PostGIS  2.3.7dev-r@@SVN_REVISION@@
static int lwgeom_write_to_buffer ( const LWGEOM geom,
TWKB_GLOBALS globals,
TWKB_STATE parent_state 
)
static

Definition at line 407 of file lwout_twkb.c.

References TWKB_STATE::accum_rels, TWKB_STATE::bbox_max, TWKB_STATE::bbox_min, bytebuffer_append_byte(), bytebuffer_append_bytebuffer(), bytebuffer_append_uvarint(), bytebuffer_create_with_size(), bytebuffer_destroy(), bytebuffer_getlength(), TWKB_GLOBALS::factor, FIRST_BYTE_SET_BBOXES, FIRST_BYTE_SET_EMPTY, FIRST_BYTE_SET_EXTENDED, FIRST_BYTE_SET_IDLIST, FIRST_BYTE_SET_SIZES, TWKB_STATE::geom_buf, TWKB_STATE::header_buf, HIGHER_DIM_SET_HASM, HIGHER_DIM_SET_HASZ, HIGHER_DIM_SET_PRECM, HIGHER_DIM_SET_PRECZ, TWKB_STATE::idlist, LWDEBUG, lwerror(), lwgeom_has_m(), lwgeom_has_z(), lwgeom_is_empty(), lwgeom_ndims(), lwgeom_to_twkb_buf(), lwgeom_twkb_type(), MAX_N_DIMS, TWKB_GLOBALS::prec_m, TWKB_GLOBALS::prec_xy, TWKB_GLOBALS::prec_z, sizeof_bbox(), TWKB_BBOX, TWKB_SIZE, TYPE_PREC_SET_PREC, TYPE_PREC_SET_TYPE, TWKB_GLOBALS::variant, write_bbox(), and zigzag8().

Referenced by lwcollection_to_twkb_buf(), and lwgeom_to_twkb_with_idlist().

