postgresql/src/include/c.h

/*-------------------------------------------------------------------------
 *
 * c.h
 *	  Fundamental C definitions.  This is included by every .c file in
 *	  PostgreSQL (via either postgres.h or postgres_fe.h, as appropriate).
 *
 *	  Note that the definitions here are not intended to be exposed to clients of
 *	  the frontend interface libraries --- so we don't worry much about polluting
 *	  the namespace with lots of stuff...
 *
 *
 * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $Id: c.h,v 1.104 2001/10/19 15:38:57 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
/*
 *----------------------------------------------------------------
 *	 TABLE OF CONTENTS
 *
 *		When adding stuff to this file, please try to put stuff
 *		into the relevant section, or add new sections as appropriate.
 *
 *	  section	description
 *	  -------	------------------------------------------------
 *		0)		pg_config.h and standard system headers
 *		1)		hacks to cope with non-ANSI C compilers
 *		2)		bool, true, false, TRUE, FALSE, NULL
 *		3)		standard system types
 *		4)		IsValid macros for system types
 *		5)		offsetof, lengthof, endof, alignment
 *		6)		widely useful macros
 *		7)		random stuff
 *		8)		system-specific hacks
 *
 * NOTE: since this file is included by both frontend and backend modules, it's
 * almost certainly wrong to put an "extern" declaration here.	typedefs and macros
 * are the kind of thing that might go here.
 *
 *----------------------------------------------------------------
 */
#ifndef C_H
#define C_H

/* We have to include stdlib.h here because it defines many of these macros
   on some platforms, and we only want our definitions used if stdlib.h doesn't
   have its own.  The same goes for stddef and stdarg if present.
*/

#include "pg_config.h"
#include "postgres_ext.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <stdarg.h>
#ifdef STRING_H_WITH_STRINGS_H
#include <strings.h>
#endif

#ifdef __CYGWIN__
#include <errno.h>
#include <sys/fcntl.h>			/* ensure O_BINARY is available */
#endif
#ifdef HAVE_SUPPORTDEFS_H
#include <SupportDefs.h>
#endif

#ifdef ENABLE_NLS
#include <libintl.h>
#else
#define gettext(x) (x)
#endif
#define gettext_noop(x) (x)


/* ----------------------------------------------------------------
 *				Section 1: hacks to cope with non-ANSI C compilers
 *
 * type prefixes (const, signed, volatile, inline) are handled in pg_config.h.
 * ----------------------------------------------------------------
 */

/*
 * CppAsString
 *		Convert the argument to a string, using the C preprocessor.
 * CppConcat
 *		Concatenate two arguments together, using the C preprocessor.
 *
 * Note: the standard Autoconf macro AC_C_STRINGIZE actually only checks
 * whether #identifier works, but if we have that we likely have ## too.
 */
#if defined(HAVE_STRINGIZE)

#define CppAsString(identifier) #identifier
#define CppConcat(x, y)			x##y

#else							/* !HAVE_STRINGIZE */

#define CppAsString(identifier) "identifier"

/*
 * CppIdentity -- On Reiser based cpp's this is used to concatenate
 *		two tokens.  That is
 *				CppIdentity(A)B ==> AB
 *		We renamed it to _private_CppIdentity because it should not
 *		be referenced outside this file.  On other cpp's it
 *		produces  A  B.
 */
#define _priv_CppIdentity(x)x
#define CppConcat(x, y)			_priv_CppIdentity(x)y

#endif	 /* !HAVE_STRINGIZE */

/*
 * dummyret is used to set return values in macros that use ?: to make
 * assignments.  gcc wants these to be void, other compilers like char
 */
#ifdef __GNUC__					/* GNU cc */
#define dummyret	void
#else
#define dummyret	char
#endif

#ifndef __GNUC__
#define __attribute__(_arg_)
#endif

/* ----------------------------------------------------------------
 *				Section 2:	bool, true, false, TRUE, FALSE, NULL
 * ----------------------------------------------------------------
 */

/*
 * bool
 *		Boolean value, either true or false.
 *
 * XXX for C++ compilers, we assume the compiler has a compatible
 * built-in definition of bool.
 */

/* BeOS defines bool already, but the compiler chokes on the
 * #ifndef unless we wrap it in this check.
 */
#ifndef __BEOS__

#ifndef __cplusplus

#ifndef bool
typedef char bool;
#endif

#ifndef true
#define true	((bool) 1)
#endif

#ifndef false
#define false	((bool) 0)
#endif

#endif	 /* not C++ */

#endif	 /* __BEOS__ */

typedef bool *BoolPtr;

