Saya tahu ini adalah pertanyaan yang lebih tua, tetapi saya sudah berkali-kali menjumpainya dan, sampai saat ini, masih belum menemukan solusi dengan templated yang bagus dengan karakteristik sebagai berikut:
- Dapat mengonversi basis apa pun (dan mendeteksi jenis basis)
- Akan mendeteksi data yang salah (yaitu memastikan seluruh string, spasi spasi kurang banyak jejak / jejak, dikonsumsi oleh konversi)
- Akan memastikan bahwa, terlepas dari jenis yang dikonversi, kisaran nilai string dapat diterima.
Jadi, ini milik saya, dengan tali penguji. Karena menggunakan fungsi C strtoull / strtoll di bawah tenda, ia selalu mengonversi dulu ke jenis terbesar yang tersedia. Kemudian, jika Anda tidak menggunakan tipe terbesar, itu akan melakukan pemeriksaan rentang tambahan untuk memverifikasi jenis Anda tidak lebih dari (di bawah) mengalir. Untuk ini, ini sedikit kurang berkinerja daripada jika seseorang dengan benar memilih strtol / strtoul. Namun, ini juga berfungsi untuk celana pendek / karakter dan, setahu saya, tidak ada fungsi perpustakaan standar yang melakukan itu juga.
Nikmati; semoga seseorang menemukannya bermanfaat.
#include <cstdlib>
#include <cerrno>
#include <limits>
#include <stdexcept>
#include <sstream>
static const int DefaultBase = 10;
template<typename T>
static inline T CstrtoxllWrapper(const char *str, int base = DefaultBase)
{
while (isspace(*str)) str++; // remove leading spaces; verify there's data
if (*str == '\0') { throw std::invalid_argument("str; no data"); } // nothing to convert
// NOTE: for some reason strtoull allows a negative sign, we don't; if
// converting to an unsigned then it must always be positive!
if (!std::numeric_limits<T>::is_signed && *str == '-')
{ throw std::invalid_argument("str; negative"); }
// reset errno and call fn (either strtoll or strtoull)
errno = 0;
char *ePtr;
T tmp = std::numeric_limits<T>::is_signed ? strtoll(str, &ePtr, base)
: strtoull(str, &ePtr, base);
// check for any C errors -- note these are range errors on T, which may
// still be out of the range of the actual type we're using; the caller
// may need to perform additional range checks.
if (errno != 0)
{
if (errno == ERANGE) { throw std::range_error("str; out of range"); }
else if (errno == EINVAL) { throw std::invalid_argument("str; EINVAL"); }
else { throw std::invalid_argument("str; unknown errno"); }
}
// verify everything converted -- extraneous spaces are allowed
if (ePtr != NULL)
{
while (isspace(*ePtr)) ePtr++;
if (*ePtr != '\0') { throw std::invalid_argument("str; bad data"); }
}
return tmp;
}
template<typename T>
T StringToSigned(const char *str, int base = DefaultBase)
{
static const long long max = std::numeric_limits<T>::max();
static const long long min = std::numeric_limits<T>::min();
long long tmp = CstrtoxllWrapper<typeof(tmp)>(str, base); // use largest type
// final range check -- only needed if not long long type; a smart compiler
// should optimize this whole thing out
if (sizeof(T) == sizeof(tmp)) { return tmp; }
if (tmp < min || tmp > max)
{
std::ostringstream err;
err << "str; value " << tmp << " out of " << sizeof(T) * 8
<< "-bit signed range (";
if (sizeof(T) != 1) err << min << ".." << max;
else err << (int) min << ".." << (int) max; // don't print garbage chars
err << ")";
throw std::range_error(err.str());
}
return tmp;
}
template<typename T>
T StringToUnsigned(const char *str, int base = DefaultBase)
{
static const unsigned long long max = std::numeric_limits<T>::max();
unsigned long long tmp = CstrtoxllWrapper<typeof(tmp)>(str, base); // use largest type
// final range check -- only needed if not long long type; a smart compiler
// should optimize this whole thing out
if (sizeof(T) == sizeof(tmp)) { return tmp; }
if (tmp > max)
{
std::ostringstream err;
err << "str; value " << tmp << " out of " << sizeof(T) * 8
<< "-bit unsigned range (0..";
if (sizeof(T) != 1) err << max;
else err << (int) max; // don't print garbage chars
err << ")";
throw std::range_error(err.str());
}
return tmp;
}
template<typename T>
inline T
StringToDecimal(const char *str, int base = DefaultBase)
{
return std::numeric_limits<T>::is_signed ? StringToSigned<T>(str, base)
: StringToUnsigned<T>(str, base);
}
template<typename T>
inline T
StringToDecimal(T &out_convertedVal, const char *str, int base = DefaultBase)
{
return out_convertedVal = StringToDecimal<T>(str, base);
}
/*============================== [ Test Strap ] ==============================*/
#include <inttypes.h>
#include <iostream>
static bool _g_anyFailed = false;
template<typename T>
void TestIt(const char *tName,
const char *s, int base,
bool successExpected = false, T expectedValue = 0)
{
#define FAIL(s) { _g_anyFailed = true; std::cout << s; }
T x;
std::cout << "converting<" << tName << ">b:" << base << " [" << s << "]";
try
{
StringToDecimal<T>(x, s, base);
// get here on success only
if (!successExpected)
{
FAIL(" -- TEST FAILED; SUCCESS NOT EXPECTED!" << std::endl);
}
else
{
std::cout << " -> ";
if (sizeof(T) != 1) std::cout << x;
else std::cout << (int) x; // don't print garbage chars
if (x != expectedValue)
{
FAIL("; FAILED (expected value:" << expectedValue << ")!");
}
std::cout << std::endl;
}
}
catch (std::exception &e)
{
if (successExpected)
{
FAIL( " -- TEST FAILED; EXPECTED SUCCESS!"