408 {
409  int i, is_empty, has_z, has_m, ndims;
410  size_t bbox_size = 0, optional_precision_byte = 0;
411  uint8_t flag = 0, type_prec = 0;
412 
413  TWKB_STATE child_state;
414  memset(&child_state, 0, sizeof(TWKB_STATE));
415  child_state.header_buf = bytebuffer_create_with_size(16);
416  child_state.geom_buf = bytebuffer_create_with_size(64);
417  child_state.idlist = parent_state->idlist;
418 
419  /* Read dimensionality from input */
420  has_z = lwgeom_has_z(geom);
421  has_m = lwgeom_has_m(geom);
422  ndims = lwgeom_ndims(geom);
423  is_empty = lwgeom_is_empty(geom);
424 
425  /* Do we need extended precision? If we have a Z or M we do. */
426  optional_precision_byte = (has_z || has_m);
427 
428  /* Both X and Y dimension use the same precision */
429  globals->factor[0] = pow(10, globals->prec_xy);
430  globals->factor[1] = globals->factor[0];
431 
432  /* Z and M dimensions have their own precisions */
433  if ( has_z )
434  globals->factor[2] = pow(10, globals->prec_z);
435  if ( has_m )
436  globals->factor[2 + has_z] = pow(10, globals->prec_m);
437 
438  /* Reset stats */
439  for ( i = 0; i < MAX_N_DIMS; i++ )
440  {
441  /* Reset bbox calculation */
442  child_state.bbox_max[i] = INT64_MIN;
443  child_state.bbox_min[i] = INT64_MAX;
444  /* Reset acumulated delta values to get absolute values on next point */
445  child_state.accum_rels[i] = 0;
446  }
447 
448  /* TYPE/PRECISION BYTE */
449  if ( abs(globals->prec_xy) > 7 )
450  lwerror("%s: X/Z precision cannot be greater than 7 or less than -7", __func__);
451 
452  /* Read the TWKB type number from the geometry */
453  TYPE_PREC_SET_TYPE(type_prec, lwgeom_twkb_type(geom));
454  /* Zig-zag the precision value before encoding it since it is a signed value */
455  TYPE_PREC_SET_PREC(type_prec, zigzag8(globals->prec_xy));
456  /* Write the type and precision byte */
457  bytebuffer_append_byte(child_state.header_buf, type_prec);
458 
459  /* METADATA BYTE */
460  /* Set first bit if we are going to store bboxes */
461  FIRST_BYTE_SET_BBOXES(flag, (globals->variant & TWKB_BBOX) && ! is_empty);
462  /* Set second bit if we are going to store resulting size */
463  FIRST_BYTE_SET_SIZES(flag, globals->variant & TWKB_SIZE);
464  /* There will be no ID-list (for now) */
465  FIRST_BYTE_SET_IDLIST(flag, parent_state->idlist && ! is_empty);
466  /* Are there higher dimensions */
467  FIRST_BYTE_SET_EXTENDED(flag, optional_precision_byte);
468  /* Empty? */
469  FIRST_BYTE_SET_EMPTY(flag, is_empty);
470  /* Write the header byte */
471  bytebuffer_append_byte(child_state.header_buf, flag);
472 
473  /* EXTENDED PRECISION BYTE (OPTIONAL) */
474  /* If needed, write the extended dim byte */
475  if( optional_precision_byte )
476  {
477  uint8_t flag = 0;
478 
479  if ( has_z && ( globals->prec_z > 7 || globals->prec_z < 0 ) )
480  lwerror("%s: Z precision cannot be negative or greater than 7", __func__);
481 
482  if ( has_m && ( globals->prec_m > 7 || globals->prec_m < 0 ) )
483  lwerror("%s: M precision cannot be negative or greater than 7", __func__);
484 
485  HIGHER_DIM_SET_HASZ(flag, has_z);
486  HIGHER_DIM_SET_HASM(flag, has_m);
487  HIGHER_DIM_SET_PRECZ(flag, globals->prec_z);
488  HIGHER_DIM_SET_PRECM(flag, globals->prec_m);
489  bytebuffer_append_byte(child_state.header_buf, flag);
490  }
491 
492  /* It the geometry is empty, we're almost done */
493  if ( is_empty )
494  {
495  /* If this output is sized, write the size of */
496  /* all following content, which is zero because */
497  /* there is none */
498  if ( globals->variant & TWKB_SIZE )
499  bytebuffer_append_byte(child_state.header_buf, 0);
500 
501  bytebuffer_append_bytebuffer(parent_state->geom_buf, child_state.header_buf);
502  bytebuffer_destroy(child_state.header_buf);
503  bytebuffer_destroy(child_state.geom_buf);
504  return 0;
505  }
506 
507  /* Write the TWKB into the output buffer */
508  lwgeom_to_twkb_buf(geom, globals, &child_state);
509 
510  /*If we have a header_buf, we know that this function is called inside a collection*/
511  /*and then we have to merge the bboxes of the included geometries*/
512  /*and put the result to the parent (the collection)*/
513  if( (globals->variant & TWKB_BBOX) && parent_state->header_buf )
514  {
515  LWDEBUG(4,"Merge bboxes");
516  for ( i = 0; i < ndims; i++ )
517  {
518  if(child_state.bbox_min[i]<parent_state->bbox_min[i])
519  parent_state->bbox_min[i] = child_state.bbox_min[i];
520  if(child_state.bbox_max[i]>parent_state->bbox_max[i])
521  parent_state->bbox_max[i] = child_state.bbox_max[i];
