PostGIS  2.2.7dev-r@@SVN_REVISION@@
static int lwgeom_write_to_buffer ( const LWGEOM geom,
TWKB_GLOBALS globals,
TWKB_STATE parent_state 
)
static

Definition at line 393 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().

394 {
395  int i, is_empty, has_z, has_m, ndims;
396  size_t bbox_size = 0, optional_precision_byte = 0;
397  uint8_t flag = 0, type_prec = 0;
398 
399  TWKB_STATE child_state;
400  memset(&child_state, 0, sizeof(TWKB_STATE));
401  child_state.header_buf = bytebuffer_create_with_size(16);
402  child_state.geom_buf = bytebuffer_create_with_size(64);
403  child_state.idlist = parent_state->idlist;
404 
405  /* Read dimensionality from input */
406  has_z = lwgeom_has_z(geom);
407  has_m = lwgeom_has_m(geom);
408  ndims = lwgeom_ndims(geom);
409  is_empty = lwgeom_is_empty(geom);
410 
411  /* Do we need extended precision? If we have a Z or M we do. */
412  optional_precision_byte = (has_z || has_m);
413 
414  /* Both X and Y dimension use the same precision */
415  globals->factor[0] = pow(10, globals->prec_xy);
416  globals->factor[1] = globals->factor[0];
417 
418  /* Z and M dimensions have their own precisions */
419  if ( has_z )
420  globals->factor[2] = pow(10, globals->prec_z);
421  if ( has_m )
422  globals->factor[2 + has_z] = pow(10, globals->prec_m);
423 
424  /* Reset stats */
425  for ( i = 0; i < MAX_N_DIMS; i++ )
426  {
427  /* Reset bbox calculation */
428  child_state.bbox_max[i] = INT64_MIN;
429  child_state.bbox_min[i] = INT64_MAX;
430  /* Reset acumulated delta values to get absolute values on next point */
431  child_state.accum_rels[i] = 0;
432  }
433 
434  /* TYPE/PRECISION BYTE */
435  if ( abs(globals->prec_xy) > 7 )
436  lwerror("%s: X/Z precision cannot be greater than 7 or less than -7", __func__);
437 
438  /* Read the TWKB type number from the geometry */
439  TYPE_PREC_SET_TYPE(type_prec, lwgeom_twkb_type(geom));
440  /* Zig-zag the precision value before encoding it since it is a signed value */
441  TYPE_PREC_SET_PREC(type_prec, zigzag8(globals->prec_xy));
442  /* Write the type and precision byte */
443  bytebuffer_append_byte(child_state.header_buf, type_prec);
444 
445  /* METADATA BYTE */
446  /* Set first bit if we are going to store bboxes */
447  FIRST_BYTE_SET_BBOXES(flag, (globals->variant & TWKB_BBOX) && ! is_empty);
448  /* Set second bit if we are going to store resulting size */
449  FIRST_BYTE_SET_SIZES(flag, globals->variant & TWKB_SIZE);
450  /* There will be no ID-list (for now) */
451  FIRST_BYTE_SET_IDLIST(flag, parent_state->idlist && ! is_empty);
452  /* Are there higher dimensions */
453  FIRST_BYTE_SET_EXTENDED(flag, optional_precision_byte);
454  /* Empty? */
455  FIRST_BYTE_SET_EMPTY(flag, is_empty);
456  /* Write the header byte */
457  bytebuffer_append_byte(child_state.header_buf, flag);
458 
459  /* EXTENDED PRECISION BYTE (OPTIONAL) */
460  /* If needed, write the extended dim byte */
461  if( optional_precision_byte )
462  {
463  uint8_t flag = 0;
464 
465  if ( has_z && ( globals->prec_z > 7 || globals->prec_z < 0 ) )
466  lwerror("%s: Z precision cannot be negative or greater than 7", __func__);
467 
468  if ( has_m && ( globals->prec_m > 7 || globals->prec_m < 0 ) )
469  lwerror("%s: M precision cannot be negative or greater than 7", __func__);
470 
471  HIGHER_DIM_SET_HASZ(flag, has_z);
472  HIGHER_DIM_SET_HASM(flag, has_m);
473  HIGHER_DIM_SET_PRECZ(flag, globals->prec_z);
474  HIGHER_DIM_SET_PRECM(flag, globals->prec_m);
475  bytebuffer_append_byte(child_state.header_buf, flag);
476  }
477 
478  /* It the geometry is empty, we're almost done */
479  if ( is_empty )
480  {
481  /* If this output is sized, write the size of */
482  /* all following content, which is zero because */
483  /* there is none */
484  if ( globals->variant & TWKB_SIZE )
485  bytebuffer_append_byte(child_state.header_buf, 0);
486 
487  bytebuffer_append_bytebuffer(parent_state->geom_buf, child_state.header_buf);
488  bytebuffer_destroy(child_state.header_buf);
489  bytebuffer_destroy(child_state.geom_buf);
490  return 0;
491  }
492 
493  /* Write the TWKB into the output buffer */
494  lwgeom_to_twkb_buf(geom, globals, &child_state);
495 
496  /*If we have a header_buf, we know that this function is called inside a collection*/
497  /*and then we have to merge the bboxes of the included geometries*/
498  /*and put the result to the parent (the collection)*/
499  if( (globals->variant & TWKB_BBOX) && parent_state->header_buf )
500  {
501  LWDEBUG(4,"Merge bboxes");
