Datum
copytext(PG_FUNCTION_ARGS)
{
- text *t = PG_GETARG_TEXT_P(0);
+ text *t = PG_GETARG_TEXT_PP(0);
+
/*
- * VARSIZE is the total size of the struct in bytes.
+ * VARSIZE_ANY_EXHDR is the size of the struct in bytes, minus the
+ * VARHDRSZ or VARHDRSZ_SHORT of its header. Construct the copy with a
+ * full-length header.
*/
- text *new_t = (text *) palloc(VARSIZE(t));
- SET_VARSIZE(new_t, VARSIZE(t));
+ text *new_t = (text *) palloc(VARSIZE_ANY_EXHDR(t) + VARHDRSZ);
+ SET_VARSIZE(new_t, VARSIZE_ANY_EXHDR(t) + VARHDRSZ);
+
/*
- * VARDATA is a pointer to the data region of the struct.
+ * VARDATA is a pointer to the data region of the new struct. The source
+ * could be a short datum, so retrieve its data through VARDATA_ANY.
*/
memcpy((void *) VARDATA(new_t), /* destination */
- (void *) VARDATA(t), /* source */
- VARSIZE(t) - VARHDRSZ); /* how many bytes */
+ (void *) VARDATA_ANY(t), /* source */
+ VARSIZE_ANY_EXHDR(t)); /* how many bytes */
PG_RETURN_TEXT_P(new_t);
}
Datum
concat_text(PG_FUNCTION_ARGS)
{
- text *arg1 = PG_GETARG_TEXT_P(0);
- text *arg2 = PG_GETARG_TEXT_P(1);
- int32 new_text_size = VARSIZE(arg1) + VARSIZE(arg2) - VARHDRSZ;
+ text *arg1 = PG_GETARG_TEXT_PP(0);
+ text *arg2 = PG_GETARG_TEXT_PP(1);
+ int32 arg1_size = VARSIZE_ANY_EXHDR(arg1);
+ int32 arg2_size = VARSIZE_ANY_EXHDR(arg2);
+ int32 new_text_size = arg1_size + arg2_size + VARHDRSZ;
text *new_text = (text *) palloc(new_text_size);
SET_VARSIZE(new_text, new_text_size);
- memcpy(VARDATA(new_text), VARDATA(arg1), VARSIZE(arg1) - VARHDRSZ);
- memcpy(VARDATA(new_text) + (VARSIZE(arg1) - VARHDRSZ),
- VARDATA(arg2), VARSIZE(arg2) - VARHDRSZ);
+ memcpy(VARDATA(new_text), VARDATA_ANY(arg1), arg1_size);
+ memcpy(VARDATA(new_text) + arg1_size, VARDATA_ANY(arg2), arg2_size);
PG_RETURN_TEXT_P(new_text);
}
]]>
* may be compressed or moved out-of-line. However datatype-specific routines
* are mostly content to deal with de-TOASTed values only, and of course
* client-side routines should never see a TOASTed value. But even in a
- * de-TOASTed value, beware of touching vl_len_ directly, as its representation
- * is no longer convenient. It's recommended that code always use the VARDATA,
- * VARSIZE, and SET_VARSIZE macros instead of relying on direct mentions of
- * the struct fields. See postgres.h for details of the TOASTed form.
+ * de-TOASTed value, beware of touching vl_len_ directly, as its
+ * representation is no longer convenient. It's recommended that code always
+ * use macros VARDATA_ANY, VARSIZE_ANY, VARSIZE_ANY_EXHDR, VARDATA, VARSIZE,
+ * and SET_VARSIZE instead of relying on direct mentions of the struct fields.
+ * See postgres.h for details of the TOASTed form.
* ----------------
*/
struct varlena
* The resulting datum can be accessed using VARSIZE_ANY() and VARDATA_ANY()
* (beware of multiple evaluations in those macros!)
*
- * WARNING: It is only safe to use pg_detoast_datum_packed() and
- * VARDATA_ANY() if you really don't care about the alignment. Either because
- * you're working with something like text where the alignment doesn't matter
- * or because you're not going to access its constituent parts and just use
- * things like memcpy on it anyways.
+ * In consumers oblivious to data alignment, call PG_DETOAST_DATUM_PACKED(),
+ * VARDATA_ANY(), VARSIZE_ANY() and VARSIZE_ANY_EXHDR(). Elsewhere, call
+ * PG_DETOAST_DATUM(), VARDATA() and VARSIZE(). Directly fetching an int16,
+ * int32 or wider field in the struct representing the datum layout requires
+ * aligned data. memcpy() is alignment-oblivious, as are most operations on
+ * datatypes, such as text, whose layout struct contains only char fields.
*
* Note: it'd be nice if these could be macros, but I see no way to do that
* without evaluating the arguments multiple times, which is NOT acceptable.
