rom/dos/findvar.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Find a local variable.
   6     Lang: English
   7 */
   8
   9 #include <aros/debug.h>
  10 #include "dos_intern.h"
  11 #include <proto/exec.h>
  12 #include <proto/utility.h>
  13 #include <string.h>
  14
  15 /*****************************************************************************
  16
  17     NAME */
  18
  19 #include <proto/dos.h>
  20 #include <dos/var.h>
  21
  22         AROS_LH2(struct LocalVar *, FindVar,
  23
  24 /*  SYNOPSIS */
  25         AROS_LHA(CONST_STRPTR, name, D1),
  26         AROS_LHA(ULONG       , type, D2),
  27
  28 /*  LOCATION */
  29         struct DosLibrary *, DOSBase, 153, Dos)
  30
  31 /*  FUNCTION
  32         Finds a local variable structure.
  33
  34     INPUTS
  35         name   --   the name of the variable you wish to find. Note that
  36                     variable names follow the same syntax and semantics
  37                     as filesystem names.
  38         type   --   The type of variable to be found (see <dos/var.h>).
  39                     Actually, only the lower 8 bits of "type" are used
  40                     by FindVar().
  41
  42     RESULT
  43         A pointer to the LocalVar structure for that variable if it was
  44         found. If the variable wasn't found, or was of the wrong type,
  45         NULL will be returned.
  46
  47     NOTES
  48
  49     EXAMPLE
  50
  51     BUGS
  52
  53     SEE ALSO
  54         DeleteVar(), GetVar(), SetVar()
  55
  56     INTERNALS
  57         For every local variable, a structure of type LocalVar exists:
  58         struct LocalVar {
  59                 struct Node lv_Node;
  60                 UWORD       lv_Flags;
  61                 UBYTE      *lv_Value;
  62                 ULONG       lv_Len;
  63         };
  64
  65         lv_Node.ln_Type
  66         holds the variable type, either LV_VAR for regular local environment
  67         variables or LV_ALIAS for shell aliases. dos/var.h also defines
  68         LVF_IGNORE (for private usage by the shell)
  69
  70         lv_Node.ln_Name
  71         holds the variable name (NUL terminated string)
  72
  73         lv_Flags
  74         stores GVF_BINARY_VAR and GVF_DONT_NULL_TERM if given as flags to
  75         SetVar(). It is only used by GetVar().
  76
  77         lv_Value
  78         holds the variable's value
  79
  80         lv_Len
  81         is the length of lv_Value
  82
  83 *****************************************************************************/
  84 {
  85     AROS_LIBFUNC_INIT
  86
  87     /* Only the lowest 8 bits are valid here */
  88     type &= 0xFF;
  89
  90     if (name != NULL)
  91     {
  92         /* We scan through the process->pr_LocalVars list */
  93         struct Process  *pr;
  94         struct LocalVar *var;
  95
  96         pr  = (struct Process *)FindTask(NULL);
  97         ASSERT_VALID_PROCESS(pr);
  98         var = (struct LocalVar *)pr->pr_LocalVars.mlh_Head;
  99
 100         ForeachNode(&pr->pr_LocalVars, var)
 101         {
 102             LONG res;
 103
 104             if (var->lv_Node.ln_Type == type)
 105             {
 106                 /* The list is alphabetically sorted. */
 107                 res = Stricmp(name, var->lv_Node.ln_Name);
 108
 109                 /* Found it */
 110                 if (res == 0)
 111                 {
 112                     return var;
 113                 }
 114
 115                 /* We have gone too far through the sorted list. */
 116                 else if (res < 0)
 117                 {
 118                     break;
 119                 }
 120             }
 121         }
 122     }
 123
 124     return NULL;
 125
 126     AROS_LIBFUNC_EXIT
 127 } /* FindVar */