/*
* This file is part of rasdaman community.
*
* Rasdaman community 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.
*
* Rasdaman community 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 rasdaman community.  If not, see <http://www.gnu.org/licenses/>.
*
* Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009 Peter Baumann /
rasdaman GmbH.
*
* For more information please see <http://www.rasdaman.org>
* or contact Peter Baumann via <baumann@rasdaman.com>.
/
/**
 * SOURCE: memfs.c
 *
 * MODULE: conversion
 *
 * PURPOSE:
 * 		Memory Filing System used by some of the convertor modules
 * 
 * COMMENTS
 *			None
*/

#include "mymalloc/mymalloc.h"

#include <stdio.h>
#include <malloc.h>
#include <string.h>
#include "conversion/memfs.hh"


/* can't use RMDBGOUT because this is C, not C++ */
const int MEMFSDBGLEVEL = 4;

extern int RManDebug;



/* This function for internal use only */
int memfs_ensure(thandle_t handle, toff_t off)
{
  memFSContext *memFS = (memFSContext *)handle;
  char **mam2=NULL;
  int mamSize2=0, i=0;

#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_ensure: %d\n", off); fflush(stdout);
  }
#endif
  /* Do we have to allocate a bigger mam? */
  mamSize2 = (off >> MEMFS_LD_BLOCKSIZE);
  if (mamSize2 >= memFS->mamSize)
  {
    /* Always allocate mam in powers of 2. That ensures that if we run out
       of space the new mam will be twice as big as the old one. */
    i = 0; while (mamSize2 != 0) {mamSize2 >>= 1; i++;}
    mamSize2 = (1 << i);
#ifdef RMANDEBUG
    if (RManDebug >= MEMFSDBGLEVEL)
    {
      printf("memfs_ensure: growing mam from %d to %d\n", memFS->mamSize, mamSize2);
      fflush(stdout);
    }
#endif
    if ((mam2 = (char **)mymalloc(mamSize2 * sizeof(char*))) == NULL)
      return -1;
    /* Copy existing mam entries */
    memcpy ((void*)mam2, (void*) memFS->mam, memFS->mamSize * sizeof(char*));
    /* Init new mam entries */
    for (i=memFS->mamSize; i < mamSize2; i++)
    {
      mam2[i] = NULL;
    }
    /* free old mam */
    free(memFS->mam);
    memFS->mam = mam2; memFS->mamSize = mamSize2;
  }
  /* Calculate again because its value might have been changed by the
     above block */
  mamSize2 = (off >> MEMFS_LD_BLOCKSIZE);
  if ((memFS->mam)[mamSize2] == NULL)
  {
    /* We don't just have to allocate this one new block but all the
       ones with lower addresses that aren't defined yet as well */
    for (i=memFS->mamHighest+1; i <= mamSize2; i++)
    {
      if (((memFS->mam)[i] = (char*)mymalloc((1 << MEMFS_LD_BLOCKSIZE) * sizeof(char))) == NULL)
	return -1;
    }
    memFS->mamHighest = mamSize2;
  }
  /* All done, the memFS can now hold an object of size off */
  return 0;
}


/* Initialise the memory filing system */
int memfs_initfs(thandle_t handle)
{
  memFSContext *memFS = (memFSContext *)handle;
  int i=0;

#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_initfs\n"); fflush(stdout);
  }
#endif
  memFS->pos = 0; memFS->high = 0;
  memFS->mamSize = MEMFS_MAM_ENTRIES;
  if ((memFS->mam = (char **)mymalloc(MEMFS_MAM_ENTRIES * sizeof(char *))) == NULL)
    return -1;
  if (((memFS->mam)[0] = (char*)mymalloc((1 << MEMFS_LD_BLOCKSIZE) * sizeof(char))) == NULL)
    return -1;
  memFS->mamHighest = 0;
  for (i=1; i<MEMFS_MAM_ENTRIES; i++)
  {
    (memFS->mam)[i] = NULL;
  }
  return 0;
}


/* Kill the memory filing system, freeing all its resources */
void memfs_killfs(thandle_t handle)
{
  memFSContext *memFS = (memFSContext *)handle;
  int i=0;

#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_killfs\n"); fflush(stdout);
  }
#endif
  for (i=0; i < memFS->mamSize; i++)
  {
    if ((memFS->mam)[i] == NULL) break;
    free((memFS->mam)[i]);
  }
  free(memFS->mam);
}


/* Reset file pointers, leave memory setup */
void memfs_newfile(thandle_t handle)
{
  memFSContext *memFS = (memFSContext *)handle;

#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_newfile\n"); fflush(stdout);
  }
#endif
  memFS->pos = 0; memFS->high = 0;
}


tsize_t memfs_read(thandle_t handle, tdata_t mem, tsize_t size)
{
  tsize_t todo=0, transfered = 0;
  int block=0, offset=0, x=0;
  memFSContext *memFS = (memFSContext *)handle;

  /* Don't read over the end of the "file" */
  todo = memFS->high - memFS->pos;
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_read: (%d, left: %d)\n", todo, memFS->high); fflush(stdout);
  }
#endif
  if (todo > size) todo = size;
  while (todo > 0)
  {
    block = (memFS->pos >> MEMFS_LD_BLOCKSIZE);
    offset = memFS->pos - (block << MEMFS_LD_BLOCKSIZE);
    /* Space left in this buffer */
    x = (1 << MEMFS_LD_BLOCKSIZE) - offset;
    if (x > todo) x = todo;
    memcpy((void*)mem, (void*)(((memFS->mam)[block]) + offset), x);
    /* tdata_t is some kind of void *, so we have to do this cast */
    mem = (tdata_t)(((char*)mem) + x);
    memFS->pos += x; transfered += x; todo -= x;
  }
  return transfered;
}


tsize_t memfs_write(thandle_t handle, tdata_t mem, tsize_t size)
{
  tsize_t transfered = 0;
  memFSContext *memFS = (memFSContext *)handle;
  int block=0, offset=0, x=0;

