h3Index.h File Reference

H3Index functions. More...

#include "QueryEngine/ExtensionFunctions/h3lib/include/faceijk.h"
#include "QueryEngine/ExtensionFunctions/h3lib/include/h3api.h"
#include "QueryEngine/ExtensionFunctions/h3lib/lib/h3Index.hpp"

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Macros
#define	H3_NUM_BITS   64
#define	H3_MAX_OFFSET   63
#define	H3_MODE_OFFSET   59
#define	H3_BC_OFFSET   45
#define	H3_RES_OFFSET   52
#define	H3_RESERVED_OFFSET   56
#define	H3_PER_DIGIT_OFFSET   3
#define	H3_HIGH_BIT_MASK   ((uint64_t)(1) << H3_MAX_OFFSET)
#define	H3_HIGH_BIT_MASK_NEGATIVE   (~H3_HIGH_BIT_MASK)
#define	H3_MODE_MASK   ((uint64_t)(15) << H3_MODE_OFFSET)
#define	H3_MODE_MASK_NEGATIVE   (~H3_MODE_MASK)
#define	H3_BC_MASK   ((uint64_t)(127) << H3_BC_OFFSET)
#define	H3_BC_MASK_NEGATIVE   (~H3_BC_MASK)
#define	H3_RES_MASK   (UINT64_C(15) << H3_RES_OFFSET)
#define	H3_RES_MASK_NEGATIVE   (~H3_RES_MASK)
#define	H3_RESERVED_MASK   ((uint64_t)(7) << H3_RESERVED_OFFSET)
#define	H3_RESERVED_MASK_NEGATIVE   (~H3_RESERVED_MASK)
#define	H3_DIGIT_MASK   ((uint64_t)(7))
#define	H3_DIGIT_MASK_NEGATIVE   (~H3_DIGIT_MASK)
#define	H3_INIT   (UINT64_C(35184372088831))
#define	H3_GET_HIGH_BIT(h3)   ((int)((((h3)&H3_HIGH_BIT_MASK) >> H3_MAX_OFFSET)))
#define	H3_SET_HIGH_BIT(h3, v)   (h3) = (((h3)&H3_HIGH_BIT_MASK_NEGATIVE) | (((uint64_t)(v)) << H3_MAX_OFFSET))
#define	H3_GET_MODE(h3)   ((int)((((h3)&H3_MODE_MASK) >> H3_MODE_OFFSET)))
#define	H3_SET_MODE(h3, v)   (h3) = (((h3)&H3_MODE_MASK_NEGATIVE) | (((uint64_t)(v)) << H3_MODE_OFFSET))
#define	H3_GET_BASE_CELL(h3)   ((int)((((h3)&H3_BC_MASK) >> H3_BC_OFFSET)))
#define	H3_SET_BASE_CELL(h3, bc)   (h3) = (((h3)&H3_BC_MASK_NEGATIVE) | (((uint64_t)(bc)) << H3_BC_OFFSET))
#define	H3_GET_RESOLUTION(h3)   ((int)((((h3)&H3_RES_MASK) >> H3_RES_OFFSET)))
#define	H3_SET_RESOLUTION(h3, res)   (h3) = (((h3)&H3_RES_MASK_NEGATIVE) | (((uint64_t)(res)) << H3_RES_OFFSET))
#define	H3_GET_INDEX_DIGIT(h3, res)   ((Direction)((((h3) >> ((MAX_H3_RES - (res)) * H3_PER_DIGIT_OFFSET)) & H3_DIGIT_MASK)))
#define	H3_SET_RESERVED_BITS(h3, v)   (h3) = (((h3)&H3_RESERVED_MASK_NEGATIVE) | (((uint64_t)(v)) << H3_RESERVED_OFFSET))
#define	H3_GET_RESERVED_BITS(h3)   ((int)((((h3)&H3_RESERVED_MASK) >> H3_RESERVED_OFFSET)))
#define	H3_SET_INDEX_DIGIT(h3, res, digit)
#define	H3_NULL   0
#define	COMPACT_SUCCESS   0
#define	COMPACT_LOOP_EXCEEDED   -1
#define	COMPACT_DUPLICATE   -2
#define	COMPACT_ALLOC_FAILED   -3

