103 lines
1.9 KiB
C++
103 lines
1.9 KiB
C++
#pragma once
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#include <string>
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//Fast to int to string
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//Source: http://stackoverflow.com/a/4351484/192001
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//Modified version to pad zeros according to padding arg
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namespace c11log {
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namespace details {
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const char digit_pairs[201] = {
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"00010203040506070809"
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"10111213141516171819"
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"20212223242526272829"
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"30313233343536373839"
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"40414243444546474849"
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"50515253545556575859"
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"60616263646566676869"
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"70717273747576777879"
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"80818283848586878889"
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"90919293949596979899"
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};
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inline std::string& fast_itostr(int n, std::string& s, int padding)
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{
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if (n == 0)
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{
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s = "0";
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return s;
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}
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int sign = -(n < 0);
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unsigned int val = (n^sign) - sign;
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int size;
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if (val >= 10000)
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{
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if (val >= 10000000)
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{
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if (val >= 1000000000)
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size = 10;
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else if (val >= 100000000)
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size = 9;
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else
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size = 8;
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}
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else
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{
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if (val >= 1000000)
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size = 7;
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else if (val >= 100000)
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size = 6;
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else
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size = 5;
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}
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}
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else
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{
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if (val >= 100)
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{
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if (val >= 1000)
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size = 4;
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else
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size = 3;
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}
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else
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{
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if (val >= 10)
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size = 2;
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else
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size = 1;
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}
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}
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size -= sign;
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if (size < padding)
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size = padding;
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s.resize(size);
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char* c = &s[0];
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if (sign)
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*c = '-';
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c += size - 1;
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while (val >= 100)
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{
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int pos = val % 100;
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val /= 100;
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*(short*)(c - 1) = *(short*)(digit_pairs + 2 * pos);
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c -= 2;
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}
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while (val > 0)
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{
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*c-- = '0' + (val % 10);
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val /= 10;
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}
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while (c >= s.data())
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*c-- = '0';
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return s;
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}
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}
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} |