Function SerializeParamList

src/backend/nodes/params.c:228–279

* Serialize a ParamListInfo structure into caller-provided storage. * * We write the number of parameters first, as a 4-byte integer, and then * write details for each parameter in turn. The details for each parameter * consist of a 4-byte type OID, 2 bytes of flags, and then the datum as * serialized by datumSerialize(). The caller is responsible for ensuring * that there is enough storag

 * paramValuesStr is not included.
 */
void
SerializeParamList(ParamListInfo paramLI, char **start_address)
{
	int			nparams;
	int			i;

	/* Write number of parameters. */
	if (paramLI == NULL || paramLI->numParams <= 0)
		nparams = 0;
	else
		nparams = paramLI->numParams;
	memcpy(*start_address, &nparams, sizeof(int));
	*start_address += sizeof(int);

	/* Write each parameter in turn. */
	for (i = 0; i < nparams; i++)
	{
		ParamExternData *prm;
		ParamExternData prmdata;
		Oid			typeOid;
		int16		typLen;
		bool		typByVal;

		/* give hook a chance in case parameter is dynamic */
		if (paramLI->paramFetch != NULL)
			prm = paramLI->paramFetch(paramLI, i + 1, false, &prmdata);
		else
			prm = &paramLI->params[i];

		typeOid = prm->ptype;

		/* Write type OID. */
		memcpy(*start_address, &typeOid, sizeof(Oid));
		*start_address += sizeof(Oid);

		/* Write flags. */
		memcpy(*start_address, &prm->pflags, sizeof(uint16));
		*start_address += sizeof(uint16);

		/* Write datum/isnull. */
		if (OidIsValid(typeOid))
			get_typlenbyval(typeOid, &typLen, &typByVal);
		else
		{
			/* If no type OID, assume by-value, like copyParamList does. */
			typLen = sizeof(Datum);
			typByVal = true;
		}
		datumSerialize(prm->value, prm->isnull, typByVal, typLen,
					   start_address);
	}
}

/*
 * Copy a ParamListInfo structure.