ardupilot/libraries/AP_HAL/utility/utoa_invert.cpp

78 lines
2.5 KiB
C++

/* Copyright (c) 2005, Dmitry Xmelkov
All rights reserved.
Rewritten in C by Soren Kuula
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
* Neither the name of the copyright holders nor the names of
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE. */
#include <stdint.h>
#include "xtoa_fast.h"
char * ultoa_invert (uint32_t val, char *s, uint8_t base) {
if (base == 8) {
do {
*s = '0' + (val & 0x7);
val >>= 3;
} while(val);
return s;
}
if (base == 16) {
do {
uint8_t digit = '0' + (val & 0xf);
#if XTOA_UPPER == 0
if (digit > '0' + 9)
digit += ('a' - '0' - 10);
#else
if (digit > '0' + 9)
digit += ('A' - '0' - 10);
#endif
*s++ = digit;
val >>= 4;
} while(val);
return s;
}
// Every base which in not hex and not oct is considered decimal.
// 33 bits would have been enough.
uint64_t xval = val;
do {
uint8_t saved = xval;
xval &= ~1;
xval += 2;
xval += xval >> 1; // *1.5
xval += xval >> 4; // *1.0625
xval += xval >> 8; // *1.00390625
xval += xval >> 16; // *1.000015259
xval += xval >> 32; // it all amounts to *1.6
xval >>= 4; // /16 ... so *1.6/16 is /10, fraction truncated.
*s++ = '0' + saved - 10 * (uint8_t)xval;
} while (xval);
return s;
}