1 files changed, 154 insertions, 0 deletions
diff --git a/src/common/StringToNumberConverter.cpp b/src/common/StringToNumberConverter.cpp
new file mode 100644
index 00000000..259e39b0
--- /dev/null
+++ b/src/common/StringToNumberConverter.cpp
@@ -0,0 +1,154 @@
+#include "cru/common/StringToNumberConverter.h"
+#include "cru/common/Exception.h"
+
+namespace cru {
+bool StringToIntegerConverterImpl::CheckParams() const {
+  if (base == 0) {
+    if (flags & StringToNumberFlags::kAllowLeadingZeroForInteger) {
+      return false;
+    } else {
+      return true;
+    }
+  }
+
+  return base >= 2 & base <= 36;
+}
+
+static bool IsSpace(char c) {
+  return c == ' ' || c == '\t' || c == '\n' || c == '\r';
+}
+
+StringToIntegerConverterImplResult StringToIntegerConverterImpl::Parse(
+    const char* const str, const Index size,
+    Index* processed_characters_count) const {
+  if (str == nullptr) throw std::invalid_argument("Invalid str.");
+  if (size < 0) throw std::invalid_argument("Invalid size.");
+  if (!CheckParams()) throw std::invalid_argument("Invalid parsing flags.");
+
+  const bool throw_on_error = (flags & StringToNumberFlags::kThrowOnError) != 0;
+
+  const char* const end = str + size;
+
+  const char* current = str;
+
+  if (flags & StringToNumberFlags::kAllowLeadingSpaces) {
+    while (current != end && IsSpace(*current)) {
+      current++;
+    }
+  }
+
+  if (current == end) {
+    if (processed_characters_count) {
+      *processed_characters_count = 0;
+    }
+    if (throw_on_error) {
+      throw Exception(u"Empty string (after reading leading spaces).");
+    } else {
+      return {false, 0};
+    }
+  }
+
+  bool negate = false;
+
+  if (*current == '-') {
+    ++current;
+    negate = true;
+  } else if (*current == '+') {
+    ++current;
+  }
+
+  if (current == end) {
+    if (processed_characters_count) {
+      *processed_characters_count = 0;
+    }
+    if (throw_on_error) {
+      throw Exception(u"Empty string (after reading sign).");
+    } else {
+      return {false, 0};
+    }
+  }
+
+  int base = this->base;
+
+  if (base == 0) {
+    if (*current == '0') {
+      ++current;
+      if (current == end) {
+        return {negate, 0};
+      } else if (*current == 'x' || *current == 'X') {
+        ++current;
+        base = 16;
+      } else if (*current == 'b' || *current == 'B') {
+        ++current;
+        base = 2;
+      } else {
+        base = 8;
+      }
+    }
+  }
+
+  if (current == end) {
+    if (processed_characters_count) {
+      *processed_characters_count = 0;
+    }
+    if (throw_on_error) {
+      throw Exception(u"Empty string (after reading head base indicator).");
+    } else {
+      return {false, 0};
+    }
+  }
+
+  const bool allow_leading_zero =
+      flags & StringToNumberFlags::kAllowLeadingZeroForInteger;
+
+  while (current != end && *current == '0') {
+    current++;
+  }
+
+  if (current == end) {
+    return {negate, 0};
+  }
+
+  const bool allow_trailing_junk =
+      flags & StringToNumberFlags::kAllowTrailingJunk;
+  const bool allow_trailing_spaces =
+      flags & StringToNumberFlags::kAllowTrailingSpaces;
+  unsigned long long result = 0;
+
+  while (current != end) {
+    const char c = *current;
+    if (c >= '0' && c <= (base > 10 ? '9' : base + '0' - 1)) {
+      result = result * base + c - '0';
+    } else if (base > 10 && c >= 'a' && c <= 'z') {
+      result = result * base + c - 'a' + 10;
+    } else if (base > 10 && c >= 'A' && c <= 'Z') {
+      result = result * base + c - 'A' + 10;
+    } else if (allow_trailing_junk) {
+      break;
+    } else if (allow_trailing_spaces && IsSpace(c)) {
+      break;
+    } else {
+      if (processed_characters_count) {
+        *processed_characters_count = 0;
+      }
+      if (throw_on_error) {
+        throw Exception(u"Read invalid character.");
+      } else {
+        return {false, 0};
+      }
+    }
+  }
+
+  if (allow_trailing_spaces) {
+    while (current != end && IsSpace(*current)) {
+      current++;
+    }
+  }
+
+  if (current != end) {
+    throw Exception(u"There is trailing junk.");
+  }
+
+  return {negate, result};
+}
+}  // namespace cru