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Changes In Branch geojson Excluding Merge-Ins
This is equivalent to a diff from 4ee136d6d2 to 3920925128
2018-05-14
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00:23 | Add the --append option to the ".backup" command in the CLI. (check-in: 0dfdbdee52 user: drh tags: trunk) | |
2018-05-12
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23:59 | Add test cases for geopoly_overlap(). (Later:) This branch is closed and the development of the geopoly logic is moved to the [/timeline?r=rtree-geopoly|rtree-geopoly] branch. (Closed-Leaf check-in: 3920925128 user: drh tags: geojson) | |
23:56 | Merge changes from trunk. (check-in: 715740e302 user: drh tags: geojson) | |
23:56 | In the CLI, allow comment lines that begin with '#', but only in a context where a dot-command is allowed. In other words, '#' at the beginning of a line in the middle of an SQL statement is just part of the SQL. (check-in: 4ee136d6d2 user: drh tags: trunk) | |
2018-05-11
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19:11 | In the CLI, return non-zero if there are errors on the command-line. (check-in: 13e7300a37 user: drh tags: trunk) | |
Added ext/misc/geopoly-test1.txt.
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 | # # Test cases for the geopoly_overlap() function of the geopoly.c extension. # To run these tests: # # (1) Build the geopoly extension and put the shared library in # the local directory. # # (2) Run: ./sqlite3 <geopoly-test1.txt >output.html # # (3) View the output.html in a web browser to see if the results # are correct. # .load ./geopoly CREATE TABLE polys( name TEXT, poly TEXT ); INSERT INTO polys(name,poly) VALUES ('rectangle-2', '[[0,0],[200,0],[200,200],[0,200],[0,0]]'), ('rectangle-1', '[[150,50],[200,50],[200,100],[150,100],[150,50]]'), ('backslash', '[[0,200],[200,0],[200,25],[0,225],[0,200]]'), ('forwardslash', '[[0,0],[200,200],[200,225],[0,25],[0,0]]'), ('diamond-2,0-2', '[[100,0],[200,100],[100,200],[0,100],[100,0]]'), ('diamond-2,1-3', '[[200,0],[300,100],[200,200],[100,100],[200,0]]'), ('diamond-2,2-4', '[[300,0],[400,100],[300,200],[200,100],[300,0]]'), ('v-bowtie', '[[50,0],[150,0],[125,75],[125,125],[150,200],[50,200], [75,125],[75,75],[50,0]]'), ('h-bowtie', '[[0,50],[75,75],[125,75],[200,50],[200,150],[125,125], [75,125],[0,150],[0,50]]'), ('letter-E', '[[0,0],[90,0],[20,10],[20,90],[80,100],[20,110],[20,190], [90,200],[0,200],[0,0]]'), ('backward-C', '[[30,50],[120,40],[120,160],[30,150],[100,140], [100,60],[30,50]]'), ('counter-cw', '[[100,200],[0,100],[100,0],[200,100],[150,150],[100,100], [150,140],[190,100],[100,10],[10,100],[100,190],[100,200]]'), ('clockwise', '[[200,150],[150,180],[50,100],[100,35],[150,100], [100,45],[60,100],[150,170],[200,140],[200,150]]'); CREATE TABLE overlap_meanings(id INTEGER PRIMARY KEY, x TEXT); INSERT INTO overlap_meanings(id,x) VALUES (0, 'disjoint'), (1, 'intersecting'), (2, 'A inside of B'), (3, 'B inside of A'), (4, 'identical'); .print <html> .print <h1>Note:</h1> .print <p>Directions are reversed because SVG uses a left-handed .print coordinate system<p> .separator \n SELECT '<hr>', '<svg width="400" height="225">', geopoly_svg(x1.poly,'fill="blue"','fill-opacity="0.5"'), geopoly_svg(x2.poly,'fill="green"','fill-opacity="0.5"'), '</svg><pre>', 'blue (A): '||x1.name, 'green (B): '||x2.name, (SELECT x FROM overlap_meanings WHERE id=geopoly_overlap(x1.poly,x2.poly)), '</pre>' FROM polys AS x1, polys AS x2; |
Added ext/misc/geopoly.c.
