本文整理汇总了C++中std::string_view::remove_prefix方法的典型用法代码示例。如果您正苦于以下问题：C++ string_view::remove_prefix方法的具体用法？C++ string_view::remove_prefix怎么用？C++ string_view::remove_prefix使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类std::string_view的用法示例。
在下文中一共展示了string_view::remove_prefix方法的10个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: parseSymbol
double Calculator::parseSymbol(std::string_view &ref)
{
double value = 0;
skipSpaces(ref);
if (!ref.empty() && ref[0] == '(')
{
ref.remove_prefix(1);
value = parseExprSum(ref);
skipSpaces(ref);
if (!ref.empty() && ref[0] == ')')
{
ref.remove_prefix(1);
return value;
}
else
{
return std::numeric_limits<double>::quiet_NaN();
}
}
else if (!ref.empty() && !std::isdigit(ref[0]) && ref[0] != '-')
{
return parseFunction(ref);
}
else
{
return parseDouble(ref);
}
}示例2: parseExprSum
double Calculator::parseExprSum(std::string_view &ref)
{
double value = parseExprMul(ref);
while (true)
{
skipSpaces(ref);
if (!ref.empty() && ref[0] == '+')
{
ref.remove_prefix(1);
value += parseExprMul(ref);
m_printStrategy->printAddition();
}
else if (!ref.empty() && ref[0] == '-')
{
ref.remove_prefix(1);
value -= parseExprMul(ref);
m_printStrategy->printSubstraction();
}
else
{
break;
}
}
return value;
}示例3: parseExprMul
double Calculator::parseExprMul(std::string_view &ref)
{
double value = parseSymbol(ref);
while (true)
{
skipSpaces(ref);
if (!ref.empty() && ref[0] == '*')
{
ref.remove_prefix(1);
value *= parseSymbol(ref);
m_printStrategy->printMultiplication();
}
else if (!ref.empty() && ref[0] == '/')
{
ref.remove_prefix(1);
value /= parseSymbol(ref);
m_printStrategy->printDivision();
}
else
{
break;
}
}
return value;
}示例4: ToValue
bool CSeqConversionDefault::ToValue(std::string_view sv)
{
m_bReady = false;
if (sv == "$$") {
m_bHex = true;
return true;
}
if (auto nextTerm = GetNextTerm(sv)) {
m_iTargetValue = m_iCurrentValue = *nextTerm;
m_iRepeat = m_iValueDiv = 1;
if (!sv.empty() && sv.front() == ':') {
if (sv.remove_prefix(1), !sv.empty()) {
if (auto divTerm = GetNextInteger(sv)) {
m_iValueDiv = *divTerm;
if (m_iValueDiv <= 0)
return false;
if (!sv.empty() && sv.front() == ':') {
if (sv.remove_prefix(1), sv.empty())
return false;
if (auto target = GetNextTerm(sv))
m_iTargetValue = *target;
else
return false;
}
}
else
return false;
}
else
return false;
}
if (!sv.empty() && sv.front() == '\'') {
if (sv.remove_prefix(1), !sv.empty()) {
if (auto repTerm = GetNextInteger(sv)) {
m_iRepeat = *repTerm;
if (m_iRepeat <= 0)
return false;
}
}
else
return false;
}
if (sv.empty()) {
m_iValueInc = m_iTargetValue - m_iCurrentValue;
m_iRepeatCounter = m_iCounter = m_iValueMod = 0;
return m_bReady = true;
}
}
return false;
}示例5: parseDouble
double Calculator::parseDouble(std::string_view &ref)
{
double value = 0;
bool isNegative = false;
bool parsedAny = false;
skipSpaces(ref);
if (!ref.empty() && ref[0] == '-')
{
isNegative = true;
ref.remove_prefix(1);
}
skipSpaces(ref);
while (!ref.empty() && std::isdigit(ref[0]))
{
parsedAny = true;
const int digit = ref[0] - '0';
value = value * 10.0f + double(digit);
ref.remove_prefix(1);
}
if (!parsedAny)
{
return std::numeric_limits<double>::quiet_NaN();
}
if (isNegative)
{
value *= -1;
}
if (ref.empty() || (ref[0] != '.'))