Functions
EXTENSION_NOINLINE H3Index	_faceIjkToH3 (const FaceIJK(fijk), int res)
EXTENSION_INLINE int	_h3LeadingNonZeroDigit (H3Index h)
EXTENSION_NOINLINE H3Index	_h3RotatePent60ccw (H3Index h)
EXTENSION_NOINLINE H3Index	_h3RotatePent60cw (H3Index h)
EXTENSION_NOINLINE H3Index	_h3Rotate60ccw (H3Index h)
EXTENSION_NOINLINE H3Index	_h3Rotate60cw (H3Index h)
EXTENSION_NOINLINE int	_h3ToFaceIjkWithInitializedFijk (H3Index h, FaceIJK(fijk))
EXTENSION_NOINLINE bool	_h3ToFaceIjk (H3Index h, FaceIJK(fijk))
EXTENSION_NOINLINE bool	_h3ToGeo (H3Index h3, GeoCoord(g))

Detailed Description

H3Index functions.

Definition in file h3Index.h.

Macro Definition Documentation

#define COMPACT_ALLOC_FAILED   -3

Definition at line 174 of file h3Index.h.

#define COMPACT_DUPLICATE   -2

Definition at line 173 of file h3Index.h.

#define COMPACT_LOOP_EXCEEDED   -1

Definition at line 172 of file h3Index.h.

#define COMPACT_SUCCESS   0

Definition at line 171 of file h3Index.h.

#define H3_BC_MASK   ((uint64_t)(127) << H3_BC_OFFSET)

1's in the 7 base cell bits, 0's everywhere else.

Definition at line 62 of file h3Index.h.

#define H3_BC_MASK_NEGATIVE   (~H3_BC_MASK)

0's in the 7 base cell bits, 1's everywhere else.

Definition at line 65 of file h3Index.h.

#define H3_BC_OFFSET   45

The bit offset of the base cell in an H3 index.

Definition at line 38 of file h3Index.h.

#define H3_DIGIT_MASK   ((uint64_t)(7))

1's in the 3 bits of res 15 digit bits, 0's everywhere else.

Definition at line 80 of file h3Index.h.

Referenced by h3ToParent().

#define H3_DIGIT_MASK_NEGATIVE   (~H3_DIGIT_MASK)

0's in the 7 base cell bits, 1's everywhere else.

Definition at line 83 of file h3Index.h.

#define H3_GET_BASE_CELL

(

h3

)

((int)((((h3)&H3_BC_MASK) >> H3_BC_OFFSET)))

Gets the integer base cell of h3.

Definition at line 117 of file h3Index.h.

Referenced by _h3ToFaceIjk(), and _h3ToFaceIjkWithInitializedFijk().

#define H3_GET_HIGH_BIT

(

h3

)

((int)((((h3)&H3_HIGH_BIT_MASK) >> H3_MAX_OFFSET)))

Gets the highest bit of the H3 index.

Definition at line 95 of file h3Index.h.

#define H3_GET_INDEX_DIGIT	(		h3,
			res
	)		((Direction)((((h3) >> ((MAX_H3_RES - (res)) * H3_PER_DIGIT_OFFSET)) & H3_DIGIT_MASK)))

Gets the resolution res integer digit (0-7) of h3.

Definition at line 139 of file h3Index.h.

Referenced by _h3LeadingNonZeroDigit(), _h3Rotate60ccw(), _h3Rotate60cw(), _h3RotatePent60ccw(), _h3RotatePent60cw(), and _h3ToFaceIjkWithInitializedFijk().

#define H3_GET_MODE

(

h3

)

((int)((((h3)&H3_MODE_MASK) >> H3_MODE_OFFSET)))

Gets the integer mode of h3.

Definition at line 106 of file h3Index.h.

