77 lines
2.6 KiB
C++
77 lines
2.6 KiB
C++
#ifndef MESSMER_CPPUTILS_CONSTEXPR_CONST_STRING_H
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#define MESSMER_CPPUTILS_CONSTEXPR_CONST_STRING_H
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#include <cstring>
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#include <string>
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#include "impl/digit_parser.h"
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namespace cpputils {
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class const_string {
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public:
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constexpr const_string(const char *str) : const_string(str, strlen(str)) { }
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constexpr unsigned int size() const {
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return _size;
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}
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constexpr char operator[](unsigned int index) const {
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return (index < size()) ? _str[index] : throw std::logic_error("Index out of bounds");
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}
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constexpr const_string dropPrefix(unsigned int prefixSize) const {
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return substr(prefixSize, _size - prefixSize);
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}
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constexpr const_string dropSuffix(unsigned int suffixSize) const {
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return substr(0, _size - suffixSize);
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}
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constexpr const_string substr(unsigned int start, unsigned int count) const {
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return (start + count <= size()) ? const_string(_str + start, count)
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: throw std::logic_error("Substring out of bounds");
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}
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constexpr unsigned int sizeOfUIntPrefix() const {
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return _hasUIntPrefix() ? (1 + dropPrefix(1).sizeOfUIntPrefix()) : 0;
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}
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constexpr unsigned int parseUIntPrefix() const {
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return _hasUIntPrefix() ? _parseUIntBackwards(_str + sizeOfUIntPrefix() - 1, sizeOfUIntPrefix())
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: throw std::logic_error("Not a valid number");
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}
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constexpr const_string dropUIntPrefix() const {
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return _hasUIntPrefix() ? dropPrefix(1).dropUIntPrefix() : *this;
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}
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constexpr bool operator==(const const_string &rhs) const {
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return _size == rhs._size && 0 == memcmp(_str, rhs._str, _size);
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}
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constexpr bool operator!=(const const_string &rhs) const {
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return !operator==(rhs);
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}
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std::string toStdString() const {
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return std::string(_str, _size);
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}
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private:
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constexpr const_string(const char *str, unsigned int size) : _str(str), _size(size) { }
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static constexpr unsigned int _parseUIntBackwards(const char *input, unsigned int numDigits) {
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return (numDigits == 0) ? 0 : (digit_parser::parseDigit(*input) +
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10 * _parseUIntBackwards(input - 1, numDigits - 1));
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}
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constexpr bool _hasUIntPrefix() const {
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return size() > 0 && digit_parser::isDigit(_str[0]);
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}
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const char *_str;
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unsigned int _size;
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};
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}
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#endif
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