X-Git-Url: https://pd.if.org/git/?p=pdclib;a=blobdiff_plain;f=functions%2F_PDCLIB%2F_PDCLIB_strtox_prelim.c;fp=functions%2F_PDCLIB%2F_PDCLIB_strtox_prelim.c;h=7be40309ed41931c09fc0302f94a2959e4a2c09f;hp=0000000000000000000000000000000000000000;hb=3082b97d8f2de1584430ad42671a0e056ed33be4;hpb=d7f27d5325d7c44d93be00662b13aa9ffdec76b1

diff --git a/functions/_PDCLIB/_PDCLIB_strtox_prelim.c b/functions/_PDCLIB/_PDCLIB_strtox_prelim.c
new file mode 100644
index 0000000..7be4030
--- /dev/null
+++ b/functions/_PDCLIB/_PDCLIB_strtox_prelim.c
@@ -0,0 +1,92 @@
+/* $Id$ */
+
+/* _PDCLIB_strtox_prelim( const char *, char *, int * )
+
+   This file is part of the Public Domain C Library (PDCLib).
+   Permission is granted to use, modify, and / or redistribute at will.
+*/
+
+#include <ctype.h>
+#include <stddef.h>
+#include <string.h>
+#ifndef REGTEST
+const char * _PDCLIB_strtox_prelim( const char * p, char * sign, int * base )
+{
+    /* skipping leading whitespace */
+    while ( isspace( *p ) ) ++p;
+    /* determining / skipping sign */
+    if ( *p != '+' && *p != '-' ) *sign = '+';
+    else *sign = *(p++);
+    /* determining base */
+    if ( *p == '0' )
+    {
+        ++p;
+        if ( ( *base == 0 || *base == 16 ) && ( *p == 'x' || *p == 'X' ) )
+        {
+            *base = 16;
+            ++p;
+            /* catching a border case here: "0x" followed by a non-digit should
+               be parsed as the unprefixed zero.
+               We have to "rewind" the parsing; having the base set to 16 if it
+               was zero previously does not hurt, as the result is zero anyway.
+            */
+            if ( memchr( _PDCLIB_digits, tolower(*p), *base ) == NULL )
+            {
+                p -= 2;
+            }
+        }
+        else if ( *base == 0 )
+        {
+            *base = 8;
+        }
+        else
+        {
+            --p;
+        }
+    }
+    else if ( ! *base )
+    {
+        *base = 10;
+    }
+    return ( ( *base >= 2 ) && ( *base <= 36 ) ) ? p : NULL;
+}
+#endif
+
+#ifdef TEST
+#include <_PDCLIB_test.h>
+
+int main( void )
+{
+#ifndef REGTEST
+    int base = 0;
+    char sign = '\0';
+    char test1[] = "  123";
+    char test2[] = "\t+0123";
+    char test3[] = "\v-0x123";
+    TESTCASE( _PDCLIB_strtox_prelim( test1, &sign, &base ) == &test1[2] );
+    TESTCASE( sign == '+' );
+    TESTCASE( base == 10 );
+    base = 0;
+    sign = '\0';
+    TESTCASE( _PDCLIB_strtox_prelim( test2, &sign, &base ) == &test2[3] );
+    TESTCASE( sign == '+' );
+    TESTCASE( base == 8 );
+    base = 0;
+    sign = '\0';
+    TESTCASE( _PDCLIB_strtox_prelim( test3, &sign, &base ) == &test3[4] );
+    TESTCASE( sign == '-' );
+    TESTCASE( base == 16 );
+    base = 10;
+    sign = '\0';
+    TESTCASE( _PDCLIB_strtox_prelim( test3, &sign, &base ) == &test3[2] );
+    TESTCASE( sign == '-' );
+    TESTCASE( base == 10 );
+    base = 1;
+    TESTCASE( _PDCLIB_strtox_prelim( test3, &sign, &base ) == NULL );
+    base = 37;
+    TESTCASE( _PDCLIB_strtox_prelim( test3, &sign, &base ) == NULL );
+#endif
+    return TEST_RESULTS;
+}
+
+#endif