/*
  tmpbuf.c      -  Round Robin Temporary buffers

  Copyright (C)                         Lumiera.org
    2008, 2010                          Christian Thaeter <ct@pipapo.org>

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of the
  License, or (at your option) any later version.

  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 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "lib/safeclib.h"
#include "lib/tmpbuf.h"


#include <string.h>
#include <pthread.h>
#include <stdint.h>
#include <stdarg.h>
#include <nobug.h>


struct lumiera_tmpbuf_struct
{
  /* tiny buffers are not aligned, anything which is smaller than sizeof(void*) */
  char tiny_buffers[LUMIERA_TMPBUF_NUM*(sizeof(void*)-1)];
  unsigned tiny_idx;
  /* first 16 static LUMIERA_TMPBUF_SMALL byte arrays */
  char small_buffers[LUMIERA_TMPBUF_NUM][LUMIERA_TMPBUF_SMALL];
  unsigned small_idx;
  /* next 16 dynamic arrays for biggier buffers */
  void* big_buffers[LUMIERA_TMPBUF_NUM];
  size_t big_sizes[LUMIERA_TMPBUF_NUM];
  unsigned big_idx;
};

static pthread_once_t lumiera_tmpbuf_tls_once = PTHREAD_ONCE_INIT;
static pthread_key_t lumiera_tmpbuf_tls_key;

void
lumiera_tmpbuf_freeall (void);

static void
lumiera_tmpbuf_destroy (void* buf)
{
  (void) buf;
  lumiera_tmpbuf_freeall ();
}

static void
lumiera_tmpbuf_init (void)
{
  pthread_key_create (&lumiera_tmpbuf_tls_key, lumiera_tmpbuf_destroy);
  atexit (lumiera_tmpbuf_freeall);
}


void
lumiera_tmpbuf_freeall (void)
{
  pthread_once (&lumiera_tmpbuf_tls_once, lumiera_tmpbuf_init);

  struct lumiera_tmpbuf_struct* buf = pthread_getspecific (lumiera_tmpbuf_tls_key);
  if (buf)
    {
      pthread_setspecific (lumiera_tmpbuf_tls_key, NULL);
      for (int idx = 0; idx < LUMIERA_TMPBUF_NUM; ++idx)
        lumiera_free (buf->big_buffers[idx]);
      lumiera_free (buf);
    }
}


void*
lumiera_tmpbuf_provide (size_t size)
{
  pthread_once (&lumiera_tmpbuf_tls_once, lumiera_tmpbuf_init);

  struct lumiera_tmpbuf_struct* buf = pthread_getspecific (lumiera_tmpbuf_tls_key);
  if (!buf)
    pthread_setspecific (lumiera_tmpbuf_tls_key,
                         buf = lumiera_calloc (1, sizeof (struct lumiera_tmpbuf_struct)));

  if (size < sizeof(void*))
    {
      buf->tiny_idx = (buf->tiny_idx + size) & ~(LUMIERA_TMPBUF_NUM*sizeof(void*)-1);
      return &buf->tiny_buffers[buf->tiny_idx-size];
    }
  else if (size <= LUMIERA_TMPBUF_SMALL)
    {
      buf->small_idx = (buf->small_idx + 1) % LUMIERA_TMPBUF_NUM;
      return buf->small_buffers[buf->small_idx];
    }
  else
    {
      buf->big_idx = (buf->big_idx + 1) & ~(LUMIERA_TMPBUF_NUM-1);

      if (buf->big_sizes[buf->big_idx] < size || buf->big_sizes[buf->big_idx] > 8*size)
        {
          lumiera_free (buf->big_buffers[buf->big_idx]);
          buf->big_sizes[buf->big_idx] = (size + LUMIERA_TMPBUF_SMALL-1) & ~(LUMIERA_TMPBUF_SMALL-1);
          buf->big_buffers[buf->big_idx] = lumiera_malloc (buf->big_sizes[buf->big_idx]);
        }
      return buf->big_buffers[buf->big_idx];
    }
}


char*
lumiera_tmpbuf_strndup (const char* src, size_t size)
{
  size_t len = strlen (src);
  len = len > size ? size : len;

  char* buf = lumiera_tmpbuf_provide (len + 1);
  strncpy (buf, src, len);
  buf[len] = '\0';

  return buf;
}


char*
lumiera_tmpbuf_snprintf (size_t size, const char* fmt, ...)
{
  va_list args;

  va_start (args, fmt);
  size_t len = vsnprintf (NULL, 0, fmt, args);
  va_end (args);

  len = len > size ? size : len;
  char* buf = lumiera_tmpbuf_provide (len+1);
  va_start (args, fmt);
  vsnprintf (buf, len+1, fmt, args);
  va_end (args);

  return buf;
}


char*
lumiera_tmpbuf_strcat3 (const char* str1, size_t str1_len,
                        const char* str2, size_t str2_len,
                        const char* str3, size_t str3_len)
{
  return lumiera_tmpbuf_snprintf (SIZE_MAX, "%.*s%s%.*s%s%.*s",
                                  str1?str1_len:0, str1?str1:"", str1?".":"",
                                  str2?str2_len:0, str2?str2:"",
                                  str3?".":"", str3?str3_len:0, str3?str3:"");
}


char*
lumiera_tmpbuf_tr (const char* in, const char* from, const char* to, const char* def)
{
  REQUIRE (strlen (from) == strlen (to), "from and to character set must have equal length");

  char* ret = lumiera_tmpbuf_strndup (in, SIZE_MAX);

  char* wpos;
  char* rpos;
  for (wpos = rpos = ret; *rpos; ++rpos, ++wpos)
    {
      char* found = strchr (from, *rpos);
      if (found)
        *wpos = to[found-from];
      else if (def)
        {
          if (*def)
            *wpos = *def;
          else
            {
              ++rpos;
              if (!*rpos)
                break;
            }
        }
      else
        return NULL;
    }
  *wpos = '\0';

  return ret;
}


/*
// Local Variables:
// mode: C
// c-file-style: "gnu"
// indent-tabs-mode: nil
// End:
*/