/* ///////////////////////////////////////////////////////////////////// */
/*! 
  \file  
  \brief Functions for handling binary I/O.

  This file provides a number of handy functions for opening, reading
  and writing binary files using single or double precision in serial
  or parallel mode.
  It is employed by the following output formats: .dbl, .flt and .vtk.
  
  In parallel mode these functions work as wrappers to the actual
  parallel implementations contained in AL_io.c.
 
  Pointer to data array must be cast into (void *) and are assumed to
  start with index 0 for both cell-centered and staggered data arrays.
  This means that if V3D is a 3D array then:
  - for a cell-centered array, V = (void *) V3D[0][0]
  - for a x-staggered array,   V = (void *)(V3D[0][0]-1)
  - for a y-staggered array,   V = (void *)(V3D[0][-1])
  - for a z-staggered array,   V = (void *)(V3D[-1][0])

  \authors A. Mignone (mignone@ph.unito.it)\n
           G. Muscianisi (g.muscianisi@cineca.it)

  \date   Sep 18, 2012
*/
/* ///////////////////////////////////////////////////////////////////// */
#include "pluto.h"

/* ********************************************************************* */
FILE *OpenBinaryFile (char *filename, int sz, char *mode)
/*!
 * Open a file for write/reading.
 *
 * \param [in] filename a valid file name
 * \param [in] dsize    the size of the each buffer element   
 *                      (sizeof(double) or sizeof(float)). This
 *                      parameter is used only in serial mode.
 * \param [in] sz       the distributed array descriptor. This parameter
 *                      replaces dsize in parallel mode
 * \param [in] mode     a string giving the opening mode (only "w" or 
 *                      "r" are allowed)
 *
 * \return The pointer to the file.
 *********************************************************************** */
{
  FILE *fp;

/* ----------------------------------------------
    when reading, check if file exists
   ---------------------------------------------- */
   
  if (strcmp(mode,"r") == 0 && prank == 0){
    fp = fopen(filename, "rb");
    if (fp == NULL){
      print1 ("! OpenBinaryFile: file %s does not exists\n", filename);
      QUIT_PLUTO(1);
    }
    fclose(fp);
  }
  
/* ------------------------------------------------ 
          file exists, keep going
   ------------------------------------------------ */
  
  #ifdef PARALLEL
   AL_File_open(filename, sz); 
   return NULL;
  #else
   if      (strcmp(mode,"w") == 0) fp = fopen(filename, "wb");
   else if (strcmp(mode,"r") == 0) fp = fopen(filename, "rb");
   if (fp == NULL){
     print1 ("! Cannot find file %s\n",filename);
     QUIT_PLUTO(1);
   }
   return (fp);
  #endif
}

/* ********************************************************************* */
int CloseBinaryFile (FILE *fbin, int sz)
/*!
 * Close file.
 *
 * \param [in] fbin     pointer to the FILE that needs to be closed (serial
 *                      mode only)
 * \param [in] sz       the distributed array descriptor for parallel mode
 *
 * \return Returns 0 on success
 *********************************************************************** */
{
  #ifdef PARALLEL 
   AL_File_close(sz); 
  #else
   fclose (fbin);
  #endif

  return(0);
}

/* ********************************************************************* */
void WriteBinaryArray (void *V, size_t dsize, int sz, FILE *fl, int istag)
/*!
 * Write an array to disk in binary format.
 *
 * \param [in] V      single pointer to a 3D array,
 *                    V[k][j][i] -->  V[i + NX1*j + NX1*NX2*k]. Must
 *                    start with index 0
 * \param [in] dsize  the size of the each buffer element   
 *                    (sizeof(double) or sizeof(float)). This
 *                    parameter is used only in serial mode.
 * \param [in] sz     the distributed array descriptor. This parameter
 *                    replaces dsize in parallel mode
 * \param [in] fl     a valid FILE pointer
 * \param [in] istag  a flag to identify cell-centered (istag = -1) or
 *                    staggered field data (istag = 0,1 or 2 for staggering 
 *                    in the x1, x2 or x3 directions) 
 *
 * \return This function has no return value.
 *
 * \remark The data array is assumed to start \a always with index 0 for
 *         both cell-centered and staggered arrays.
 *********************************************************************** */
{
  int i, j, k;
  int ioff, joff, koff;
  char *Vc;