/* and this if you can handle 1-byte-header datums: */
#define PG_GETARG_VARLENA_PP(n) PG_DETOAST_DATUM_PACKED(PG_GETARG_DATUM(n))
/* DatumGetFoo macros for varlena types will typically look like this: */
-#define DatumGetByteaP(X) ((bytea *) PG_DETOAST_DATUM(X))
#define DatumGetByteaPP(X) ((bytea *) PG_DETOAST_DATUM_PACKED(X))
-#define DatumGetTextP(X) ((text *) PG_DETOAST_DATUM(X))
#define DatumGetTextPP(X) ((text *) PG_DETOAST_DATUM_PACKED(X))
-#define DatumGetBpCharP(X) ((BpChar *) PG_DETOAST_DATUM(X))
#define DatumGetBpCharPP(X) ((BpChar *) PG_DETOAST_DATUM_PACKED(X))
-#define DatumGetVarCharP(X) ((VarChar *) PG_DETOAST_DATUM(X))
#define DatumGetVarCharPP(X) ((VarChar *) PG_DETOAST_DATUM_PACKED(X))
#define DatumGetHeapTupleHeader(X) ((HeapTupleHeader) PG_DETOAST_DATUM(X))
/* And we also offer variants that return an OK-to-write copy */
#define DatumGetBpCharPSlice(X,m,n) ((BpChar *) PG_DETOAST_DATUM_SLICE(X,m,n))
#define DatumGetVarCharPSlice(X,m,n) ((VarChar *) PG_DETOAST_DATUM_SLICE(X,m,n))
/* GETARG macros for varlena types will typically look like this: */
-#define PG_GETARG_BYTEA_P(n) DatumGetByteaP(PG_GETARG_DATUM(n))
#define PG_GETARG_BYTEA_PP(n) DatumGetByteaPP(PG_GETARG_DATUM(n))
-#define PG_GETARG_TEXT_P(n) DatumGetTextP(PG_GETARG_DATUM(n))
#define PG_GETARG_TEXT_PP(n) DatumGetTextPP(PG_GETARG_DATUM(n))
-#define PG_GETARG_BPCHAR_P(n) DatumGetBpCharP(PG_GETARG_DATUM(n))
#define PG_GETARG_BPCHAR_PP(n) DatumGetBpCharPP(PG_GETARG_DATUM(n))
-#define PG_GETARG_VARCHAR_P(n) DatumGetVarCharP(PG_GETARG_DATUM(n))
#define PG_GETARG_VARCHAR_PP(n) DatumGetVarCharPP(PG_GETARG_DATUM(n))
#define PG_GETARG_HEAPTUPLEHEADER(n) DatumGetHeapTupleHeader(PG_GETARG_DATUM(n))
/* And we also offer variants that return an OK-to-write copy */
#define PG_GETARG_TEXT_P_SLICE(n,a,b) DatumGetTextPSlice(PG_GETARG_DATUM(n),a,b)
#define PG_GETARG_BPCHAR_P_SLICE(n,a,b) DatumGetBpCharPSlice(PG_GETARG_DATUM(n),a,b)
#define PG_GETARG_VARCHAR_P_SLICE(n,a,b) DatumGetVarCharPSlice(PG_GETARG_DATUM(n),a,b)
+/*
+ * Obsolescent variants that guarantee INT alignment for the return value.
+ * Few operations on these particular types need alignment, mainly operations
+ * that cast the VARDATA pointer to a type like int16[]. Most code should use
+ * the ...PP(X) counterpart. Nonetheless, these appear frequently in code
+ * predating the PostgreSQL 8.3 introduction of the ...PP(X) variants.
+ */
+#define DatumGetByteaP(X) ((bytea *) PG_DETOAST_DATUM(X))
+#define DatumGetTextP(X) ((text *) PG_DETOAST_DATUM(X))
+#define DatumGetBpCharP(X) ((BpChar *) PG_DETOAST_DATUM(X))
+#define DatumGetVarCharP(X) ((VarChar *) PG_DETOAST_DATUM(X))
+#define PG_GETARG_BYTEA_P(n) DatumGetByteaP(PG_GETARG_DATUM(n))
+#define PG_GETARG_TEXT_P(n) DatumGetTextP(PG_GETARG_DATUM(n))
+#define PG_GETARG_BPCHAR_P(n) DatumGetBpCharP(PG_GETARG_DATUM(n))
+#define PG_GETARG_VARCHAR_P(n) DatumGetVarCharP(PG_GETARG_DATUM(n))
/* To return a NULL do this: */
#define PG_RETURN_NULL() \
/* Externally visible macros */
/*
- * VARDATA, VARSIZE, and SET_VARSIZE are the recommended API for most code
- * for varlena datatypes. Note that they only work on untoasted,
- * 4-byte-header Datums!
- *
- * Code that wants to use 1-byte-header values without detoasting should
- * use VARSIZE_ANY/VARSIZE_ANY_EXHDR/VARDATA_ANY. The other macros here
- * should usually be used only by tuple assembly/disassembly code and
- * code that specifically wants to work with still-toasted Datums.
