Provided by: libgetdata-doc_0.11.0-13_all bug

NAME

       gd_alter_bit,  gd_alter_carray,  gd_alter_clincom,  gd_alter_const,  gd_alter_cpolynom,  gd_alter_crecip,
       gd_alter_divide, gd_alter_indir, gd_alter_lincom,  gd_alter_linterp,  gd_alter_multiply,  gd_alter_phase,
       gd_alter_polynom,  gd_alter_raw, gd_alter_recip, gd_alter_sarray, gd_alter_sbit, gd_alter_sindir — modify
       a field in a Dirfile

SYNOPSIS

       #include <getdata.h>

       int gd_alter_bit(DIRFILE *dirfile, const char *field_code, const char *in_field, int bitnum, int
              numbits);

       int gd_alter_carray(DIRFILE *dirfile, const char *field_code, gd_type_t const_type, size_t array_len);

       int gd_alter_clincom(DIRFILE *dirfile, const char *field_code, int n_fields, const char **in_fields,
              const double complex *cm, const double complex *cb);

       int gd_alter_const(DIRFILE *dirfile, const char *field_code, gd_type_t const_type);

       int gd_alter_cpolynom(DIRFILE *dirfile, const char *field_code, int poly_ord, const char *in_field, const
              double complex *ca);

       int gd_alter_crecip(DIRFILE *dirfile, const char *field_code, const char *in_field, complex double
              cdividend);

       int gd_alter_divide(DIRFILE *dirfile, const char *field_code, const char *in_field1, const char
              *in_field2);

       int gd_alter_indir(DIRFILE *dirfile, const char *field_code, const char *index_field, const char
              *carray_field);

       int gd_alter_lincom(DIRFILE *dirfile, const char *field_code, int n_fields, const char **in_fields, const
              double *m, const double *b);

       int gd_alter_linterp(DIRFILE *dirfile, const char *field_code, const char *in_field, const char *table,
              int rename_table);

       int gd_alter_mplex(DIRFILE *dirfile, const char *field_name, const char *in_field, const char
              *count_field, int count_val, int period);

       int gd_alter_multiply(DIRFILE *dirfile, const char *field_code, const char *in_field1, const char
              *in_field2);

       int gd_alter_phase(DIRFILE *dirfile, const char *field_code, const char *in_field, gd_int64_t shift);

       int gd_alter_polynom(DIRFILE *dirfile, const char *field_code, int poly_ord, const char *in_field, const
              double *ca);

       int gd_alter_raw(DIRFILE *dirfile, const char *field_code, gd_type_t data_type, unsigned int spf, int
              recode);

       int gd_alter_recip(DIRFILE *dirfile, const char *field_code, const char *in_field, double dividend);

       int gd_alter_sarray(DIRFILE *dirfile, const char *field_code, size_t array_len);

       int gd_alter_sbit(DIRFILE *dirfile, const char *field_code, const char *in_field, int bitnum, int
              numbits);

       int gd_alter_sindir(DIRFILE *dirfile, const char *field_code, const char *index_field, const char
              *sarray_field);

       int gd_alter_window(DIRFILE *dirfile, const char *field_code, const char *in_field, const char
              *check_field, gd_windop_t windop, gd_triplet_t threshold);

DESCRIPTION

       These  functions  provide  alternatives  to using the gd_alter_entry(3) function to modify a field of the
       indicated type in the dirfile specified by dirfile.

       In all of these calls, field_code indicates the the field to be modified, which may be a  regular  field,
       or  a  metafield  specified  by  its  full  (slashed) field code, but should not contain a representation
       suffix.  The meaning and valid types of other  arguments  may  be  obtained  from  the  get_entry(3)  and
       dirfile-format(5)  manual  pages.  The gd_int64_t type is a signed 64-bit integer type.  The gd_triplet_t
       type is defined as:

           typedef union {
             gd_int64_t i;
             gd_uint64_t u;
             double r;
           } gd_triplet_t;

       Which element of this gd_triplet_t union to set depends on the operator selected for  the  WINDOW  field.
       See gd_entry(3) for details.

       The   gd_alter_clincom()  and  gd_alter_cpolynom()  functions  are  identical  to  gd_alter_lincom()  and
       gd_alter_polynom(), except they take complex scalar parameters, instead of purely real values.  This only
       matters  for  the  input  of  new  parameters;  if the scalar parameters are not changed (by passing NULL
       instead of a list of scalars), the functions can be  used  interchangeably,  regardless  of  whether  the
       altered field has complex scalar parameters or not.

       If the corresponding parameters are to be changed, the gd_alter_lincom() and gd_alter_clincom() functions
       take pointers to three arrays of length n_fields containing the input field names (in_fields),  the  gain
       factors (m or cm), and the offset terms (b or cb).  Similarly, gd_alter_polynom() and gd_alter_cpolynom()
       take an array of length poly_ord + 1 containing the polynomial co-efficients (a or ca).

       Some field parameters have special values which indicate no change  should  be  made  to  the  parameter.
       These special values are:

       NULL:   any of the string parameters, also m, b, a, cm, cb, or ca;

       0:      spf, n_fields, numbits, cdividend, dividend, or array_len;

       -1:     bitnum or period;

       GD_NULL:
               data_type or const_type;

       GD_WINDOP_UNK:
               windop.

       All  field  parameters  introduced with this interface must contain literal parameters.  Field parameters
       which are scalar fields cannot be introduced with these functions.  To do  that,  use  gd_alter_entry(3),
       gd_alter_spec(3) or gd_malter_spec(3), as appropriate.

       If  rename_table  is  non-zero,  the look-up table referenced by the LINTERP field will be renamed to the
       path given by table.  If recode is non-zero, the binary file associated with the RAW field  will  be  re-
       encoded  to reflect the new field parameters.  In this case, the field's I/O pointer will be reset to the
       beginning-of-frame.