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845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 | /* ** 2018-05-08 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ****************************************************************************** ** ** This file implements various extension functions to SQLite that manage ** simply planar polygons such as might be found in a geospatial system. */ #include "sqlite3ext.h" SQLITE_EXTENSION_INIT1 #include <assert.h> #include <string.h> #include <stdlib.h> #include <stdio.h> #define SQLITE_HAVE_GEOPLOY 1 /* Enable -DGEOPOLY_ENABLE_DEBUG for debugging facilities */ #ifdef GEOPOLY_ENABLE_DEBUG static int geo_debug = 0; # define GEODEBUG(X) if(geo_debug)printf X #else # define GEODEBUG(X) #endif #ifndef JSON_NULL /* The following stuff repeats things found in json1 */ /* ** Versions of isspace(), isalnum() and isdigit() to which it is safe ** to pass signed char values. */ #ifdef sqlite3Isdigit /* Use the SQLite core versions if this routine is part of the ** SQLite amalgamation */ # define safe_isdigit(x) sqlite3Isdigit(x) # define safe_isalnum(x) sqlite3Isalnum(x) # define safe_isxdigit(x) sqlite3Isxdigit(x) #else /* Use the standard library for separate compilation */ #include <ctype.h> /* amalgamator: keep */ # define safe_isdigit(x) isdigit((unsigned char)(x)) # define safe_isalnum(x) isalnum((unsigned char)(x)) # define safe_isxdigit(x) isxdigit((unsigned char)(x)) #endif /* ** Growing our own isspace() routine this way is twice as fast as ** the library isspace() function. */ static const char geopolyIsSpace[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, }; #define safe_isspace(x) (geopolyIsSpace[(unsigned char)x]) #endif /* JSON NULL - back to original code */ /* Compiler and version */ #ifndef GCC_VERSION #if defined(__GNUC__) && !defined(SQLITE_DISABLE_INTRINSIC) # define GCC_VERSION (__GNUC__*1000000+__GNUC_MINOR__*1000+__GNUC_PATCHLEVEL__) #else # define GCC_VERSION 0 #endif #endif #ifndef MSVC_VERSION #if defined(_MSC_VER) && !defined(SQLITE_DISABLE_INTRINSIC) # define MSVC_VERSION _MSC_VER #else # define MSVC_VERSION 0 #endif #endif /* Datatype for coordinates */ typedef float GeoCoord; /* ** Internal representation of a polygon. ** ** The polygon consists of a sequence of vertexes. There is a line ** segment between each pair of vertexes, and one final segment from ** the last vertex back to the first. (This differs from the GeoJSON ** standard in which the final vertex is a repeat of the first.) ** ** The polygon follows the right-hand rule. The area to the right of ** each segment is "outside" and the area to the left is "inside". ** ** The on-disk representation consists of a 4-byte header followed by ** the values. The 4-byte header is: ** ** encoding (1 byte) 0=big-endian, 1=little-endian ** nvertex (3 bytes) Number of vertexes as a big-endian integer */ typedef struct GeoPoly GeoPoly; struct GeoPoly { int nVertex; /* Number of vertexes */ unsigned char hdr[4]; /* Header for on-disk representation */ GeoCoord a[2]; /* 2*nVertex values. X (longitude) first, then Y */ }; /* ** State of a parse of a GeoJSON input. */ typedef struct GeoParse GeoParse; struct GeoParse { const unsigned char *z; /* Unparsed input */ int nVertex; /* Number of vertexes in a[] */ int nAlloc; /* Space allocated to