ubgpsuite/lonetix/numlib_atoi.c

214 lines
4.2 KiB
C

// SPDX-License-Identifier: LGPL-3.0-or-later
/**
* \file numlib_atoi.c
*
* Implements ASCII to integer conversion.
*
* \copyright The DoubleFourteen Code Forge (C) All Rights Reserved
* \author Lorenzo Cogotti
*/
#include "numlib.h"
#include <assert.h>
#include <limits.h>
static int digitval(char ch)
{
if (ch >= '0' && ch <= '9')
return ch - '0';
else if (ch >= 'A' && ch <= 'Z')
return ch - 'A' + 10;
else if (ch >= 'a' && ch <= 'z')
return ch - 'a' + 10;
else
return -1;
}
static unsigned long long ParseInt(const char *s,
char **endptr,
unsigned base,
int *signp,
NumConvRet *outcome)
{
int d;
// Single optional + or -
char c;
int sign;
const char *startptr = s;
unsigned long long u = 0;
sign = 1;
if (base > 36) {
*outcome = NCVEBADBASE;
goto done;
}
c = *s;
if (c == '-' || c == '+') {
sign -= (c == '-') << 1;
s++;
}
// Determine base
if (base == 0) {
if (s[0] == '0') {
if (s[1] == 'x' || s[1] == 'X') {
s += 2;
base = 16;
} else if (s[1] == 'b' || s[1] == 'B') {
s += 2;
base = 2;
} else {
s++;
base = 8;
}
} else {
base = 10;
}
} else if (base == 16) {
if (s[0] == '0' && (s[1] == 'x' || s[1] == 'X'))
s += 2;
} else if (base == 2) {
if (s[0] == '0' && (s[1] == 'b' || s[1] == 'B'))
s += 2;
}
// Convert numeric value
*outcome = NCVENOERR; // assume successful conversion
while ((d = digitval(*s)) >= 0 && d < (int) base) {
unsigned long long v = u * base + d;
if (u > v) {
// Overflow
v = ULLONG_MAX;
*outcome = NCVEOVERFLOW;
}
u = v;
s++;
}
if (s == startptr)
*outcome = NCVENOTHING;
done:
if (endptr)
*endptr = (char *) s;
*signp = sign;
return u;
}
unsigned long long Atoull(const char *s,
char **endp,
unsigned base,
NumConvRet *outcome)
{
NumConvRet result;
if (!outcome)
outcome = &result;
int sign;
unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
if (sign < 0)
*outcome = NCVEUNDERFLOW;
return sign * mag;
}
unsigned long Atoul(const char *s,
char **endp,
unsigned base,
NumConvRet *outcome)
{
NumConvRet result;
if (!outcome)
outcome = &result;
int sign;
unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
if (mag > ULONG_MAX)
*outcome = NCVEOVERFLOW;
if (sign < 0)
*outcome = NCVEUNDERFLOW;
return sign * mag;
}
unsigned Atou(const char *s, char **endp, unsigned base, NumConvRet *outcome)
{
NumConvRet result;
if (!outcome)
outcome = &result;
int sign;
unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
if (mag > UINT_MAX)
*outcome = NCVEOVERFLOW;
if (sign < 0)
*outcome = NCVEUNDERFLOW;
return sign * mag;
}
long long Atoll(const char *s, char **endp, unsigned base, NumConvRet *outcome)
{
NumConvRet result;
if (!outcome)
outcome = &result;
int sign;
unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
if (sign > 0 && mag > LLONG_MAX) {
*outcome = NCVEOVERFLOW;
return LLONG_MAX;
}
if (sign < 0 && mag > -((unsigned long long) LLONG_MIN)) {
*outcome = NCVEUNDERFLOW;
return LLONG_MIN;
}
return sign * mag;
}
long Atol(const char *s, char **endp, unsigned base, NumConvRet *outcome)
{
NumConvRet result;
if (!outcome)
outcome = &result;
int sign;
unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
if (sign > 0 && mag > LONG_MAX) {
*outcome = NCVEOVERFLOW;
return LONG_MAX;
}
if (sign < 0 && mag > -((unsigned long) LONG_MIN)) {
*outcome = NCVEUNDERFLOW;
return LONG_MIN;
}
return sign * mag;
}
int Atoi(const char *s, char **endp, unsigned base, NumConvRet *outcome)
{
NumConvRet result;
if (!outcome)
outcome = &result;
int sign;
unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
if (sign > 0 && mag > INT_MAX) {
*outcome = NCVEOVERFLOW;
return INT_MAX;
}
if (sign < 0 && mag > -((unsigned) INT_MIN)) {
*outcome = NCVEUNDERFLOW;
return INT_MIN;
}
return sign * mag;
}