  /* Make sure there's enough room for this write */
  if (memfs_ensure(handle, memFS->pos + size) < 0) return 0;
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_write (%d)\n",size); fflush(stdout);
  }
#endif
  while (size > 0)
  {
    /* See memfs_read */
    block = (memFS->pos >> MEMFS_LD_BLOCKSIZE);
    offset = memFS->pos - (block << MEMFS_LD_BLOCKSIZE);
    x = (1 << MEMFS_LD_BLOCKSIZE) - offset;
    if (x > size) x = size;
    memcpy((void*)(((memFS->mam)[block]) + offset), (void*)mem, x);
    mem = (tdata_t)(((char *)mem) + x);
    memFS->pos += x; transfered += x; size -= x;
  }
  if (memFS->pos > memFS->high) {memFS->high = memFS->pos;}
  return transfered;
}


toff_t memfs_seek(thandle_t handle, toff_t offset, int mode)
{
  memFSContext *memFS = (memFSContext *)handle;

  switch (mode)
  {
  case SEEK_SET: memFS->pos = offset; break;
  case SEEK_CUR: memFS->pos += offset; break;
  case SEEK_END: memFS->pos = memFS->high + offset; break;
  default: break;
  }
  if (memFS->pos < 0) memFS->pos = 0;
  /* Don't limit to end of file (this actually caused problems!) */
  memfs_ensure(handle, memFS->pos);
  if (memFS->pos > memFS->high) memFS->high = memFS->pos;
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_seek: Set pos to %d\n", memFS->pos); fflush(stdout);
  }
#endif
  return memFS->pos;
}


int memfs_close(thandle_t handle)
{
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_close:\n"); fflush(stdout);
  }
#endif
  return 1;	/* = success? */
}


toff_t memfs_size(thandle_t handle)
{
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_size:\n"); fflush(stdout);
  }
#endif
  return (((memFSContext *)handle)->high);
}


int memfs_map(thandle_t handle, tdata_t *memp, toff_t *top)
{
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_map: %p, %d\n", *memp, *top); fflush(stdout);
  }
#endif
  return 0;
}


void memfs_unmap(thandle_t handle, tdata_t mem, toff_t to)
{
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_unmap: %p, %d\n", mem, to); fflush(stdout);
  }
#endif
}






/* Read-only from memory (simple chunky model, not block-oriented) */
void memfs_chunk_initfs(thandle_t handle, char *src, r_Long size)
{
  memFSContext *memFS = (memFSContext *)handle;

#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_chunk_initfs: %p, %d\n", src, size); fflush(stdout);
  }
#endif
  memFS->pos = 0;
  memFS->chunk = src;
  memFS->high = size;
}


tsize_t memfs_chunk_read(thandle_t handle, tdata_t mem, tsize_t size)
{
  tsize_t todo=0;
  memFSContext *memFS = (memFSContext *)handle;

  todo = memFS->high - memFS->pos;
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_chunk_read: %d (left %d)\n", size, todo); fflush(stdout);
  }
#endif
  if (todo > size) todo = size;
  if (todo > 0)
  {
    memcpy((void*)mem, (void*)(memFS->chunk + memFS->pos), todo);
    memFS->pos += todo;
  }
  return todo;
}


toff_t memfs_chunk_seek(thandle_t handle, toff_t offset, int mode)
{
  memFSContext *memFS = (memFSContext *)handle;

  switch (mode)
  {
    case SEEK_SET: memFS->pos = offset; break;
    case SEEK_CUR: memFS->pos += offset; break;
    case SEEK_END: memFS->pos = memFS->high + offset; break;
    default: break;
  }
  if (memFS->pos < 0) memFS = 0;
  /* Since file can't be extended this is OK here */
  if (memFS->pos > memFS->high) memFS->pos = memFS->high;
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_chunk_seek: Position to %d\n", memFS->pos); fflush(stdout);
  }
#endif
  return memFS->pos;
}


int memfs_chunk_close(thandle_t handle)
{
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_chunk_close:\n"); fflush(stdout);
  }
#endif
  return 1;
}


toff_t memfs_chunk_size(thandle_t handle)
{
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_chunk_size:\n"); fflush(stdout);
  }
#endif
  return (((memFSContext *)handle)->high);
}


/* Map file to memory -- since we already have it in memory in the
   first place this is very simple. */
int memfs_chunk_map(thandle_t handle, tdata_t *memp, toff_t *top)
{
  memFSContext *memFS = (memFSContext *)handle;

#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_chunk_map:\n"); fflush(stdout);
  }
#endif
  *memp = (tdata_t)(memFS->chunk); *top = (toff_t)(memFS->high);
  return 1; /* Success? */
}

void memfs_chunk_unmap(thandle_t handle, tdata_t mem, toff_t to)
{
#ifdef RMANDEBUG
  if (RManDebug >= MEMFSDBGLEVEL)
  {
    printf("memfs_chunk_unmap: %p, %d\n", mem, to); fflush(stdout);
  }
#endif
}