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-rw-r--r--src/openvic-simulation/utility/StringUtils.hpp127
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diff --git a/src/openvic-simulation/utility/StringUtils.hpp b/src/openvic-simulation/utility/StringUtils.hpp
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+#include <cstdint>
+#include <limits>
+#include <string_view>
+
+namespace OpenVic::StringUtils {
+ /* The constexpr function 'string_to_uint64' will convert a string into a uint64_t integer value.
+ * The function takes four parameters: the input string (as a pair of pointers marking the start and
+ * end of the string), a bool pointer for reporting success, and the base for numerical conversion.
+ * The base parameter defaults to 10 (decimal), but it can be any value between 2 and 36. If the base
+ * given is 0, it will be set to 16 if the string starts with "0x" or "0X", otherwise 8 if the string
+ * still starts with "0", otherwise 10. The success bool pointer parameter is used to report whether
+ * or not conversion was successful. It can be nullptr if this information is not needed.
+ */
+ constexpr uint64_t string_to_uint64(char const* str, const char* const end, bool* successful = nullptr, int base = 10) {
+ if (successful != nullptr) *successful = false;
+
+ // Base value should be between 2 and 36. If it's not, return 0 as an invalid case.
+ if (str == nullptr || end <= str || base < 0 || base == 1 || base > 36)
+ return 0;
+
+ // The result of the conversion will be stored in this variable.
+ uint64_t result = 0;
+
+ // If base is zero, base is determined by the string prefix.
+ if (base == 0) {
+ if (*str == '0') {
+ if (str + 1 != end && (str[1] == 'x' || str[1] == 'X')) {
+ base = 16; // Hexadecimal.
+ str += 2; // Skip '0x' or '0X'
+ if (str == end) return 0;
+ } else {
+ base = 8; // Octal.
+ }
+ } else {
+ base = 10; // Decimal.
+ }
+ } else if (base == 16) {
+ // If base is 16 and string starts with '0x' or '0X', skip these characters.
+ if (*str == '0' && str + 1 != end && (str[1] == 'x' || str[1] == 'X')) {
+ str += 2;
+ if (str == end) return 0;
+ }
+ }
+
+ // Convert the number in the string.
+ for (; str != end; ++str) {
+ int digit;
+ if (*str >= '0' && *str <= '9') {
+ digit = *str - '0'; // Calculate digit value for '0'-'9'.
+ } else if (*str >= 'a' && *str <= 'z') {
+ digit = *str - 'a' + 10; // Calculate digit value for 'a'-'z'.
+ } else if (*str >= 'A' && *str <= 'Z') {
+ digit = *str - 'A' + 10; // Calculate digit value for 'A'-'Z'.
+ } else {
+ break; // Stop conversion if current character is not a digit.
+ }
+
+ if (digit >= base) {
+ break; // Stop conversion if current digit is greater than or equal to the base.
+ }
+
+ // Check for overflow on multiplication
+ if (result > std::numeric_limits<uint64_t>::max() / base) {
+ return std::numeric_limits<uint64_t>::max();
+ }
+
+ result *= base;
+
+ // Check for overflow on addition
+ if (result > std::numeric_limits<uint64_t>::max() - digit) {
+ return std::numeric_limits<uint64_t>::max();
+ }
+
+ result += digit;
+ }
+
+ // If successful is not null and the entire string was parsed,
+ // set *successful to true (if not it is already false).
+ if (successful != nullptr && str == end) *successful = true;
+
+ return result;
+ }
+
+ constexpr uint64_t string_to_uint64(char const* str, size_t length, bool* successful = nullptr, int base = 10) {
+ return string_to_uint64(str, str + length, successful, base);
+ }
+
+ inline uint64_t string_to_uint64(const std::string_view str, bool* successful = nullptr, int base = 10) {
+ return string_to_uint64(str.data(), str.length(), successful, base);
+ }
+
+ constexpr int64_t string_to_int64(char const* str, const char* const end, bool* successful = nullptr, int base = 10) {
+ if (successful != nullptr) *successful = false;
+
+ if (str == nullptr || end <= str) return 0;
+
+ // This flag will be set if the number is negative.
+ bool is_negative = false;
+
+ // Check if there is a sign character.
+ if (*str == '+' || *str == '-') {
+ if (*str == '-')
+ is_negative = true;
+ ++str;
+ if (str == end) return 0;
+ }
+
+ const uint64_t result = string_to_uint64(str, end, successful, base);
+ if (!is_negative) {
+ if (result >= std::numeric_limits<int64_t>::max())
+ return std::numeric_limits<int64_t>::max();
+ return result;
+ } else {
+ if (result > std::numeric_limits<int64_t>::max())
+ return std::numeric_limits<int64_t>::min();
+ return -result;
+ }
+ }
+
+ constexpr int64_t string_to_int64(char const* str, size_t length, bool* successful = nullptr, int base = 10) {
+ return string_to_int64(str, str + length, successful, base);
+ }
+
+ inline int64_t string_to_int64(const std::string_view str, bool* successful = nullptr, int base = 10) {
+ return string_to_int64(str.data(), str.length(), successful, base);
+ }
+}