lib/flags.c

   1 /* flags.c */
   2
   3 #include "flags.h"
   4
   5 /*
   6  * setflags:
   7  *  Applies a "+x-y+zab" style string to the inflags value.
   8  *
   9  * The "flagmask" input restricts the flags that can be changed.
  10  * The "reject" input specifies whether to silently drop or actively reject if:
  11  *  REJECT_UNKNOWN:    An unknown flag was specified
  12  *  REJECT_DISALLOWED: An attempt was made to manipute a flag disallowed by flagmask
  13  */
  14
  15 int setflags(flag_t *inflags, flag_t flagmask, char *flagstr, const flag *flagslist, short reject) {
  16   int dir,i;
  17   flag_t newflags;
  18   char *ch;
  19
  20   /* Work with a temporary copy */
  21   newflags=*inflags;
  22
  23   /* Default is to add flags */
  24   dir=1;
  25
  26   for(ch=flagstr;*ch;ch++) {
  27     if (*ch=='+') {
  28       dir=1;
  29       continue;
  30     }
  31
  32     if (*ch=='-') {
  33       dir=0;
  34       continue;
  35     }
  36
  37     for(i=0;flagslist[i].flagchar!='\0';i++) {
  38       if (*ch==flagslist[i].flagchar) {
  39         /* Check that the change is allowed */
  40         if (flagmask & flagslist[i].flagbit) {
  41           if (dir==0) {
  42             newflags &= (~flagslist[i].flagbit);
  43           } else {
  44             newflags |= flagslist[i].flagbit;
  45           }
  46         } else {
  47           if (reject & REJECT_DISALLOWED) {
  48             return REJECT_DISALLOWED;
  49           }
  50         }
  51         /* We matched, stop looking */
  52         break;
  53       }
  54     }
  55
  56     if (flagslist[i].flagchar=='\0') {
  57       /* We didn't match anything */
  58       if (reject & REJECT_UNKNOWN) {
  59         return REJECT_UNKNOWN;
  60       }
  61     }
  62   }
  63
  64   /* We reached the end without bailing out; assign the flag changes */
  65   *inflags=newflags;
  66   return REJECT_NONE;
  67 }
  68
  69 /*
  70  * printflags:
  71  *  Prints out which flags are currently set in a flag block
  72  */
  73 char *printflags(flag_t inflags, const flag *flaglist) {
  74   static char buf[18];
  75   int i;
  76   char *ch=buf;
  77
  78   *ch++='+';
  79
  80   for (i=0;flaglist[i].flagchar!='\0' && i<16;i++) {
  81     if (inflags&flaglist[i].flagbit) {
  82       *ch++=flaglist[i].flagchar;
  83     }
  84   }
  85
  86   *ch='\0';
  87   return buf;
  88 }
  89
  90 /* ugh */
  91
  92 char *printflags_noprefix(flag_t inflags, const flag *flaglist) {
  93   static char buf[18];
  94   int i;
  95   char *ch=buf;
  96
  97   for (i=0;flaglist[i].flagchar!='\0' && i<16;i++) {
  98     if (inflags&flaglist[i].flagbit) {
  99       *ch++=flaglist[i].flagchar;
 100     }
 101   }
 102
 103   *ch='\0';
 104   return buf;
 105 }
 106
 107
 108
 109 /*
 110  * printflagdiff:
 111  *  Prints the flag changes needed to change "oldflags" into "newflags"
 112  */
 113
 114 char *printflagdiff(flag_t oldflags, flag_t newflags, const flag *flaglist) {
 115   static char buf[30];
 116   int i;
 117   char *ch=buf;
 118   int chd=0;
 119
 120   /* Removes first */
 121
 122   for (i=0;flaglist[i].flagchar!='\0' && i<16;i++) {
 123     if ((oldflags & flaglist[i].flagbit) && !(newflags & flaglist[i].flagbit)) {
 124       if (chd==0) {
 125         chd=1;
 126         *ch++='-';
 127       }
 128       *ch++=flaglist[i].flagchar;
 129     }
 130   }
 131
 132   /* Now adds */
 133   chd=0;
 134
 135   for (i=0;flaglist[i].flagchar!='\0' && i<16;i++) {
 136     if (!(oldflags & flaglist[i].flagbit) && (newflags & flaglist[i].flagbit)) {
 137       if (chd==0) {
 138         chd=1;
 139         *ch++='+';
 140       }
 141       *ch++=flaglist[i].flagchar;
 142     }
 143   }
 144
 145   *ch='\0';
 146   return buf;
 147 }