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/*
* Copyright (C) 2016 Robin Gareus <robin@gareus.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef PBD_NATSORT
#define PBD_NATSORT
#include <ctype.h>
#include <stdlib.h>
namespace PBD {
inline bool
is_integer (const char* i)
{
return isdigit (*i) || (*i == '-' && isdigit (i[1]));
}
/* return scale factor for SI metric prefix x 1000
* (to allow milli for integers)
*/
inline int64_t
order_of_magnitude (const char* i)
{
if (!is_integer (i)) {
return 0;
}
while (isdigit (*++i)) ;
if (!*i) {
return 1e3;
}
switch (*i) {
case 'm':
return 1;
case 'c':
return 10;
case 'd':
return 100;
case 'k':
/* fallthrough */
case 'K':
return 1e6;
case 'M':
return 1e9;
case 'G':
return 1e12;
case 'T':
return 1e15;
}
return 1e3;
}
/* this method sorts negative integers before
* positive ones, and also handles hexadecimal
* numbers when prefixed with "0x" or "0X".
* SI metric prefixes for integers are handled.
* (floating point, and rational numbers are
* not directy handled)
*/
inline bool
numerically_less (const char* a, const char* b)
{
const char* d_a = NULL;
const char* d_b = NULL;
for (;*a && *b; ++a, ++b) {
if (is_integer (a) && is_integer (b) && !d_a) {
d_a = a; d_b = b;
continue;
}
if (d_a) {
const int64_t ia = strtoll (d_a, NULL, 0) * order_of_magnitude (d_a);
const int64_t ib = strtoll (d_b, NULL, 0) * order_of_magnitude (d_b);
if (ia != ib) {
return ia < ib;
}
}
d_a = d_b = NULL;
if (*a == *b) {
continue;
}
return *a < *b;
}
if (d_a) {
return strtoll (d_a, NULL, 0) * order_of_magnitude (d_a) < strtoll (d_b, NULL, 0) * order_of_magnitude (d_b);
}
/* if we reach here, either strings are same length and equal
* or one is longer than the other.
*/
if (*a) { return false; }
if (*b) { return true; }
return false; // equal
}
inline bool
naturally_less (const char* a, const char* b)
{
const char* d_a = NULL;
const char* d_b = NULL;
for (;*a && *b; ++a, ++b) {
if (isdigit (*a) && isdigit (*b) && !d_a) {
d_a = a; d_b = b;
continue;
}
if (d_a) {
const int ia = atoi (d_a);
const int ib = atoi (d_b);
if (ia != ib) {
return ia < ib;
}
}
d_a = d_b = NULL;
if (*a == *b) {
continue;
}
return *a < *b;
}
if (d_a) {
return atoi (d_a) < atoi (d_b);
}
/* if we reach here, either strings are same length and equal
* or one is longer than the other.
*/
if (*a) { return false; }
if (*b) { return true; }
return false; // equal
}
} // namespace PBD
#endif // PBD_NATSORT
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