522  }
523  }
524 
525  /* Did we have a box? If so, how big? */
526  bbox_size = 0;
527  if( globals->variant & TWKB_BBOX )
528  {
529  LWDEBUG(4,"We want boxes and will calculate required size");
530  bbox_size = sizeof_bbox(&child_state, ndims);
531  }
532 
533  /* Write the size if wanted */
534  if( globals->variant & TWKB_SIZE )
535  {
536  /* Here we have to add what we know will be written to header */
537  /* buffer after size value is written */
538  size_t size_to_register = bytebuffer_getlength(child_state.geom_buf);
539  size_to_register += bbox_size;
540  bytebuffer_append_uvarint(child_state.header_buf, size_to_register);
541  }
542 
543  if( globals->variant & TWKB_BBOX )
544  write_bbox(&child_state, ndims);
545 
546  bytebuffer_append_bytebuffer(parent_state->geom_buf,child_state.header_buf);
547  bytebuffer_append_bytebuffer(parent_state->geom_buf,child_state.geom_buf);
548 
549  bytebuffer_destroy(child_state.header_buf);
550  bytebuffer_destroy(child_state.geom_buf);
551  return 0;
552 }
#define FIRST_BYTE_SET_EMPTY(flag, bool)
Definition: lwout_twkb.h:57
float factor[4]
Definition: lwout_twkb.h:82
#define HIGHER_DIM_SET_PRECM(flag, prec)
Definition: lwout_twkb.h:73
#define TYPE_PREC_SET_TYPE(flag, type)
Macros for manipulating the 'type_precision' int.
Definition: lwout_twkb.h:66
void bytebuffer_append_bytebuffer(bytebuffer_t *write_to, bytebuffer_t *write_from)
Writes a uint8_t value to the buffer.
Definition: bytebuffer.c:172
uint8_t variant
Definition: lwout_twkb.h:78
static int lwgeom_to_twkb_buf(const LWGEOM *geom, TWKB_GLOBALS *globals, TWKB_STATE *ts)
Definition: lwout_twkb.c:362
void bytebuffer_append_byte(bytebuffer_t *s, const uint8_t val)
Writes a uint8_t value to the buffer.
Definition: bytebuffer.c:145
static uint8_t lwgeom_twkb_type(const LWGEOM *geom)
Definition: lwout_twkb.c:31
#define LWDEBUG(level, msg)
Definition: lwgeom_log.h:83
bytebuffer_t * bytebuffer_create_with_size(size_t size)
Allocate a new bytebuffer_t.
Definition: bytebuffer.c:44
static void write_bbox(TWKB_STATE *ts, int ndims)
Writes the bbox in varints in the form: xmin, xdelta, ymin, ydelta.
Definition: lwout_twkb.c:89
#define HIGHER_DIM_SET_HASZ(flag, bool)
Definition: lwout_twkb.h:69
int lwgeom_has_z(const LWGEOM *geom)
Return LW_TRUE if geometry has Z ordinates.
Definition: lwgeom.c:849
int lwgeom_ndims(const LWGEOM *geom)
Return the number of dimensions (2, 3, 4) in a geometry.
Definition: lwgeom.c:863
int8_t prec_z
Definition: lwout_twkb.h:80
uint8_t zigzag8(int8_t val)
Definition: varint.c:183
bytebuffer_t * header_buf
Definition: lwout_twkb.h:88
static size_t sizeof_bbox(TWKB_STATE *ts, int ndims)
Calculates the size of the bbox in varints in the form: xmin, xdelta, ymin, ydelta.
Definition: lwout_twkb.c:72
int64_t accum_rels[MAX_N_DIMS]
Definition: lwout_twkb.h:95
const int64_t * idlist
Definition: lwout_twkb.h:92
#define FIRST_BYTE_SET_SIZES(flag, bool)
Definition: lwout_twkb.h:54
void bytebuffer_append_uvarint(bytebuffer_t *b, const uint64_t val)
Writes a unsigned varInt to the buffer.
Definition: bytebuffer.c:200
int8_t prec_xy
Definition: lwout_twkb.h:79
#define FIRST_BYTE_SET_BBOXES(flag, bool)
Header true/false flags.
Definition: lwout_twkb.h:53
int8_t prec_m
Definition: lwout_twkb.h:81
#define TYPE_PREC_SET_PREC(flag, prec)
Definition: lwout_twkb.h:67
#define MAX_N_DIMS
Definition: lwout_twkb.h:43
#define HIGHER_DIM_SET_PRECZ(flag, prec)
Definition: lwout_twkb.h:72
void bytebuffer_destroy(bytebuffer_t *s)
Free the bytebuffer_t and all memory managed within it.
Definition: bytebuffer.c:75
#define TWKB_BBOX
Definition: liblwgeom.h:2063
#define FIRST_BYTE_SET_EXTENDED(flag, bool)
Definition: lwout_twkb.h:56
int64_t bbox_max[MAX_N_DIMS]
Definition: lwout_twkb.h:94
#define TWKB_SIZE
Definition: liblwgeom.h:2064
#define HIGHER_DIM_SET_HASM(flag, bool)
Definition: lwout_twkb.h:70
int lwgeom_is_empty(const LWGEOM *geom)
Return true or false depending on whether a geometry is an "empty" geometry (no vertices members) ...
Definition: lwgeom.c:1310
bytebuffer_t * geom_buf
Definition: lwout_twkb.h:89
int lwgeom_has_m(const LWGEOM *geom)
Return LW_TRUE if geometry has M ordinates.
Definition: lwgeom.c:856
#define FIRST_BYTE_SET_IDLIST(flag, bool)
Definition: lwout_twkb.h:55
size_t bytebuffer_getlength(bytebuffer_t *s)
Returns the length of the current buffer.
Definition: bytebuffer.c:325
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:102
int64_t bbox_min[MAX_N_DIMS]
Definition: lwout_twkb.h:93

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