/* Copyright (c) 2008-2025 the MRtrix3 contributors.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * Covered Software is provided under this License on an "as is"
 * basis, without warranty of any kind, either expressed, implied, or
 * statutory, including, without limitation, warranties that the
 * Covered Software is free of defects, merchantable, fit for a
 * particular purpose or non-infringing.
 * See the Mozilla Public License v. 2.0 for more details.
 *
 * For more details, see http://www.mrtrix.org/.
 */

#ifndef __NIFTI2_HEADER
#define __NIFTI2_HEADER

/*---------------------------------------------------------------------------*/
/* Changes to the header from NIFTI-1 to NIFTI-2 are intended to allow for
   larger and more accurate fields.  The changes are as follows:

      - short dim[8]         -> int64_t dim[8]
      - float intent_p1,2,3  -> double intent_p1,2,3    (3 fields)
      - float pixdim[8]      -> double pixdim[8]
      - float vox_offset     -> int64_t vox_offset
      - float scl_slope      -> double scl_slope
      - float scl_inter      -> double scl_inter
      - float cal_max        -> double cal_max
      - float cal_min        -> double cal_min
      - float slice_duration -> double slice_duration
      - float toffset        -> double toffset
      - short slice_start    -> int64_t slice_start
      - short slice_end      -> int64_t slice_end
      - char slice_code      -> int32_t slice_code
      - char xyzt_units      -> int32_t xyzt_units
      - short intent_code    -> int32_t intent_code
      - short qform_code     -> int32_t qform_code
      - short sform_code     -> int32_t sform_code
      - float quatern_b,c,d  -> double quatern_b,c,d    (3 fields)
      - float srow_x,y,z[4]  -> double srow_x,y,z[4]    (3 fields)
      - char magic[4]        -> char magic[8]
      - char unused_str[15]  -> padding added at the end of the header   

      - previously unused fields have been removed:
           data_type, db_name, extents, session_error, regular, glmax, glmin

      - the field ordering has been changed
-----------------------------------------------------------------------------*/

#include <stdint.h>

/*=================*/
#ifdef  __cplusplus
extern "C" {
#endif
/*=================*/

/*! \struct nifti_2_header
    \brief Data structure defining the fields in the nifti2 header.
           This binary header should be found at the beginning of a valid
           NIFTI-2 header file.
 */

/* hopefully cross-platform solution to byte padding added by some compilers */
#pragma pack(push)
#pragma pack(1)

                         /***************************/ /**********************/ /************/
struct nifti_2_header {  /* NIFTI-2 usage           */ /* NIFTI-1 usage      */ /*  offset  */
                         /***************************/ /**********************/ /************/
   int   sizeof_hdr;     /*!< MUST be 540           */ /* int sizeof_hdr; (348) */   /*   0 */
   char  magic[8] ;      /*!< MUST be valid signature. */  /* char magic[4];    */   /*   4 */
   int16_t datatype;     /*!< Defines data type!    */ /* short datatype;       */   /*  12 */
   int16_t bitpix;       /*!< Number bits/voxel.    */ /* short bitpix;         */   /*  14 */
   int64_t dim[8];       /*!< Data array dimensions.*/ /* short dim[8];         */   /*  16 */
   double intent_p1 ;    /*!< 1st intent parameter. */ /* float intent_p1;      */   /*  80 */
   double intent_p2 ;    /*!< 2nd intent parameter. */ /* float intent_p2;      */   /*  88 */
   double intent_p3 ;    /*!< 3rd intent parameter. */ /* float intent_p3;      */   /*  96 */
   double pixdim[8];     /*!< Grid spacings.        */ /* float pixdim[8];      */   /* 104 */
   int64_t vox_offset;   /*!< Offset into .nii file */ /* float vox_offset;     */   /* 168 */
   double scl_slope ;    /*!< Data scaling: slope.  */ /* float scl_slope;      */   /* 176 */
   double scl_inter ;    /*!< Data scaling: offset. */ /* float scl_inter;      */   /* 184 */
   double cal_max;       /*!< Max display intensity */ /* float cal_max;        */   /* 192 */
   double cal_min;       /*!< Min display intensity */ /* float cal_min;        */   /* 200 */
   double slice_duration;/*!< Time for 1 slice.     */ /* float slice_duration; */   /* 208 */
   double toffset;       /*!< Time axis shift.      */ /* float toffset;        */   /* 216 */
   int64_t slice_start;  /*!< First slice index.    */ /* short slice_start;    */   /* 224 */
   int64_t slice_end;    /*!< Last slice index.     */ /* short slice_end;      */   /* 232 */
   char  descrip[80];    /*!< any text you like.    */ /* char descrip[80];     */   /* 240 */
   char  aux_file[24];   /*!< auxiliary filename.   */ /* char aux_file[24];    */   /* 320 */
   int qform_code ;      /*!< NIFTI_XFORM_* code.   */ /* short qform_code;     */   /* 344 */
   int sform_code ;      /*!< NIFTI_XFORM_* code.   */ /* short sform_code;     */   /* 348 */
   double quatern_b ;    /*!< Quaternion b param.   */ /* float quatern_b;      */   /* 352 */
   double quatern_c ;    /*!< Quaternion c param.   */ /* float quatern_c;      */   /* 360 */
   double quatern_d ;    /*!< Quaternion d param.   */ /* float quatern_d;      */   /* 368 */
   double qoffset_x ;    /*!< Quaternion x shift.   */ /* float qoffset_x;      */   /* 376 */
   double qoffset_y ;    /*!< Quaternion y shift.   */ /* float qoffset_y;      */   /* 384 */
   double qoffset_z ;    /*!< Quaternion z shift.   */ /* float qoffset_z;      */   /* 392 */
   double srow_x[4] ;    /*!< 1st row affine transform. */  /* float srow_x[4]; */   /* 400 */
   double srow_y[4] ;    /*!< 2nd row affine transform. */  /* float srow_y[4]; */   /* 432 */
   double srow_z[4] ;    /*!< 3rd row affine transform. */  /* float srow_z[4]; */   /* 464 */
   int slice_code ;      /*!< Slice timing order.   */ /* char slice_code;      */   /* 496 */
   int xyzt_units ;      /*!< Units of pixdim[1..4] */ /* char xyzt_units;      */   /* 500 */
   int intent_code ;     /*!< NIFTI_INTENT_* code.  */ /* short intent_code;    */   /* 504 */
   char intent_name[16]; /*!< 'name' or meaning of data. */ /* char intent_name[16]; */  /* 508 */
   char dim_info;        /*!< MRI slice ordering.   */      /* char dim_info;        */  /* 524 */
   char unused_str[15];  /*!< unused, filled with \0 */                                  /* 525 */
} ;                   /**** 540 bytes total ****/
typedef struct nifti_2_header nifti_2_header ;

/* restore packing behavior */
#pragma pack(pop)

/*=================*/
#ifdef  __cplusplus
}
#endif
/*=================*/

#endif /* __NIFTI2_HEADER */