#define H3_GET_RESERVED_BITS

(

h3

)

((int)((((h3)&H3_RESERVED_MASK) >> H3_RESERVED_OFFSET)))

Gets a value in the reserved space. Should always be zero for valid indexes.

Definition at line 152 of file h3Index.h.

#define H3_GET_RESOLUTION

(

h3

)

((int)((((h3)&H3_RES_MASK) >> H3_RES_OFFSET)))

Gets the integer resolution of h3.

Definition at line 128 of file h3Index.h.

Referenced by _h3LeadingNonZeroDigit(), _h3Rotate60ccw(), _h3Rotate60cw(), _h3RotatePent60ccw(), _h3RotatePent60cw(), _h3ToFaceIjk(), _h3ToFaceIjkWithInitializedFijk(), _h3ToGeo(), and h3ToParent().

#define H3_HIGH_BIT_MASK   ((uint64_t)(1) << H3_MAX_OFFSET)

1 in the highest bit, 0's everywhere else.

Definition at line 50 of file h3Index.h.

#define H3_HIGH_BIT_MASK_NEGATIVE   (~H3_HIGH_BIT_MASK)

0 in the highest bit, 1's everywhere else.

Definition at line 53 of file h3Index.h.

#define H3_INIT   (UINT64_C(35184372088831))

H3 index with mode 0, res 0, base cell 0, and 7 for all index digits. Typically used to initialize the creation of an H3 cell index, which expects all direction digits to be 7 beyond the cell's resolution.

Definition at line 90 of file h3Index.h.

Referenced by _faceIjkToH3().

#define H3_MAX_OFFSET   63

The bit offset of the max resolution digit in an H3 index.

Definition at line 32 of file h3Index.h.

#define H3_MODE_MASK   ((uint64_t)(15) << H3_MODE_OFFSET)

1's in the 4 mode bits, 0's everywhere else.

Definition at line 56 of file h3Index.h.

#define H3_MODE_MASK_NEGATIVE   (~H3_MODE_MASK)

0's in the 4 mode bits, 1's everywhere else.

Definition at line 59 of file h3Index.h.

#define H3_MODE_OFFSET   59

The bit offset of the mode in an H3 index.

Definition at line 35 of file h3Index.h.

#define H3_NULL   0

Invalid index used to indicate an error from geoToH3 and related functions or missing data in arrays of h3 indices. Analogous to NaN in floating point.

Definition at line 165 of file h3Index.h.

Referenced by _faceIjkToH3(), geoToH3(), and h3ToParent().

#define H3_NUM_BITS   64

The number of bits in an H3 index.

Definition at line 29 of file h3Index.h.

#define H3_PER_DIGIT_OFFSET   3

The number of bits in a single H3 resolution digit.

Definition at line 47 of file h3Index.h.

#define H3_RES_MASK   (UINT64_C(15) << H3_RES_OFFSET)

1's in the 4 resolution bits, 0's everywhere else.

Definition at line 68 of file h3Index.h.

#define H3_RES_MASK_NEGATIVE   (~H3_RES_MASK)

0's in the 4 resolution bits, 1's everywhere else.

Definition at line 71 of file h3Index.h.

#define H3_RES_OFFSET   52

The bit offset of the resolution in an H3 index.

Definition at line 41 of file h3Index.h.

#define H3_RESERVED_MASK   ((uint64_t)(7) << H3_RESERVED_OFFSET)

1's in the 3 reserved bits, 0's everywhere else.

Definition at line 74 of file h3Index.h.

#define H3_RESERVED_MASK_NEGATIVE   (~H3_RESERVED_MASK)

0's in the 3 reserved bits, 1's everywhere else.

Definition at line 77 of file h3Index.h.

#define H3_RESERVED_OFFSET   56

The bit offset of the reserved bits in an H3 index.

Definition at line 44 of file h3Index.h.

#define H3_SET_BASE_CELL	(		h3,
			bc
	)		(h3) = (((h3)&H3_BC_MASK_NEGATIVE) | (((uint64_t)(bc)) << H3_BC_OFFSET))

Sets the integer base cell of h3 to bc.