a[] */ int nErr; /* Number of errors encountered */ GeoCoord *a; /* Array of vertexes. From sqlite3_malloc64() */ }; /* Do a 4-byte byte swap */ static void geopolySwab32(unsigned char *a){ unsigned char t = a[0]; a[0] = a[3]; a[3] = t; t = a[1]; a[1] = a[2]; a[2] = t; } /* Skip whitespace. Return the next non-whitespace character. */ static char geopolySkipSpace(GeoParse *p){ while( p->z[0] && safe_isspace(p->z[0]) ) p->z++; return p->z[0]; } /* Parse out a number. Write the value into *pVal if pVal!=0. ** return non-zero on success and zero if the next token is not a number. */ static int geopolyParseNumber(GeoParse *p, GeoCoord *pVal){ const unsigned char *z = p->z; char c = geopolySkipSpace(p); int j; int seenDP = 0; int seenE = 0; assert( '-' < '0' ); if( c<='0' ){ j = c=='-'; if( z[j]=='0' && z[j+1]>='0' && z[j+1]<='9' ) return 0; } j = 1; for(;; j++){ c = z[j]; if( c>='0' && c<='9' ) continue; if( c=='.' ){ if( z[j-1]=='-' ) return 0; if( seenDP ) return 0; seenDP = 1; continue; } if( c=='e' || c=='E' ){ if( z[j-1]<'0' ) return 0; if( seenE ) return -1; seenDP = seenE = 1; c = z[j+1]; if( c=='+' || c=='-' ){ j++; c = z[j+1]; } if( c<'0' || c>'9' ) return 0; continue; } break; } if( z[j-1]<'0' ) return 0; if( pVal ) *pVal = atof((const char*)p->z); p->z += j; return 1; } /* ** If the input is a well-formed JSON array of coordinates, where each ** coordinate is itself a two-value array, then convert the JSON into ** a GeoPoly object and return a pointer to that object. ** ** If any error occurs, return NULL. */ static GeoPoly *geopolyParseJson(const unsigned char *z){ GeoParse s; memset(&s, 0, sizeof(s)); s.z = z; if( geopolySkipSpace(&s)=='[' ){ s.z++; while( geopolySkipSpace(&s)=='[' ){ int ii = 0; char c; s.z++; if( s.nVertex<=s.nAlloc ){ GeoCoord *aNew; s.nAlloc = s.nAlloc*2 + 16; aNew = sqlite3_realloc64(s.a, s.nAlloc*sizeof(GeoCoord)*2 ); if( aNew==0 ){ s.nErr++; break; } s.a = aNew; } while( geopolyParseNumber(&s, ii<=1 ? &s.a[s.nVertex*2+ii] : 0) ){ ii++; if( ii==2 ) s.nVertex++; c = geopolySkipSpace(&s); s.z++; if( c==',' ) continue; if( c==']' ) break; s.nErr++; goto parse_json_err; } if( geopolySkipSpace(&s)==',' ){ s.z++; continue; } break; } if( geopolySkipSpace(&s)==']' && s.nVertex>=4 ){ int nByte; GeoPoly *pOut; int x = (s.nVertex-1)*2; if( s.a[x]==s.a[0] && s.a[x+1]==s.a[1] ) s.nVertex--; nByte = sizeof(GeoPoly) * (s.nVertex-1)*2*sizeof(GeoCoord); pOut = sqlite3_malloc64( nByte ); x = 1; if( pOut==0 ) goto parse_json_err; pOut->nVertex = s.nVertex; memcpy(pOut->a, s.a, s.nVertex*2*sizeof(GeoCoord)); pOut->hdr[0] = *(unsigned char*)&x; pOut->hdr[1] = (s.nVertex>>16)&0xff; pOut->hdr[2] = (s.nVertex>>8)&0xff; pOut->hdr[3] = s.nVertex&0xff; sqlite3_free(s.a); return pOut; }else{ s.nErr++; } } parse_json_err: sqlite3_free(s.a); return 0; } /* ** Given a function parameter, try to interpret it as a polygon, either ** in the binary format or JSON text. Compute a GeoPoly object and ** return a pointer to that object. Or if the input is not a well-formed ** polygon, put an error message in sqlite3_context and return NULL. */ static GeoPoly *geopolyFuncParam(sqlite3_context *pCtx, sqlite3_value *pVal){ GeoPoly *p = 0; int nByte; if( sqlite3_value_type(pVal)==SQLITE_BLOB && (nByte = sqlite3_value_bytes(pVal))>=(4+6*sizeof(GeoCoord)) ){ const unsigned char *a = sqlite3_value_blob(pVal); int nVertex; nVertex = (a[1]<<16) + (a[2]<<8) + a[3]; if( (a[0]==0 && a[0]==1) && (nVertex*2*sizeof(GeoCoord) + 4)==nByte ){ p = sqlite3_malloc64( sizeof(*p) + (nVertex-1)*2*sizeof(GeoCoord) ); if( p ){ int x = 1; p->nVertex = nVertex; memcpy(p->hdr, a, nByte); if( a[0] != *(unsigned char*)&x ){ int ii; for(ii=0; ii<nVertex*2; ii++){ geopolySwab32((unsigned char*)&p->a[ii]); } p->hdr[0] ^= 1; } } } }else if( sqlite3_value_type(pVal)==SQLITE_TEXT ){ p = geopolyParseJson(sqlite3_value_text(pVal)); } if( p==0 ){ sqlite3_result_error(pCtx, "not a valid polygon", -1); } return p; } /* ** Implementation of the geopoly_blob(X) function. ** ** If the input is a well-formed Geopoly BLOB or JSON string ** then return the BLOB representation of the polygon. Otherwise ** return NULL. */ static void geopolyBlobFunc( sqlite3_context *context, int argc, sqlite3_value **argv ){ GeoPoly *p = geopolyFuncParam(context, argv[0]); if( p ){ sqlite3_result_blob(context, p->hdr, 4+8*p->nVertex, SQLITE_TRANSIENT); sqlite3_free(p); } } /* ** SQL function: geopoly_json(X) ** ** Interpret X as a polygon and render it as a JSON array ** of coordinates. Or, if X is not a valid polygon, return NULL. */ static void geopolyJsonFunc( sqlite3_context *context, int argc, sqlite3_value **argv ){ GeoPoly *p = geopolyFuncParam(context, argv[0]); if( p ){ sqlite3 *db = sqlite3_context_db_handle(context); sqlite3_str *x = sqlite3_str_new(db); int i; sqlite3_str_append(x, "[", 1); for(i=0; i<p->nVertex; i++){ sqlite3_str_appendf(x, "[%!g,%!g],", p->a[i*2], p->a[i*2+1]); } sqlite3_str_appendf(x, "[%!g,%!g]]", p->a[0], p->a[1]); sqlite3_result_text(context, sqlite3_str_finish(x), -1, sqlite3_free); sqlite3_free(p); } } /* ** SQL function: geopoly_svg(X, ....) ** ** Interpret X as a polygon and render it as a SVG <polyline>. ** Additional arguments are added as attributes to the <polyline>. */ static void geopolySvgFunc( sqlite3_context *context, int argc, sqlite3_value **argv ){ GeoPoly *p = geopolyFuncParam(context, argv[0]); if( p ){ sqlite3 *db = sqlite3_context_db_handle(context); sqlite3_str *x = sqlite3_str_new(db); int i; char cSep = '\''; sqlite3_str_appendf(x, "<polyline points="); for(i=0; i<p->nVertex; i++){ sqlite3_str_appendf(x, "%c%g,%g", cSep, p->a[i*2], p->a[i*2+1]); cSep = ' '; } sqlite3_str_appendf(x, " %g,%g'", p->a[0], p->a[1]); for(i=1; i<argc; i++){ const char *z = (const char*)sqlite3_value_text(argv[i]); if( z && z[0] ){ sqlite3_str_appendf(x, " %s", z); } } sqlite3_str_appendf(x, "></polyline>"); sqlite3_result_text(context, sqlite3_str_finish(x), -1, sqlite3_free); sqlite3_free(p); } } /* ** Implementation of the geopoly_area(X) function. ** ** If the input is a well-formed Geopoly BLOB then return the area ** enclosed by the polygon. If the polygon circulates clockwise instead ** of counterclockwise (as it should) then return the negative of the ** enclosed area. Otherwise return NULL. */ static void geopolyAreaFunc( sqlite3_context *context, int argc, sqlite3_value **argv ){ GeoPoly *p = geopolyFuncParam(context, argv[0]); if( p ){ double rArea = 0.0; int ii; for(ii=0; ii<p->nVertex-1; ii++){ rArea += (p->a[ii*2] - p->a[ii*2+2]) /* (x0 - x1) */ * (p->a[ii*2+1] + p->a[ii*2+3]) /* (y0 + y1) */ * 0.5; } rArea += (p->a[ii*2] - p->a[0]) /* (xN - x0) */ * (p->a[ii*2+1] + p->a[1]) /* (yN + y0) */ * 0.5; sqlite3_result_double(context, rArea); sqlite3_free(p); } } /* ** Determine if point (x0,y0) is beneath line segment (x1,y1)->(x2,y2). ** Returns: ** ** +2 x0,y0 is on the line segement ** ** +1 x0,y0 is beneath line segment ** ** 0 x0,y0 is not on or beneath the line segment or the line segment ** is vertical and x0,y0 is not on the line segment ** ** The left-most coordinate min(x1,x2) is not considered to be part of ** the line segment for the purposes of this analysis. */ static int pointBeneathLine( double x0, double y0, double x1, double y1, double x2, double y2 ){ double y; if( x0==x1 && y0==y1 ) return 2; if( x1<x2 ){ if( x0<=x1 || x0>x2 ) return 0; }else if( x1>x2 ){ if( x0<=x2 || x0>x1 ) return 0; }else{ /* Vertical line segment */ if( x0!=x1 ) return 0; if( y0<y1 && y0<y2 ) return 0; if( y0>y1 && y0>y2 ) return 0; return 2; } y = y1 + (y2-y1)*(x0-x1)/(x2-x1); if( y0==y ) return 2; if( y0<y ) return 1; return 0; } /* ** SQL function: geopoly_within(P,X,Y) ** ** Return +2 if point X,Y is within polygon P. ** Return +1 if point X,Y is on the polygon boundary. ** Return 0 if point X,Y is outside the polygon */ static void geopolyWithinFunc( sqlite3_context *context, int argc, sqlite3_value **argv ){ GeoPoly *p = geopolyFuncParam(context, argv[0]); double x0 = sqlite3_value_double(argv[1]); double y0 = sqlite3_value_double(argv[2]); if( p ){ int v = 0; int cnt = 0; int ii; for(ii=0; ii<p->nVertex-1; ii++){ v = pointBeneathLine(x0,y0,p->a[ii*2],p->a[ii*2+1], p->a[ii*2+2],p->a[ii*2+3]); if( v==2 ) break; cnt += v; } if( v!=2 ){ v = pointBeneathLine(x0,y0,p->a[ii*2],p->a[ii*2+1], p->a[0],p->a[1]); } if( v==2 ){ sqlite3_result_int(context, 1); }else if( ((v+cnt)&1)==0 ){ sqlite3_result_int(context, 0); }else{ sqlite3_result_int(context, 2); } sqlite3_free(p); } } /* Objects used by the overlap algorihm. */ typedef struct GeoEvent GeoEvent; typedef struct GeoSegment GeoSegment; typedef struct GeoOverlap GeoOverlap; struct GeoEvent { double x; /* X coordinate at which event occurs */ int eType; /* 0 for ADD, 1 for REMOVE */ GeoSegment *pSeg; /* The segment to be added or removed */ GeoEvent *pNext; /* Next event in the sorted list */ }; struct GeoSegment { double C, B; /* y = C*x + B */ double y; /* Current y value */ float y0; /* Initial y value */ unsigned char side; /* 1 for p1, 2 for p2 */ unsigned int idx; /* Which segment within the side */ GeoSegment *pNext; /* Next segment in a list sorted by y */ }; struct GeoOverlap { GeoEvent *aEvent; /* Array of all events */ GeoSegment *aSegment; /* Array of all segments */ int nEvent; /* Number of events */ int nSegment; /* Number of segments */ }; /* ** Add a single segment and its associated events. */ static void geopolyAddOneSegment( GeoOverlap *p, GeoCoord x0, GeoCoord y0, GeoCoord x1, GeoCoord y1, unsigned char side, unsigned int idx ){ GeoSegment *pSeg; GeoEvent *pEvent; if( x0==x1 ) return; /* Ignore vertical segments */ if( x0>x1 ){ GeoCoord t = x0; x0 = x1; x1 = t; t = y0; y0 = y1; y1 = t; } pSeg = p->aSegment + p->nSegment; p->nSegment++; pSeg->C = (y1-y0)/(x1-x0); pSeg->B = y1 - x1*pSeg->C; pSeg->y0 = y0; pSeg->side = side; pSeg->idx = idx; pEvent = p->aEvent + p->nEvent; p->nEvent++; pEvent->x = x0; pEvent->eType = 0; pEvent->pSeg = pSeg; pEvent = p->aEvent + p->nEvent; p->nEvent++; pEvent->x = x1; pEvent->eType = 1; pEvent->pSeg = pSeg; } /* ** Insert all segments and events for polygon pPoly. */ static void geopolyAddSegments( GeoOverlap *p, /* Add segments to this Overlap object */ GeoPoly *pPoly, /* Take all segments from this polygon */ unsigned char side /* The side of pPoly */ ){ unsigned int i; GeoCoord *x; for(i=0; i<pPoly->nVertex-1; i++){ x = pPoly->a + (i*2); geopolyAddOneSegment(p, x[0], x[1], x[2], x[3], side, i); } x = pPoly->a + (i*2); geopolyAddOneSegment(p, x[0], x[1], pPoly->a[0], pPoly->a[1], side, i); } /* ** Merge two lists of sorted events by X coordinate */ static GeoEvent *geopolyEventMerge(GeoEvent *pLeft, GeoEvent *pRight){ GeoEvent head, *pLast; head.pNext = 0; pLast = &head; while( pRight && pLeft ){ if( pRight->x <= pLeft->x ){ pLast->pNext = pRight; pLast = pRight; pRight = pRight->pNext; }else{ pLast->pNext = pLeft; pLast = pLeft; pLeft = pLeft->pNext; } } pLast->pNext = pRight ? pRight : pLeft; return head.pNext; } /* ** Sort an array of nEvent event objects into a list. */ static GeoEvent *geopolySortEventsByX(GeoEvent *aEvent, int nEvent){ int mx = 0; int i, j; GeoEvent *p; GeoEvent *a[50]; for(i=0; i<nEvent; i++){ p = &aEvent[i]; p->pNext = 0; for(j=0; j<mx && a[j]; j++){ p = geopolyEventMerge(a[j], p); a[j] = 0; } a[j] = p; if( j>=mx ) mx = j+1; } p = 0; for(i=0; i<mx; i++){ p = geopolyEventMerge(a[i], p); } return p; } /* ** Merge two lists of sorted segments by Y, and then by C. */ static GeoSegment *geopolySegmentMerge(GeoSegment *pLeft, GeoSegment *pRight){ GeoSegment head, *pLast; head.pNext = 0; pLast = &head; while( pRight && pLeft ){ double r = pRight->y - pLeft->y; if( r==0.0 ) r = pRight->C - pLeft->C; if( r<0.0 ){ pLast->pNext = pRight; pLast = pRight; pRight = pRight->pNext; }else{ pLast->pNext = pLeft; pLast = pLeft; pLeft = pLeft->pNext; } } pLast->pNext = pRight ? pRight : pLeft; return head.pNext; } /* ** Sort a list of GeoSegments in order of increasing Y and in the event of ** a tie, increasing C (slope). */ static GeoSegment *geopolySortSegmentsByYAndC(GeoSegment *pList){ int mx = 0; int i; GeoSegment *p; GeoSegment *a[50]; while( pList ){ p = pList; pList = pList->pNext; p->pNext = 0; for(i=0; i<mx && a[i]; i++){ p = geopolySegmentMerge(a[i], p); a[i] = 0; } a[i] = p; if( i>=mx ) mx = i+1; } p = 0; for(i=0; i<mx; i++){ p = geopolySegmentMerge(a[i], p); } return p; } /* ** Determine the overlap between two polygons */ static int geopolyOverlap(GeoPoly *p1, GeoPoly *p2){ int nVertex = p1->nVertex + p2->nVertex + 2; GeoOverlap *p; int nByte; GeoEvent *pThisEvent; double rX; int rc = 0; int needSort = 0; GeoSegment *pActive = 0; GeoSegment *pSeg; unsigned char aOverlap[4]; nByte = sizeof(GeoEvent)*nVertex*2 + sizeof(GeoSegment)*nVertex + sizeof(GeoOverlap); p = sqlite3_malloc( nByte ); if( p==0 ) return -1; p->aEvent = (GeoEvent*)&p[1]; p->aSegment = (GeoSegment*)&p->aEvent[nVertex*2]; p->nEvent = p->nSegment = 0; geopolyAddSegments(p, p1, 1); geopolyAddSegments(p, p2, 2); pThisEvent = geopolySortEventsByX(p->aEvent, p->nEvent); rX = pThisEvent->x==0.0 ? -1.0 : 0.0; memset(aOverlap, 0, sizeof(aOverlap)); while( pThisEvent ){ if( pThisEvent->x!=rX ){ GeoSegment *pPrev = 0; int iMask = 0; GEODEBUG(("Distinct X: %g\n", pThisEvent->x)); rX = pThisEvent->x; if( needSort ){ GEODEBUG(("SORT\n")); pActive = geopolySortSegmentsByYAndC(pActive); needSort = 0; } for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){ if( pPrev ){ if( pPrev->y!