#ifndef TRUE
#define TRUE	1
#endif

#ifndef FALSE
#define FALSE	0
#endif

/*
 * NULL
 *		Null pointer.
 */
#ifndef NULL
#define NULL	((void *) 0)
#endif


/* ----------------------------------------------------------------
 *				Section 3:	standard system types
 * ----------------------------------------------------------------
 */

/*
 * Pointer
 *		Variable holding address of any memory resident object.
 *
 *		XXX Pointer arithmetic is done with this, so it can't be void *
 *		under "true" ANSI compilers.
 */
typedef char *Pointer;

/*
 * intN
 *		Signed integer, EXACTLY N BITS IN SIZE,
 *		used for numerical computations and the
 *		frontend/backend protocol.
 */
#ifndef __BEOS__				/* this shouldn't be required, but is is! */
typedef signed char int8;		/* == 8 bits */
typedef signed short int16;		/* == 16 bits */
typedef signed int int32;		/* == 32 bits */

#endif	 /* __BEOS__ */

/*
 * uintN
 *		Unsigned integer, EXACTLY N BITS IN SIZE,
 *		used for numerical computations and the
 *		frontend/backend protocol.
 */
#ifndef __BEOS__				/* this shouldn't be required, but is is! */
typedef unsigned char uint8;	/* == 8 bits */
typedef unsigned short uint16;	/* == 16 bits */
typedef unsigned int uint32;	/* == 32 bits */

#endif	 /* __BEOS__ */

/*
 * boolN
 *		Boolean value, AT LEAST N BITS IN SIZE.
 */
typedef uint8 bool8;			/* >= 8 bits */
typedef uint16 bool16;			/* >= 16 bits */
typedef uint32 bool32;			/* >= 32 bits */

/*
 * bitsN
 *		Unit of bitwise operation, AT LEAST N BITS IN SIZE.
 */
typedef uint8 bits8;			/* >= 8 bits */
typedef uint16 bits16;			/* >= 16 bits */
typedef uint32 bits32;			/* >= 32 bits */

/*
 * wordN
 *		Unit of storage, AT LEAST N BITS IN SIZE,
 *		used to fetch/store data.
 */
typedef uint8 word8;			/* >= 8 bits */
typedef uint16 word16;			/* >= 16 bits */
typedef uint32 word32;			/* >= 32 bits */

/*
 * floatN
 *		Floating point number, AT LEAST N BITS IN SIZE,
 *		used for numerical computations.
 *
 *		Since sizeof(floatN) may be > sizeof(char *), always pass
 *		floatN by reference.
 *
 * XXX: these typedefs are now deprecated in favor of float4 and float8.
 * They will eventually go away.
 */
typedef float float32data;
typedef double float64data;
typedef float *float32;
typedef double *float64;

/*
 * 64-bit integers
 */
#ifndef __BEOS__				/* this is already defined on BeOS */
#ifdef HAVE_LONG_INT_64
/* Plain "long int" fits, use it */
typedef long int int64;
typedef unsigned long int uint64;

#else
#ifdef HAVE_LONG_LONG_INT_64
/* We have working support for "long long int", use that */
typedef long long int int64;
typedef unsigned long long int uint64;

#else
/* Won't actually work, but fall back to long int so that code compiles */
typedef long int int64;
typedef unsigned long int uint64;

#define INT64_IS_BUSTED
#endif
#endif
#endif	 /* __BEOS__ */

/*
 * Size
 *		Size of any memory resident object, as returned by sizeof.
 */
typedef size_t Size;

/*
 * Index
 *		Index into any memory resident array.
 *
 * Note:
 *		Indices are non negative.
 */
typedef unsigned int Index;

/*
 * Offset
 *		Offset into any memory resident array.
 *
 * Note:
 *		This differs from an Index in that an Index is always
 *		non negative, whereas Offset may be negative.
 */
typedef signed int Offset;

/*
 * Common Postgres datatype names (as used in the catalogs)
 */
typedef int16 int2;
typedef int32 int4;
typedef float float4;
typedef double float8;

/*
 * Oid, RegProcedure, TransactionId, CommandId
 */

/* typedef Oid is in postgres_ext.h */

/* unfortunately, both regproc and RegProcedure are used */
typedef Oid regproc;
typedef Oid RegProcedure;

typedef uint32 TransactionId;

typedef uint32 CommandId;

#define FirstCommandId	((CommandId) 0)

/*
 * Array indexing support
 */
#define MAXDIM 6
typedef struct
{
	int			indx[MAXDIM];
} IntArray;

/* ----------------
 *		Variable-length datatypes all share the 'struct varlena' header.
 *
 * NOTE: for TOASTable types, this is an oversimplification, since the value 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.  See postgres.h for details of the TOASTed form.
 * ----------------
 */
struct varlena
{
	int32		vl_len;
	char		vl_dat[1];
};