       If gd_alter_carray() is used to increase the length of  a  CARRAY  field,  the  added  elements  will  be
       uninitialised.   Use  gd_put_carray_slice(3) or equivalent to initialise them.  Similarly, increasing the
       length of a SARRAY with gd_alter_sarray() will set the added elements to  the  empty  string  ("").   Use
       gd_put_sarray_slice(3) or equivalent to modify them.

       See  NOTES  below for information on using gd_alter_clincom(), gd_alter_crecip(), and gd_alter_cpolynom()
       in the C89 GetData API.

RETURN VALUE

       On success, these functions return zero.  On error, a negative-valued error code is  returned.   Possible
       error codes are:

       GD_E_ACCMODE
               The specified dirfile was opened read-only.

       GD_E_ALLOC
               The library was unable to allocate memory.

       GD_E_BAD_CODE
               The  field  specified  by  field_code was not found, or a supplied field code did not contain the
               appropriate prefix or suffix.

       GD_E_BAD_DIRFILE
               The supplied dirfile was invalid.

       GD_E_BAD_ENTRY
               One or more of the field parameters specified was invalid.

       GD_E_BAD_FIELD_TYPE
               The field specified by field_code was of the wrong type for the function called.

       GD_E_BAD_TYPE
               The data_type const_type argument was invalid.

       GD_E_IO An I/O error occurred while translating the binary file associated with a modified RAW field,  or
               an I/O error occurred while attempting to rename a LINTERP table file.

       GD_E_PROTECTED
               The  metadata  of  the fragment was protected from change.  Or, a request to translate the binary
               file associated with a RAW field was attempted, but the data of the fragment was protected.

       GD_E_UNKNOWN_ENCODING
               The encoding scheme of the indicated format specification fragment is not known to  the  library.
               As  a  result,  the library was unable to translate the binary file be associated with a modified
               RAW field.

       GD_E_UNSUPPORTED
               The encoding scheme of the indicated format specification fragment does not  support  translating
               the binary file associated with a modified RAW field.

       The  error code is also stored in the DIRFILE object and may be retrieved after these functions return by
       calling  gd_error(3).   A  descriptive  error  string  for  the  error  may  be   obtained   by   calling
       gd_error_string(3).

NOTES

       The  C89  GetData  API  provides  different  prototypes  for gd_alter_clincom(), gd_alter_cpolynom(), and
       gd_alter_crecip():

       #define GD_C89_API
       #include <getdata.h>

       int gd_alter_clincom(DIRFILE *dirfile, const char *field_code, int n_fields, const char **in_fields,
              const double *cm, const double *cb);

       int gd_alter_cpolynom(DIRFILE *dirfile, const char *field_code, int poly_ord, const char *in_fields,
              const double *ca);

       int gd_alter_crecip(DIRFILE *dirfile, const char *field_code, const char *in_field, const double
              cdividend[2]);

       In this case, the array pointers passed as cm, cb or ca should have twice as many (purely real) elements,
       consisting of alternating real and imaginary parts for the complex data.  That  is,  for  example,  ca[0]
       should  be  the  real part of the first co-efficient, ca[1] the imaginary part of the first co-efficient,
       ca[2] the real part of the second co-efficient, ca[3] the imaginary part of the second co-efficient,  and
       so on.  Similarly, the cdividend parameter becomes a double precision array of length two.

       For  gd_alter_clincom() and gd_alter_cpolynom(), these are simply different (but equivalent) declarations
       of the C99 function entry point.  For gd_alter_crecip(), however,  a  different  entry  point  is  needed
       (since  the  cdividend  parameter  is  passed  by  reference  instead  of by value).  In the interests of
       portability, the  C89  version  of  gd_alter_crecip()  is  always  available,  and  may  be  accessed  as
       gd_alter_crecip89(),  with the C89 prototype, in both the C99 and C89 APIs.  Passing NULL as cdividend is
       equivalent to specifying a dividend of zero: it indicates no change to the dividend parameter.

HISTORY

       The       functions       dirfile_alter_bit(),       dirfile_alter_const(),       dirfile_alter_lincom(),
       dirfile_alter_linterp(),   dirfile_alter_multiply(),   dirfile_alter_phase(),   and   dirfile_alter_raw()
       appeared in GetData-0.5.0.

       The   functions   dirfile_alter_clincom(),   dirfile_alter_cpolynom(),    dirfile_alter_polynom(),    and
       dirfile_alter_sbit() appeared in GetData-0.6.0.

       In  GetData-0.7.0,  the  functions  were renamed to gd_alter_bit(), gd_alter_clincom(), gd_alter_const(),
       gd_alter_cpolynom(),  gd_alter_lincom(),   gd_alter_linterp(),   gd_alter_multiply(),   gd_alter_phase(),
       gd_alter_polynom(),    gd_alter_raw(),    and    gd_alter_sbit().    The   functions   gd_alter_carray(),
       gd_alter_crecip(), gd_alter_crecip89(), gd_alter_divide(), and gd_alter_recip()  also  appeared  in  this
       version.

       The functions gd_alter_mplex() and gd_alter_window() appeared in GetData-0.8.0.

       In GetData-0.10.0, the error return from these functions changed from -1 to a negative-valued error code.
       The functions gd_alter_indir(), gd_alter_sarray(), and gd_alter_sindir() also appeared in this version.

SEE ALSO

       gd_alter_entry(3), gd_alter_spec(3), gd_error(3), gd_error_string(3), gd_malter_spec(3), gd_metaflush(3),
       gd_open(3), gd_put_carray_slice(3), gd_put_sarray_slice(3), dirfile-format(5)