- *
- * WARNING: It is only safe to use VARDATA_ANY() -- typically with
- * PG_DETOAST_DATUM_PACKED() -- if you really don't care about the alignment.
- * Either because you're working with something like text where the alignment
- * doesn't matter or because you're not going to access its constituent parts
- * and just use things like memcpy on it anyways.
+ * In consumers oblivious to data alignment, call PG_DETOAST_DATUM_PACKED(),
+ * VARDATA_ANY(), VARSIZE_ANY() and VARSIZE_ANY_EXHDR(). Elsewhere, call
+ * PG_DETOAST_DATUM(), VARDATA() and VARSIZE(). Directly fetching an int16,
+ * int32 or wider field in the struct representing the datum layout requires
+ * aligned data. memcpy() is alignment-oblivious, as are most operations on
+ * datatypes, such as text, whose layout struct contains only char fields.
+ *
+ * Code assembling a new datum should call VARDATA() and SET_VARSIZE().
+ * (Datums begin life untoasted.)
+ *
+ * Other macros here should usually be used only by tuple assembly/disassembly
+ * code and code that specifically wants to work with still-toasted Datums.
*/
#define VARDATA(PTR) VARDATA_4B(PTR)
#define VARSIZE(PTR) VARSIZE_4B(PTR)
/*
* fmgr interface macros
*/
-#define DatumGetInetP(X) ((inet *) PG_DETOAST_DATUM(X))
#define DatumGetInetPP(X) ((inet *) PG_DETOAST_DATUM_PACKED(X))
#define InetPGetDatum(X) PointerGetDatum(X)
-#define PG_GETARG_INET_P(n) DatumGetInetP(PG_GETARG_DATUM(n))
#define PG_GETARG_INET_PP(n) DatumGetInetPP(PG_GETARG_DATUM(n))
#define PG_RETURN_INET_P(x) return InetPGetDatum(x)
+/* obsolescent variants */
+#define DatumGetInetP(X) ((inet *) PG_DETOAST_DATUM(X))
+#define PG_GETARG_INET_P(n) DatumGetInetP(PG_GETARG_DATUM(n))
/* macaddr is a fixed-length pass-by-reference datatype */
#define DatumGetMacaddrP(X) ((macaddr *) DatumGetPointer(X))
#define MacaddrPGetDatum(X) PointerGetDatum(X)
Datum
copytext(PG_FUNCTION_ARGS)
{
- text *t = PG_GETARG_TEXT_P(0);
+ text *t = PG_GETARG_TEXT_PP(0);
/*
- * VARSIZE is the total size of the struct in bytes.
+ * VARSIZE_ANY_EXHDR is the size of the struct in bytes, minus the
+ * VARHDRSZ or VARHDRSZ_SHORT of its header. Construct the copy with a
+ * full-length header.
*/
- text *new_t = (text *) palloc(VARSIZE(t));
+ text *new_t = (text *) palloc(VARSIZE_ANY_EXHDR(t) + VARHDRSZ);
- SET_VARSIZE(new_t, VARSIZE(t));
+ SET_VARSIZE(new_t, VARSIZE_ANY_EXHDR(t) + VARHDRSZ);
/*
- * VARDATA is a pointer to the data region of the struct.
+ * VARDATA is a pointer to the data region of the new struct. The source
+ * could be a short datum, so retrieve its data through VARDATA_ANY.
*/
memcpy((void *) VARDATA(new_t), /* destination */
- (void *) VARDATA(t), /* source */
- VARSIZE(t) - VARHDRSZ); /* how many bytes */
+ (void *) VARDATA_ANY(t), /* source */
+ VARSIZE_ANY_EXHDR(t)); /* how many bytes */
PG_RETURN_TEXT_P(new_t);
}
Datum
concat_text(PG_FUNCTION_ARGS)
{
- text *arg1 = PG_GETARG_TEXT_P(0);
- text *arg2 = PG_GETARG_TEXT_P(1);
- int32 arg1_size = VARSIZE(arg1) - VARHDRSZ;
- int32 arg2_size = VARSIZE(arg2) - VARHDRSZ;
+ text *arg1 = PG_GETARG_TEXT_PP(0);
+ text *arg2 = PG_GETARG_TEXT_PP(1);
+ int32 arg1_size = VARSIZE_ANY_EXHDR(arg1);
+ int32 arg2_size = VARSIZE_ANY_EXHDR(arg2);
int32 new_text_size = arg1_size + arg2_size + VARHDRSZ;
text *new_text = (text *) palloc(new_text_size);
SET_VARSIZE(new_text, new_text_size);
- memcpy(VARDATA(new_text), VARDATA(arg1), arg1_size);
- memcpy(VARDATA(new_text) + arg1_size, VARDATA(arg2), arg2_size);
+ memcpy(VARDATA(new_text), VARDATA_ANY(arg1), arg1_size);
+ memcpy(VARDATA(new_text) + arg1_size, VARDATA_ANY(arg2), arg2_size);
PG_RETURN_TEXT_P(new_text);
}
projects / postgresql / commitdiff