rsspice 0.1.0

//
// GENERATED FILE
//

use super::*;
use crate::SpiceContext;
use f2rust_std::*;

pub const MINCOS: f64 = 0.000000000000001;
const KWDNLN: i32 = 32;
const MAXNML: i32 = 4;
const NSHAPS: i32 = 4;
const NUMASP: i32 = 3;
const VALLEN: i32 = 80;

struct SaveVars {
    ANGSHP: ActualCharArray,
    SHAPID: ActualCharArray,
}

impl SaveInit for SaveVars {
    fn new() -> Self {
        let mut ANGSHP = ActualCharArray::new(KWDNLN, 1..=NUMASP);
        let mut SHAPID = ActualCharArray::new(KWDNLN, 1..=NSHAPS);

        {
            use f2rust_std::data::Val;

            let mut clist = [
                Val::C(b"CIRCLE"),
                Val::C(b"ELLIPSE"),
                Val::C(b"POLYGON"),
                Val::C(b"RECTANGLE"),
            ]
            .into_iter();
            for I in intrinsics::range(1, NSHAPS, 1) {
                fstr::assign(SHAPID.get_mut(I), clist.next().unwrap().into_str());
            }

            debug_assert!(clist.next().is_none(), "DATA not fully initialised");
        }
        {
            use f2rust_std::data::Val;

            let mut clist =
                [Val::C(b"CIRCLE"), Val::C(b"ELLIPSE"), Val::C(b"RECTANGLE")].into_iter();
            for I in intrinsics::range(1, NUMASP, 1) {
                fstr::assign(ANGSHP.get_mut(I), clist.next().unwrap().into_str());
            }