  #ifdef PARALLEL
   MPI_Barrier (MPI_COMM_WORLD);
   AL_Write_array (V, sz, istag);
   return;
  #else
   Vc = (char *) V;
   ioff = (istag == 0); 
   joff = (istag == 1); 
   koff = (istag == 2);

   for (k = KBEG; k <= KEND + koff; k++) {
   for (j = JBEG; j <= JEND + joff; j++) {
     i = IBEG + (NX1_TOT + ioff)*(j + (NX2_TOT + joff)*k);
     fwrite (Vc + i*dsize, dsize, NX1 + ioff, fl);
   }}
  #endif

}
/* ********************************************************************* */
void ReadBinaryArray (void *V, size_t dsize, int sz, FILE *fl, int istag,
                      int swap_endian)
/*!
 * Read a double-precision array from binary file. 
 *
 * \param [in] V      pointer to a 3D array,
 *                    V[k][j][i] -->  V[i + NX1*j + NX1*NX2*k]. Must
 *                    start with index 0
 * \param [in] dsize  the size of the each buffer element   
 *                    (sizeof(double) or sizeof(float)). This
 *                    parameter is used only in serial mode.
 * \param [in] sz     the distributed array descriptor. This parameter
 *                    replaces dsize in parallel mode
 * \param [in] fl     a valid FILE pointer
 * \param [in] istag  a flag to identify cell-centered (istag = -1) or
 *                    staggered field data (istag = 0,1 or 2 for staggering 
 *                    in the x1, x2 or x3 directions) 
 * \param [in]  swap_endian  a flag for swapping endianity
 *
 * \return This function has no return value.
 *
 * \remark The data array V is assumed to start \a always with index 0
 *         for  both cell-centered and staggered arrays.
 *********************************************************************** */
{
  int i, j, k;
  int ioff, joff, koff;
  char *Vc;

/* ---------------------------------------
    parallel reading handled by ArrayLib
   --------------------------------------- */

  #ifdef PARALLEL 
   AL_Read_array (V, sz, istag);
  #else

/* ---------------------------------------
      serial reading
   --------------------------------------- */

   Vc = (char *) V;
   ioff = (istag == 0); 
   joff = (istag == 1); 
   koff = (istag == 2);

   for (k = KBEG; k <= KEND + koff; k++) {
   for (j = JBEG; j <= JEND + joff; j++) {
     i = IBEG + (NX1_TOT + ioff)*(j + (NX2_TOT + joff)*k);
     fread (Vc + i*dsize, dsize, NX1 + ioff, fl);
   }}
  #endif

/* -----------------------------------
     now swap endian if necessary
   ----------------------------------- */

  if (swap_endian){
    double *Vd;
    Vd = (double *) V;
    ioff = (istag == 0); 
    joff = (istag == 1); 
    koff = (istag == 2);

    for (k = KBEG-koff; k <= KEND + koff; k++) {
    for (j = JBEG-joff; j <= JEND + joff; j++) {
    for (i = IBEG-ioff; i <= IEND + ioff; i++) {
      SWAP_VAR(Vd[i + (NX1_TOT + ioff)*(j + (NX2_TOT + joff)*k)]);
    }}}     
  }

}

/* ********************************************************************* */
float ***Convert_dbl2flt (double ***Vdbl, int swap_endian)
/*!
 * Convert the array dbl_arr (in double precision) to single
 * precision in flt_arr. Swap endianity if swap_endian == 1.
 *
 *********************************************************************** */
{
  int i, j, k;
  float  flt;
  static float ***Vflt;
  
  if (Vflt == NULL) Vflt = ARRAY_3D(NX3_TOT, NX2_TOT, NX1_TOT, float);

  if (!swap_endian){
    DOM_LOOP(k,j,i){
      Vflt[k][j][i] = (float)Vdbl[k][j][i];
    }
  }else{
    DOM_LOOP(k,j,i){
      flt = (float) Vdbl[k][j][i];
      SWAP_VAR(flt);
      Vflt[k][j][i] = flt;
    }
  }

  return (Vflt);
}