Definition at line 122 of file h3Index.h.

Referenced by _faceIjkToH3().

#define H3_SET_HIGH_BIT	(		h3,
			v
	)		(h3) = (((h3)&H3_HIGH_BIT_MASK_NEGATIVE) | (((uint64_t)(v)) << H3_MAX_OFFSET))

Sets the highest bit of the h3 to v.

Definition at line 100 of file h3Index.h.

#define H3_SET_INDEX_DIGIT	(		h3,
			res,
			digit
	)

Value:

(h3) = (((h3) & ~((H3_DIGIT_MASK << ((MAX_H3_RES - (res)) * H3_PER_DIGIT_OFFSET)))) | \
          (((uint64_t)(digit)) << ((MAX_H3_RES - (res)) * H3_PER_DIGIT_OFFSET)))

Sets the resolution res digit of h3 to the integer digit (0-7)

Definition at line 157 of file h3Index.h.

Referenced by _faceIjkToH3(), _h3Rotate60ccw(), _h3Rotate60cw(), _h3RotatePent60ccw(), _h3RotatePent60cw(), and h3ToParent().

#define H3_SET_MODE	(		h3,
			v
	)		(h3) = (((h3)&H3_MODE_MASK_NEGATIVE) | (((uint64_t)(v)) << H3_MODE_OFFSET))

Sets the integer mode of h3 to v.

Definition at line 111 of file h3Index.h.

Referenced by _faceIjkToH3().

#define H3_SET_RESERVED_BITS	(		h3,
			v
	)		(h3) = (((h3)&H3_RESERVED_MASK_NEGATIVE) | (((uint64_t)(v)) << H3_RESERVED_OFFSET))

Sets a value in the reserved space. Setting to non-zero may produce invalid indexes.

Definition at line 146 of file h3Index.h.

#define H3_SET_RESOLUTION	(		h3,
			res
	)		(h3) = (((h3)&H3_RES_MASK_NEGATIVE) | (((uint64_t)(res)) << H3_RES_OFFSET))

Sets the integer resolution of h3.

Definition at line 133 of file h3Index.h.

Referenced by _faceIjkToH3(), and h3ToParent().

Function Documentation

EXTENSION_NOINLINE H3Index _faceIjkToH3	(	const	FaceIJKfijk,
		int	res
	)

Convert an FaceIJK address to the corresponding H3Index.

Parameters

fijk	The FaceIJK address.
res	The cell resolution.

Returns

The encoded H3Index (or H3_NULL on failure).

Definition at line 643 of file h3Index.hpp.

References _baseCellIsCwOffset(), _downAp7(), _downAp7r(), _faceIjkToBaseCell(), _faceIjkToBaseCellCCWrot60(), _h3LeadingNonZeroDigit(), _h3Rotate60ccw(), _h3Rotate60cw(), _h3RotatePent60ccw(), _ijkNormalize(), _ijkSub(), _isBaseCellPentagon(), _unitIjkToDigit(), _upAp7(), _upAp7r(), CoordIJK, CoordIJK_clone, CoordIJK_copy, CoordIJK_ptr, FACE_INDEX, FaceIJK, FaceIJK_clone, H3_HEXAGON_MODE, H3_INIT, H3_NULL, H3_SET_BASE_CELL, H3_SET_INDEX_DIGIT, H3_SET_MODE, H3_SET_RESOLUTION, H3Index, I_INDEX, isResClassIII(), J_INDEX, K_AXES_DIGIT, K_INDEX, and MAX_FACE_COORD.

Referenced by geoToH3().