            debug_assert!(clist.next().is_none(), "DATA not fully initialised");
        }

        Self { ANGSHP, SHAPID }
    }
}

/// Get instrument FOV parameters
///
/// Return the field-of-view (FOV) parameters for a specified
/// instrument. The instrument is specified by its NAIF ID code.
///
/// # Required Reading
///
/// * [NAIF_IDS](crate::required_reading::naif_ids)
///
/// # Brief I/O
///
/// ```text
///  VARIABLE  I/O  DESCRIPTION
///  --------  ---  --------------------------------------------------
///  INSTID     I   NAIF ID of an instrument.
///  ROOM       I   Maximum number of vectors that can be returned.
///  SHAPE      O   Instrument FOV shape.
///  FRAME      O   Name of the frame in which FOV vectors are defined.
///  BSIGHT     O   Boresight vector.
///  N          O   Number of boundary vectors returned.
///  BOUNDS     O   FOV boundary vectors.
/// ```
///
/// # Detailed Input
///
/// ```text
///  INSTID   is the NAIF ID of an instrument.
///
///  ROOM     is the maximum number of 3-dimensional vectors that can
///           be returned in BOUNDS.
/// ```
///
/// # Detailed Output
///
/// ```text
///  SHAPE    is a character string that describes the "shape" of
///           the field of view. Possible values returned are:
///
///              'POLYGON'
///              'RECTANGLE'
///              'CIRCLE'
///              'ELLIPSE'
///
///           If the value of SHAPE is 'POLYGON' the field of view
///           of the instrument is a pyramidal polyhedron. The
///           vertex of the pyramid is at the instrument focal
///           point. The rays along the edges of the pyramid are
///           parallel to the vectors returned in BOUNDS.
///
///           If the value of SHAPE is 'RECTANGLE' the field of view
///           of the instrument is a rectangular pyramid. The vertex
///           of the pyramid is at the instrument focal point. The
///           rays along the edges of the pyramid are parallel to
///           the vectors returned in BOUNDS. Moreover, in this
///           case, the boresight points along the axis of symmetry
///           of the rectangular pyramid.
///
///           If the value of SHAPE is 'CIRCLE' the field of view of
///           the instrument is a circular cone centered on the
///           boresight vector. The vertex of the cone is at the
///           instrument focal point. A single vector will be
///           returned in BOUNDS. This vector will be parallel to a
///           ray that lies in the cone that makes up the boundary
///           of the field of view.
///
///           If the value of SHAPE is 'ELLIPSE' the field of view
///           of the instrument is an elliptical cone with the
///           boresight vector as the axis of the cone. In this
///           case two vectors are returned in BOUNDS. One of the
///           vectors returned in BOUNDS points to the end of the
///           semi-major axis of a perpendicular cross section of
///           the elliptic cone. The other vector points to the end
///           of the semi-minor axis of a perpendicular cross
///           section of the cone.
///
///  FRAME    is the name of the reference frame in which the field
///           of view boundary vectors are defined.
///
///  BSIGHT   is a vector representing the principal instrument view
///           direction that can be
///
///              -  the central pixel view direction,
///              -  the optical axis direction,
///              -  the FOV geometric center view direction,
///              -  an axis of the FOV frame,
///
///           or any other vector specified for this purpose
///           in the IK FOV definition. The length of BSIGHT
///           is not specified other than being non-zero.
///
///  N        is the number of boundary vectors returned.
///
///  BOUNDS   is an array of vectors that point to the "corners" of
///           the instrument field of view. (See the discussion
///           accompanying SHAPE for an expansion of the term
///           "corner of the field of view.") Note that the vectors
///           returned in BOUNDS are not necessarily unit vectors.
///           Their magnitudes will be as set in the IK (for
///           'CORNERS'-style FOV specifications) or the same as the
///           magnitude of the boresight (for 'ANGLES'-style FOV
///           specifications.)
/// ```
///
/// # Parameters
///
/// ```text
///  MINCOS   is the lower limit on the value of the cosine of the
///           cross or reference angles in the 'ANGLES' specification
///           cases. The current value for MINCOS is 1.0D-15.
/// ```
///
/// # Exceptions
///
/// ```text
///  1)  If the frame associated with the instrument can not be found,
///      the error SPICE(FRAMEMISSING) is signaled.
///
///  2)  If the shape of the instrument field of view can not be found
///      in the kernel pool, the error SPICE(SHAPEMISSING) is signaled
///      signaled.
///
///  3)  If the FOV_SHAPE specified by the instrument kernel is not
///      one of the four values: 'CIRCLE', 'POLYGON', 'ELLIPSE', or
///      'RECTANGLE', the error SPICE(SHAPENOTSUPPORTED) is signaled.
///      If the 'ANGLES' specification is used, FOV_SHAPE must be
///      one of the three values: 'CIRCLE', 'ELLIPSE', or 'RECTANGLE'.
///
///  4)  If the direction of the boresight cannot be located in the
///      kernel pool, the error SPICE(BORESIGHTMISSING) is signaled.
///
///  5)  If the number of components for the boresight vector in the
///      kernel pool is not 3, or they are not numeric, the error
///      SPICE(BADBORESIGHTSPEC) is signaled.
///
///  6)  If the boresight vector is the zero vector, the error
///      SPICE(ZEROBORESIGHT) is signaled.
///
///  7)  If the 'ANGLES' specification is not present in the kernel
///      pool and the boundary vectors for the edge of the field of
///      view cannot be found in the kernel pool, the error
///      SPICE(BOUNDARYMISSING) is signaled.
///
///  8)  If there is insufficient room (as specified by the argument
///      ROOM) to return all of the vectors associated with the
///      boundary of the field of view, the error
///      SPICE(BOUNDARYTOOBIG) is signaled.
///
///  9)  If the number of components of vectors making up the field of
///      view is not a multiple of 3, the error SPICE(BADBOUNDARY) is
///      signaled.
///
///  10) If the number of components of vectors making up the field of
///      view is not compatible with the shape specified for the field
///      of view, the error SPICE(BADBOUNDARY) is signaled.
///
///  11) If the reference vector for the 'ANGLES' specification can not
///      be found in the kernel pool, the error SPICE(REFVECTORMISSING)
///      is signaled.
///
///  12) If the reference vector stored in the kernel pool to support
///      the 'ANGLES' specification contains an incorrect number of
///      components, contains 3 character components, or is parallel to
///      the boresight, the error SPICE(BADREFVECTORSPEC) is signaled.
///
///  13) If the 'ANGLES' specification is present in the kernel pool
///      and the reference angle stored in the kernel pool to support
///      the 'ANGLES' specification is absent from the kernel pool, the
///      error SPICE(REFANGLEMISSING) is signaled.
///
///  14) If the keyword that stores the angular units for the angles
///      used in the 'ANGLES' specification is absent from the kernel
///      pool, the error SPICE(UNITSMISSING) is signaled.
///
///  15) If the value used for the units in the 'ANGLES' specification
///      is not one of the supported angular units of CONVRT, an error
///      is signaled by a routine in the call tree of this routine.
///
///  16) If the keyword that stores the cross angle for the 'ANGLES'
///      specification is needed and is absent from the kernel pool,
///      the error SPICE(CROSSANGLEMISSING) is signaled.
///
///  17) If the angles for the 'RECTANGLE'/'ANGLES' specification case
///      have cosines that are less than those stored in the parameter
///      MINCOS, the error SPICE(BADBOUNDARY) is signaled.
///
///  18) If the class specification contains something other than
///      'ANGLES' or 'CORNERS', the error SPICE(UNSUPPORTEDSPEC) is
///      signaled.
///
///  19) In the event that the CLASS_SPEC keyword is absent from the
///      kernel pool for the instrument whose FOV is sought, this
///      module assumes the 'CORNERS' specification is to be utilized.
/// ```
///
/// # Files
///
/// ```text
///  This routine relies upon having successfully loaded an instrument
///  kernel (IK file) via the routine FURNSH prior to calling this
///  routine.
/// ```
///
/// # Particulars
///
/// ```text
///  This routine provides a common interface for retrieving from the
///  kernel pool the geometric characteristics of an instrument field
///  of view for a wide variety of remote sensing instruments
///  across many different space missions.
///
///  Given the NAIF instrument ID, (and having "loaded" the
///  instrument field of view description via the routine FURNSH)
///  this routine returns the boresight of the instrument, the
///  "shape" of the field of view, a collection of vectors
///  that point along the edges of the field of view, and the
///  name of the reference frame in which these vectors are defined.
///
///  Currently this routine supports two classes of specifications
///  for FOV definitions: "corners" and "angles".
///
///  The "corners" specification requires that the following keywords
///  defining the shape, boresight, boundary vectors, and reference
///  frame of the FOV be provided in one of the text kernel files
///  (normally an IK file) loaded into the kernel pool (in the
///  keywords below <INSTID> is replaced with the instrument ID as
///  passed into the module):
///
///     INS<INSTID>_FOV_CLASS_SPEC         must be set to 'CORNERS' or
///                                        omitted to indicate the
///                                        "corners"-class
///                                        specification.
///
///     INS<INSTID>_FOV_SHAPE              must be set to one of these
///                                        values:
///
///                                           'CIRCLE'
///                                           'ELLIPSE'
///                                           'RECTANGLE'
///                                           'POLYGON'
///
///     INS<INSTID>_FOV_FRAME              must contain the name of
///                                        the frame in which the
///                                        boresight and boundary
///                                        corner vectors are defined.
///
///     INS<INSTID>_BORESIGHT              must be set to a 3D vector
///                                        defining the boresight in
///                                        the FOV frame specified in
///                                        the FOV_FRAME keyword.
///
///     INS<INSTID>_FOV_BOUNDARY   or
///     INS<INSTID>_FOV_BOUNDARY_CORNERS   must be set to one (for
///                                        FOV_SHAPE = 'CIRCLE'), two
///                                        (for FOV_SHAPE =
///                                        'ELLIPSE'), four (for
///                                        FOV_SHAPE = 'RECTANGLE'),
///                                        or three or more (for
///                                        'POLYGON') 3D vectors
///                                        defining the corners of the
///                                        FOV in the FOV frame
///                                        specified in the FOV_FRAME
///                                        keyword. The vectors should
///                                        be listed in either
///                                        clockwise or
///                                        counterclockwise order.
///                                        This is required by some
///                                        SPICE routines that make
///                                        use of FOV specifications.
///
///  The "angles" specification requires the following keywords
///  defining the shape, boresight, reference vector, reference and
///  cross angular extents of the FOV be provided in one of the text
///  kernel files (normally an IK file) loaded into the kernel
///  pool (in the keywords below <INSTID> is replaced with the
///  instrument ID as passed into the module):
///
///     INS<INSTID>_FOV_CLASS_SPEC         must be set to 'ANGLES' to
///                                        indicate the "angles"-class
///                                        specification.
///
///     INS<INSTID>_FOV_SHAPE              must be set to one of these
///                                        values:
///
///                                           'CIRCLE'
///                                           'ELLIPSE'
///                                           'RECTANGLE'
///
///     INS<INSTID>_FOV_FRAME              must contain the name of
///                                        the frame in which the
///                                        boresight and the computed
///                                        boundary corner vectors are
///                                        defined.
///
///     INS<INSTID>_BORESIGHT              must be set to a 3D vector
///                                        defining the boresight in
///                                        the FOV frame specified in
///                                        the FOV_FRAME keyword.
///
///     INS<INSTID>_FOV_REF_VECTOR         must be set to a 3D vector
///                                        that together with the
///                                        boresight vector defines
///                                        the plane in which the
///                                        first angular extent of the
///                                        FOV specified in the
///                                        FOV_REF_ANGLE keyword is
///                                        measured.