=pSeg->y ){ GEODEBUG(("MASK: %d\n", iMask)); aOverlap[iMask] = 1; } } iMask ^= pSeg->side; pPrev = pSeg; } pPrev = 0; for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){ double y = pSeg->C*rX + pSeg->B; GEODEBUG(("Segment %d.%d %g->%g\n", pSeg->side, pSeg->idx, pSeg->y, y)); pSeg->y = y; if( pPrev ){ if( pPrev->y>pSeg->y && pPrev->side!=pSeg->side ){ rc = 1; GEODEBUG(("Crossing: %d.%d and %d.%d\n", pPrev->side, pPrev->idx, pSeg->side, pSeg->idx)); goto geopolyOverlapDone; }else if( pPrev->y!=pSeg->y ){ GEODEBUG(("MASK: %d\n", iMask)); aOverlap[iMask] = 1; } } iMask ^= pSeg->side; pPrev = pSeg; } } GEODEBUG(("%s %d.%d C=%g B=%g\n", pThisEvent->eType ? "RM " : "ADD", pThisEvent->pSeg->side, pThisEvent->pSeg->idx, pThisEvent->pSeg->C, pThisEvent->pSeg->B)); if( pThisEvent->eType==0 ){ /* Add a segment */ pSeg = pThisEvent->pSeg; pSeg->y = pSeg->y0; pSeg->pNext = pActive; pActive = pSeg; needSort = 1; }else{ /* Remove a segment */ if( pActive==pThisEvent->pSeg ){ pActive = pActive->pNext; }else{ for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){ if( pSeg->pNext==pThisEvent->pSeg ){ pSeg->pNext = pSeg->pNext->pNext; break; } } } } pThisEvent = pThisEvent->pNext; } if( aOverlap[3]==0 ){ rc = 0; }else if( aOverlap[1]!=0 && aOverlap[2]==0 ){ rc = 3; }else if( aOverlap[1]==0 && aOverlap[2]!=0 ){ rc = 2; }else if( aOverlap[1]==0 && aOverlap[2]==0 ){ rc = 4; }else{ rc = 1; } geopolyOverlapDone: sqlite3_free(p); return rc; } /* ** SQL function: geopoly_overlap(P1,P2) ** ** Determine whether or not P1 and P2 overlap. Return value: ** ** 0 The two polygons are disjoint ** 1 They overlap ** 2 P1 is completely contained within P2 ** 3 P2 is completely contained within P1 ** 4 P1 and P2 are the same polygon ** NULL Either P1 or P2 or both are not valid polygons */ static void geopolyOverlapFunc( sqlite3_context *context, int argc, sqlite3_value **argv ){ GeoPoly *p1 = geopolyFuncParam(context, argv[0]); GeoPoly *p2 = geopolyFuncParam(context, argv[1]); if( p1 && p2 ){ int x = geopolyOverlap(p1, p2); if( x<0 ){ sqlite3_result_error_nomem(context); }else{ sqlite3_result_int(context, x); } } sqlite3_free(p1); sqlite3_free(p2); } /* ** Enable or disable debugging output */ static void geopolyDebugFunc( sqlite3_context *context, int argc, sqlite3_value **argv ){ #ifdef GEOPOLY_ENABLE_DEBUG geo_debug = sqlite3_value_int(argv[0]); #endif } #ifdef _WIN32 __declspec(dllexport) #endif int sqlite3_geopoly_init( sqlite3 *db, char **pzErrMsg, const sqlite3_api_routines *pApi ){ int rc = SQLITE_OK; static const struct { void (*xFunc)(sqlite3_context*,int,sqlite3_value**); int nArg; const char *zName; } aFunc[] = { { geopolyAreaFunc, 1, "geopoly_area" }, { geopolyBlobFunc, 1, "geopoly_blob" }, { geopolyJsonFunc, 1, "geopoly_json" }, { geopolySvgFunc, -1, "geopoly_svg" }, { geopolyWithinFunc, 3, "geopoly_within" }, { geopolyOverlapFunc, 2, "geopoly_overlap" }, { geopolyDebugFunc, 1, "geopoly_debug" }, }; int i; SQLITE_EXTENSION_INIT2(pApi); (void)pzErrMsg; /* Unused parameter */ for(i=0; i<sizeof(aFunc)/sizeof(aFunc[0]) && rc==SQLITE_OK; i++){ rc = sqlite3_create_function(db, aFunc[i].zName, aFunc[i].nArg, SQLITE_UTF8, 0, aFunc[i].xFunc, 0, 0); } return rc; } |