From bcdad5b8762060c82a0b7840cb905e69ddb9a65e Mon Sep 17 00:00:00 2001
From: Steven Le Rouzic <steven.lerouzic@gmail.com>
Date: Thu, 3 Jul 2025 18:37:18 +0200
Subject: Add numbers parsing

---
 asl/strings/parse_number.cpp | 162 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 162 insertions(+)
 create mode 100644 asl/strings/parse_number.cpp

(limited to 'asl/strings/parse_number.cpp')

diff --git a/asl/strings/parse_number.cpp b/asl/strings/parse_number.cpp
new file mode 100644
index 0000000..3b6b689
--- /dev/null
+++ b/asl/strings/parse_number.cpp
@@ -0,0 +1,162 @@
+// Copyright 2025 Steven Le Rouzic
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
+#include "asl/strings/parse_number.hpp"
+
+namespace asl
+{
+
+bool parse_float_impl(const char** begin, const char* end, float*);
+bool parse_double_impl(const char** begin, const char* end, double*);
+
+} // namespace asl
+
+asl::status_or<asl::parse_number_result<float>> asl::parse_float(asl::string_view sv)
+{
+    const auto* begin = sv.data();
+    // NOLINTNEXTLINE(*-pointer-arithmetic)
+    const auto* end = begin + sv.size();
+    if (float value{}; parse_float_impl(&begin, end, &value))
+    {
+        return parse_number_result<float>{
+            .value     = value,
+            .remaining = string_view{begin, end},
+        };
+    }
+    return invalid_argument_error();
+}
+
+asl::status_or<asl::parse_number_result<double>> asl::parse_double(asl::string_view sv)
+{
+    const auto* begin = sv.data();
+    // NOLINTNEXTLINE(*-pointer-arithmetic)
+    const auto* end = begin + sv.size();
+    if (float value{}; parse_float_impl(&begin, end, &value))
+    {
+        return parse_number_result<double>{
+            .value     = value,
+            .remaining = string_view{begin, end},
+        };
+    }
+    return invalid_argument_error();
+}
+
+namespace
+{
+
+constexpr int8_t kBase16Table[256] = {
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+     0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
+    -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+};
+
+// @Todo Maybe monomorph this for common bases (2, 16, 10)?
+
+template<typename T>
+asl::status_or<asl::parse_number_result<T>> parse_integer(asl::string_view sv, int base)
+{
+    ASL_ASSERT(base >= 2 && base <= 16);
+
+    if (sv.is_empty()) { return asl::invalid_argument_error(); }
+
+    T value = 0;
+    bool is_negative = false;
+
+    if (asl::is_signed_integer<T> && sv[0] == '-')
+    {
+        is_negative = true;
+        sv = sv.substr(1);
+    }
+
+    isize_t cursor = 0;
+    while (cursor < sv.size())
+    {
+        // NOLINTNEXTLINE(*-array-index)
+        int8_t digit = kBase16Table[static_cast<uint8_t>(sv[cursor])];
+        if (digit < 0 || digit >= base) { break; }
+
+        if (__builtin_mul_overflow(value, static_cast<T>(base), &value))
+        {
+            return asl::invalid_argument_error("overflow");
+        }
+
+        if (asl::is_signed_integer<T> && is_negative)
+        {
+            digit = static_cast<T>(-digit);
+        }
+
+        if (__builtin_add_overflow(value, static_cast<T>(digit), &value))
+        {
+            return asl::invalid_argument_error("overflow");
+        }
+
+        cursor += 1;
+    }
+
+    if (cursor == 0)
+    {
+        return asl::invalid_argument_error();
+    }
+
+    return asl::parse_number_result<T>{
+        .value     = value,
+        .remaining = sv.substr(cursor),
+    };
+}
+
+} // anonymous namespace
+
+asl::status_or<asl::parse_number_result<uint8_t>> asl::parse_uint8(string_view sv, int base)
+{
+    return parse_integer<uint8_t>(sv, base);
+}
+
+asl::status_or<asl::parse_number_result<uint16_t>> asl::parse_uint16(string_view sv, int base)
+{
+    return parse_integer<uint16_t>(sv, base);
+}
+
+asl::status_or<asl::parse_number_result<uint32_t>> asl::parse_uint32(string_view sv, int base)
+{
+    return parse_integer<uint32_t>(sv, base);
+}
+
+asl::status_or<asl::parse_number_result<uint64_t>> asl::parse_uint64(string_view sv, int base)
+{
+    return parse_integer<uint64_t>(sv, base);
+}
+
+asl::status_or<asl::parse_number_result<int8_t>> asl::parse_int8(string_view sv, int base)
+{
+    return parse_integer<int8_t>(sv, base);
+}
+
+asl::status_or<asl::parse_number_result<int16_t>> asl::parse_int16(string_view sv, int base)
+{
+    return parse_integer<int16_t>(sv, base);
+}
+
+asl::status_or<asl::parse_number_result<int32_t>> asl::parse_int32(string_view sv, int base)
+{
+    return parse_integer<int32_t>(sv, base);
+}
+
+asl::status_or<asl::parse_number_result<int64_t>> asl::parse_int64(string_view sv, int base)
+{
+    return parse_integer<int64_t>(sv, base);
+}
+
-- 
cgit