<< " (got:" << e.what() << ")" << std::endl);
}
else
{
std::cout << "; expected exception encounterd: [" << e.what() << "]" << std::endl;
}
}
}
#define TEST(t, s, ...) \
TestIt<t>(#t, s, __VA_ARGS__);
int main()
{
std::cout << "============ variable base tests ============" << std::endl;
TEST(int, "-0xF", 0, true, -0xF);
TEST(int, "+0xF", 0, true, 0xF);
TEST(int, "0xF", 0, true, 0xF);
TEST(int, "-010", 0, true, -010);
TEST(int, "+010", 0, true, 010);
TEST(int, "010", 0, true, 010);
TEST(int, "-10", 0, true, -10);
TEST(int, "+10", 0, true, 10);
TEST(int, "10", 0, true, 10);
std::cout << "============ base-10 tests ============" << std::endl;
TEST(int, "-010", 10, true, -10);
TEST(int, "+010", 10, true, 10);
TEST(int, "010", 10, true, 10);
TEST(int, "-10", 10, true, -10);
TEST(int, "+10", 10, true, 10);
TEST(int, "10", 10, true, 10);
TEST(int, "00010", 10, true, 10);
std::cout << "============ base-8 tests ============" << std::endl;
TEST(int, "777", 8, true, 0777);
TEST(int, "-0111 ", 8, true, -0111);
TEST(int, "+0010 ", 8, true, 010);
std::cout << "============ base-16 tests ============" << std::endl;
TEST(int, "DEAD", 16, true, 0xDEAD);
TEST(int, "-BEEF", 16, true, -0xBEEF);
TEST(int, "+C30", 16, true, 0xC30);
std::cout << "============ base-2 tests ============" << std::endl;
TEST(int, "-10011001", 2, true, -153);
TEST(int, "10011001", 2, true, 153);
std::cout << "============ irregular base tests ============" << std::endl;
TEST(int, "Z", 36, true, 35);
TEST(int, "ZZTOP", 36, true, 60457993);
TEST(int, "G", 17, true, 16);
TEST(int, "H", 17);
std::cout << "============ space deliminated tests ============" << std::endl;
TEST(int, "1337 ", 10, true, 1337);
TEST(int, " FEAD", 16, true, 0xFEAD);
TEST(int, " 0711 ", 0, true, 0711);
std::cout << "============ bad data tests ============" << std::endl;
TEST(int, "FEAD", 10);
TEST(int, "1234 asdfklj", 10);
TEST(int, "-0xF", 10);
TEST(int, "+0xF", 10);
TEST(int, "0xF", 10);
TEST(int, "-F", 10);
TEST(int, "+F", 10);
TEST(int, "12.4", 10);
TEST(int, "ABG", 16);
TEST(int, "10011002", 2);
std::cout << "============ int8_t range tests ============" << std::endl;
TEST(int8_t, "7F", 16, true, std::numeric_limits<int8_t>::max());
TEST(int8_t, "80", 16);
TEST(int8_t, "-80", 16, true, std::numeric_limits<int8_t>::min());
TEST(int8_t, "-81", 16);
TEST(int8_t, "FF", 16);
TEST(int8_t, "100", 16);
std::cout << "============ uint8_t range tests ============" << std::endl;
TEST(uint8_t, "7F", 16, true, std::numeric_limits<int8_t>::max());
TEST(uint8_t, "80", 16, true, std::numeric_limits<int8_t>::max()+1);
TEST(uint8_t, "-80", 16);
TEST(uint8_t, "-81", 16);
TEST(uint8_t, "FF", 16, true, std::numeric_limits<uint8_t>::max());
TEST(uint8_t, "100", 16);
std::cout << "============ int16_t range tests ============" << std::endl;
TEST(int16_t, "7FFF", 16, true, std::numeric_limits<int16_t>::max());
TEST(int16_t, "8000", 16);
TEST(int16_t, "-8000", 16, true, std::numeric_limits<int16_t>::min());
TEST(int16_t, "-8001", 16);
TEST(int16_t, "FFFF", 16);
TEST(int16_t, "10000", 16);
std::cout << "============ uint16_t range tests ============" << std::endl;
TEST(uint16_t, "7FFF", 16, true, std::numeric_limits<int16_t>::max());
TEST(uint16_t, "8000", 16, true, std::numeric_limits<int16_t>::max()+1);
TEST(uint16_t, "-8000", 16);
TEST(uint16_t, "-8001", 16);
