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c.h
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/*-------------------------------------------------------------------------
*
* 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) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/c.h
*
*-------------------------------------------------------------------------
*/
/*
*----------------------------------------------------------------
* 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) compiler characteristics
* 2) bool, true, false
* 3) standard system types
* 4) IsValid macros for system types
* 5) offsetof, lengthof, alignment
* 6) assertions
* 7) widely useful macros
* 8) random stuff
* 9) system-specific hacks
*
* NOTE: since this file is included by both frontend and backend modules,
* it's usually wrong to put an "extern" declaration here, unless it's
* ifdef'd so that it's seen in only one case or the other.
* typedefs and macros are the kind of thing that might go here.
*
*----------------------------------------------------------------
*/
#ifndef C_H
#define C_H
#include "postgres_ext.h"
/* Must undef pg_config_ext.h symbols before including pg_config.h */
#undef PG_INT64_TYPE
#include "pg_config.h"
#include "pg_config_manual.h" /* must be after pg_config.h */
#include "pg_config_os.h" /* must be before any system header files */
/* System header files that should be available everywhere in Postgres */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <stdarg.h>
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif
#include <sys/types.h>
#include <errno.h>
#if defined(WIN32) || defined(__CYGWIN__)
#include <fcntl.h> /* ensure O_BINARY is available */
#endif
#include <locale.h>
#ifdef ENABLE_NLS
#include <libintl.h>
#endif
/* ----------------------------------------------------------------
* Section 1: compiler characteristics
*
* type prefixes (const, signed, volatile, inline) are handled in pg_config.h.
* ----------------------------------------------------------------
*/
/*
* Disable "inline" if PG_FORCE_DISABLE_INLINE is defined.
* This is used to work around compiler bugs and might also be useful for
* investigatory purposes.
*/
#ifdef PG_FORCE_DISABLE_INLINE
#undef inline
#define inline
#endif
/*
* Attribute macros
*
* GCC: https://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
* GCC: https://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html
* Sunpro: https://docs.oracle.com/cd/E18659_01/html/821-1384/gjzke.html
* XLC: http://www-01.ibm.com/support/knowledgecenter/SSGH2K_11.1.0/com.ibm.xlc111.aix.doc/language_ref/function_attributes.html
* XLC: http://www-01.ibm.com/support/knowledgecenter/SSGH2K_11.1.0/com.ibm.xlc111.aix.doc/language_ref/type_attrib.html
*/
/* only GCC supports the unused attribute */
#ifdef __GNUC__
#define pg_attribute_unused() __attribute__((unused))
#else
#define pg_attribute_unused()
#endif
/*
* Append PG_USED_FOR_ASSERTS_ONLY to definitions of variables that are only
* used in assert-enabled builds, to avoid compiler warnings about unused
* variables in assert-disabled builds.
*/
#ifdef USE_ASSERT_CHECKING
#define PG_USED_FOR_ASSERTS_ONLY
#else
#define PG_USED_FOR_ASSERTS_ONLY pg_attribute_unused()
#endif
/* GCC and XLC support format attributes */
#if defined(__GNUC__) || defined(__IBMC__)
#define pg_attribute_format_arg(a) __attribute__((format_arg(a)))
#define pg_attribute_printf(f,a) __attribute__((format(PG_PRINTF_ATTRIBUTE, f, a)))
#else
#define pg_attribute_format_arg(a)
#define pg_attribute_printf(f,a)
#endif
/* GCC, Sunpro and XLC support aligned, packed and noreturn */
#if defined(__GNUC__) || defined(__SUNPRO_C) || defined(__IBMC__)
#define pg_attribute_aligned(a) __attribute__((aligned(a)))
#define pg_attribute_noreturn() __attribute__((noreturn))
#define pg_attribute_packed() __attribute__((packed))
#define HAVE_PG_ATTRIBUTE_NORETURN 1
#else
/*
* NB: aligned and packed are not given default definitions because they
* affect code functionality; they *must* be implemented by the compiler
* if they are to be used.
*/
#define pg_attribute_noreturn()
#endif
/*
* Use "pg_attribute_always_inline" in place of "inline" for functions that
* we wish to force inlining of, even when the compiler's heuristics would
* choose not to. But, if possible, don't force inlining in unoptimized
* debug builds.
*/
#if (defined(__GNUC__) && __GNUC__ > 3 && defined(__OPTIMIZE__)) || defined(__SUNPRO_C) || defined(__IBMC__)
/* GCC > 3, Sunpro and XLC support always_inline via __attribute__ */
#define pg_attribute_always_inline __attribute__((always_inline)) inline
#elif defined(_MSC_VER)
/* MSVC has a special keyword for this */
#define pg_attribute_always_inline __forceinline
#else
/* Otherwise, the best we can do is to say "inline" */
#define pg_attribute_always_inline inline
#endif
/*
* Forcing a function not to be inlined can be useful if it's the slow path of
* a performance-critical function, or should be visible in profiles to allow
* for proper cost attribution. Note that unlike the pg_attribute_XXX macros
* above, this should be placed before the function's return type and name.