#define VARHDRSZ		((int32) sizeof(int32))

/*
 * These widely-used datatypes are just a varlena header and the data bytes.
 * There is no terminating null or anything like that --- the data length is
 * always VARSIZE(ptr) - VARHDRSZ.
 */
typedef struct varlena bytea;
typedef struct varlena text;
typedef struct varlena BpChar;	/* blank-padded char, ie SQL char(n) */
typedef struct varlena VarChar; /* var-length char, ie SQL varchar(n) */

/*
 * Fixed-length array types (these are not varlena's!)
 */

typedef int2 int2vector[INDEX_MAX_KEYS];
typedef Oid oidvector[INDEX_MAX_KEYS];

/*
 * We want NameData to have length NAMEDATALEN and int alignment,
 * because that's how the data type 'name' is defined in pg_type.
 * Use a union to make sure the compiler agrees.
 */
typedef union nameData
{
	char		data[NAMEDATALEN];
	int			alignmentDummy;
} NameData;
typedef NameData *Name;

#define NameStr(name)	((name).data)


/* ----------------------------------------------------------------
 *				Section 4:	IsValid macros for system types
 * ----------------------------------------------------------------
 */
/*
 * BoolIsValid
 *		True iff bool is valid.
 */
#define BoolIsValid(boolean)	((boolean) == false || (boolean) == true)

/*
 * PointerIsValid
 *		True iff pointer is valid.
 */
#define PointerIsValid(pointer) ((void*)(pointer) != NULL)

/*
 * PointerIsAligned
 *		True iff pointer is properly aligned to point to the given type.
 */
#define PointerIsAligned(pointer, type) \
		(((long)(pointer) % (sizeof (type))) == 0)

#define OidIsValid(objectId)  ((bool) ((objectId) != InvalidOid))

#define RegProcedureIsValid(p)	OidIsValid(p)


/* ----------------------------------------------------------------
 *				Section 5:	offsetof, lengthof, endof, alignment
 * ----------------------------------------------------------------
 */
/*
 * offsetof
 *		Offset of a structure/union field within that structure/union.
 *
 *		XXX This is supposed to be part of stddef.h, but isn't on
 *		some systems (like SunOS 4).
 */
#ifndef offsetof
#define offsetof(type, field)	((long) &((type *)0)->field)
#endif	 /* offsetof */

/*
 * lengthof
 *		Number of elements in an array.
 */
#define lengthof(array) (sizeof (array) / sizeof ((array)[0]))

/*
 * endof
 *		Address of the element one past the last in an array.
 */
#define endof(array)	(&array[lengthof(array)])

/* ----------------
 * Alignment macros: align a length or address appropriately for a given type.
 *
 * There used to be some incredibly crufty platform-dependent hackery here,
 * but now we rely on the configure script to get the info for us. Much nicer.
 *
 * NOTE: TYPEALIGN will not work if ALIGNVAL is not a power of 2.
 * That case seems extremely unlikely to occur in practice, however.
 * ----------------
 */

#define TYPEALIGN(ALIGNVAL,LEN) (((long)(LEN) + (ALIGNVAL-1)) & ~(ALIGNVAL-1))

#define SHORTALIGN(LEN)			TYPEALIGN(ALIGNOF_SHORT, (LEN))
#define INTALIGN(LEN)			TYPEALIGN(ALIGNOF_INT, (LEN))
#define LONGALIGN(LEN)			TYPEALIGN(ALIGNOF_LONG, (LEN))
#define DOUBLEALIGN(LEN)		TYPEALIGN(ALIGNOF_DOUBLE, (LEN))
#define MAXALIGN(LEN)			TYPEALIGN(MAXIMUM_ALIGNOF, (LEN))


/* ----------------------------------------------------------------
 *				Section 6:	widely useful macros
 * ----------------------------------------------------------------
 */
/*
 * Max
 *		Return the maximum of two numbers.
 */
#define Max(x, y)		((x) > (y) ? (x) : (y))

/*
 * Min
 *		Return the minimum of two numbers.
 */
#define Min(x, y)		((x) < (y) ? (x) : (y))

/*
 * Abs
 *		Return the absolute value of the argument.
 */
#define Abs(x)			((x) >= 0 ? (x) : -(x))