///
///     INS<INSTID>_FOV_REF_ANGLE          must be set to the angle
///                                        that is 1/2 of the total
///                                        FOV angular extent in the
///                                        plane defined by the
///                                        boresight and the vector
///                                        specified in the
///                                        FOV_REF_VECTOR keyword. The
///                                        the FOV angular half-extents
///                                        are measured from the
///                                        boresight vector.
///
///     INS<INSTID>_FOV_CROSS_ANGLE        must be set to the angle
///                                        that is 1/2 of the total
///                                        FOV angular extent in the
///                                        plane containing the
///                                        boresight and perpendicular
///                                        to the plane defined by the
///                                        boresight and the vector
///                                        specified in the
///                                        FOV_REF_VECTOR keyword. The
///                                        the FOV angular half-extents
///                                        are measured from the
///                                        boresight vector. This
///                                        keyword is not required for
///                                        FOV_SHAPE = 'CIRCLE'.
///
///     INS<INSTID>_FOV_ANGLE_UNITS        must specify units for the
///                                        angles given in the
///                                        FOV_REF_ANGLE and
///                                        FOV_CROSS_ANGLE keywords.
///                                        Any angular units
///                                        recognized by CONVRT are
///                                        acceptable.
///
///  The INS<INSTID>_FOV_REF_ANGLE and INS<INSTID>_FOV_CROSS_ANGLE
///  keywords can have any values for the 'CIRCLE' and 'ELLIPSE'
///  FOV shapes but must satisfy the condition COS( ANGLE ) > 0 for
///  the 'RECTANGLE' shape.
///
///  This routine is intended to be an intermediate level routine.
///  It is expected that users of this routine will be familiar
///  with the SPICE frames subsystem and will be comfortable writing
///  software to further manipulate the vectors retrieved by this
///  routine.
/// ```
///
/// # Examples
///
/// ```text
///  The numerical results shown for this example may differ across
///  platforms. The results depend on the SPICE kernels used as input,
///  the compiler and supporting libraries, and the machine specific
///  arithmetic implementation.
///
///  1) Load an IK, fetch the parameters for each of the FOVs defined
///     within and print these parameters to the screen.
///
///     Use the kernel shown below, an IK defining four FOVs of
///     various shapes and sizes, to load the FOV definitions.
///
///
///        KPL/IK
///
///        File name: getfov_ex1.ti
///
///        The keywords below define a circular, 10-degree wide FOV
///        with the boresight along the +Z axis of the 'SC999_INST001'
///        frame for an instrument with ID -999001 using the
///        "angles"-class specification.
///
///        \begindata
///           INS-999001_FOV_CLASS_SPEC       = 'ANGLES'
///           INS-999001_FOV_SHAPE            = 'CIRCLE'
///           INS-999001_FOV_FRAME            = 'SC999_INST001'
///           INS-999001_BORESIGHT            = ( 0.0, 0.0, 1.0 )
///           INS-999001_FOV_REF_VECTOR       = ( 1.0, 0.0, 0.0 )
///           INS-999001_FOV_REF_ANGLE        = ( 5.0 )
///           INS-999001_FOV_ANGLE_UNITS      = ( 'DEGREES' )
///        \begintext
///
///        The keywords below define an elliptical FOV with 2- and
///        4-degree angular extents in the XZ and XY planes and the
///        boresight along the +X axis of the 'SC999_INST002' frame for
///        an instrument with ID -999002 using the "corners"-class
///        specification.
///
///        \begindata
///           INS-999002_FOV_SHAPE            = 'ELLIPSE'
///           INS-999002_FOV_FRAME            = 'SC999_INST002'
///           INS-999002_BORESIGHT            = ( 1.0, 0.0, 0.0 )
///           INS-999002_FOV_BOUNDARY_CORNERS = (
///                                   1.0,  0.0,        0.01745506,
///                                   1.0,  0.03492077, 0.0        )
///        \begintext
///
///        The keywords below define a rectangular FOV with 1.2- and
///        0.2-degree angular extents in the ZX and ZY planes and the
///        boresight along the +Z axis of the 'SC999_INST003' frame for
///        an instrument with ID -999003 using the "angles"-class
///        specification.
///
///        \begindata
///           INS-999003_FOV_CLASS_SPEC       = 'ANGLES'
///           INS-999003_FOV_SHAPE            = 'RECTANGLE'
///           INS-999003_FOV_FRAME            = 'SC999_INST003'
///           INS-999003_BORESIGHT            = ( 0.0, 0.0, 1.0 )
///           INS-999003_FOV_REF_VECTOR       = ( 1.0, 0.0, 0.0 )
///           INS-999003_FOV_REF_ANGLE        = ( 0.6 )
///           INS-999003_FOV_CROSS_ANGLE      = ( 0.1 )
///           INS-999003_FOV_ANGLE_UNITS      = ( 'DEGREES' )
///        \begintext
///
///        The keywords below define a triangular FOV with the
///        boresight along the +Y axis of the 'SC999_INST004' frame
///        for an instrument with ID -999004 using the "corners"-class
///        specification.
///
///        \begindata
///           INS-999004_FOV_SHAPE            = 'POLYGON'
///           INS-999004_FOV_FRAME            = 'SC999_INST004'
///           INS-999004_BORESIGHT            = (  0.0,  1.0,  0.0 )
///           INS-999004_FOV_BOUNDARY_CORNERS = (  0.0,  0.8,  0.5,
///                                                0.4,  0.8, -0.2,
///                                               -0.4,  0.8, -0.2 )
///        \begintext
///
///        End of IK
///
///
///     Example code begins here.
///
///
///           PROGRAM GETFOV_EX1
///           IMPLICIT NONE
///
///     C
///     C     Local parameters
///     C
///           INTEGER               MAXBND
///           PARAMETER           ( MAXBND = 4 )
///
///           INTEGER               NUMINS
///           PARAMETER           ( NUMINS = 4 )
///
///           INTEGER               WDSIZE
///           PARAMETER           ( WDSIZE = 32 )
///
///     C
///     C     Local variables
///     C
///           CHARACTER*(WDSIZE)    FRAME
///           CHARACTER*(WDSIZE)    SHAPE
///
///           DOUBLE PRECISION      BOUNDS ( 3, MAXBND )
///           DOUBLE PRECISION      BSIGHT ( 3 )
///
///           INTEGER               I
///           INTEGER               INSIDS ( NUMINS )
///           INTEGER               J
///           INTEGER               N
///
///     C
///     C     Define the instrument IDs.
///     C
///           DATA                  INSIDS  /  -999001, -999002,
///          .                                 -999003, -999004  /
///
///     C
///     C     Load the IK file.
///     C
///           CALL FURNSH( 'getfov_ex1.ti' )
///
///     C
///     C     For each instrument ...
///     C
///           WRITE (*,'(A)') '--------------------------------------'
///           DO I = 1, NUMINS
///
///     C
///     C        ... fetch FOV parameters and ...
///     C
///              CALL GETFOV ( INSIDS(I), MAXBND,
///          .                 SHAPE, FRAME, BSIGHT, N, BOUNDS )
///
///     C
///     C        ... print them to the screen.
///     C
///              WRITE (*,'(A,I7)')     'Instrument ID: ', INSIDS(I)
///              WRITE (*,'(2A)')       '    FOV shape: ', SHAPE
///              WRITE (*,'(2A)')       '    FOV frame: ', frame
///              WRITE (*,'(A,3F12.8)') 'FOV boresight: ', BSIGHT
///
///              WRITE (*,'(A)') '  FOV corners: '
///              DO J = 1, N
///                 WRITE (*,'(A,3F12.8)') '               ',
///          .                  BOUNDS(1,J), BOUNDS(2,J), BOUNDS(3,J)
///              END DO
///              WRITE (*,'(A)')
///          .            '--------------------------------------'
///
///           END DO
///
///           END
///
///
///     When this program was executed on a Mac/Intel/gfortran/64-bit
///     platform, the output was:
///
///
///     --------------------------------------
///     Instrument ID: -999001
///         FOV shape: CIRCLE
///         FOV frame: SC999_INST001
///     FOV boresight:   0.00000000  0.00000000  1.00000000
///       FOV corners:
///                      0.08715574  0.00000000  0.99619470
///     --------------------------------------
///     Instrument ID: -999002
///         FOV shape: ELLIPSE
///         FOV frame: SC999_INST002
///     FOV boresight:   1.00000000  0.00000000  0.00000000
///       FOV corners:
///                      1.00000000  0.00000000  0.01745506
///                      1.00000000  0.03492077  0.00000000
///     --------------------------------------
///     Instrument ID: -999003
///         FOV shape: RECTANGLE
///         FOV frame: SC999_INST003
///     FOV boresight:   0.00000000  0.00000000  1.00000000
///       FOV corners:
///                      0.01047177  0.00174523  0.99994365
///                     -0.01047177  0.00174523  0.99994365
///                     -0.01047177 -0.00174523  0.99994365
///                      0.01047177 -0.00174523  0.99994365
///     --------------------------------------
///     Instrument ID: -999004
///         FOV shape: POLYGON
///         FOV frame: SC999_INST004
///     FOV boresight:   0.00000000  1.00000000  0.00000000
///       FOV corners:
///                      0.00000000  0.80000000  0.50000000
///                      0.40000000  0.80000000 -0.20000000
///                     -0.40000000  0.80000000 -0.20000000
///     --------------------------------------
/// ```
///
/// # Restrictions
///
/// ```text
///  1)  This routine will not operate unless an I-kernel for the
///      instrument with the NAIF ID specified in INSTID have been
///      loaded via a call to FURNSH prior to calling this routine and
///      this IK contains the specification for the instrument field of
///      view consistent with the expectations of this routine.
/// ```
///
/// # Author and Institution
///
/// ```text
///  C.H. Acton         (JPL)
///  N.J. Bachman       (JPL)
///  J. Diaz del Rio    (ODC Space)
///  M. Liukis          (JPL)
///  B.V. Semenov       (JPL)
///  W.L. Taber         (JPL)
///  F.S. Turner        (JPL)
/// ```
///
/// # Version
///
/// ```text
/// -    SPICELIB Version 2.3.0, 17-DEC-2021 (JDR) (ML) (BVS)
///
///         Bug fix: added missing exception for the boresight vector
///         being the zero vector.
///
///         Updated long error message for 'BADBOUNDARY' exception to
///         correctly describe the check that's actually done.
///
///         Edited the header to comply with NAIF standard. Removed
///         unnecessary $Revisions section.
///
///         Updated entry #5 and added entries #14 and #18 to $Exceptions
///         section. Updated $Restrictions section.
///
///         Updated $Particulars to describe the actual condition that
///         reference and cross angles values must satisfy.
///
///         Updated to check FAILED() after calls to CONVRT to prevent
///         use of uninitialized values in subsequent calls.
///
/// -    SPICELIB Version 2.2.0, 22-MAR-2017 (JDR) (BVS)
///
///         Header updates: made various header changes to make it
///         compliant with the SPICE standard header format; updated
///         BSIGHT description; added explanation of output boundary
///         vector magnitudes; made other minor header corrections.
///
///         Updated code to remove unnecessary lines in the SPICE
///         error handling IF-THEN-ELSE statements.
///
/// -    SPICELIB Version 2.1.1, 05-FEB-2009 (BVS)
///
///         Header updates: added information about required IK keywords;
///         replaced old example with a new one more focused on GETFOV and
///         IK keywords.
///
/// -    SPICELIB Version 2.1.0, 23-OCT-2005 (NJB) (BVS)
///
///         Fixed bug causing incorrect computation of the boundary
///         vectors for a rectangular FOV specified using the angular
///         extents method if the reference vector was provided as a
///         non-unit vector and/or was non-perpendicular to the
///         specified boresight.
///
///         Updated to remove non-standard use of duplicate arguments
///         in CONVRT, UNORM, VHAT, VSCL and VCROSS calls.
///
///         Replaced header reference to LDPOOL with reference to FURNSH.
///
/// -    SPICELIB Version 2.0.1, 29-JUL-2003 (NJB) (CHA)
///
///         Various header changes were made to improve clarity. Some
///         minor header corrections were made.
///
/// -    SPICELIB Version 2.0.0, 15-MAY-2001 (FST)
///
///         Updated the routine to support the new ANGLES specification
///         for RECTANGLE, ELLIPSE, and CIRCLE.
///
/// -    SPICELIB Version 1.1.2, 10-MAY-2000 (WLT)
///
///         Removed the unused variable INDEX.
///
/// -    SPICELIB Version 1.1.1, 13-APR-2000 (WLT)
///
///         This routine was harvested from the NEAR specific routine
///         of the same name. It was enhanced to support the 'RECTANGLE'
///         shape for a field of view (a special case of 'POLYGON'
///         added for the sake of Cassini users).
/// ```
pub fn getfov(
    ctx: &mut SpiceContext,
    instid: i32,
    room: i32,
    shape: &mut str,
    frame: &mut str,
    bsight: &mut [f64; 3],
    n: &mut i32,
    bounds: &mut [[f64; 3]],
) -> crate::Result<()> {
    GETFOV(
        instid,
        room,
        fstr::StrBytes::new(shape).as_mut(),
        fstr::StrBytes::new(frame).as_mut(),
        bsight,
        n,
        bounds.as_flattened_mut(),
        ctx.raw_context(),
    )?;
    ctx.handle_errors()?;
    Ok(())
}