502  for ( i = 0; i < ndims; i++ )
503  {
504  if(child_state.bbox_min[i]<parent_state->bbox_min[i])
505  parent_state->bbox_min[i] = child_state.bbox_min[i];
506  if(child_state.bbox_max[i]>parent_state->bbox_max[i])
507  parent_state->bbox_max[i] = child_state.bbox_max[i];
508  }
509  }
510 
511  /* Did we have a box? If so, how big? */
512  bbox_size = 0;
513  if( globals->variant & TWKB_BBOX )
514  {
515  LWDEBUG(4,"We want boxes and will calculate required size");
516  bbox_size = sizeof_bbox(&child_state, ndims);
517  }
518 
519  /* Write the size if wanted */
520  if( globals->variant & TWKB_SIZE )
521  {
522  /* Here we have to add what we know will be written to header */
523  /* buffer after size value is written */
524  size_t size_to_register = bytebuffer_getlength(child_state.geom_buf);
525  size_to_register += bbox_size;
526  bytebuffer_append_uvarint(child_state.header_buf, size_to_register);
527  }
528 
529  if( globals->variant & TWKB_BBOX )
530  write_bbox(&child_state, ndims);
531 
532  bytebuffer_append_bytebuffer(parent_state->geom_buf,child_state.header_buf);
533  bytebuffer_append_bytebuffer(parent_state->geom_buf,child_state.geom_buf);
534 
535  bytebuffer_destroy(child_state.header_buf);
536  bytebuffer_destroy(child_state.geom_buf);
537  return 0;
538 }
#define FIRST_BYTE_SET_EMPTY(flag, bool)
Definition: lwout_twkb.h:33
float factor[4]
Definition: lwout_twkb.h:58
#define HIGHER_DIM_SET_PRECM(flag, prec)
Definition: lwout_twkb.h:49
#define TYPE_PREC_SET_TYPE(flag, type)
Macros for manipulating the 'type_precision' int.
Definition: lwout_twkb.h:42
void bytebuffer_append_bytebuffer(bytebuffer_t *write_to, bytebuffer_t *write_from)
Writes a uint8_t value to the buffer.
Definition: bytebuffer.c:184
uint8_t variant
Definition: lwout_twkb.h:54
static int lwgeom_to_twkb_buf(const LWGEOM *geom, TWKB_GLOBALS *globals, TWKB_STATE *ts)
Definition: lwout_twkb.c:348
void bytebuffer_append_byte(bytebuffer_t *s, const uint8_t val)
Writes a uint8_t value to the buffer.
Definition: bytebuffer.c:157
static uint8_t lwgeom_twkb_type(const LWGEOM *geom)
Definition: lwout_twkb.c:17
#define LWDEBUG(level, msg)
Definition: lwgeom_log.h:50
bytebuffer_t * bytebuffer_create_with_size(size_t size)
Allocate a new bytebuffer_t.
Definition: bytebuffer.c:56
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:75
#define HIGHER_DIM_SET_HASZ(flag, bool)
Definition: lwout_twkb.h:45
int lwgeom_has_z(const LWGEOM *geom)
Return LW_TRUE if geometry has Z ordinates.
Definition: lwgeom.c:836
int lwgeom_ndims(const LWGEOM *geom)
Return the number of dimensions (2, 3, 4) in a geometry.
Definition: lwgeom.c:850
int8_t prec_z
Definition: lwout_twkb.h:56
uint8_t zigzag8(int8_t val)
Definition: varint.c:174
bytebuffer_t * header_buf
Definition: lwout_twkb.h:64
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:58
int64_t accum_rels[MAX_N_DIMS]
Definition: lwout_twkb.h:71
const int64_t * idlist
Definition: lwout_twkb.h:68
#define FIRST_BYTE_SET_SIZES(flag, bool)
Definition: lwout_twkb.h:30
void bytebuffer_append_uvarint(bytebuffer_t *b, const uint64_t val)
Writes a unsigned varInt to the buffer.
Definition: bytebuffer.c:212
int8_t prec_xy
Definition: lwout_twkb.h:55
#define FIRST_BYTE_SET_BBOXES(flag, bool)
Header true/false flags.
Definition: lwout_twkb.h:29
int8_t prec_m
Definition: lwout_twkb.h:57
#define TYPE_PREC_SET_PREC(flag, prec)
Definition: lwout_twkb.h:43
#define MAX_N_DIMS
Definition: lwout_twkb.h:19
#define HIGHER_DIM_SET_PRECZ(flag, prec)
Definition: lwout_twkb.h:48
void bytebuffer_destroy(bytebuffer_t *s)
Free the bytebuffer_t and all memory managed within it.
Definition: bytebuffer.c:87
#define TWKB_BBOX
Definition: liblwgeom.h:1947
#define FIRST_BYTE_SET_EXTENDED(flag, bool)
Definition: lwout_twkb.h:32
int64_t bbox_max[MAX_N_DIMS]
Definition: lwout_twkb.h:70
#define TWKB_SIZE
Definition: liblwgeom.h:1948
#define HIGHER_DIM_SET_HASM(flag, bool)
Definition: lwout_twkb.h:46
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:1297
bytebuffer_t * geom_buf
Definition: lwout_twkb.h:65
int lwgeom_has_m(const LWGEOM *geom)
Return LW_TRUE if geometry has M ordinates.
Definition: lwgeom.c:843
#define FIRST_BYTE_SET_IDLIST(flag, bool)
Definition: lwout_twkb.h:31
size_t bytebuffer_getlength(bytebuffer_t *s)
Returns the length of the current buffer.
Definition: bytebuffer.c:337
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:74
int64_t bbox_min[MAX_N_DIMS]
Definition: lwout_twkb.h:69

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