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