/*
 * StrNCpy
 *	Like standard library function strncpy(), except that result string
 *	is guaranteed to be null-terminated --- that is, at most N-1 bytes
 *	of the source string will be kept.
 *	Also, the macro returns no result (too hard to do that without
 *	evaluating the arguments multiple times, which seems worse).
 *
 *	BTW: when you need to copy a non-null-terminated string (like a text
 *	datum) and add a null, do not do it with StrNCpy(..., len+1).  That
 *	might seem to work, but it fetches one byte more than there is in the
 *	text object.  One fine day you'll have a SIGSEGV because there isn't
 *	another byte before the end of memory.	Don't laugh, we've had real
 *	live bug reports from real live users over exactly this mistake.
 *	Do it honestly with "memcpy(dst,src,len); dst[len] = '\0';", instead.
 */
#define StrNCpy(dst,src,len) \
	do \
	{ \
		char * _dst = (dst); \
		Size _len = (len); \
\
		if (_len > 0) \
		{ \
			strncpy(_dst, (src), _len); \
			_dst[_len-1] = '\0'; \
		} \
	} while (0)


/* Get a bit mask of the bits set in non-int32 aligned addresses */
#define INT_ALIGN_MASK (sizeof(int32) - 1)

/*
 * MemSet
 *	Exactly the same as standard library function memset(), but considerably
 *	faster for zeroing small word-aligned structures (such as parsetree nodes).
 *	This has to be a macro because the main point is to avoid function-call
 *	overhead.
 *
 *	We got the 64 number by testing this against the stock memset() on
 *	BSD/OS 3.0. Larger values were slower.	bjm 1997/09/11
 *
 *	I think the crossover point could be a good deal higher for
 *	most platforms, actually.  tgl 2000-03-19
 */
#define MemSet(start, val, len) \
	do \
	{ \
		int32 * _start = (int32 *) (start); \
		int		_val = (val); \
		Size	_len = (len); \
\
		if ((((long) _start) & INT_ALIGN_MASK) == 0 && \
			(_len & INT_ALIGN_MASK) == 0 && \
			_val == 0 && \
			_len <= MEMSET_LOOP_LIMIT) \
		{ \
			int32 * _stop = (int32 *) ((char *) _start + _len); \
			while (_start < _stop) \
				*_start++ = 0; \
		} \
		else \
			memset((char *) _start, _val, _len); \
	} while (0)

#define MEMSET_LOOP_LIMIT  64


/* ----------------------------------------------------------------
 *				Section 7:	random stuff
 * ----------------------------------------------------------------
 */

/* msb for char */
#define CSIGNBIT (0x80)

#define STATUS_OK				(0)
#define STATUS_ERROR			(-1)
#define STATUS_EOF				(-2)
#define STATUS_FOUND			(1)


/* ----------------------------------------------------------------
 *				Section 8: system-specific hacks
 *
 *		This should be limited to things that absolutely have to be
 *		included in every source file.	The port-specific header file
 *		is usually a better place for this sort of thing.
 * ----------------------------------------------------------------
 */

#ifdef __CYGWIN__
#define PG_BINARY	O_BINARY
#define PG_BINARY_R "rb"
#define PG_BINARY_W "wb"
#else
#define PG_BINARY	0
#define PG_BINARY_R "r"
#define PG_BINARY_W "w"
#endif

#if defined(sun) && defined(__sparc__) && !defined(__SVR4)
#include <unistd.h>
#endif

/* These are for things that are one way on Unix and another on NT */
#define NULL_DEV		"/dev/null"

/* defines for dynamic linking on Win32 platform */
#ifdef __CYGWIN__
#if __GNUC__ && ! defined (__declspec)
#error You need egcs 1.1 or newer for compiling!
#endif
#ifdef BUILDING_DLL
#define DLLIMPORT __declspec (dllexport)
#else							/* not BUILDING_DLL */
#define DLLIMPORT __declspec (dllimport)
#endif
#elif defined(WIN32) && defined(_MSC_VER)	/* not CYGWIN */
#if defined(_DLL)
#define DLLIMPORT __declspec (dllexport)
#else							/* not _DLL */
#define DLLIMPORT __declspec (dllimport)
#endif
#else							/* not CYGWIN, not MSVC */
#define DLLIMPORT
#endif

/* Provide prototypes for routines not present in a particular machine's
 * standard C library.	It'd be better to put these in pg_config.h, but
 * in pg_config.h we haven't yet included anything that defines size_t...
 */

#ifndef HAVE_SNPRINTF_DECL
extern int	snprintf(char *str, size_t count, const char *fmt, ...)
/* This extension allows gcc to check the format string */
__attribute__((format(printf, 3, 4)));
#endif

#ifndef HAVE_VSNPRINTF_DECL
extern int	vsnprintf(char *str, size_t count, const char *fmt, va_list args);
#endif

#if !defined(HAVE_MEMMOVE) && !defined(memmove)
#define memmove(d, s, c)		bcopy(s, d, c)
#endif

/* ----------------
 *		end of c.h
 * ----------------
 */
#endif	 /* C_H */