Name

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COPY_STRUCT

Purpose

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  Copy all fields with matching tag names from one structure to another

Explanation

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      COPY_STRUCT is similar to the intrinisc STRUCT_ASSIGN procedure but
      has optional keywords to exclude or specify specific tags.
 
Fields with matching tag names are copied from one structure array to
another structure array of different type.
This allows copying of tag values when equating the structures of
different types is not allowed, or when not all tags are to be copied.
Can also recursively copy from/to structures nested within structures.
Note that the number of elements in the output structure array
is automatically adjusted to equal the length of input structure array.
If this not desired then use pro copy_struct_inx which allows
specifying via subscripts which elements are copied where in the arrays.

Calling Sequence

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copy_struct, struct_From, struct_To, NT_copied
copy_struct, struct_From, struct_To, EXCEPT=["image","misc"]
copy_struct, struct_From, struct_To, /RECUR_TANDEM

Inputs

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struct_From = structure array to copy from.
struct_To = structure array to copy values to.

Keywords

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EXCEPT_TAGS = string array of tag names to ignore (to NOT copy).
Used at all levels of recursion.
SELECT_TAGS = tag names to copy (takes priority over EXCEPT).
This keyword is not passed to recursive calls in order
to avoid the confusion of not copying tags in sub-structures.
/RECUR_FROM = search for sub-structures in struct_From, and then
call copy_struct recursively for those nested structures.
/RECUR_TO = search for sub-structures of struct_To, and then
call copy_struct recursively for those nested structures.
/RECUR_TANDEM = call copy_struct recursively for the sub-structures
with matching Tag names in struct_From and struct_To
(for use when Tag names match but sub-structure types differ).

Outputs

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struct_To = structure array to which new tag values are copied.
NT_copied = incremented by total # of tags copied (optional)
  INTERNAL:
Recur_Level = # of times copy_struct calls itself.
This argument is for internal recursive execution only.
The user call is 1, subsequent recursive calls increment it,
and the counter is decremented before returning.
The counter is used just to find out if argument checking
should be performed, and to set NT_copied = 0 first call.

External Calls

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pro match (when keyword SELECT_TAGS is specified)

Procedure

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Match Tag names and then use corresponding Tag numbers.

History

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written 1989 Frank Varosi STX @ NASA/GSFC
  mod Jul.90 by F.V. added option to copy sub-structures RECURSIVELY.
mod Aug.90 by F.V. adjust # elements in TO (output) to equal
# elements in FROM (input) & count # of fields copied.
mod Jan.91 by F.V. added Recur_Level as internal argument so that
argument checking done just once, to avoid confusion.
Checked against Except_Tags in RECUR_FROM option.
mod Oct.91 by F.V. added option SELECT_TAGS= selected field names.
mod Aug.95 by W. Landsman to fix match of a single selected tag.
mod Mar.97 by F.V. do not pass the SELECT_TAGS keyword in recursion.
Converted to IDL V5.0 W. Landsman September 1997
      mod May 01 by D. Schlegel use long integers