gserialized2_hash()

int32_t gserialized2_hash

(

const GSERIALIZED *

g

)

Returns a hash code for the srid/type/geometry information in the GSERIALIZED.

Ignores metadata like flags and optional boxes, etc.

Definition at line 301 of file gserialized2.c.

{
        int32_t hval;
        int32_t pb = 0, pc = 0;
        /* Point to just the type/coordinate part of buffer */
        size_t hsz1 = gserialized2_header_size(g1);
        uint8_t *b1 = (uint8_t *)g1 + hsz1;
        /* Calculate size of type/coordinate buffer */
        size_t sz1 = SIZE_GET(g1->size);
        size_t bsz1 = sz1 - hsz1;
        /* Calculate size of srid/type/coordinate buffer */
        int32_t srid = gserialized2_get_srid(g1);
        size_t bsz2 = bsz1 + sizeof(int);
        uint8_t *b2 = lwalloc(bsz2);
        /* Copy srid into front of combined buffer */
        memcpy(b2, &srid, sizeof(int));
        /* Copy type/coordinates into rest of combined buffer */
        memcpy(b2+sizeof(int), b1, bsz1);
        /* Hash combined buffer */
        hashlittle2(b2, bsz2, (uint32_t *)&pb, (uint32_t *)&pc);
        lwfree(b2);
        hval = pb ^ pc;
        return hval;
}

References gserialized2_get_srid(), gserialized2_header_size(), hashlittle2(), lwalloc(), lwfree(), GSERIALIZED::size, and SIZE_GET.

Referenced by gserialized_hash().

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