source/fud_string_convert.cpp')

diff --git a/source/fud_string_convert.cpp b/source/fud_string_convert.cpp
new file mode 100644
index 0000000..428ab36
--- /dev/null
+++ b/source/fud_string_convert.cpp
@@ -0,0 +1,110 @@
+/*
+ * libfud
+ * Copyright 2024 Dominick Allen
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "fud_string_convert.hpp"
+
+namespace fud::impl {
+
+FudStatus checkPlusSigned(StringView& view, size_t& skipIndex)
+{
+    auto isPlusSigned = view.data()[0] == '+';
+    if (isPlusSigned && view.length() == 1) {
+        return FudStatus::ArgumentInvalid;
+    }
+    if (isPlusSigned) {
+        view.advanceUnsafe();
+        skipIndex++;
+    }
+    return FudStatus::Success;
+}
+
+Result<bool, FudStatus> checkNegative(StringView& view, size_t& skipIndex)
+{
+    bool isNegative = view.data()[0] == '-';
+    if (isNegative && view.length() == 1) {
+        return FudStatus::ArgumentInvalid;
+    }
+    if (isNegative) {
+        skipIndex += 1;
+        view.advanceUnsafe();
+    }
+    return isNegative;
+}
+
+Result<Radix, FudStatus> determineRadix(StringView input, size_t& index)
+{
+    if (input.length() < 1) {
+        return FudStatus::ArgumentInvalid;
+    }
+
+    if (input.length() == 1 && input.data()[0] == '0') {
+        return Radix::Octal;
+    }
+
+    if (input.length() == 1) {
+        return Radix::Decimal;
+    }
+
+    if (input.data()[0] == '0' && (input.data()[1] == 'x' || input.data()[1] == 'X')) {
+        index += 2;
+        return Radix::Hexadecimal;
+    }
+
+    if (input.data()[0] == '0') {
+        auto nextChar = input.data()[1];
+        auto nextVal = AsciiLookup[nextChar];
+        if (nextVal >= 0 && nextVal < static_cast<uint8_t>(Radix::Octal)) {
+            return Radix::Octal;
+        }
+        if (nextVal >= static_cast<uint8_t>(Radix::Octal)) {
+            return FudStatus::ArgumentInvalid;
+        }
+    }
+
+    return Radix::Decimal;
+}
+
+Result<uint8_t, FudStatus> getRadix(StringView& view, size_t& skipIndex, Option<uint8_t> specifiedRadixOption)
+{
+    if (specifiedRadixOption.isNone()) {
+        size_t radixIndex = 0;
+        auto status = determineRadix(view, radixIndex);
+        if (status.isOkay()) {
+            skipIndex += radixIndex;
+            view.advanceUnsafe(radixIndex);
+            return static_cast<uint8_t>(status.takeOkay());
+        }
+        return status.takeError();
+    }
+
+    auto radix = specifiedRadixOption.value();
+    if (radix == static_cast<uint8_t>(Radix::Hexadecimal) && view.length() > 2 &&
+        (view.data()[1] == 'x' || view.data()[1] == 'X')) {
+        skipIndex += 2;
+        view.advanceUnsafe(2);
+    } else if (radix == static_cast<uint8_t>(Radix::Binary) && view.length() > 2 && view.data()[1] == 'b') {
+        skipIndex += 2;
+        view.advanceUnsafe(2);
+    } else if (radix == static_cast<uint8_t>(Radix::Octal) && view.length() > 2 && view.data()[1] == '0') {
+        skipIndex += 2;
+        view.advanceUnsafe(2);
+    }
+
+    return radix;
+}
+
+} // namespace fud::impl
-- 
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