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      1 /* ----------------------------------------------------------------------- *
      2  *
      3  *   Copyright 2004-2009 H. Peter Anvin - All Rights Reserved
      4  *   Copyright 2009 Intel Corporation; author: H. Peter Anvin
      5  *
      6  *   Permission is hereby granted, free of charge, to any person
      7  *   obtaining a copy of this software and associated documentation
      8  *   files (the "Software"), to deal in the Software without
      9  *   restriction, including without limitation the rights to use,
     10  *   copy, modify, merge, publish, distribute, sublicense, and/or
     11  *   sell copies of the Software, and to permit persons to whom
     12  *   the Software is furnished to do so, subject to the following
     13  *   conditions:
     14  *
     15  *   The above copyright notice and this permission notice shall
     16  *   be included in all copies or substantial portions of the Software.
     17  *
     18  *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     19  *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
     20  *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     21  *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
     22  *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
     23  *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     24  *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     25  *   OTHER DEALINGS IN THE SOFTWARE.
     26  *
     27  * ----------------------------------------------------------------------- */
     28 
     29 /*
     30  * argv.c
     31  *
     32  * Parse a single C string into argc and argv (argc is return value.)
     33  * memptr points to available memory.
     34  */
     35 
     36 #include <inttypes.h>
     37 #include <stddef.h>
     38 #include <stdio.h>
     39 #include <syslinux/align.h>
     40 #include <com32.h>
     41 
     42 extern char _end[];		/* Symbol created by linker */
     43 void *__mem_end = &_end;	/* Global variable for use by malloc() */
     44 
     45 int __parse_argv(char ***argv, const char *str)
     46 {
     47     char dummy_argv0[] = "";
     48     char *mem = __mem_end;
     49     const char *p = str;
     50     char *q = mem;
     51     char *r;
     52     char **arg;
     53     int wasspace = 1;
     54     int argc = 1;
     55 
     56     /* First copy the string, turning whitespace runs into nulls */
     57     for (p = str;; p++) {
     58 	if (*p <= ' ') {
     59 	    if (!wasspace) {
     60 		wasspace = 1;
     61 		*q++ = '\0';
     62 	    }
     63 	} else {
     64 	    if (wasspace) {
     65 		argc++;
     66 		wasspace = 0;
     67 	    }
     68 	    *q++ = *p;
     69 	}
     70 
     71 	/* This test is AFTER we have processed the null byte;
     72 	   we treat it as a whitespace character so it terminates
     73 	   the last argument */
     74 	if (!*p)
     75 	    break;
     76     }
     77 
     78     /* Now create argv */
     79     arg = (char **)ALIGN_UP_FOR(q, char *);
     80     *argv = arg;
     81     *arg++ = __com32.cs_name ? (char *)__com32.cs_name : dummy_argv0; /* argv[0] */
     82 
     83     q--;			/* Point q to final null */
     84     if (mem < q)
     85 	*arg++ = mem;		/* argv[1] */
     86 
     87     for (r = mem; r < q; r++) {
     88 	if (*r == '\0') {
     89 	    *arg++ = r + 1;
     90 	}
     91     }
     92 
     93     *arg++ = NULL;		/* Null pointer at the end */
     94     __mem_end = arg;		/* End of memory we used */
     95 
     96     return argc;
     97 }
     98