                                                                      {
  // initialize the index
  H3Index h = H3_INIT;
  H3_SET_MODE(h, H3_HEXAGON_MODE);
  H3_SET_RESOLUTION(h, res);

  // check for res 0/base cell
  if (res == 0) {
    if (fijk[I_INDEX] > MAX_FACE_COORD || fijk[J_INDEX] > MAX_FACE_COORD ||
        fijk[K_INDEX] > MAX_FACE_COORD) {
      // out of range input
      return H3_NULL;
    }

    H3_SET_BASE_CELL(h, _faceIjkToBaseCell(fijk));
    return h;
  }

  // we need to find the correct base cell FaceIJK for this H3 index;
  // start with the passed in face and resolution res ijk coordinates
  // in that face's coordinate system
  FaceIJK(fijkBC) = FaceIJK_clone(fijk);

  // build the H3Index from finest res up
  // adjust r for the fact that the res 0 base cell offsets the indexing
  // digits
  CoordIJK_ptr(ijk) = fijkBC;
  for (int r = res - 1; r >= 0; r--) {
    CoordIJK(lastIJK) = CoordIJK_clone(ijk);
    CoordIJK(lastCenter);
    if (isResClassIII(r + 1)) {
      // rotate ccw
      _upAp7(ijk);
      CoordIJK_copy(lastCenter, ijk);
      _downAp7(lastCenter);
    } else {
      // rotate cw
      _upAp7r(ijk);
      CoordIJK_copy(lastCenter, ijk);
      _downAp7r(lastCenter);
    }

    CoordIJK(diff);
    _ijkSub(lastIJK, lastCenter, diff);
    _ijkNormalize(diff);

    H3_SET_INDEX_DIGIT(h, r + 1, _unitIjkToDigit(diff));
  }

  // fijkBC should now hold the IJK of the base cell in the
  // coordinate system of the current face

  if (fijkBC[I_INDEX] > MAX_FACE_COORD || fijkBC[J_INDEX] > MAX_FACE_COORD ||
      fijkBC[K_INDEX] > MAX_FACE_COORD) {
    // out of range input
    return H3_NULL;
  }

  // lookup the correct base cell
  int baseCell = _faceIjkToBaseCell(fijkBC);
  H3_SET_BASE_CELL(h, baseCell);

  // rotate if necessary to get canonical base cell orientation
  // for this base cell
  int numRots = _faceIjkToBaseCellCCWrot60(fijkBC);
  if (_isBaseCellPentagon(baseCell)) {
    // force rotation out of missing k-axes sub-sequence
    if (_h3LeadingNonZeroDigit(h) == K_AXES_DIGIT) {
      // check for a cw/ccw offset face; default is ccw
      if (_baseCellIsCwOffset(baseCell, fijkBC[FACE_INDEX])) {
        h = _h3Rotate60cw(h);
      } else {
        h = _h3Rotate60ccw(h);
      }
    }

    for (int i = 0; i < numRots; i++)
      h = _h3RotatePent60ccw(h);
  } else {
    for (int i = 0; i < numRots; i++) {
      h = _h3Rotate60ccw(h);
    }
  }

  return h;
}

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EXTENSION_INLINE int _h3LeadingNonZeroDigit

(

H3Index

h

)

Determines whether one resolution is a valid child resolution of another. Each resolution is considered a valid child resolution of itself.

Parameters

parentRes	int resolution of the parent
childRes	int resolution of the child

Returns

The validity of the child resolution maxH3ToChildrenSize returns the maximum number of children possible for a given child level.

Parameters

h	H3Index to find the number of children of
childRes	The resolution of the child level you're interested in

Returns

int count of maximum number of children (equal for hexagons, less for pentagons makeDirectChild takes an index and immediately returns the immediate child index based on the specified cell number. Bit operations only, could generate invalid indexes if not careful (deleted cell under a pentagon).

Parameters

h	H3Index to find the direct child of
cellNumber	int id of the direct child (0-6)

Returns

The new H3Index for the child h3ToChildren takes the given hexagon id and generates all of the children at the specified resolution storing them into the provided memory pointer. It's assumed that maxH3ToChildrenSize was used to determine the allocation.