//$Procedure GETFOV ( Get instrument FOV parameters )
pub fn GETFOV(
    INSTID: i32,
    ROOM: i32,
    SHAPE: &mut [u8],
    FRAME: &mut [u8],
    BSIGHT: &mut [f64],
    N: &mut i32,
    BOUNDS: &mut [f64],
    ctx: &mut Context,
) -> f2rust_std::Result<()> {
    let save = ctx.get_vars::<SaveVars>();
    let save = &mut *save.borrow_mut();

    let mut BSIGHT = DummyArrayMut::new(BSIGHT, 1..=3);
    let mut BOUNDS = DummyArrayMut2D::new(BOUNDS, 1..=3, 1..);
    let mut ANGUNT = [b' '; VALLEN as usize];
    let mut KWAUNT = [b' '; KWDNLN as usize];
    let mut KWBORE = [b' '; KWDNLN as usize];
    let mut KWBOUN = [b' '; KWDNLN as usize];
    let mut KWCANG = [b' '; KWDNLN as usize];
    let mut KWFRAM = [b' '; KWDNLN as usize];
    let mut KWORD = [b' '; KWDNLN as usize];
    let mut KWRANG = [b' '; KWDNLN as usize];
    let mut KWRVEC = [b' '; KWDNLN as usize];
    let mut KWSHAP = [b' '; KWDNLN as usize];
    let mut KWSPEC = [b' '; KWDNLN as usize];
    let mut SPEC = [b' '; VALLEN as usize];
    let mut TYPE = [b' '; 1 as usize];
    let mut B = StackArray::<f64, 3>::new(1..=3);
    let mut B1 = StackArray::<f64, 3>::new(1..=3);
    let mut B2 = StackArray::<f64, 3>::new(1..=3);
    let mut BMAG: f64 = 0.0;
    let mut COSCAN: f64 = 0.0;
    let mut COSRAN: f64 = 0.0;
    let mut CRSANG: f64 = 0.0;
    let mut NORMAL = StackArray2D::<f64, 12>::new(1..=3, 1..=MAXNML);
    let mut REFANG: f64 = 0.0;
    let mut REFVEC = StackArray::<f64, 3>::new(1..=3);
    let mut SINCAN: f64 = 0.0;
    let mut SINRAN: f64 = 0.0;
    let mut TMPANG: f64 = 0.0;
    let mut TMPVEC = StackArray::<f64, 3>::new(1..=3);
    let mut VMAG: f64 = 0.0;
    let mut I: i32 = 0;
    let mut MXCMP: i32 = 0;
    let mut FOUND: bool = false;

