datatype

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nifti1.h header documentation

/---------------------------------------------------------------------------/
/* TYPE OF DATA (acceptable values for datatype field):
   ---------------------------------------------------
   Values of datatype smaller than 256 are ANALYZE 7.5 compatible.
   Larger values are NIFTI-1 additions.  These are all multiples of 256, so
   that no bits below position 8 are set in datatype.  But there is no need
   to use only powers-of-2, as the original ANALYZE 7.5 datatype codes do.
   The additional codes are intended to include a complete list of basic
   scalar types, including signed and unsigned integers from 8 to 64 bits,
   floats from 32 to 128 bits, and complex (float pairs) from 64 to 256 bits.
   Note that most programs will support only a few of these datatypes!
   A NIFTI-1 program should fail gracefully (e.g., print a warning message)
   when it encounters a dataset with a type it doesn't like.
-----------------------------------------------------------------------------*/

DEFINED CODES

#undef DT_UNKNOWN  / defined in dirent.h on some Unix systems /
                            /--- the original ANALYZE 7.5 type codes ---/
#define DT_NONE                    0
#define DT_UNKNOWN                 0     / what it says, dude           /
#define DT_BINARY                  1     / binary (1 bit/voxel)         /
#define DT_UNSIGNED_CHAR           2     / unsigned char (8 bits/voxel) /
#define DT_SIGNED_SHORT            4     / signed short (16 bits/voxel) /
#define DT_SIGNED_INT              8     / signed int (32 bits/voxel)   /
#define DT_FLOAT                  16     / float (32 bits/voxel)        /
#define DT_COMPLEX                32     / complex (64 bits/voxel)      /
#define DT_DOUBLE                 64     / double (64 bits/voxel)       /
#define DT_RGB                   128     / RGB triple (24 bits/voxel)   /
#define DT_ALL                   255     / not very useful (?)          /
                            /----- another set of names for the same ---/
#define DT_UINT8                   2
#define DT_INT16                   4
#define DT_INT32                   8
#define DT_FLOAT32                16
#define DT_COMPLEX64              32
#define DT_FLOAT64                64
#define DT_RGB24                 128
                            /------------------- new codes for NIFTI ---/
#define DT_INT8                  256     / signed char (8 bits)         /
#define DT_UINT16                512     / unsigned short (16 bits)     /
#define DT_UINT32                768     / unsigned int (32 bits)       /
#define DT_INT64                1024     / long long (64 bits)          /
#define DT_UINT64               1280     / unsigned long long (64 bits) /
#define DT_FLOAT128             1536     / long double (128 bits)       /
#define DT_COMPLEX128           1792     / double pair (128 bits)       /
#define DT_COMPLEX256           2048     / long double pair (256 bits)  /
                            /------- aliases for all the above codes ---/

#define NIFTI_TYPE_UINT8           2 /! unsigned char. /
#define NIFTI_TYPE_INT16           4 /! signed short. /
#define NIFTI_TYPE_INT32           8 /! signed int. /
#define NIFTI_TYPE_FLOAT32        16 /! 32 bit float. /
#define NIFTI_TYPE_COMPLEX64      32 /! 64 bit complex = 2 32 bit floats. /
#define NIFTI_TYPE_FLOAT64        64 /! 64 bit float = double. /
#define NIFTI_TYPE_RGB24         128 /! 3 8 bit bytes. /
#define NIFTI_TYPE_INT8          256 /! signed char. /
#define NIFTI_TYPE_UINT16        512 /! unsigned short. /
#define NIFTI_TYPE_UINT32        768 /! unsigned int. /
#define NIFTI_TYPE_INT64        1024 /! signed long long. /
#define NIFTI_TYPE_UINT64       1280 /! unsigned long long. /
#define NIFTI_TYPE_FLOAT128     1536 /! 128 bit float = long double. /
#define NIFTI_TYPE_COMPLEX128   1792 /! 128 bit complex = 2 64 bit floats. /
#define NIFTI_TYPE_COMPLEX256   2048 /! 256 bit complex = 2 128 bit floats /

sample typedefs for complicated types

typedef struct { float       r,i;     } complex_float ;
typedef struct { double      r,i;     } complex_double ;
typedef struct { long double r,i;     } complex_longdouble ;
typedef struct { unsigned char r,g,b; } rgb_byte ;