Parameters

h	H3Index to find the children of
childRes	int the child level to produce
children	H3Index* the memory to store the resulting addresses in h3ToCenterChild produces the center child index for a given H3 index at the specified resolution
h	H3Index to find center child of
childRes	The resolution to switch to

Returns

H3Index of the center child, or H3_NULL if you actually asked for a parent compact takes a set of hexagons all at the same resolution and compresses them by pruning full child branches to the parent level. This is also done for all parents recursively to get the minimum number of hex addresses that perfectly cover the defined space.

Parameters

h3Set	Set of hexagons
compactedSet	The output array of compressed hexagons (preallocated)
numHexes	The size of the input and output arrays (possible that no contiguous regions exist in the set at all and no compression possible)

Returns

an error code on bad input data uncompact takes a compressed set of hexagons and expands back to the original set of hexagons.

Parameters

compactedSet	Set of hexagons
numHexes	The number of hexes in the input set
h3Set	Output array of decompressed hexagons (preallocated)
maxHexes	The size of the output array to bound check against
res	The hexagon resolution to decompress to

Returns

An error code if output array is too small or any hexagon is smaller than the output resolution. maxUncompactSize takes a compacted set of hexagons are provides an upper-bound estimate of the size of the uncompacted set of hexagons.

Parameters

compactedSet	Set of hexagons
numHexes	The number of hexes in the input set
res	The hexagon resolution to decompress to

Returns

The number of hexagons to allocate memory for, or a negative number if an error occurs. h3IsResClassIII takes a hexagon ID and determines if it is in a Class III resolution (rotated versus the icosahedron and subject to shape distortion adding extra points on icosahedron edges, making them not true hexagons).

Parameters

h	The H3Index to check.

Returns

Returns 1 if the hexagon is class III, otherwise 0. h3IsPentagon takes an H3Index and determines if it is actually a pentagon.

Parameters

h	The H3Index to check.

Returns

Returns 1 if it is a pentagon, otherwise 0. Returns the highest resolution non-zero digit in an H3Index.

Parameters

h	The H3Index.

Returns

The highest resolution non-zero digit in the H3Index.

Definition at line 551 of file h3Index.hpp.

References CENTER_DIGIT, H3_GET_INDEX_DIGIT, and H3_GET_RESOLUTION.

Referenced by _faceIjkToH3(), _h3RotatePent60ccw(), _h3RotatePent60cw(), and _h3ToFaceIjk().

                                                       {
  for (int r = 1; r <= H3_GET_RESOLUTION(h); r++)
    if (H3_GET_INDEX_DIGIT(h, r))
      return H3_GET_INDEX_DIGIT(h, r);

  // if we're here it's all 0's
  return CENTER_DIGIT;
}

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EXTENSION_NOINLINE H3Index _h3Rotate60ccw

(

H3Index

h

)

Rotate an H3Index 60 degrees counter-clockwise.

Parameters

h	The H3Index.

Definition at line 616 of file h3Index.hpp.

References _rotate60ccw(), H3_GET_INDEX_DIGIT, H3_GET_RESOLUTION, H3_SET_INDEX_DIGIT, and run_benchmark_import::res.

Referenced by _faceIjkToH3(), and _h3RotatePent60ccw().

                                                     {
  for (int r = 1, res = H3_GET_RESOLUTION(h); r <= res; r++) {
    Direction oldDigit = H3_GET_INDEX_DIGIT(h, r);
    H3_SET_INDEX_DIGIT(h, r, _rotate60ccw(oldDigit));
  }

  return h;
}

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EXTENSION_NOINLINE H3Index _h3Rotate60cw

(

H3Index

h

)

Rotate an H3Index 60 degrees clockwise.

Parameters

h	The H3Index.

Definition at line 629 of file h3Index.hpp.

References _rotate60cw(), H3_GET_INDEX_DIGIT, H3_GET_RESOLUTION, H3_SET_INDEX_DIGIT, and run_benchmark_import::res.

Referenced by _faceIjkToH3(), _h3RotatePent60cw(), and _h3ToFaceIjk().

