/*
 * Copyright 2005-2015 ECMWF.
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 *
 * In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
 * virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
 */

#include "grib_api_internal.h"

/* #define CHECK_FOR_LEAKS */

#if MANAGE_MEM

#if GRIB_PTHREADS
static pthread_once_t once  = PTHREAD_ONCE_INIT;
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

static void init() {
  pthread_mutexattr_t attr;

  pthread_mutexattr_init(&attr);
  pthread_mutexattr_settype(&attr,PTHREAD_MUTEX_RECURSIVE);
  pthread_mutex_init(&mutex,&attr);
  pthread_mutexattr_destroy(&attr);

}
#endif

union align {
  double d;
  int    n;
  void * p;
  long   l;
};

#define WORD sizeof(union align)

static size_t page_size = 0;

typedef struct {
  int   pages;     /* Number of pages to allocate */
  int   clear;     /* clear newly allocated memory */
  int   first;     /* Allocate in first only */
  void *priv;
} mempool;


typedef struct memblk {
  struct memblk *next;
  long     cnt;
  size_t   left;
  size_t   size;
  char     buffer[WORD];
} memblk;

static memblk *reserve = NULL;

/*
   typedef struct memprocs {
   struct memprocs *next;
   memproc          proc;
   void            *data;
   } memprocs;

   static memprocs *mprocs = NULL;
 */

#define HEADER_SIZE  (sizeof(memblk) - WORD)

static mempool _transient_mem = {
  10,
  0,
  1,
};

static mempool *transient_mem = &_transient_mem;

static mempool _permanent_mem = {
  10,
  0,
  1,
};

static mempool *permanent_mem = &_permanent_mem;

static void *fast_new(size_t s,mempool *pool)
{
  char *p;
  memblk *m;

  GRIB_PTHREAD_ONCE(&once,&init)
  GRIB_MUTEX_LOCK(&mutex)

  m = (memblk*)pool->priv;

  /* align */

  s = ((s+WORD-1)/WORD)*WORD;

  if(pool->first)
  {
    if(m && (m->left < s))
      m = NULL;
  }

  while(m && (m->left < s))
    m = m->next;

  if(m == NULL)
  {
    memblk *p;
    size_t    size;
    if(!page_size) page_size = getpagesize();

    size = page_size*pool->pages;

    if(s > size - HEADER_SIZE)
    {
      /* marslog(LOG_WARN,"Object of %d bytes is too big for grib_fast_new",s); */
      /* marslog(LOG_WARN,"Block size if %d bytes", size - HEADER_SIZE); */
      size = ((s + HEADER_SIZE + (page_size-1)) / page_size) * page_size;
    }

    p = (memblk*)(pool->clear?calloc(size,1):malloc(size));
    if(!p) {
      GRIB_MUTEX_UNLOCK(&mutex)
      return NULL;
    }

    p->next = (memblk*)pool->priv;
    p->cnt  = 0;
    p->size = p->left = size-HEADER_SIZE;
    m       = p;
    pool->priv = (void*)p;
  }

  p = &m->buffer[m->size - m->left];
  m->left -= s;
  m->cnt++;

  GRIB_MUTEX_UNLOCK(&mutex)

  return p;
}



static void fast_delete(void *p,mempool *pool)
{
  memblk *m ;
  memblk *n = NULL;

  GRIB_PTHREAD_ONCE(&once,&init)
  GRIB_MUTEX_LOCK(&mutex)

  m = (memblk*)pool->priv;

  while(m)
  {
    if( ((char*)p >= (char*)&m->buffer[0]) &&
        ((char*)p < (char*)&m->buffer[m->size]))
    {
      m->cnt--;
      if(m->cnt == 0)
      {
        if(n) n->next = m->next;
        else pool->priv = (void*)m->next;
        free((void*)m);
      }
      GRIB_MUTEX_UNLOCK(&mutex)
      return;
    }

    n = m;
    m = m->next;
  }
  Assert(1==0);
}

static void *fast_realloc(void *p,size_t s,mempool *pool)
{
  void *q;