    //
    // SPICELIB functions
    //

    //
    // Local parameters
    //

    //
    // Keyword Name Length.
    //

    //
    // Maximum Number of Normal Vectors.
    //

    //
    // Number of CORNER Shapes Supported.
    //

    //
    // Number of ANGLE Shapes Supported.
    //

    //
    // Maximum Length of String Data from the kernel pool.
    //

    //
    // Local variables
    //

    //
    // Allowed values of shape identifier. Note that these must be
    // supplied in ascending order
    //

    //
    // Allowed values of the shape identifier for the ANGLES
    // specification.  Note that these must be supplied in ascending
    // order.
    //

    //
    // Standard SPICE error handling.
    //
    if RETURN(ctx) {
        return Ok(());
    }

    CHKIN(b"GETFOV", ctx)?;

    fstr::assign(&mut KWBOUN, b"INS#_FOV_BOUNDARY");
    fstr::assign(&mut KWBORE, b"INS#_BORESIGHT");
    fstr::assign(&mut KWSHAP, b"INS#_FOV_SHAPE");
    fstr::assign(&mut KWFRAM, b"INS#_FOV_FRAME");
    fstr::assign(&mut KWSPEC, b"INS#_FOV_CLASS_SPEC");
    fstr::assign(&mut KWRVEC, b"INS#_FOV_REF_VECTOR");
    fstr::assign(&mut KWRANG, b"INS#_FOV_REF_ANGLE");
    fstr::assign(&mut KWCANG, b"INS#_FOV_CROSS_ANGLE");
    fstr::assign(&mut KWAUNT, b"INS#_FOV_ANGLE_UNITS");

    MXCMP = (3 * ROOM);

    //
    // Look for the frame keyword and get frame name if found,
    // complain if not.
    //
    REPMI(&KWFRAM, b"#", INSTID, &mut KWORD, ctx);
    GCPOOL(
        &KWORD,
        1,
        1,
        &mut I,
        CharArrayMut::from_mut(FRAME),
        &mut FOUND,
        ctx,
    )?;

    if !FOUND {
        SETMSG(b"The variable, \'#\', specifying the frame which instrument # FOV components are defined relative to was not found in the kernel pool. Check whether IK file for the instrument was loaded into the program and whether this variable is specified in that file.", ctx);
        ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
        ERRINT(b"#", INSTID, ctx);
        SIGERR(b"SPICE(FRAMEMISSING)", ctx)?;
        CHKOUT(b"GETFOV", ctx)?;
        return Ok(());
    }

    //
    // Look for the shape keyword and get shape identifier if found,
    // complain if not.
    //
    REPMI(&KWSHAP, b"#", INSTID, &mut KWORD, ctx);
    GCPOOL(
        &KWORD,
        1,
        1,
        &mut I,
        CharArrayMut::from_mut(SHAPE),
        &mut FOUND,
        ctx,
    )?;

    if !FOUND {
        SETMSG(b"The variable, \'#\', specifying the shape of the instrument # FOV was not found in the kernel pool. Check whether IK file for the instrument was loaded into the program and whether this variable is specified in that file.", ctx);
        ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
        ERRINT(b"#", INSTID, ctx);
        SIGERR(b"SPICE(SHAPEMISSING)", ctx)?;
        CHKOUT(b"GETFOV", ctx)?;
        return Ok(());
    }

    //
    // Create an upper case, left justified value for SHAPE.  This will
    // provide the desired case-insensitivity to the keyword value.
    //
    UCASE(&SHAPE.to_vec(), SHAPE, ctx);
    LJUST(&SHAPE.to_vec(), SHAPE);

    //
    // Check whether shape identified that we got is one from the list
    // of supported, complain if not.
    //
    if (BSRCHC(
        fstr::substr(SHAPE, 1..=RTRIM(SHAPE)),
        NSHAPS,
        save.SHAPID.as_arg(),
    ) == 0)
    {
        SETMSG(b"The FOV shape, \'#\', specified in the keyword, \'#\', for the instrument # is not supported. See GETFOV subroutine header for the list of supported instrument FOV shapes.", ctx);
        ERRCH(b"#", fstr::substr(SHAPE, 1..=RTRIM(SHAPE)), ctx);
        ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
        ERRINT(b"#", INSTID, ctx);
        SIGERR(b"SPICE(SHAPENOTSUPPORTED)", ctx)?;
        CHKOUT(b"GETFOV", ctx)?;
        return Ok(());
    }

    //
    // Look for the boresight keyword and get boresight vector if found,
    // complain if not.
    //
    REPMI(&KWBORE, b"#", INSTID, &mut KWORD, ctx);
    DTPOOL(&KWORD, &mut FOUND, &mut I, &mut TYPE, ctx)?;

    if !FOUND {
        SETMSG(b"The variable, \'#\', specifying the boresight of the instrument # was not found in the kernel pool. Check whether IK file for the instrument was loaded into the program and whether this variable is specified in that file.", ctx);
        ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
        ERRINT(b"#", INSTID, ctx);
        SIGERR(b"SPICE(BORESIGHTMISSING)", ctx)?;
        CHKOUT(b"GETFOV", ctx)?;
        return Ok(());
    }

    //
    // Check whether boresight specified by three coordinates;
    // complain if not.
    //
    if (I != 3) {
        SETMSG(b"The number of the boresight vector components specified in the \'#\' variable is not 3, it is #. Correct it in the corresponding IK file to be a 3-dimensional vector. ", ctx);
        ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
        ERRINT(b"#", I, ctx);
        SIGERR(b"SPICE(BADBORESIGHTSPEC)", ctx)?;
        CHKOUT(b"GETFOV", ctx)?;
        return Ok(());
    } else if fstr::ne(&TYPE, b"N") {
        SETMSG(b"The boresight vector, stored in the \'#\' variable, has not been stored as a vector of three numbers.  It has been stored as a vector of three strings. ", ctx);
        ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
        SIGERR(b"SPICE(BADBORESIGHTSPEC)", ctx)?;
        CHKOUT(b"GETFOV", ctx)?;
        return Ok(());
    }

    GDPOOL(&KWORD, 1, 3, &mut I, BSIGHT.as_slice_mut(), &mut FOUND, ctx)?;

    //
    // Check whether boresight is a zero vector; complain if it is.
    //
    if VZERO(BSIGHT.as_slice()) {
        SETMSG(
            b"The boresight vector, stored in the \'#\' variable, is the zero vector.",
            ctx,
        );
        ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
        SIGERR(b"SPICE(ZEROBORESIGHT)", ctx)?;
        CHKOUT(b"GETFOV", ctx)?;
        return Ok(());
    }