                                                    {
  for (int r = 1, res = H3_GET_RESOLUTION(h); r <= res; r++) {
    H3_SET_INDEX_DIGIT(h, r, _rotate60cw(H3_GET_INDEX_DIGIT(h, r)));
  }

  return h;
}

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EXTENSION_NOINLINE H3Index _h3RotatePent60ccw

(

H3Index

h

)

Rotate an H3Index 60 degrees counter-clockwise about a pentagonal center.

Parameters

h	The H3Index.

Definition at line 564 of file h3Index.hpp.

References _h3LeadingNonZeroDigit(), _h3Rotate60ccw(), _rotate60ccw(), H3_GET_INDEX_DIGIT, H3_GET_RESOLUTION, H3_SET_INDEX_DIGIT, K_AXES_DIGIT, and run_benchmark_import::res.

Referenced by _faceIjkToH3().

                                                         {
  // rotate in place; skips any leading 1 digits (k-axis)

  int foundFirstNonZeroDigit = 0;
  for (int r = 1, res = H3_GET_RESOLUTION(h); r <= res; r++) {
    // rotate this digit
    H3_SET_INDEX_DIGIT(h, r, _rotate60ccw(H3_GET_INDEX_DIGIT(h, r)));

    // look for the first non-zero digit so we
    // can adjust for deleted k-axes sequence
    // if necessary
    if (!foundFirstNonZeroDigit && H3_GET_INDEX_DIGIT(h, r) != 0) {
      foundFirstNonZeroDigit = 1;

      // adjust for deleted k-axes sequence
      if (_h3LeadingNonZeroDigit(h) == K_AXES_DIGIT)
        h = _h3Rotate60ccw(h);
    }
  }
  return h;
}

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EXTENSION_NOINLINE H3Index _h3RotatePent60cw

(

H3Index

h

)

Rotate an H3Index 60 degrees clockwise about a pentagonal center.

Parameters

h	The H3Index.

Definition at line 590 of file h3Index.hpp.

References _h3LeadingNonZeroDigit(), _h3Rotate60cw(), _rotate60cw(), H3_GET_INDEX_DIGIT, H3_GET_RESOLUTION, H3_SET_INDEX_DIGIT, K_AXES_DIGIT, and run_benchmark_import::res.

                                                        {
  // rotate in place; skips any leading 1 digits (k-axis)

  int foundFirstNonZeroDigit = 0;
  for (int r = 1, res = H3_GET_RESOLUTION(h); r <= res; r++) {
    // rotate this digit
    H3_SET_INDEX_DIGIT(h, r, _rotate60cw(H3_GET_INDEX_DIGIT(h, r)));

    // look for the first non-zero digit so we
    // can adjust for deleted k-axes sequence
    // if necessary
    if (!foundFirstNonZeroDigit && H3_GET_INDEX_DIGIT(h, r) != 0) {
      foundFirstNonZeroDigit = 1;

      // adjust for deleted k-axes sequence
      if (_h3LeadingNonZeroDigit(h) == K_AXES_DIGIT)
        h = _h3Rotate60cw(h);
    }
  }
  return h;
}

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EXTENSION_NOINLINE bool _h3ToFaceIjk	(	H3Index	h,
		FaceIJK(fijk)
	)

Convert an H3Index to a FaceIJK address.

Parameters

h	The H3Index.
fijk	The corresponding FaceIJK address.

Definition at line 783 of file h3Index.hpp.

References _adjustOverageClassII(), _downAp7r(), _h3LeadingNonZeroDigit(), _h3Rotate60cw(), _h3ToFaceIjkWithInitializedFijk(), _isBaseCellPentagon(), _upAp7r(), baseCellData, CoordIJK, CoordIJK_clone, CoordIJK_copy, FaceIJK_copy, H3_GET_BASE_CELL, H3_GET_RESOLUTION, isResClassIII(), NO_OVERAGE, and run_benchmark_import::res.

Referenced by _h3ToGeo().

