UNIX 6th Ed. - /usr/source/iolib/alloc.c

   1: #
   2: /*
   3:  * C library -- alloc/free
   4:  */
   5: 
   6: #define logical char *
   7: 
   8: struct fb {
   9:     logical size;
  10:     char    *next;
  11: };
  12: 
  13: int freelist[] {
  14:     0,
  15:     -1,
  16: };
  17: logical slop    2;
  18: 
  19: alloc(asize)
  20: logical asize;
  21: {
  22:     register logical size;
  23:     register logical np;
  24:     register logical cp;
  25: 
  26:     if ((size = asize) == 0)
  27:         return(0);
  28:     size =+ 3;
  29:     size =& ~01;
  30:     for (;;) {
  31:         for (cp=freelist; (np= cp->next) != -1; cp=np) {
  32:             if (np->size>=size) {
  33:                 if (size+slop >= np->size) {
  34:                     cp->next = np->next;
  35:                     return(&np->next);
  36:                 }
  37:                 cp = cp->next = np+size;
  38:                 cp->size = np->size - size;
  39:                 cp->next = np->next;
  40:                 np->size = size;
  41:                 return(&np->next);
  42:             }
  43:         }
  44:         asize = size<1024? 1024: size;
  45:         if ((cp = sbrk(asize)) == -1) {
  46:             return (-1);
  47:         }
  48:         cp->size = asize;
  49:         free(&cp->next);
  50:     }
  51: }
  52: 
  53: free(aptr)
  54: char *aptr;
  55: {
  56:     register logical ptr;
  57:     register logical cp;
  58:     register logical np;
  59: 
  60:     ptr = aptr-2;
  61:     cp = freelist;
  62:     while ((np = cp->next) < ptr)
  63:         cp = np;
  64:     if (ptr+ptr->size == np) {
  65:         ptr->size =+ np->size;
  66:         ptr->next = np->next;
  67:         np = ptr;
  68:     } else
  69:         ptr->next = np;
  70:     if (cp+cp->size == ptr) {
  71:         cp->size =+ ptr->size;
  72:         cp->next = ptr->next;
  73:     } else
  74:         cp->next = ptr;
  75: }

Defined functions

Defined variables

Defined struct's

Defined macros