{
m_printStrategy->printNumber(value);
return value;
}
ref.remove_prefix(1);
double factor = 1.f;
while (!ref.empty() && std::isdigit(ref[0]))
{
const int digit = ref[0] - '0';
factor *= 0.1f;
value += factor * double(digit);
ref.remove_prefix(1);
}
m_printStrategy->printNumber(value);
return value;
}示例6: skipSpaces
void Calculator::skipSpaces(std::string_view &ref)
{
size_t i = 0;
while (i < ref.size() && std::isspace(ref[i]))
{
++i;
}
ref.remove_prefix(i);
}示例7: ParseArguments
double Calculator::ParseArguments(std::string_view &ref)
{
double value = 0;
if (!ref.empty() && ref[0] == '(')
{
ref.remove_prefix(1);
value = parseExprSum(ref);
skipSpaces(ref);
if (!ref.empty() && ref[0] == ')')
{
ref.remove_prefix(1);
return value;
}
else
{
return std::numeric_limits<double>::quiet_NaN();
}
}
else
{
return std::numeric_limits<double>::quiet_NaN();
}
}示例8: parseFunction
double Calculator::parseFunction(std::string_view &ref)
{
try
{
std::string_view partStr = ref.substr(0, 3);
if (partStr == std::string_view("sin"))
{
ref.remove_prefix(3);
m_printStrategy->printFunctionName("sin");
return sin(ParseArguments(ref) * M_PI / 180);
}
else if (partStr == std::string_view("cos"))
{
ref.remove_prefix(3);
m_printStrategy->printFunctionName("cos");
return cos(ParseArguments(ref) * M_PI / 180);
}
else
{
std::string_view partStr = ref.substr(0, 4);
if (partStr == std::string_view("sqrt"))
{
ref.remove_prefix(4);
m_printStrategy->printFunctionName("sqrt");
return sqrt(ParseArguments(ref));
}
}
}
catch(const std::out_of_range&)
{
return std::numeric_limits<double>::quiet_NaN();
}
return std::numeric_limits<double>::quiet_NaN();
}示例9: if
std::optional<int> CSeqConversionDefault::GetNextInteger(std::string_view &sv, bool Signed) const
{
re::svmatch m;
if (m_bHex) {
static const std::regex HEX_RE {R"(^([\+-]?)[0-9A-Fa-f]+)", std::regex_constants::optimize};
if (std::regex_search(sv.begin(), sv.end(), m, HEX_RE))
if (!(Signed && !m[1].length()))
if (auto val = conv::to_int(re::sv_from_submatch(m[0]), 16)) {
sv.remove_prefix(std::distance(sv.begin(), m.suffix().first));
return val;
}
}
else {
static const std::regex NUMBER_RE {R"(^([\+-]?)[0-9]+)", std::regex_constants::optimize};
static const std::regex HEX_PREFIX_RE {R"(^([\+-]?)[\$x]([0-9A-Fa-f]+))", std::regex_constants::optimize}; // do not allow 0x prefix
if (std::regex_search(sv.begin(), sv.end(), m, HEX_PREFIX_RE)) {
if (!(Signed && !m[1].length()))
if (auto val = conv::to_int(re::sv_from_submatch(m[2]), 16)) {
if (m[1] == "-")
*val = -*val;
sv.remove_prefix(std::distance(sv.begin(), m.suffix().first));
return val;
}
}
else if (std::regex_search(sv.begin(), sv.end(), m, NUMBER_RE)) {
if (!(Signed && !m[1].length()))
if (auto val = conv::to_int(re::sv_from_submatch(m[0]))) {
sv.remove_prefix(std::distance(sv.begin(), m.suffix().first));
return val;
}
}
}
return std::nullopt;
}
std::optional<int> CSeqConversionDefault::GetNextTerm(std::string_view &sv)
{
return GetNextInteger(sv);
}
std::string CSeqConversion5B::ToString(char Value) const
{
std::string Str = std::to_string(Value & 0x1F);
uint8_t m = (uint8_t)Value & 0xE0;
if ((m & value_cast(s5b_mode_t::Square)) == value_cast(s5b_mode_t::Square))
Str.push_back('t');
if ((m & value_cast(s5b_mode_t::Noise)) == value_cast(s5b_mode_t::Noise))
Str.push_back('n');
if ((m & value_cast(s5b_mode_t::Envelope)) == value_cast(s5b_mode_t::Envelope))
Str.push_back('e');
// auto m = enum_cast<s5b_mode_t>((unsigned char)Value);
// if ((m & s5b_mode_t::Square) == s5b_mode_t::Square)
// Str.push_back('t');
// if ((m & s5b_mode_t::Noise) == s5b_mode_t::Noise)
// Str.push_back('n');
// if ((m & s5b_mode_t::Envelope) == s5b_mode_t::Envelope)
// Str.push_back('e');
return Str;
}
bool CSeqConversion5B::ToValue(std::string_view sv)
{
m_iEnableFlags = -1;
return CSeqConversionDefault::ToValue(sv);
}
char CSeqConversion5B::GetValue()
{
return CSeqConversionDefault::GetValue() | m_iEnableFlags;
}
std::optional<int> CSeqConversion5B::GetNextTerm(std::string_view &sv)
{
if (auto o = GetNextInteger(sv)) {
static const std::regex S5B_FLAGS_RE {R"(^[TtNnEe]*)", std::regex_constants::optimize};
if (re::svmatch m; std::regex_search(sv.begin(), sv.end(), m, S5B_FLAGS_RE)) {
if (m_iEnableFlags == -1) {
m_iEnableFlags = 0;
auto flags = re::sv_from_submatch(m[0]);
if (flags.find_first_of("Tt") != std::string::npos)
m_iEnableFlags |= value_cast(s5b_mode_t::Square);
if (flags.find_first_of("Nn") != std::string::npos)
m_iEnableFlags |= value_cast(s5b_mode_t::Noise);
if (flags.find_first_of("Ee") != std::string::npos)
m_iEnableFlags |= value_cast(s5b_mode_t::Envelope);
}
sv.remove_prefix(std::distance(sv.begin(), m.suffix().first));
}示例10: trim
std::string_view trim(std::string_view str)
{
str.remove_prefix(str.find_first_not_of(' '));
str.remove_suffix(str.size() - (str.find_last_not_of(' ') + 1));
return str;
}