sys_parseargs.c

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#include "fb.h"

/* dst     - preallocated buffer to hold processed args
   src     - source string for arguments, may contain embedded null chars
   length  - length of src
   returns -1 on error, or number of arguments */
int fb_hParseArgs( char *dst, const char *src, ssize_t length )
{
        int in_quote = 0, argc = 0;
        ssize_t bs_count = 0, i = 0;
        const char *s = src;
        char *p = dst;

        /* s  - next char to read from src
           p  - next char to write in dst */

        /* return -1 to indicate error */
        if( src == NULL || dst == NULL || length < 0 )
                return -1;

        /* skip leading white space */
        while( i < length && (*s == ' ' || *s == '\0') ) {
                i++;
                s++;
        }

        /* scan for arguments. ' ' and '\0' are delimiters */
        while( i < length ) {
                bs_count = 0;

                do {
                        if( *s == '\\' ) {
                                *p++ = *s;
                                bs_count++;
                        } else {
                                if( *s == '\"') {
                                        if( bs_count & 1 ) {
                                                p -= ((bs_count - 1) >> 1) + 1;
                                                *p++ = *s;
                                        } else {
                                                p -= ( bs_count >> 1 );
                                                in_quote = !in_quote;
                                        }
                                } else if( *s == ' ' || *s == '\0' ) {
                                        if( in_quote ) {
                                                *p++ = ' ';
                                        } else {
                                                *p++ = '\0';
                                                break;
                                        }
                                } else {
                                        *p++ = *s;
                                }

                                bs_count = 0;
                        }

                        i++;
                        s++;

                } while ( i < length );

                argc++;

                /* skip trailing white space */
                while( i < length && ( *s == ' ' || *s == '\0' ) ) {
                        i++;
                        s++;
                }
        }

        *p = '\0';

        /* return arguments found */
        return argc;
}