feat(baseN): digitsMap

Makefile

@@ -83,6 +83,7 @@ docs:
 cover: ${DIRS} ${patsubst %, ${BINDIR}/%${-g}-cov, ${TESTS}}
 	rm -f **/*.gcda
 	${patsubst %, ./${BINDIR}/%${-g}-cov;, ${TESTS}}
+	mkdir cov
 	gcovr --html-nested cov/index.html --txt --exclude-throw-branches
 
 ${OBJDIR}/%${-g}-cov.o: ${SRCDIR}/%.cpp ${INCDIR}/${LIB}/%.hpp

include/basen/baseN.hpp

@@ -7,6 +7,13 @@
 
 namespace baseN
 {
+    /**
+     * @param digits char[base] array of digits
+     * @param digits_size size of digits array. Equals to base
+     * @param map [out] int8_t[256] array, where at an index equal to the value of the symbol is the index of this symbol in the digits array. -1 if there is no symbol
+     * @throw std::logic_error if alphabet contain same chars
+     */
+    void digitsMap(const char *digits, uint8_t digits_size, int8_t *map);
     /**
      * @param str [in] pointer to string
      * @param str_size

src/baseN.cpp

@@ -9,6 +9,18 @@ static constexpr auto log256 = std::log(256);
 
 namespace baseN
 {
+    void digitsMap(const char *digits, uint8_t digits_size, int8_t *map)
+    {
+        std::fill(map, map + 256, -1);
+        for (uint8_t i = 0; i < digits_size; i++)
+        {
+            if (map[(int8_t)digits[i]] != -1)
+            {
+                throw std::logic_error("baseN::digitsMap: alphabet contain same chars");
+            }
+            map[(int8_t)digits[i]] = i;
+        }
+    }
     bool isValid(const char *str, uint64_t str_size, const int8_t *map) noexcept
     {
         return std::all_of(str, str + str_size, [map](char ch)

test/test-baseN.cpp

@@ -7,6 +7,14 @@
 
 using namespace baseN;
 
+TEST(baseN, digitsMap)
+{
+    int8_t map[256];
+    digitsMap(base58::digits, 58, map);
+    EXPECT_TRUE(std::equal(map, map + 256, base58::map));
+
+    EXPECT_THROW(digitsMap("11", 2, map), std::logic_error);
+}
 TEST(baseN, isValid)
 {
     std::vector<std::pair<bool, std::string>> tests = {