91 lines
2.4 KiB
C
91 lines
2.4 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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#ifndef REGTEST
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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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#endif
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#ifdef TEST
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#include "_PDCLIB_test.h"
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int main( void )
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{
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#ifndef REGTEST
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int base = 0;
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char sign = '\0';
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char test1[] = " 123";
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char test2[] = "\t+0123";
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char test3[] = "\v-0x123";
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TESTCASE( _PDCLIB_strtox_prelim( test1, &sign, &base ) == &test1[2] );
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TESTCASE( sign == '+' );
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TESTCASE( base == 10 );
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base = 0;
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sign = '\0';
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TESTCASE( _PDCLIB_strtox_prelim( test2, &sign, &base ) == &test2[3] );
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TESTCASE( sign == '+' );
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TESTCASE( base == 8 );
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base = 0;
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sign = '\0';
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TESTCASE( _PDCLIB_strtox_prelim( test3, &sign, &base ) == &test3[4] );
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TESTCASE( sign == '-' );
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TESTCASE( base == 16 );
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base = 10;
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sign = '\0';
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TESTCASE( _PDCLIB_strtox_prelim( test3, &sign, &base ) == &test3[2] );
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TESTCASE( sign == '-' );
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TESTCASE( base == 10 );
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base = 1;
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TESTCASE( _PDCLIB_strtox_prelim( test3, &sign, &base ) == NULL );
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base = 37;
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TESTCASE( _PDCLIB_strtox_prelim( test3, &sign, &base ) == NULL );
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#endif
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return TEST_RESULTS;
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}
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#endif
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