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7b416c8c1a
represented as "char ...[4]" not "int32". Since the length word is never supposed to be accessed via this struct member anyway, this won't break any existing code that is following the rules. The advantage is that C compilers will no longer assume that a pointer to struct varlena is word-aligned, which prevents incorrect optimizations in TOAST-pointer access and perhaps other places. gcc doesn't seem to do this (at least not at -O2), but the problem is demonstrable on some other compilers. I changed struct inet as well, but didn't bother to touch a lot of other struct definitions in which it wouldn't make any difference because there were other fields forcing int alignment anyway. Hopefully none of those struct definitions are used for accessing unaligned Datums.
84 lines
2.6 KiB
C
84 lines
2.6 KiB
C
/*-------------------------------------------------------------------------
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*
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* inet.h
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* Declarations for operations on INET datatypes.
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*
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*
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* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/utils/inet.h,v 1.28.2.1 2008/02/23 19:11:55 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef INET_H
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#define INET_H
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#include "fmgr.h"
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/*
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* This is the internal storage format for IP addresses
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* (both INET and CIDR datatypes):
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*/
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typedef struct
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{
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unsigned char family; /* PGSQL_AF_INET or PGSQL_AF_INET6 */
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unsigned char bits; /* number of bits in netmask */
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unsigned char ipaddr[16]; /* up to 128 bits of address */
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} inet_struct;
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/*
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* Referencing all of the non-AF_INET types to AF_INET lets us work on
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* machines which may not have the appropriate address family (like
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* inet6 addresses when AF_INET6 isn't present) but doesn't cause a
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* dump/reload requirement. Existing databases used AF_INET for the family
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* type on disk.
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*/
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#define PGSQL_AF_INET (AF_INET + 0)
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#define PGSQL_AF_INET6 (AF_INET + 1)
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/*
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* Both INET and CIDR addresses are represented within Postgres as varlena
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* objects, ie, there is a varlena header in front of the struct type
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* depicted above. This struct depicts what we actually have in memory
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* in "uncompressed" cases. Note that since the maximum data size is only
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* 18 bytes, INET/CIDR will invariably be stored into tuples using the
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* 1-byte-header varlena format. However, we have to be prepared to cope
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* with the 4-byte-header format too, because various code may helpfully
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* try to "decompress" 1-byte-header datums.
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*/
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typedef struct
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{
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char vl_len_[4]; /* Do not touch this field directly! */
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inet_struct inet_data;
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} inet;
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/*
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* This is the internal storage format for MAC addresses:
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*/
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typedef struct macaddr
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{
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unsigned char a;
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unsigned char b;
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unsigned char c;
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unsigned char d;
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unsigned char e;
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unsigned char f;
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} macaddr;
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/*
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* fmgr interface macros
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*/
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#define DatumGetInetP(X) ((inet *) PG_DETOAST_DATUM_PACKED(X))
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#define InetPGetDatum(X) PointerGetDatum(X)
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#define PG_GETARG_INET_P(n) DatumGetInetP(PG_GETARG_DATUM(n))
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#define PG_RETURN_INET_P(x) return InetPGetDatum(x)
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/* macaddr is a fixed-length pass-by-reference datatype */
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#define DatumGetMacaddrP(X) ((macaddr *) DatumGetPointer(X))
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#define MacaddrPGetDatum(X) PointerGetDatum(X)
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#define PG_GETARG_MACADDR_P(n) DatumGetMacaddrP(PG_GETARG_DATUM(n))
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#define PG_RETURN_MACADDR_P(x) return MacaddrPGetDatum(x)
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#endif /* INET_H */
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