added compile time pattern parsing

include/omath/utility/pattern_scan.hpp

@@ -3,9 +3,12 @@
 //
 
 #pragma once
+#include <algorithm>
+#include <array>
 #include <expected>
 #include <optional>
 #include <span>
+#include <stdexcept>
 #include <string_view>
 #include <vector>
 
@@ -15,6 +18,8 @@ class unit_test_pattern_scan_corner_case_1_Test;
 class unit_test_pattern_scan_corner_case_2_Test;
 class unit_test_pattern_scan_corner_case_3_Test;
 class unit_test_pattern_scan_corner_case_4_Test;
+class unit_test_pattern_scan_consteval_read_test_Test;
+class unit_test_pattern_scan_consteval_spacing_and_case_Test;
 // ReSharper restore CppInconsistentNaming
 namespace omath
 {
@@ -29,8 +34,21 @@ namespace omath
         friend unit_test_pattern_scan_corner_case_2_Test;
         friend unit_test_pattern_scan_corner_case_3_Test;
         friend unit_test_pattern_scan_corner_case_4_Test;
+        friend unit_test_pattern_scan_consteval_read_test_Test;
+        friend unit_test_pattern_scan_consteval_spacing_and_case_Test;
 
     public:
+        template<std::size_t N>
+        struct fixed_string final
+        {
+            char value[N]{};
+
+            constexpr fixed_string(const char (&text)[N])
+            {
+                std::ranges::copy(text, value);
+            }
+        };
+
         [[nodiscard]]
         static std::span<std::byte>::iterator scan_for_pattern(const std::span<std::byte>& range,
                                                                const std::string_view& pattern);
@@ -49,9 +67,26 @@ namespace omath
             if (!parsed_pattern) [[unlikely]]
                 return end;
 
+            return scan_for_parsed_pattern(begin, end, parsed_pattern.value());
+        }
+        template<fixed_string Pattern, class IteratorType>
+        requires std::input_or_output_iterator<std::remove_cvref_t<IteratorType>>
+        static IteratorType scan_for_pattern(const IteratorType& begin, const IteratorType& end)
+        {
+            constexpr auto parsed_pattern = parse_pattern<Pattern>();
+
+            return scan_for_parsed_pattern(begin, end, parsed_pattern);
+        }
+
+    private:
+        template<class IteratorType, class ParsedPattern>
+        requires std::input_or_output_iterator<std::remove_cvref_t<IteratorType>>
+        static IteratorType scan_for_parsed_pattern(const IteratorType& begin, const IteratorType& end,
+                                                    const ParsedPattern& parsed_pattern)
+        {
             const auto whole_range_size = static_cast<std::ptrdiff_t>(std::distance(begin, end));
 
-            const auto pattern_size = static_cast<std::ptrdiff_t>(parsed_pattern->size());
+            const auto pattern_size = static_cast<std::ptrdiff_t>(parsed_pattern.size());
             const std::ptrdiff_t scan_size = whole_range_size - pattern_size;
 
             if (scan_size < 0)
@@ -61,9 +96,9 @@ namespace omath
             {
                 bool found = true;
 
-                for (std::ptrdiff_t j = 0; j < static_cast<std::ptrdiff_t>(parsed_pattern->size()); j++)
+                for (std::ptrdiff_t j = 0; j < static_cast<std::ptrdiff_t>(parsed_pattern.size()); j++)
                 {
-                    found = parsed_pattern->at(j) == std::nullopt || parsed_pattern->at(j) == *(begin + i + j);
+                    found = parsed_pattern.at(j) == std::nullopt || parsed_pattern.at(j) == *(begin + i + j);
 