    //
    // At this point we have gotten all the specification independent
    // information.  Now check for the presence of the FOV class
    // specification keyword.  If it's absent, we default to CORNERS.
    //
    fstr::assign(&mut SPEC, b"CORNERS");

    REPMI(&KWSPEC, b"#", INSTID, &mut KWORD, ctx);
    GCPOOL(
        &KWORD,
        1,
        1,
        &mut I,
        CharArrayMut::from_mut(&mut SPEC),
        &mut FOUND,
        ctx,
    )?;

    if EQSTR(b"CORNERS", &SPEC) {
        //
        // Look for the FOV boundary vectors, check whether output array
        // is big enough to hold them; complain if not.
        //
        REPMI(&KWBOUN, b"#", INSTID, &mut KWORD, ctx);
        DTPOOL(&KWORD, &mut FOUND, N, &mut TYPE, ctx)?;

        if !FOUND {
            SUFFIX(b"_CORNERS", 0, &mut KWORD);
            DTPOOL(&KWORD, &mut FOUND, N, &mut TYPE, ctx)?;
        }

        if !FOUND {
            REPMI(&KWBOUN, b"#", INSTID, &mut KWORD, ctx);
            SETMSG(b"The variable, \'#\', specifying the boundary vectors of the instrument # FOV was not found in the kernel pool. Check whether IK file for the instrument was loaded into the program and whether this variable is specified in that file.", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            ERRINT(b"#", INSTID, ctx);
            SIGERR(b"SPICE(BOUNDARYMISSING)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }

        //
        // Check whether we have enough room to get all boundary vectors,
        // complain if not.
        //
        if (*N > MXCMP) {
            SETMSG(b"The number of boundary vector components specified in the \'#\' pool variable is bigger than room to hold them in output array specified by the ROOM input variable of the GETFOV subroutine.", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            SIGERR(b"SPICE(BOUNDARYTOOBIG)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }

        //
        // Check whether number of boundary components can be divided by 3
        // without reminder.
        //
        if (intrinsics::MOD(*N, 3) != 0) {
            SETMSG(b"The boundary vector components specified in the \'#\' pool variable do  not represent a set of 3-dimensional vectors. Number of components assigned to the variable cannot be divided by 3 without reminder. ", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            SIGERR(b"SPICE(BADBOUNDARY)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }

        //
        // Boundaries are OK. Get them.
        //
        GDPOOL(&KWORD, 1, MXCMP, N, BOUNDS.as_slice_mut(), &mut FOUND, ctx)?;

        *N = (*N / 3);

        if (fstr::eq(SHAPE, b"CIRCLE") && (*N != 1)) {
            SETMSG(b"The boundary is specified to be circular, and as such, the values associated with keyword, \'#\', should contain one vector.  There are #.", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            ERRINT(b"#", *N, ctx);
            SIGERR(b"SPICE(BADBOUNDARY)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        } else if (fstr::eq(SHAPE, b"ELLIPSE") && (*N != 2)) {
            SETMSG(b"The boundary is specified to be elliptical, and as such, the values associated with keyword, \'#\', should contain two vectors.  There are #.", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            ERRINT(b"#", *N, ctx);
            SIGERR(b"SPICE(BADBOUNDARY)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        } else if (fstr::eq(SHAPE, b"RECTANGLE") && (*N != 4)) {
            SETMSG(b"The boundary is specified to be rectangular, and as such, the values associated with keyword, \'#\', should contain four vectors.  There are #.", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            ERRINT(b"#", *N, ctx);
            SIGERR(b"SPICE(BADBOUNDARY)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        } else if (fstr::eq(SHAPE, b"POLYGON") && (*N < 3)) {
            SETMSG(b"The boundary is specified to be polygonal, and as such, the values associated with keyword, \'#\', should contain at least three vectors.  There are #.", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            ERRINT(b"#", *N, ctx);
            SIGERR(b"SPICE(BADBOUNDARY)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }

    //
    // Now check to see if the FOV specification is ANGLES and
    // compute the boundary corner vectors.
    //
    } else if EQSTR(b"ANGLES", &SPEC) {
        //
        // Check whether shape identified that we got is one from the list
        // of supported shapes for the ANGLE specification; complain
        // if not.
        //
        if (BSRCHC(
            fstr::substr(SHAPE, 1..=RTRIM(SHAPE)),
            NUMASP,
            save.ANGSHP.as_arg(),
        ) == 0)
        {
            SETMSG(b"The FOV shape, \'#\', specified in the keyword, \'#\', for the instrument # is not supported for the ANGLES specification.", ctx);
            ERRCH(b"#", fstr::substr(SHAPE, 1..=RTRIM(SHAPE)), ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            ERRINT(b"#", INSTID, ctx);
            SIGERR(b"SPICE(SHAPENOTSUPPORTED)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }

        //
        // Now fetch all of the elements independent of shape from the
        // ANGLES specification.  Start by looking for the reference
        // vector keyword.  If found, fetch it otherwise complain.
        //
        REPMI(&KWRVEC, b"#", INSTID, &mut KWORD, ctx);
        DTPOOL(&KWORD, &mut FOUND, &mut I, &mut TYPE, ctx)?;

        if !FOUND {
            SETMSG(b"The variable, \'#\', specifying the FOV reference vector of the instrument # was not found in the kernel pool. Check whether IK file for the instrument was loaded into the program and whether this variable is specified in that file.", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            ERRINT(b"#", INSTID, ctx);
            SIGERR(b"SPICE(REFVECTORMISSING)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }

        //
        // Now check whether reference vector is specified by three
        // coordinates; complain if not.
        //
        if (I != 3) {
            SETMSG(b"The number of the reference vector components specified in the \'#\' keyword is not 3, it is #. Check the corresponding IK FOV definition for errors.", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            ERRINT(b"#", I, ctx);
            SIGERR(b"SPICE(BADREFVECTORSPEC)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        } else if fstr::ne(&TYPE, b"N") {
            SETMSG(b"The reference vector, stored in \'#\', has not been stored as a vector of three numbers.  It has been stored as a vector of three strings. ", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            SIGERR(b"SPICE(BADREFVECTORSPEC)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }

        GDPOOL(&KWORD, 1, 3, &mut I, REFVEC.as_slice_mut(), &mut FOUND, ctx)?;

        //
        // We require that the reference vector is not parallel
        // to the boresight vector. Use NORMAL(1,1) to temporarily
        // store the result of the cross product.
        //
        VCRSS(
            BSIGHT.as_slice(),
            REFVEC.as_slice(),
            NORMAL.subarray_mut([1, 1]),
        );

        if (VNORM(NORMAL.subarray([1, 1])) == 0.0) {
            SETMSG(b"The reference vector, stored in \'#\', is parallel to the instrument boresight vector.  This is not allowed by the ANGLES FOV specification.", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            SIGERR(b"SPICE(BADREFVECTORSPEC)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }

