simset.h

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/* Copyright (c) 2012, 2025, Oracle and/or its affiliates.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.
 
   This program is designed to work with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have either included with
   the program or referenced in the documentation.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.
 
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
#ifndef SIMSET_H
#define SIMSET_H
 
#include <stddef.h>
#ifndef XCOM_STANDALONE
#include "my_compiler.h"
#endif
#include "xcom/x_platform.h"
 
struct linkage;
typedef struct linkage linkage;
 
struct linkage {
  unsigned int type; /* Not strictly necessary, used for rudimentary run time
                        type check */
  linkage *suc;      /* Next in list */
  linkage *pred;     /* Previous in list */
};
 
extern char *dbg_linkage(linkage *self); /* Debug link */
 
/* fwd decl */
static inline linkage *link_out(linkage *self); /* Remove link from list */
 
/* Forward iterator */
#define FWD_ITER(head, type, action)                      \
  {                                                       \
    linkage *p = link_first(head);                        \
    while (p != (head)) {                                 \
      linkage *_next = link_first(p);                     \
      {                                                   \
        type *link_iter = (type *)p;                      \
        (void)link_iter;                                  \
        action;                                           \
      } /* Cast to void avoids unused variable warning */ \
      p = _next;                                          \
    }                                                     \
  }
 
/* Reverse iterator */
#define REV_ITER(head, type, action)                      \
  {                                                       \
    linkage *p = link_last(head);                         \
    while (p != (head)) {                                 \
      linkage *_next = link_last(p);                      \
      {                                                   \
        type *link_iter = (type *)p;                      \
        (void)link_iter;                                  \
        action;                                           \
      } /* Cast to void avoids unused variable warning */ \
      p = _next;                                          \
    }                                                     \
  }
 
/* Get containing struct from pointer to member and type */
#define container_of(ptr, type, member) \
  ((type *)(((char *)(ptr)) - offsetof(type, member)))
 
#define NULL_TYPE 0xdefaced
 
#ifdef USE_LINK_SANITY_CHECK
#define LINK_SANITY_CHECK(x) \
  {                          \
    assert((x)->suc);        \
    assert((x)->pred);       \
  }
#define TYPE_SANITY_CHECK(x, y) \
  { assert((x)->type == (y)->type); }
#else
#define LINK_SANITY_CHECK(x)
#define TYPE_SANITY_CHECK(x, y)
#endif
 
#define link_into(self, s) link_precede(self, s)
 
#define TYPE_HASH(x) 0
 
/* purecov: begin deadcode */
static inline linkage *link_first(linkage *self) { return self->suc; }
 
static inline linkage *link_last(linkage *self) { return self->pred; }
/* purecov: end */
static inline linkage *link_extract_first(linkage *self) {
  return link_out(self->suc);
}
 
static inline linkage *link_extract_last(linkage *self) {
  return link_out(self->pred);
}
 
static inline int link_empty(linkage *self) { return self == self->suc; }
 
static inline linkage *link_init(linkage *self, unsigned int type) {
  /* XDBG("%s ",__func__); */
  self->type = type;
  self->suc = self->pred = self;
  LINK_SANITY_CHECK(self);
  return self;
}
 
static inline linkage *link_out(linkage *self) {
  /* XDBG("%s ",__func__); */
  if (!link_empty(self)) {
    TYPE_SANITY_CHECK(self, self->suc);
    TYPE_SANITY_CHECK(self, self->pred);
    self->suc->pred = self->pred;
    self->pred->suc = self->suc;
    self->suc = self->pred = self;
  }
  LINK_SANITY_CHECK(self);
  return self;
}
 
static inline void link_follow(linkage *self, linkage *ptr) {
  /* XDBG("%s ",__func__); */
  link_out(self);
  if (ptr) {
    TYPE_SANITY_CHECK(self, ptr);
    LINK_SANITY_CHECK(ptr);
    self->pred = ptr;
    self->suc = ptr->suc;
    self->suc->pred = ptr->suc = self;
    LINK_SANITY_CHECK(self);
  }
}
 
static inline void link_precede(linkage *self, linkage *ptr) {
  /* XDBG("%s ",__func__); */
  link_out(self);
  if (ptr) {
    TYPE_SANITY_CHECK(self, ptr);
    LINK_SANITY_CHECK(ptr);
    self->suc = ptr;
    self->pred = ptr->pred;
    self->pred->suc = ptr->pred = self;
    LINK_SANITY_CHECK(self);
  }
}
 
/* purecov: begin deadcode */
static inline int cardinal(linkage *self) {
  int n = 0;
  FWD_ITER(self, linkage, n++);
  return n;
}
/* purecov: end */
 
#endif