stream operator << for number/cpp_int_backend with 8 bit or less precision not working

[neal.p.smith@…]

for 8 bit or less numbers << with hex format sets characters to the numeric value of their digit rather than the ascii value. ie if the character should be 'F' the returned value is 15 rather than the ASCII value for F.

number<cpp_int_backend<7, 7, unsigned_magnitude, unchecked, void>> myNum07( "0xF"); number<cpp_int_backend<8, 8, unsigned_magnitude, unchecked, void>> myNum08( "0x0F"); number<cpp_int_backend<9, 9, unsigned_magnitude, unchecked, void>> myNum09( "0x0F"); number<cpp_int_backend<16, 16, unsigned_magnitude, unchecked, void>> myNum16("0x000F");

char outBuf[1000]; std::stringstream ss; ss << setfill('0'); ss << "7 bit : " << std::setw(2) << std::hex << myNum07 << endl; ss << "8 bit : " << std::setw(2) << std::hex << myNum08 << endl; ss << "9 bit : " << std::setw(2) << std::hex << myNum09 << endl; ss << "16 bit: " << std::setw(2) << std::hex << myNum16 << endl; strncpy(outBuf, ss.str().c_str(), 999); printf("%s\n", outBuf);

output is:

---

7 bit : 0☼ 8 bit : 0☼ 9 bit : 0f 16 bit: 0f

[John Maddock]

(In [84928]) Correct output of small-integer types. Fixes #8745.