                     if (!found)
                         break;
@@ -73,10 +108,97 @@ namespace omath
             }
             return end;
         }
-
-    private:
         [[nodiscard]]
         static std::expected<std::vector<std::optional<std::byte>>, PatternScanError>
         parse_pattern(const std::string_view& pattern_string);
+
+        [[nodiscard]]
+        constexpr static bool is_space(const char c)
+        {
+            return c == ' ' || c == '\t' || c == '\n' || c == '\r';
+        }
+
+        [[nodiscard]]
+        constexpr static int hex_value(const char c)
+        {
+            if (c >= '0' && c <= '9')
+                return c - '0';
+            if (c >= 'A' && c <= 'F')
+                return c - 'A' + 10;
+            if (c >= 'a' && c <= 'f')
+                return c - 'a' + 10;
+            return -1;
+        }
+        template<fixed_string Pattern>
+        [[nodiscard]]
+        static consteval std::size_t signature_size()
+        {
+            std::size_t count = 0;
+            bool in_token = false;
+
+            for (std::size_t i = 0; i + 1 < sizeof(Pattern.value); ++i)
+            {
+                if (is_space(Pattern.value[i]))
+                {
+                    in_token = false;
+                }
+                else if (!in_token)
+                {
+                    ++count;
+                    in_token = true;
+                }
+            }
+
+            return count;
+        }
+
+        template<fixed_string Pattern>
+        static consteval std::array<std::optional<std::byte>, signature_size<Pattern>()> parse_pattern()
+        {
+            std::array<std::optional<std::byte>, signature_size<Pattern>()> result{};
+            std::size_t out = 0;
+            std::size_t i = 0;
+
+            while (i + 1 < sizeof(Pattern.value))
+            {
+                while (i + 1 < sizeof(Pattern.value) && is_space(Pattern.value[i]))
+                    ++i;
+
+                const std::size_t token_start = i;
+
+                while (i + 1 < sizeof(Pattern.value) && !is_space(Pattern.value[i]))
+                    ++i;
+
+                const std::size_t token_size = i - token_start;
+
+                if (token_size == 0)
+                    continue;
+
+                // ReSharper disable once CppTooWideScope
+                const bool is_wildcard = (token_size == 1 || token_size == 2) && Pattern.value[token_start] == '?';
+
+                if (is_wildcard)
+                {
+                    if (token_size == 2 && Pattern.value[token_start + 1] != '?')
+                        throw std::logic_error("invalid wildcard token");
+
+                    result[out++] = std::nullopt;
+                    continue;
+                }
+
+                if (token_size != 2)
+                    throw std::logic_error("invalid byte token");
+
+                const int high = hex_value(Pattern.value[token_start]);
+                const int low = hex_value(Pattern.value[token_start + 1]);
+
+                if (high < 0 || low < 0)
+                    throw std::logic_error("invalid hex byte");
+
+                result[out++] = static_cast<std::byte>((high << 4) | low);
+            }
+
+            return result;
+        }
     };
 } // namespace omath

tests/general/unit_test_pattern_scan.cpp

@@ -4,8 +4,8 @@
 #include "omath/utility/pe_pattern_scan.hpp"
 #include "gtest/gtest.h"
 #include <omath/utility/pattern_scan.hpp>
-#include <source_location>
 #include <print>
+#include <source_location>
 TEST(unit_test_pattern_scan, read_test)
 {
     const auto result = omath::PatternScanner::parse_pattern("FF ? ?? E9");
@@ -51,3 +51,37 @@ TEST(unit_test_pattern_scan, corner_case_4)
     const auto result = omath::PatternScanner::parse_pattern("X ? ?? E9 ");
     EXPECT_FALSE(result.has_value());
 }
+
+TEST(unit_test_pattern_scan, consteval_read_test)
+{
+    constexpr auto result = omath::PatternScanner::parse_pattern<"FF ? ?? E9">();
+
+    static_assert(result.size() == 4);
+    static_assert(result[0] == static_cast<std::byte>(0xFF));
+    static_assert(result[1] == std::nullopt);
+    static_assert(result[2] == std::nullopt);
+    static_assert(result[3] == static_cast<std::byte>(0xE9));
+
+    EXPECT_EQ(result[0], static_cast<std::byte>(0xFF));
+    EXPECT_EQ(result[1], std::nullopt);
+    EXPECT_EQ(result[2], std::nullopt);
+    EXPECT_EQ(result[3], static_cast<std::byte>(0xE9));
+}
+
+TEST(unit_test_pattern_scan, consteval_spacing_and_case)
+{
+    constexpr auto result = omath::PatternScanner::parse_pattern<" \tde\nAD\r?? ? ef ">();
+
+    static_assert(result.size() == 5);
+    static_assert(result[0] == static_cast<std::byte>(0xDE));
+    static_assert(result[1] == static_cast<std::byte>(0xAD));
+    static_assert(result[2] == std::nullopt);
+    static_assert(result[3] == std::nullopt);
+    static_assert(result[4] == static_cast<std::byte>(0xEF));
+
+    EXPECT_EQ(result[0], static_cast<std::byte>(0xDE));
+    EXPECT_EQ(result[1], static_cast<std::byte>(0xAD));
+    EXPECT_EQ(result[2], std::nullopt);
+    EXPECT_EQ(result[3], std::nullopt);
+    EXPECT_EQ(result[4], static_cast<std::byte>(0xEF));
+}

tests/general/unit_test_pattern_scan_extra.cpp

@@ -14,6 +14,16 @@ TEST(unit_test_pattern_scan_extra, IteratorScanFound)
     EXPECT_EQ(std::distance(buf.begin(), it), 0);
 }
 
+TEST(unit_test_pattern_scan_extra, ConstevalIteratorScan)
+{
+    std::vector<std::byte> buf = {static_cast<std::byte>(0x00), static_cast<std::byte>(0xDE),
+                                  static_cast<std::byte>(0xAD), static_cast<std::byte>(0xBE),
+                                  static_cast<std::byte>(0xEF), static_cast<std::byte>(0x11)};
+    const auto it = PatternScanner::scan_for_pattern<"DE ?? BE EF">(buf.begin(), buf.end());
+    EXPECT_NE(it, buf.end());
+    EXPECT_EQ(std::distance(buf.begin(), it), 1);
+}
+
 TEST(unit_test_pattern_scan_extra, IteratorScanNotFound)
 {
     std::vector<std::byte> buf = {static_cast<std::byte>(0x00), static_cast<std::byte>(0x11),