drivers/filter/optset.c

   1 /* This file provides functionality to parse strings of comma-separated
   2  * options, each being either a single key name or a key=value pair, where the
   3  * value may be enclosed in quotes. A table of optset entries is provided to
   4  * determine which options are recognized, how to parse their values, and where
   5  * to store those. Unrecognized options are silently ignored; improperly
   6  * formatted options are silently set to reasonably acceptable values.
   7  *
   8  * The entry points into this file are:
   9  *   optset_parse       parse the given options string using the given table
  10  *
  11  * Created:
  12  *   May 2009 (D.C. van Moolenbroek)
  13  */
  14
  15 #define _MINIX 1
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <minix/config.h>
  19 #include <minix/const.h>
  20
  21 #include "optset.h"
  22
  23 FORWARD _PROTOTYPE( void optset_parse_entry, (struct optset *entry,
  24                                                 char *ptr, int len)     );
  25
  26 /*===========================================================================*
  27  *                              optset_parse_entry                           *
  28  *===========================================================================*/
  29 PRIVATE void optset_parse_entry(entry, ptr, len)
  30 struct optset *entry;
  31 char *ptr;
  32 int len;
  33 {
  34 /* Parse and store the value of a single option.
  35  */
  36   char *dst;
  37   int val;
  38
  39   switch (entry->os_type) {
  40   case OPT_BOOL:
  41         *((int *) entry->os_ptr) = entry->os_val;
  42
  43         break;
  44
  45   case OPT_STRING:
  46         if (len >= entry->os_val)
  47                 len = entry->os_val - 1;
  48
  49         dst = (char *) entry->os_ptr;
  50
  51         if (len > 0)
  52                 memcpy(dst, ptr, len);
  53         dst[len] = 0;
  54
  55         break;
  56
  57   case OPT_INT:
  58         if (len > 0)
  59                 val = strtol(ptr, NULL, entry->os_val);
  60         else
  61                 val = 0;
  62
  63         *((int *) entry->os_ptr) = val;
  64
  65         break;
  66   }
  67 }
  68
  69 /*===========================================================================*
  70  *                              optset_parse                                 *
  71  *===========================================================================*/
  72 PUBLIC void optset_parse(table, string)
  73 struct optset *table;
  74 char *string;
  75 {
  76 /* Parse a string of options, using the provided table of optset entries.
  77  */
  78   char *p, *kptr, *vptr;
  79   int i, klen, vlen;
  80
  81   for (p = string; *p; ) {
  82         /* Get the key name for the field. */
  83         for (kptr = p, klen = 0; *p && *p != '=' && *p != ','; p++, klen++);
  84
  85         if (*p == '=') {
  86                 /* The field has an associated value. */
  87                 vptr = ++p;
  88
  89                 /* If the first character after the '=' is a quote character,
  90                  * find a matching quote character followed by either a comma
  91                  * or the terminating null character, and use the string in
  92                  * between. Otherwise, use the string up to the next comma or
  93                  * the terminating null character.
  94                  */
  95                 if (*p == '\'' || *p == '"') {
  96                         p++;
  97
  98                         for (vlen = 0; *p && (*p != *vptr ||
  99                                 (p[1] && p[1] != ',')); p++, vlen++);
 100
 101                         if (*p) p++;
 102                         vptr++;
 103                 }
 104                 else
 105                         for (vlen = 0; *p && *p != ','; p++, vlen++);
 106         }
 107         else {
 108                 vptr = NULL;
 109                 vlen = 0;
 110         }
 111
 112         if (*p == ',') p++;
 113
 114         /* Find a matching entry for this key in the given table. If found,
 115          * call optset_parse_entry() on it. Silently ignore the option
 116          * otherwise.
 117          */
 118         for (i = 0; table[i].os_name != NULL; i++) {
 119                 if (strlen(table[i].os_name) == klen &&
 120                         !strncasecmp(table[i].os_name, kptr, klen)) {
 121
 122                         optset_parse_entry(&table[i], vptr, vlen);
 123
 124                         break;
 125                 }
 126         }
 127   }
 128 }