        //
        // Retrieve the reference angle from the kernel pool.
        //
        REPMI(&KWRANG, b"#", INSTID, &mut KWORD, ctx);
        GDPOOL(
            &KWORD,
            1,
            1,
            &mut I,
            std::slice::from_mut(&mut REFANG),
            &mut FOUND,
            ctx,
        )?;

        if !FOUND {
            SETMSG(b"The variable, \'#\', specifying the reference angle which describes instrument # FOV angular extent was not found in the kernel pool. Check whether IK file for the instrument was loaded into the program and whether this variable is specified in that file.", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            ERRINT(b"#", INSTID, ctx);
            SIGERR(b"SPICE(REFANGLEMISSING)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }

        //
        // Retrieve the angle units from the kernel pool.
        //
        REPMI(&KWAUNT, b"#", INSTID, &mut KWORD, ctx);
        GCPOOL(
            &KWORD,
            1,
            1,
            &mut I,
            CharArrayMut::from_mut(&mut ANGUNT),
            &mut FOUND,
            ctx,
        )?;

        if !FOUND {
            SETMSG(b"The variable, \'#\', specifying the angular units in which instrument # FOV extent is defined was not found in the kernel pool. Check whether IK file for the instrument was loaded into the program and whether this variable is specified in that file.", ctx);
            ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
            ERRINT(b"#", INSTID, ctx);
            SIGERR(b"SPICE(UNITSMISSING)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }

        //
        // Convert the reference angle to radians.
        //
        CONVRT(REFANG, &ANGUNT, b"RADIANS", &mut TMPANG, ctx)?;

        if FAILED(ctx) {
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }

        REFANG = TMPANG;

        //
        // Branch to shape specific code.
        //
        if fstr::eq(SHAPE, b"CIRCLE") {
            //
            // First check to see that the caller left enough room
            // to store the required number of boundary corner
            // vectors.
            //
            if (ROOM < 1) {
                SETMSG(b"The FOV shape for instrument # is specified to be circular.  There should be room for at least one boundary vector.  There is room for #. ", ctx);
                ERRINT(b"#", INSTID, ctx);
                ERRINT(b"#", ROOM, ctx);
                SIGERR(b"SPICE(BOUNDARYTOOBIG)", ctx)?;
                CHKOUT(b"GETFOV", ctx)?;
                return Ok(());
            }

            //
            // The plan to compute the boundary corner vector is to
            // rotate the BSIGHT by REFANG towards REFVEC.  To do
            // this first compute the axis we need to rotate about.
            //
            VCRSS(
                BSIGHT.as_slice(),
                REFVEC.as_slice(),
                NORMAL.subarray_mut([1, 1]),
            );

            //
            // Now rotate by REFANG about NORMAL(1,1) using the routine
            // VROTV.
            //
            VROTV(
                BSIGHT.as_slice(),
                NORMAL.subarray([1, 1]),
                REFANG,
                BOUNDS.subarray_mut([1, 1]),
            );

            //
            // Lastly, since we computed a single boundary corner vector,
            // set N = 1.
            //
            *N = 1;
        } else if fstr::eq(SHAPE, b"ELLIPSE") {
            //
            // The elliptical case requires the additional cross angle
            // keyword's presence in the kernel pool. Attempt to
            // retrieve it.
            //
            REPMI(&KWCANG, b"#", INSTID, &mut KWORD, ctx);
            GDPOOL(
                &KWORD,
                1,
                1,
                &mut I,
                std::slice::from_mut(&mut CRSANG),
                &mut FOUND,
                ctx,
            )?;

            if !FOUND {
                SETMSG(b"The variable, \'#\', specifying the cross angle which describes instrument # FOV angular extent was not found in the kernel pool. Check whether IK file for the instrument was loaded into the program and whether this variable is specified in that file.", ctx);
                ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
                ERRINT(b"#", INSTID, ctx);
                SIGERR(b"SPICE(CROSSANGLEMISSING)", ctx)?;
                CHKOUT(b"GETFOV", ctx)?;
                return Ok(());
            }

            //
            // Convert the cross angle to radians.
            //
            CONVRT(CRSANG, &ANGUNT, b"RADIANS", &mut TMPANG, ctx)?;

            if FAILED(ctx) {
                CHKOUT(b"GETFOV", ctx)?;
                return Ok(());
            }

            CRSANG = TMPANG;
            //
            // Now check to see that the caller left enough room
            // to store the required number of boundary corner
            // vectors.
            //
            if (ROOM < 2) {
                SETMSG(b"The FOV shape for instrument # is specified to be elliptical.  There should be room for at least two boundary vectors.  There is room for #. ", ctx);
                ERRINT(b"#", INSTID, ctx);
                ERRINT(b"#", ROOM, ctx);
                SIGERR(b"SPICE(BOUNDARYTOOBIG)", ctx)?;
                CHKOUT(b"GETFOV", ctx)?;
                return Ok(());
            }

            //
            // The plan to compute the first boundary corner vector is
            // to rotate the BSIGHT by REFANG towards REFVEC.  To
            // do this first compute the axis we need to rotate about.
            //
            VCRSS(
                BSIGHT.as_slice(),
                REFVEC.as_slice(),
                NORMAL.subarray_mut([1, 1]),
            );

            //
            // Now rotate by REFANG about NORMAL(1,1) using the routine
            // VROTV.
            //
            VROTV(
                BSIGHT.as_slice(),
                NORMAL.subarray([1, 1]),
                REFANG,
                BOUNDS.subarray_mut([1, 1]),
            );

            //
            // At this point we have one boundary vector.  We need the
            // second and final one.  The strategy we will use is the
            // following: rotate BSIGHT by CRSANG towards NORMAL(1,1).
            // This will give us boundary corner vectors listed in a
            // counter-clockwise fashion about the boresight.
            //
            VCRSS(
                BSIGHT.as_slice(),
                NORMAL.subarray([1, 1]),
                TMPVEC.as_slice_mut(),
            );
            VEQU(TMPVEC.as_slice(), NORMAL.subarray_mut([1, 2]));
            //
            // Now rotate BSIGHT by CRSANG about the NORMAL(1,2) using
            // the routine VROTV.
            //
            VROTV(
                BSIGHT.as_slice(),
                NORMAL.subarray([1, 2]),
                CRSANG,
                BOUNDS.subarray_mut([1, 2]),
            );

            //
            // Lastly, since we computed two boundary corner vectors,
            // set N = 2.
            //
            *N = 2;
        } else if fstr::eq(SHAPE, b"RECTANGLE") {
            //
            // The rectangular case requires the additional cross angle
            // keyword's presence in the kernel pool. Attempt to
            // retrieve it.
            //
            REPMI(&KWCANG, b"#", INSTID, &mut KWORD, ctx);
            GDPOOL(
                &KWORD,
                1,
                1,
                &mut I,
                std::slice::from_mut(&mut CRSANG),
                &mut FOUND,
                ctx,
            )?;

            if !FOUND {
                SETMSG(b"The variable, \'#\', specifying the cross angle which describes instrument # FOV angular extent was not found in the kernel pool. Check whether IK file for the instrument was loaded into the program and whether this variable is specified in that file.", ctx);
                ERRCH(b"#", fstr::substr(&KWORD, 1..=RTRIM(&KWORD)), ctx);
                ERRINT(b"#", INSTID, ctx);
                SIGERR(b"SPICE(CROSSANGLEMISSING)", ctx)?;
                CHKOUT(b"GETFOV", ctx)?;
                return Ok(());
            }

