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https://github.com/justinian/jsix.git
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Justin C. Miller
95a35cd0bf
Moving libc from its separate repo into this one, minor resulting build fixes, and a hacky way to add -I for libc headers in builds.
51 lines
1.4 KiB
C
51 lines
1.4 KiB
C
/* _PDCLIB_strtox_prelim( const char *, char *, int * )
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This file is part of the Public Domain C Library (PDCLib).
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Permission is granted to use, modify, and / or redistribute at will.
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*/
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#include <ctype.h>
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#include <stddef.h>
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#include <string.h>
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const char * _PDCLIB_strtox_prelim( const char * p, char * sign, int * base )
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{
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/* skipping leading whitespace */
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while ( isspace( *p ) ) ++p;
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/* determining / skipping sign */
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if ( *p != '+' && *p != '-' ) *sign = '+';
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else *sign = *(p++);
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/* determining base */
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if ( *p == '0' )
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{
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++p;
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if ( ( *base == 0 || *base == 16 ) && ( *p == 'x' || *p == 'X' ) )
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{
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*base = 16;
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++p;
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/* catching a border case here: "0x" followed by a non-digit should
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be parsed as the unprefixed zero.
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We have to "rewind" the parsing; having the base set to 16 if it
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was zero previously does not hurt, as the result is zero anyway.
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*/
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if ( memchr( _PDCLIB_digits, tolower(*p), *base ) == NULL )
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{
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p -= 2;
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}
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}
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else if ( *base == 0 )
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{
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*base = 8;
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}
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else
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{
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--p;
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}
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}
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else if ( ! *base )
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{
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*base = 10;
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}
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return ( ( *base >= 2 ) && ( *base <= 36 ) ) ? p : NULL;
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}
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