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https://github.com/Rockbox/rockbox.git
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60 lines
1.4 KiB
C
60 lines
1.4 KiB
C
/* The following file is (with slight modifications for Rockbox) from dietlibc
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* version 0.31 which is licensed under the GPL version 2: */
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#include <stdlib.h>
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#include <errno.h>
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#include <ctype.h>
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#include <limits.h>
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#include <gcc_extensions.h>
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unsigned long int strtoul(const char *ptr, char **endptr, int base)
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{
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int neg = 0, overflow = 0;
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unsigned long int v=0;
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const char* orig;
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const char* nptr=ptr;
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while(UNLIKELY(isspace(*nptr))) ++nptr;
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if (*nptr == '-') { neg=1; nptr++; }
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else if (*nptr == '+') ++nptr;
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orig=nptr;
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if (base==16 && nptr[0]=='0') goto skip0x;
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if (base) {
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register unsigned int b=base-2;
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if (UNLIKELY(b>34)) { errno=EINVAL; return 0; }
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} else {
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if (*nptr=='0') {
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base=8;
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skip0x:
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if ((nptr[1]=='x'||nptr[1]=='X') && isxdigit(nptr[2])) {
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nptr+=2;
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base=16;
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}
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} else
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base=10;
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}
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while(LIKELY(*nptr)) {
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register unsigned char c=*nptr;
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c=(c>='a'?c-'a'+10:c>='A'?c-'A'+10:c<='9'?c-'0':0xff);
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if (UNLIKELY(c>=base)) break; /* out of base */
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{
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register unsigned long x=(v&0xff)*base+c;
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register unsigned long w=(v>>8)*base+(x>>8);
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if (w>(ULONG_MAX>>8)) overflow=1;
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v=(w<<8)+(x&0xff);
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}
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++nptr;
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}
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if (UNLIKELY(nptr==orig)) { /* no conversion done */
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nptr=ptr;
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errno=EINVAL;
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v=0;
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}
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if (endptr) *endptr=(char *)nptr;
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if (overflow) {
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errno=ERANGE;
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return ULONG_MAX;
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}
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return (neg?-v:v);
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}
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