  /* I'll come back here later... */

  if((q = fast_new(s,pool)) == NULL) return NULL;
  memcpy(q,p,s);

  fast_delete(p,pool);

  return q;
}

#if 0
/*
   void fast_memory_info(const char *title,mempool *pool)
   {
   memblk *m = (memblk*)pool->priv;
   int count = 0;
   int size = 0;
   while(m)
   {
   count++;
   size += m->size;
   m = m->next;
   }
   marslog(LOG_INFO,"%s : %sbytes %d blocks",
   title,
   bytename(size),count);
   }

   void memory_info()
   {
   memblk *r = reserve;
   long size = 0;
   while(r)
   {
   marslog(LOG_INFO,"Large buffer: %sbytes %s",
   bytename(r->size),r->cnt?"in use":"free");
   size += r->size;
   r = r->next;
   }

   marslog(LOG_INFO,"Total large : %sbytes",bytename(size));
   fast_memory_info("Transient memory",transient_mem);
   fast_memory_info("Permanent memory",permanent_mem);
   }
 */
#endif

void *grib_transient_malloc(const grib_context* c,size_t s)
{
  return fast_new(s,transient_mem);
}

void *grib_transient_realloc(const grib_context* c,void *p,size_t s)
{
  return fast_realloc(p,s,transient_mem);
}

void  grib_transient_free(const grib_context* c,void* p)
{
  fast_delete(p,transient_mem);
}

void *grib_permanent_malloc(const grib_context* c,size_t s)
{
  return fast_new(s,permanent_mem);
}

void *grib_permanent_realloc(const grib_context* c,void *p,size_t s)
{
  return fast_realloc(p,s,permanent_mem);
}

void  grib_permanent_free(const grib_context* c,void* p)
{
  fast_delete(p,permanent_mem);
}

void *grib_buffer_malloc(const grib_context* c,size_t s)
{
  memblk *r;

  GRIB_PTHREAD_ONCE(&once,&init)
  GRIB_MUTEX_LOCK(&mutex)

  s = ((s+WORD-1)/WORD)*WORD;
  r = reserve;
  while(r)
  {
    if(r->cnt == 0 && r->size == s)
      break;
    r = r->next;
  }

  if(r)
  {
    /* marslog(LOG_DBUG,"Reusing %ld bytes %d",s,r->size); */
  }
  else
  {
    size_t size = s + HEADER_SIZE;
    /* marslog(LOG_DBUG,"Allocating %d (%d)bytes",s,size); */
    r = (memblk*)malloc(size);
    if(!r) return NULL;
    r->next = reserve;
    reserve = r;
  }
  r->size = s;
  r->cnt  = 1;

  GRIB_MUTEX_UNLOCK(&mutex)

  return &r->buffer[0];

}

void grib_buffer_free(const grib_context* c,void *p)
{
  memblk *r;
  memblk *s;

  GRIB_PTHREAD_ONCE(&once,&init)
  GRIB_MUTEX_LOCK(&mutex)

  r = (memblk*)(((char*)p) - HEADER_SIZE);
  s = reserve;
  while(s && (s!=r)) s = s->next;
  if(s == NULL)
    ; /* marslog(LOG_WARN,"release_mem: invalid pointer"); */
  else
  {
    s->cnt = 0;
  }

  GRIB_MUTEX_UNLOCK(&mutex)
}

void *grib_buffer_realloc(const grib_context* c,void *p,size_t s)
{
  memblk *r = (memblk*)(((char*)p) - HEADER_SIZE);
  void * n = grib_buffer_malloc(c,s);
  memcpy(n,p,r->size < s? r->size:s);
  grib_buffer_free(c,p);
  return n;
}

/*

   int purge_mem(void)
   {
   memblk *p = reserve;
   memblk *q = NULL;
   while(p)
   {
   if(p->cnt == 0)
   {
   if(q) q->next = p->next;
   else reserve = p->next;
   free(p);
   return 1;
   }
   q = p;
   p = p->next;
   }
   return 0;
   }

   void install_memory_proc(memproc proc,void *data)
   {
   memprocs *p = NEW_CLEAR(memprocs);
   p->proc = proc;
   p->data = data;
   p->next = mprocs;
   mprocs  = p;
   }

   void remove_memory_proc(memproc proc,void *data)
   {
   memprocs *p = mprocs;
   memprocs *q = NULL;

   while(p)
   {
   if(p->proc == proc && p->data == data)
   {
   if(q) q->next = p->next; else mprocs = p->next;
   FREE(p);
   return;
   }
   q = p;
   p = p->next;
   }
   marslog(LOG_WARN,"remove_memory_proc: cannot find proc");
   }
 */

#endif
