TeslaRel410/sda4/DPL3/VRENDER/NAMES.C

/*{{{  comment*/
/*

    File names.c

    This module contains functions to move from
    i860 pointer <--> i860 name
    This is primarily for SuperVision distributed rendering systems
    where the same data item will be held in different places on different
    boards

    Phil Atkin

    (c) Division Ltd. 1991
*/

/*}}}  */
/*{{{  discussion*/
/*

In superVision we have a problem that the same data item will not
appear in the same place on different processors. We need to implement
a naming system which allows us to uniquely identify a piece of data
and find its location in memory. There are two strategies for this - we
either try to maintain as many REAL pointers as we can in the i860 and
resort to names only across the dView/i860 boundary, OR we swallow the big
pill and use names EVERYWHERE, including the internal linked lists. Currently
we load no more than 400 instances (the corridor maze demo). If I build a
hash table of 512 locations, at the moment no programs will need to indirect
more than once to get the physical location from the name.
OK, that's decided it - ALL references to dView-visible items will be by NAME.

Internal linked lists will be maintained as pointers. The dpl processor
ignores the NEXT field anyway, so the only problem then is heirarchy.

IMPACTS
-------

Backward compatibility
----------------------

NULL needs to be an invalid name.
Walking linked lists, we need to go nameToAddress() on each item.

heirachy
--------

In heirarchies, the link, next and daddy fields are NAMES. Therefore
heirarchy stuff needs nameToAddress() in the loop.

Creation
--------

We get a new name. Add it to the hash table, and hand the pointer back
to the dView.

Deletion
--------

Do what we do now, but in addition delete any hash-table storage.



I believe we NEVER need to go addressToName()


*/
/*}}}  */
/*{{{  includes*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "dpltypes.h"
/*}}}  */
/*{{{  local typedefs*/
#define max_pages  512
#define mask_pages ((max_pages)-1)

typedef struct s_ypage {
  struct s_ypage *next;
  int name;
  dpl_type name_type;
  void *address;
} yellowPage;
/*}}}  */
/*{{{  statics*/
static yellowPage *yellowPages [max_pages];

static int init=0;

/*}}}  */
/*{{{  externally visible*/

/* the first name handed out is 1 */

int allocatedNames=1;
/*}}}  */

/*{{{  void checkNull ( void *p, char *s )*/
void checkNull ( void *p, char *s )
{
  if (p==NULL) {
    printf( "NULL pointer in %s\n", s );
    fflush(stdout);
    exit (666);
  }
  /*
  else
    printf ( "ok pointer in %s\n", s );
  */
}
/*}}}  */

/*{{{  int initNames ()*/
int initNames ()
{
  int i;
  /* printf ("initNames\n"); */
  if (init==0) {
    for (i=0; i<max_pages; i++) {
      yellowPages[i]=NULL;
    }
    init=1;
  }
}
/*}}}  */
/*{{{  addName ( int item_name, void *location, dpl_type type )*/
static void
addName ( int item_name, void *location, dpl_type type )
{
  yellowPage *head=yellowPages[item_name&mask_pages], *node=head;
  /*
  printf ("add name address 0x%x name %d type %s\n",
     location, item_name, type_to_string(type));
  */
  /* find somewhere to put this item */
  if (head == NULL) {
    /* nothing in this hash entry, create first location */
    head=(yellowPage *) malloc ( sizeof (yellowPage));
    checkNull ( head, "createName");
    head->address=location;
    head->name=item_name;
    head->name_type=type;
    head->next=NULL;
    yellowPages[item_name&mask_pages] = head;
  }
  else {
    /* find tail of list */
    while (node->next != NULL) {
      node=node->next;
    }
    node->next=(yellowPage *) malloc ( sizeof (yellowPage));
    node=node->next;
    checkNull ( node, "createName");
    node->address=location;
    node->name=item_name;
    node->name_type=type;
    node->next=NULL;
  }
/*  printf ("newName returning %d\n", item_name ); */
  return ( item_name );
}
/*}}}  */
/*{{{  int newName ( void *location, dpl_type type )*/
int newName ( void *location, dpl_type type )
{
/*  printf ("newName %d\n", item_name ); */
  if (location == NULL)
    return 0;
  else {
    int item_name=allocatedNames++;

    addName ( item_name, location, type );

    return  ( item_name );
  }
}
/*}}}  */
/*{{{  int deleteName ( int item_name, dpl_type type )*/
int deleteName ( int item_name, dpl_type type )
{
  yellowPage *head=yellowPages[item_name&mask_pages],
             *node=head,
             *prev=NULL;

  while (node->name != item_name) {
    prev=node;
    node=node->next;

    if (node==NULL) {
      printf ("Name 0x%x (%s) not found\n",
               item_name, type_to_string(type) );
      exit (666);
    }
  }

  if (type != (-1)) {
    if (node->name_type != type ) {
      printf ("deleteName: name 0x%x wrong type, expected %s found %s\n",
               item_name, type_to_string(type),
                          type_to_string(node->name_type) );
      exit (666);
    }
  }

  if (prev == NULL) {
    yellowPages[item_name&mask_pages] = node->next;
    free ( node );
  }
  else {
    prev->next=node->next;
    free (node);
  }
}
/*}}}  */
/*{{{  void *nameToAddress ( int item_name, dpl_type type )*/
void *nameToAddress ( int item_name, dpl_type type )
{
  yellowPage *head;

  if (item_name == 0) return NULL;


  for (head=yellowPages[item_name&mask_pages];head;head=head->next) {
    if (head->name == item_name) {
      if (head->name_type == type) {
        return head->address;
      }
      else if (type == (dpl_type) (-1)) {
        return head->address;
      }
      else {
        printf ("nameToAddress: name 0x%x wrong type, expected %s found %s address 0x%x\n",
           item_name, type_to_string(type),
                      type_to_string(head->name_type),
                      head->address);
        printf ("allocatedNames = %d\n", allocatedNames );

        return NULL;
      }
    }
  }
  return NULL;
}
/*}}}  */
/*{{{  int addressToName ( void *item, dpl_type type )*/
int addressToName ( void *item, dpl_type type )
{
  int i;

  for (i=0; i<(mask_pages)+1; i++ ) {
    yellowPage *head=yellowPages[i];

    while (head) {
      if (head->address == item) {
        if (type == (-1))
          return head->name;
        else if (head->name_type == type)
          return head->name;
        else
          printf ("found item 0x%x name 0x%x, wrong type\n",
                   item, head->name );
      }
      head=head->next;
    }
  }
  return 0;
}
/*}}}  */
/*{{{  int check_name ( int name)*/
int check_name ( int name)
{
  return ((name < 0) || (name > allocatedNames));
}
/*}}}  */