dos/argv.c

   1 #ident "$Id$"
   2 /* ----------------------------------------------------------------------- *
   3  *
   4  *   Copyright 2004 H. Peter Anvin - All Rights Reserved
   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
  40 #define ALIGN_UP(p,t)       ((t *)(((uintptr_t)(p) + (sizeof(t)-1)) & ~(sizeof(t)-1)))
  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 *mem = __mem_end;
  48   const char *p = str;
  49   char *q = mem;
  50   char *r;
  51   char **arg;
  52   int wasspace = 0;
  53   int argc = 1;
  54
  55   /* First copy the string, turning whitespace runs into nulls */
  56   for ( p = str ; ; p++ ) {
  57     if ( *p <= ' ' ) {
  58       if ( !wasspace ) {
  59         wasspace = 1;
  60         *q++ = '\0';
  61       }
  62     } else {
  63       if ( wasspace ) {
  64         argc++;
  65         wasspace = 0;
  66       }
  67       *q++ = *p;
  68     }
  69
  70     /* This test is AFTER we have processed the null byte;
  71        we treat it as a whitespace character so it terminates
  72        the last argument */
  73     if ( ! *p )
  74       break;
  75   }
  76
  77   /* Now create argv */
  78   arg = ALIGN_UP(q,char *);
  79   *argv = arg;
  80   *arg++ = mem;                 /* argv[0] */
  81
  82   q--;                          /* Point q to final null */
  83   for ( r = mem ; r < q ; r++ ) {
  84     if ( *r == '\0' ) {
  85       *arg++ = r+1;
  86     }
  87   }
  88
  89   *arg++ = NULL;                /* Null pointer at the end */
  90   __mem_end = arg;              /* End of memory we used */
  91
  92   return argc;
  93 }