/* wydawca - automatic release submission daemon
   Copyright (C) 2007, 2009, 2010 Sergey Poznyakoff

   Wydawca 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 3 of the License, or (at your
   option) any later version.

   Wydawca 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 wydawca. If not, see <http://www.gnu.org/licenses/>. */

#include "wydawca.h"

struct txtacc_entry
{
  char *buf;              /* Text buffer */
  size_t size;            /* Buffer size */  
  size_t len;             /* Actual number of bytes in buffer */ 
};
#define TXTACC_BUFSIZE 1024
#define txtacc_entry_freesize(e) ((e)->size - (e)->len)

struct txtacc
{
  struct grecs_list *cur;  /* Current build list */
  struct grecs_list *mem;  /* List of already allocated elements */
};

static struct txtacc_entry *
txtacc_alloc_entry (struct grecs_list *list, size_t size)
{
  struct txtacc_entry *p = xmalloc (sizeof (*p));
  p->buf = xmalloc (size);
  p->size = size;
  p->len = 0;
  grecs_list_append (list, p);
  return p;
}

static struct txtacc_entry *
txtacc_cur_entry (struct txtacc *acc)
{
  struct txtacc_entry *ent;

  if (grecs_list_size (acc->cur) == 0)
    return txtacc_alloc_entry (acc->cur, TXTACC_BUFSIZE);
  ent = acc->cur->tail->data;
  if (txtacc_entry_freesize (ent) == 0)
    ent = txtacc_alloc_entry (acc->cur, TXTACC_BUFSIZE);
  return ent;
}

static void
txtacc_entry_append (struct txtacc_entry *ent, const char *p, size_t size)
{
  memcpy (ent->buf + ent->len, p, size);
  ent->len += size;
} 

static void
txtacc_entry_tailor (struct txtacc_entry *ent)
{
  if (ent->size > ent->len)
    {
      char *p = realloc (ent->buf, ent->len);
      if (!p)
	return;
      ent->buf = p;
      ent->size = ent->len;
    }
}

static void
txtacc_entry_free (void *p)
{
  if (p)
    {
      struct txtacc_entry *ent = p;
      free (ent->buf);
      free (ent);
    }
}

struct txtacc *
txtacc_create ()
{
  struct txtacc *acc = xmalloc (sizeof (*acc));
  acc->cur = grecs_list_create ();
  acc->cur->free_entry = txtacc_entry_free;
  acc->mem = grecs_list_create ();
  acc->mem->free_entry = txtacc_entry_free;
  return acc;
}

void
txtacc_free (struct txtacc *acc)
{
  grecs_list_free (acc->cur);
  grecs_list_free (acc->mem);
  free (acc);
}

void
txtacc_grow (struct txtacc *acc, const char *buf, size_t size)
{
  while (size)
    {
      struct txtacc_entry *ent = txtacc_cur_entry (acc);
      size_t rest = txtacc_entry_freesize (ent);
      if (rest > size)
	rest = size;
      txtacc_entry_append (ent, buf, rest);
      buf += rest;
      size -= rest;
    }
}

char *
txtacc_finish (struct txtacc *acc, int steal)
{
  struct grecs_list_entry *ep;
  struct txtacc_entry *txtent;
  size_t size;
  char *p;
  
  switch (grecs_list_size (acc->cur))
    {
    case 0:
      return NULL;

    case 1:
      txtent = acc->cur->head->data;
      acc->cur->head->data = NULL;
      txtacc_entry_tailor (txtent);
      break;

    default:
      size = 0;
      for (ep = acc->cur->head; ep; ep = ep->next)
	{
	  txtent = ep->data;
	  size += txtent->len;
	}
      
      txtent = txtacc_alloc_entry (acc->mem, size);
      for (ep = acc->cur->head; ep; ep = ep->next)
	{
	  struct txtacc_entry *tp = ep->data;
	  txtacc_entry_append (txtent, tp->buf, tp->len);
	}
    }
  
  grecs_list_clear (acc->cur);
  p = txtent->buf;
  if (steal)
    free (txtent);
  else
    grecs_list_append (acc->mem, txtent);
  return p;
}

void
txtacc_free_string (struct txtacc *acc, char *str)
{
  struct grecs_list_entry *ep;
  for (ep = acc->mem->head; ep; ep = ep->next)
    {
      struct txtacc_entry *tp = ep->data;
      if (tp->buf == str)
	{
	  grecs_list_remove_entry(acc->mem, ep);
	  free (tp->buf);
	  return;
	}
    }
}