src/xdrfile_xtc.c

   1 /* -*- mode: c; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*-
   2  *
   3  * $Id$
   4  *
   5  * Copyright (c) Erik Lindahl, David van der Spoel 2003,2004.
   6  * Coordinate compression (c) by Frans van Hoesel.
   7  *
   8  * IN contrast to the rest of Gromacs, XDRFILE is distributed under the
   9  * BSD license, so you can use it any way you wish, including closed source:
  10  *
  11  * Permission is hereby granted, free of charge, to any person obtaining a
  12  * copy of this software and associated documentation files (the "Software"),
  13  * to deal in the Software without restriction, including without limitation
  14  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  15  * and/or sell copies of the Software, and to permit persons to whom the
  16  * Software is furnished to do so, subject to the following conditions:
  17  *
  18  * The above copyright notice and this permission notice shall be included in
  19  * all copies or substantial portions of the Software.
  20  *
  21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  22  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  23  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  24  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  25  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  26  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  27  * DEALINGS IN THE SOFTWARE.
  28  */
  29
  30 #include <stdlib.h>
  31 #include "xdrfile.h"
  32 #include "xdrfile_xtc.h"
  33
  34 #define MAGIC 1995
  35
  36 enum { FALSE, TRUE };
  37
  38 static int xtc_header(XDRFILE *xd,int *natoms,int *step,float *time,bool bRead)
  39 {
  40         int result,magic,n=1;
  41
  42         /* Note: read is same as write. He he he */
  43         magic  = MAGIC;
  44         if ((result = xdrfile_write_int(&magic,n,xd)) != n)
  45                 {
  46                         if (bRead)
  47                                 return exdrENDOFFILE;
  48                         else
  49                                 return exdrINT;
  50                 }
  51         if (magic != MAGIC)
  52                 return exdrMAGIC;
  53         if ((result = xdrfile_write_int(natoms,n,xd)) != n)
  54                 return exdrINT;
  55         if ((result = xdrfile_write_int(step,n,xd)) != n)
  56                 return exdrINT;
  57         if ((result = xdrfile_write_float(time,n,xd)) != n)
  58                 return exdrFLOAT;
  59
  60         return exdrOK;
  61 }
  62
  63 static int xtc_coord(XDRFILE *xd,int *natoms,matrix box,rvec *x,float *prec,
  64                                          bool bRead)
  65 {
  66         int i,j,result;
  67
  68         /* box */
  69         result = xdrfile_read_float(box[0],DIM*DIM,xd);
  70         if (DIM*DIM != result)
  71                 return exdrFLOAT;
  72         else
  73                 {
  74                         if (bRead)
  75                                 {
  76                                         result = xdrfile_decompress_coord_float(x[0],natoms,prec,xd);
  77                                         if (result != *natoms)
  78                                                 return exdr3DX;
  79                                 }
  80                         else
  81                                 {
  82                                         result = xdrfile_compress_coord_float(x[0],*natoms,*prec,xd);
  83                                         if (result != *natoms)
  84                                                 return exdr3DX;
  85                                 }
  86                 }
  87         return exdrOK;
  88 }
  89
  90 int read_xtc_natoms(char *fn,int *natoms)
  91 {
  92         XDRFILE *xd;
  93         int step,result;
  94         float time;
  95
  96         xd = xdrfile_open(fn,"r");
  97         if (NULL == xd)
  98                 return exdrFILENOTFOUND;
  99         result = xtc_header(xd,natoms,&step,&time,TRUE);
 100         xdrfile_close(xd);
 101
 102         return result;
 103 }
 104
 105 int read_xtc(XDRFILE *xd,
 106                          int natoms,int *step,float *time,
 107                          matrix box,rvec *x,float *prec)
 108 /* Read subsequent frames */
 109 {
 110         int result;
 111
 112         if ((result = xtc_header(xd,&natoms,step,time,TRUE)) != exdrOK)
 113                 return result;
 114
 115         if ((result = xtc_coord(xd,&natoms,box,x,prec,1)) != exdrOK)
 116                 return result;
 117
 118         return exdrOK;
 119 }
 120
 121 int write_xtc(XDRFILE *xd,
 122                           int natoms,int step,float time,
 123                           matrix box,rvec *x,float prec)
 124 /* Write a frame to xtc file */
 125 {
 126         int result;
 127
 128         if ((result = xtc_header(xd,&natoms,&step,&time,FALSE)) != exdrOK)
 129                 return result;
 130
 131         if ((result = xtc_coord(xd,&natoms,box,x,&prec,0)) != exdrOK)
 132                 return result;
 133
 134         return exdrOK;
 135 }