TEST(uint16_t, "FFFF", 16, true, std::numeric_limits<uint16_t>::max());
TEST(uint16_t, "10000", 16);
std::cout << "============ int32_t range tests ============" << std::endl;
TEST(int32_t, "7FFFFFFF", 16, true, std::numeric_limits<int32_t>::max());
TEST(int32_t, "80000000", 16);
TEST(int32_t, "-80000000", 16, true, std::numeric_limits<int32_t>::min());
TEST(int32_t, "-80000001", 16);
TEST(int32_t, "FFFFFFFF", 16);
TEST(int32_t, "100000000", 16);
std::cout << "============ uint32_t range tests ============" << std::endl;
TEST(uint32_t, "7FFFFFFF", 16, true, std::numeric_limits<int32_t>::max());
TEST(uint32_t, "80000000", 16, true, std::numeric_limits<int32_t>::max()+1);
TEST(uint32_t, "-80000000", 16);
TEST(uint32_t, "-80000001", 16);
TEST(uint32_t, "FFFFFFFF", 16, true, std::numeric_limits<uint32_t>::max());
TEST(uint32_t, "100000000", 16);
std::cout << "============ int64_t range tests ============" << std::endl;
TEST(int64_t, "7FFFFFFFFFFFFFFF", 16, true, std::numeric_limits<int64_t>::max());
TEST(int64_t, "8000000000000000", 16);
TEST(int64_t, "-8000000000000000", 16, true, std::numeric_limits<int64_t>::min());
TEST(int64_t, "-8000000000000001", 16);
TEST(int64_t, "FFFFFFFFFFFFFFFF", 16);
TEST(int64_t, "10000000000000000", 16);
std::cout << "============ uint64_t range tests ============" << std::endl;
TEST(uint64_t, "7FFFFFFFFFFFFFFF", 16, true, std::numeric_limits<int64_t>::max());
TEST(uint64_t, "8000000000000000", 16, true, std::numeric_limits<int64_t>::max()+1);
TEST(uint64_t, "-8000000000000000", 16);
TEST(uint64_t, "-8000000000000001", 16);
TEST(uint64_t, "FFFFFFFFFFFFFFFF", 16, true, std::numeric_limits<uint64_t>::max());
TEST(uint64_t, "10000000000000000", 16);
std::cout << std::endl << std::endl
<< (_g_anyFailed ? "!! SOME TESTS FAILED !!" : "ALL TESTS PASSED")
<< std::endl;
return _g_anyFailed;
}
StringToDecimaladalah metode pengguna-tanah; itu kelebihan beban sehingga bisa disebut seperti ini:
int a; a = StringToDecimal<int>("100");
atau ini:
int a; StringToDecimal(a, "100");
Saya benci mengulangi tipe int, jadi lebih suka yang terakhir. Ini memastikan bahwa jika tipe 'a' berubah, maka seseorang tidak mendapatkan hasil yang buruk. Saya berharap kompiler dapat mengetahuinya seperti:
int a; a = StringToDecimal("100");
... tetapi, C ++ tidak menyimpulkan tipe pengembalian templat, jadi itu yang terbaik yang bisa saya dapatkan.
Implementasinya cukup sederhana:
CstrtoxllWrappermembungkus keduanya strtoulldan strtoll, memanggil mana saja yang perlu berdasarkan pada ketandatanganan tipe templat dan memberikan beberapa jaminan tambahan (mis. input negatif tidak diizinkan jika tidak ditandatangani dan memastikan seluruh string dikonversi).
CstrtoxllWrapperdigunakan oleh StringToSigneddan StringToUnsigneddengan tipe terbesar (panjang panjang / tak bertanda panjang) tersedia untuk kompiler; ini memungkinkan konversi maksimal dilakukan. Kemudian, jika perlu, StringToSigned/ StringToUnsignedmelakukan pemeriksaan jangkauan akhir pada tipe yang mendasarinya. Akhirnya, metode titik akhir,StringToDecimal ,, memutuskan mana dari metode templat StringTo * yang akan dipanggil berdasarkan penandatanganan jenis yang mendasarinya.
Saya pikir sebagian besar sampah dapat dioptimalkan oleh kompiler; hampir semuanya harus deterministik saat kompilasi. Setiap komentar tentang aspek ini akan menarik bagi saya!