Provided by: libgetdata-doc_0.9.0-2.2_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_lincom, gd_alter_linterp, gd_alter_multiply, gd_alter_phase,  gd_alter_polynom,
       gd_alter_raw, gd_alter_recip, gd_alter_sbit — 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_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_shift_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_sbit(DIRFILE *dirfile, const char *field_code, const char *in_field, int bitnum, int
              numbits);

       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_shift_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.

       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, any of these functions returns zero.   On error, -1 is returned and the dirfile error is set
       to a non-zero error value.  Possible error values 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 or 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 dirfile error may be retrieved by calling gd_error(3).  A descriptive error string for the last error
       encountered can be obtained from a call to 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.

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), dirfile-format(5)