                                                               {
  int baseCell = H3_GET_BASE_CELL(h);
  // adjust for the pentagonal missing sequence; all of sub-sequence 5 needs
  // to be adjusted (and some of sub-sequence 4 below)
  if (_isBaseCellPentagon(baseCell) && _h3LeadingNonZeroDigit(h) == 5)
    h = _h3Rotate60cw(h);

  // start with the "home" face and ijk+ coordinates for the base cell of c
  FaceIJK_copy(fijk, baseCellData[baseCell].homeFijk);
  if (!_h3ToFaceIjkWithInitializedFijk(h, fijk))
    return true;  // no overage is possible; h lies on this face

  // if we're here we have the potential for an "overage"; i.e., it is
  // possible that c lies on an adjacent face

  CoordIJK(origIJK) = CoordIJK_clone(fijk);

  // if we're in Class III, drop into the next finer Class II grid
  int res = H3_GET_RESOLUTION(h);
  if (isResClassIII(res)) {
    // Class III
    _downAp7r(fijk);
    res++;
  }

  // adjust for overage if needed
  // a pentagon base cell with a leading 4 digit requires special handling
  int pentLeading4 = (_isBaseCellPentagon(baseCell) && _h3LeadingNonZeroDigit(h) == 4);
  if (_adjustOverageClassII(fijk, res, pentLeading4, 0) != NO_OVERAGE) {
    // if the base cell is a pentagon we have the potential for secondary
    // overages
    if (_isBaseCellPentagon(baseCell)) {
      while (_adjustOverageClassII(fijk, res, 0, 0) != NO_OVERAGE)
        continue;
    }

    if (res != H3_GET_RESOLUTION(h))
      _upAp7r(fijk);
  } else if (res != H3_GET_RESOLUTION(h)) {
    CoordIJK_copy(fijk, origIJK);
  }
  return true;
}

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EXTENSION_NOINLINE int _h3ToFaceIjkWithInitializedFijk	(	H3Index	h,
		FaceIJK(fijk)
	)

Convert an H3Index to the FaceIJK address on a specified icosahedral face.

Parameters

h	The H3Index.
fijk	The FaceIJK address, initialized with the desired face and normalized base cell coordinates.

Returns

Returns 1 if the possibility of overage exists, otherwise 0.

Definition at line 753 of file h3Index.hpp.

References _downAp7(), _downAp7r(), _isBaseCellPentagon(), _neighbor(), H3_GET_BASE_CELL, H3_GET_INDEX_DIGIT, H3_GET_RESOLUTION, I_INDEX, isResClassIII(), J_INDEX, K_INDEX, and run_benchmark_import::res.

Referenced by _h3ToFaceIjk().

                                                                                 {
  int* ijk = fijk;
  int res = H3_GET_RESOLUTION(h);

  // center base cell hierarchy is entirely on this face
  int possibleOverage = 1;
  if (!_isBaseCellPentagon(H3_GET_BASE_CELL(h)) &&
      (res == 0 || (fijk[I_INDEX] == 0 && fijk[J_INDEX] == 0 && fijk[K_INDEX] == 0)))
    possibleOverage = 0;

  for (int r = 1; r <= res; r++) {
    if (isResClassIII(r)) {
      // Class III == rotate ccw
      _downAp7(ijk);
    } else {
      // Class II == rotate cw
      _downAp7r(ijk);
    }

    _neighbor(ijk, H3_GET_INDEX_DIGIT(h, r));
  }

  return possibleOverage;
}

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EXTENSION_NOINLINE bool _h3ToGeo	(	H3Index	h3,
		GeoCoord(g)
	)

Determines the spherical coordinates of the center point of an H3 index.

Parameters

h3	The H3 index.
g	The spherical coordinates of the H3 cell center. Note: spherical coordinates are in radians.

Definition at line 834 of file h3Index.hpp.

References _faceIjkToGeo(), _h3ToFaceIjk(), FaceIJK, and H3_GET_RESOLUTION.

Referenced by h3ToGeoPacked(), h3ToLat(), and h3ToLon().

                                                          {
  FaceIJK(fijk);
  _h3ToFaceIjk(h3, fijk);
  _faceIjkToGeo(fijk, H3_GET_RESOLUTION(h3), g);
  return true;
}

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