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/* $Id: pgc_casts.c 1586 2018-03-18 09:26:31Z coelho $
*
* additional cast functions.
*/
#include "postgres.h"
#include "executor/spi.h"
#include "catalog/pg_type.h"
#include "utils/varbit.h"
#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif
extern Datum varbitfrombytea(PG_FUNCTION_ARGS);
extern Datum varbittobytea(PG_FUNCTION_ARGS);
extern Datum varbittoint2(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(varbitfrombytea);
PG_FUNCTION_INFO_V1(varbittobytea);
PG_FUNCTION_INFO_V1(varbittoint2);
/* create a bit string from a byte array.
*/
Datum varbitfrombytea(PG_FUNCTION_ARGS)
{
bytea *arg = PG_GETARG_BYTEA_P(0);
int32 typmod = PG_GETARG_INT32(1); /* for ::BIT(10) syntax */
/* bool isExplicit = PG_GETARG_BOOL(2); */
int datalen = VARSIZE(arg) - VARHDRSZ;
int bitlen = BITS_PER_BYTE * datalen;
int len, resbitlen, resdatalen, needlen;
VarBit *result;
/* truncate or expand if required */
if (typmod>=0)
{
resbitlen = typmod;
resdatalen = (resbitlen + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
needlen = datalen>resdatalen? resdatalen: datalen;
}
else
{
resbitlen = bitlen;
resdatalen = datalen;
needlen = datalen;
}
len = VARBITTOTALLEN(resbitlen);
result = (VarBit *) palloc(len);
SET_VARSIZE(result, len);
VARBITLEN(result) = resbitlen;
memcpy(VARBITS(result), VARDATA(arg), needlen);
if (resdatalen > needlen)
{
unsigned char *ptr = VARBITS(result) + needlen;
while (needlen<resdatalen)
{
*ptr++ = '\000';
needlen++;
}
}
PG_RETURN_VARBIT_P(result);
}
Datum varbittobytea(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
bool isExplicit = PG_GETARG_BOOL(2);
int bitlen = VARBITLEN(arg);
int datalen = (bitlen + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
int len = datalen + VARHDRSZ;
bytea *result;
/* no implicit cast if data size is changed */
if (!isExplicit && (bitlen != BITS_PER_BYTE*datalen))
ereport(ERROR,
(errcode(ERRCODE_STRING_DATA_LENGTH_MISMATCH),
errmsg("bit length %d would be round up, use explicit cast",
bitlen)));
result = (bytea *) palloc(len);
SET_VARSIZE(result, len);
memcpy(VARDATA(result), VARBITS(arg), datalen);
PG_RETURN_BYTEA_P(result);
}
// hmmm... I'm quite unsure about byte order and so...
Datum varbittoint2(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
bool isExplicit = PG_GETARG_BOOL(2);
int bitlen = VARBITLEN(arg);
int16 result = 0;
/* no implicit cast if data size is changed */
if (!isExplicit && (bitlen != BITS_PER_BYTE*2))
ereport(ERROR,
(errcode(ERRCODE_STRING_DATA_LENGTH_MISMATCH),
errmsg("bit length %d would be round up, use explicit cast",
bitlen)));
memcpy(&result, VARBITS(arg), 2);
PG_RETURN_INT16(result);
}
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