Split mathhelpers.hpp into dedicated include files for each functiona…

…lity

src/api/exchanges/src/bithumbprivateapi.cpp

@@ -42,9 +42,10 @@
 #include "exchangepublicapitypes.hpp"
 #include "file.hpp"
 #include "httprequesttype.hpp"
+#include "ipow.hpp"
 #include "market.hpp"
-#include "mathhelpers.hpp"
 #include "monetaryamount.hpp"
+#include "ndigits.hpp"
 #include "opened-order.hpp"
 #include "orderid.hpp"
 #include "ordersconstraints.hpp"

src/http-request/src/besturlpicker.cpp

@@ -9,7 +9,7 @@
 #include <string_view>
 
 #include "cct_log.hpp"
-#include "mathhelpers.hpp"
+#include "ipow.hpp"
 
 namespace cct {
 BestURLPicker::BestURLPicker(std::span<const std::string_view> baseUrls)

src/objects/include/monetaryamount.hpp

@@ -15,7 +15,8 @@
 #include "cct_log.hpp"
 #include "cct_string.hpp"
 #include "currencycode.hpp"
-#include "mathhelpers.hpp"
+#include "ipow.hpp"
+#include "ndigits.hpp"
 
 namespace cct {
 

src/objects/src/monetaryamount.cpp

@@ -23,7 +23,8 @@
 #include "cct_exception.hpp"
 #include "cct_invalid_argument_exception.hpp"
 #include "currencycode.hpp"
-#include "mathhelpers.hpp"
+#include "ipow.hpp"
+#include "ndigits.hpp"
 #include "stringhelpers.hpp"
 
 namespace cct {

src/objects/test/monetaryamount_test.cpp

@@ -9,7 +9,7 @@
 #include "cct_invalid_argument_exception.hpp"
 #include "cct_string.hpp"
 #include "currencycode.hpp"
-#include "mathhelpers.hpp"
+#include "ipow.hpp"
 
 namespace cct {
 

src/tech/CMakeLists.txt

@@ -91,8 +91,13 @@ else()
 endif()
 
 add_unit_test(
-    mathhelpers_test
-    test/mathhelpers_test.cpp
+    ndigits_test
+    test/ndigits_test.cpp
+)
+
+add_unit_test(
+    ipow_test
+    test/ipow_test.cpp
 )
 
 add_unit_test(

src/tech/include/ipow.hpp

@@ -0,0 +1,104 @@
+#pragma once
+
+#include <array>
+#include <cstdint>
+#include <limits>
+
+namespace cct {
+/// constexpr and integral version of math.power.
+/// Taken from https://gist.github.com/orlp/3551590
+constexpr int64_t ipow(int64_t base, uint8_t exp) noexcept {
+  constexpr uint8_t highest_bit_set[] = {0,   1,   2,   2,   3,   3,   3,   3,   4,   4,   4,   4,   4,   4,   4,
+                                         4,   5,   5,   5,   5,   5,   5,   5,   5,   5,   5,   5,   5,   5,   5,
+                                         5,   5,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,
+                                         6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,   6,
+                                         6,   6,   6,   255,  // anything past 63 is a guaranteed overflow with base > 1
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+                                         255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255};
+
+  int64_t result = 1;
+
+  switch (highest_bit_set[exp]) {
+    case 255:  // we use 255 as an overflow marker and return 0 on overflow/underflow
+      return base == 1 ? 1 : (base == -1 ? (1 - 2 * (exp & 1)) : 0);
+    case 6:
+      if ((exp & 1U) != 0) {
+        result *= base;
+      }
+      exp >>= 1;
+      base *= base;
+      [[fallthrough]];
+    case 5:
+      if ((exp & 1U) != 0) {
+        result *= base;
+      }
+      exp >>= 1;
+      base *= base;
+      [[fallthrough]];
+    case 4:
+      if ((exp & 1U) != 0) {
+        result *= base;
+      }
+      exp >>= 1;
+      base *= base;
+      [[fallthrough]];
+    case 3:
+      if ((exp & 1U) != 0) {
+        result *= base;
+      }
+      exp >>= 1;
+      base *= base;
+      [[fallthrough]];
+    case 2:
+      if ((exp & 1U) != 0) {
+        result *= base;
+      }
+      exp >>= 1;
+      base *= base;
+      [[fallthrough]];
+    case 1:
+      if ((exp & 1U) != 0) {
+        result *= base;
+      }
+      [[fallthrough]];
+    default:
+      return result;
+  }
+}
+
+/// Optimization of ipow(10, uint8_t exp)
+constexpr int64_t ipow10(uint8_t exp) noexcept {
+  constexpr const int64_t kPow10Table[] = {1LL,
+                                           10LL,
+                                           100LL,
+                                           1000LL,
+                                           10000LL,
+                                           100000LL,
+                                           1000000LL,
+                                           10000000LL,
+                                           100000000LL,
+                                           1000000000LL,
+                                           10000000000LL,
+                                           100000000000LL,
+                                           1000000000000LL,
+                                           10000000000000LL,
+                                           100000000000000LL,
+                                           1000000000000000LL,
+                                           10000000000000000LL,
+                                           100000000000000000LL,
+                                           1000000000000000000LL};
+  return exp < sizeof(kPow10Table) / sizeof(kPow10Table[0]) ? kPow10Table[exp] : std::numeric_limits<int64_t>::max();
+}
+
+}  // namespace cct

src/tech/include/levenshteindistancecalculator.hpp

@@ -5,10 +5,9 @@
 #include "cct_vector.hpp"
 
 namespace cct {
+
 class LevenshteinDistanceCalculator {
  public:
-  LevenshteinDistanceCalculator() noexcept = default;
-
   /// Computes the levenshtein distance between both input words.
   /// Complexity is in 'word1.length() * word2.length()' in time,
   /// min(word1.length(), word2.length()) in space.
@@ -18,4 +17,5 @@ class LevenshteinDistanceCalculator {
   // This is only for caching purposes, so that repeated calls to distance calculation do not allocate memory each time
   vector<int> _minDistance;
 };
+
 }  // namespace cct

src/tech/include/nchars.hpp

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <concepts>
+
+#include "ndigits.hpp"
+
+namespace cct {
+
+/// Count the number of digits including the possible minus sign for negative integrals.
+constexpr int nchars(std::signed_integral auto n) noexcept { return ndigits(n) + static_cast<int>(n < 0); }
+
+/// Synonym of ndigits for unsigned types.
+constexpr int nchars(std::unsigned_integral auto n) noexcept { return ndigits(n); }
+
+}  // namespace cct