            //
            // Convert the cross angle to radians.
            //
            CONVRT(CRSANG, &ANGUNT, b"RADIANS", &mut TMPANG, ctx)?;

            if FAILED(ctx) {
                CHKOUT(b"GETFOV", ctx)?;
                return Ok(());
            }

            CRSANG = TMPANG;
            //
            // Now check to see that the caller left enough room
            // to store the required number of boundary corner
            // vectors.
            //
            if (ROOM < 4) {
                SETMSG(b"The FOV shape for instrument # is specified to be rectangular.  There should be room for at least four boundary vectors.  There is room for #. ", ctx);
                ERRINT(b"#", INSTID, ctx);
                ERRINT(b"#", ROOM, ctx);
                SIGERR(b"SPICE(BOUNDARYTOOBIG)", ctx)?;
                CHKOUT(b"GETFOV", ctx)?;
                return Ok(());
            }

            //
            // Here's the general strategy laid out in simple terms:
            //
            // (1) Normalize BSIGHT, label it B.
            //
            // (2) Compute the unit vector in the plane defined by REFVEC
            //     and B that is normal to B and pointing towards
            //     REFVEC, label this B1.
            //
            // (3) Cross B and B1 to obtain B2. These three vectors
            //     form a basis that is 'aligned' with the FOV cone.
            //
            // (4) Compute the inward normals to the sides of the
            //     rectangular cone in a counter-clockwise order
            //     about the boresight:
            //
            //       NORMAL(1) = -COS(REFANG)*B1 + SIN(REFANG)*B
            //       NORMAL(2) = -COS(CRSANG)*B2 + SIN(CRSANG)*B
            //       NORMAL(3) =  COS(REFANG)*B1 + SIN(REFANG)*B
            //       NORMAL(4) =  COS(CRSANG)*B2 + SIN(CRSANG)*B
            //
            // (5) Compute the appropriate cross products to obtain
            //     a set of boundary corner vectors:
            //
            //       BOUNDS(1) = NORMAL(1) x NORMAL(2)
            //       BOUNDS(2) = NORMAL(2) x NORMAL(3)
            //       BOUNDS(3) = NORMAL(3) x NORMAL(4)
            //       BOUNDS(4) = NORMAL(4) x NORMAL(1)
            //
            // (6) Unitize and scale BOUNDS to match the length
            //     of the BSIGHT.
            //
            // Start with step (1).
            //
            UNORM(BSIGHT.as_slice(), B.as_slice_mut(), &mut BMAG);

            //
            // Now proceed to (2). Since we already know that REFVEC
            // and BSIGHT are not parallel, the following yields a
            // non-zero vector:
            //
            VPERP(REFVEC.as_slice(), BSIGHT.as_slice(), B1.as_slice_mut());

            //
            // Unitize B1.
            //
            VHAT(B1.as_slice(), TMPVEC.as_slice_mut());
            VEQU(TMPVEC.as_slice(), B1.as_slice_mut());

            //
            // Step (3), compute B2 by crossing B and B1.
            //
            VCRSS(B.as_slice(), B1.as_slice(), B2.as_slice_mut());

            //
            // Before proceeding onto step (4), verify that the
            // results of the calculations in step (4) will make
            // sense.  Check the cosines of CRSANG and REFANG.
            // Signal an error if both are not positive numbers.
            // Use MINCOS as a tolerance.
            //
            COSRAN = f64::cos(REFANG);
            COSCAN = f64::cos(CRSANG);

            if ((COSRAN < MINCOS) || (COSCAN < MINCOS)) {
                SETMSG(b"The angular extents specified in the FOV definition for instrument # result in degenerate or improper boundary corner vectors. This usually happens when one (or both) of the angles results in the angular separation between the boresight and the FOV side plane that it defines being equal to or greater than 90 degrees.", ctx);
                ERRINT(b"#", INSTID, ctx);
                SIGERR(b"SPICE(BADBOUNDARY)", ctx)?;
                CHKOUT(b"GETFOV", ctx)?;
                return Ok(());
            }

            //
            // Compute the NORMAL vectors to complete step (4).
            //
            SINRAN = f64::sin(REFANG);
            SINCAN = f64::sin(CRSANG);

            VLCOM(
                -COSRAN,
                B1.as_slice(),
                SINRAN,
                B.as_slice(),
                NORMAL.subarray_mut([1, 1]),
            );
            VLCOM(
                -COSCAN,
                B2.as_slice(),
                SINCAN,
                B.as_slice(),
                NORMAL.subarray_mut([1, 2]),
            );
            VLCOM(
                COSRAN,
                B1.as_slice(),
                SINRAN,
                B.as_slice(),
                NORMAL.subarray_mut([1, 3]),
            );
            VLCOM(
                COSCAN,
                B2.as_slice(),
                SINCAN,
                B.as_slice(),
                NORMAL.subarray_mut([1, 4]),
            );

            //
            // We are almost finished. Compute the boundary corner
            // vectors completing step (5).
            //
            VCRSS(
                NORMAL.subarray([1, 1]),
                NORMAL.subarray([1, 2]),
                BOUNDS.subarray_mut([1, 1]),
            );
            VCRSS(
                NORMAL.subarray([1, 2]),
                NORMAL.subarray([1, 3]),
                BOUNDS.subarray_mut([1, 2]),
            );
            VCRSS(
                NORMAL.subarray([1, 3]),
                NORMAL.subarray([1, 4]),
                BOUNDS.subarray_mut([1, 3]),
            );
            VCRSS(
                NORMAL.subarray([1, 4]),
                NORMAL.subarray([1, 1]),
                BOUNDS.subarray_mut([1, 4]),
            );

            //
            // Step (6), normalize the boundary corner vectors
            // and scale by BMAG, the magnitude of BSIGHT.
            //
            {
                let m1__: i32 = 1;
                let m2__: i32 = 4;
                let m3__: i32 = 1;
                I = m1__;
                for _ in 0..((m2__ - m1__ + m3__) / m3__) as i32 {
                    UNORM(BOUNDS.subarray([1, I]), TMPVEC.as_slice_mut(), &mut VMAG);
                    VSCL(BMAG, TMPVEC.as_slice(), BOUNDS.subarray_mut([1, I]));

                    I += m3__;
                }
            }

            //
            // Lastly since we are returning 4 boundary corner vectors,
            // set N = 4.
            //
            *N = 4;
        } else {
            //
            // If we end up here something is terribly wrong with
            // this module or SPICE in general.
            //
            SETMSG(b"This error is never supposed to occur. We have an undefined shape for the ANGLES specification that passed the shape check.", ctx);
            SIGERR(b"SPICE(BUG)", ctx)?;
            CHKOUT(b"GETFOV", ctx)?;
            return Ok(());
        }
    } else {
        SETMSG(b"The FOV class specification is set to \'#\' which is currently unsupported. See the GETFOV subroutine header for more information.", ctx);
        ERRCH(b"#", &SPEC, ctx);
        SIGERR(b"SPICE(UNSUPPORTEDSPEC)", ctx)?;
        CHKOUT(b"GETFOV", ctx)?;
        return Ok(());
    }

    //
    // Standard SPICE error handling.
    //
    CHKOUT(b"GETFOV", ctx)?;
    Ok(())
}