*/
/* GCC, Sunpro and XLC support noinline via __attribute__ */
#if (defined(__GNUC__) && __GNUC__ > 2) || defined(__SUNPRO_C) || defined(__IBMC__)
#define pg_noinline __attribute__((noinline))
/* msvc via declspec */
#elif defined(_MSC_VER)
#define pg_noinline __declspec(noinline)
#else
#define pg_noinline
#endif
/*
* Mark a point as unreachable in a portable fashion. This should preferably
* be something that the compiler understands, to aid code generation.
* In assert-enabled builds, we prefer abort() for debugging reasons.
*/
#if defined(HAVE__BUILTIN_UNREACHABLE) && !defined(USE_ASSERT_CHECKING)
#define pg_unreachable() __builtin_unreachable()
#elif defined(_MSC_VER) && !defined(USE_ASSERT_CHECKING)
#define pg_unreachable() __assume(0)
#else
#define pg_unreachable() abort()
#endif
/*
* Hints to the compiler about the likelihood of a branch. Both likely() and
* unlikely() return the boolean value of the contained expression.
*
* These should only be used sparingly, in very hot code paths. It's very easy
* to mis-estimate likelihoods.
*/
#if __GNUC__ >= 3
#define likely(x) __builtin_expect((x) != 0, 1)
#define unlikely(x) __builtin_expect((x) != 0, 0)
#else
#define likely(x) ((x) != 0)
#define unlikely(x) ((x) != 0)
#endif
/*
* CppAsString
* Convert the argument to a string, using the C preprocessor.
* CppAsString2
* Convert the argument to a string, after one round of macro expansion.
* CppConcat
* Concatenate two arguments together, using the C preprocessor.
*
* Note: There used to be support here for pre-ANSI C compilers that didn't
* support # and ##. Nowadays, these macros are just for clarity and/or
* backward compatibility with existing PostgreSQL code.
*/
#define CppAsString(identifier) #identifier
#define CppAsString2(x) CppAsString(x)
#define CppConcat(x, y) x##y
/*
* 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
/* Which __func__ symbol do we have, if any? */
#ifdef HAVE_FUNCNAME__FUNC
#define PG_FUNCNAME_MACRO __func__
#else
#ifdef HAVE_FUNCNAME__FUNCTION
#define PG_FUNCNAME_MACRO __FUNCTION__
#else
#define PG_FUNCNAME_MACRO NULL
#endif
#endif
/* ----------------------------------------------------------------
* Section 2: bool, true, false
* ----------------------------------------------------------------
*/
/*
* bool
* Boolean value, either true or false.
*
* Use stdbool.h if available and its bool has size 1. That's useful for
* better compiler and debugger output and for compatibility with third-party
* libraries. But PostgreSQL currently cannot deal with bool of other sizes;
* there are static assertions around the code to prevent that.
*
* For C++ compilers, we assume the compiler has a compatible built-in
* definition of bool.
*/
#ifndef __cplusplus
#if defined(HAVE_STDBOOL_H) && SIZEOF_BOOL == 1
#include <stdbool.h>
#define USE_STDBOOL 1
#else
#ifndef bool
typedef char bool;
#endif
#ifndef true
#define true ((bool) 1)
#endif
#ifndef false
#define false ((bool) 0)
#endif
#endif
#endif /* not C++ */
/* ----------------------------------------------------------------
* 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 HAVE_INT8
typedef signed char int8; /* == 8 bits */
typedef signed short int16; /* == 16 bits */
typedef signed int int32; /* == 32 bits */
#endif /* not HAVE_INT8 */
/*
* uintN
* Unsigned integer, EXACTLY N BITS IN SIZE,
* used for numerical computations and the
* frontend/backend protocol.
*/
#ifndef HAVE_UINT8
typedef unsigned char uint8; /* == 8 bits */
typedef unsigned short uint16; /* == 16 bits */
typedef unsigned int uint32; /* == 32 bits */
#endif /* not HAVE_UINT8 */
/*
* 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 */
/*
* 64-bit integers
*/
#ifdef HAVE_LONG_INT_64
/* Plain "long int" fits, use it */
#ifndef HAVE_INT64
typedef long int int64;
#endif
#ifndef HAVE_UINT64
typedef unsigned long int uint64;
#endif
#define INT64CONST(x) (x##L)
#define UINT64CONST(x) (x##UL)
#elif defined(HAVE_LONG_LONG_INT_64)
/* We have working support for "long long int", use that */
#ifndef HAVE_INT64
typedef long long int int64;
#endif
#ifndef HAVE_UINT64
typedef unsigned long long int uint64;
#endif
#define INT64CONST(x) (x##LL)
#define UINT64CONST(x) (x##ULL)
#else
/* neither HAVE_LONG_INT_64 nor HAVE_LONG_LONG_INT_64 */
#error must have a working 64-bit integer datatype
#endif
/* snprintf format strings to use for 64-bit integers */
#define INT64_FORMAT "%" INT64_MODIFIER "d"
#define UINT64_FORMAT "%" INT64_MODIFIER "u"
/*
* 128-bit signed and unsigned integers
* There currently is only limited support for such types.
* E.g. 128bit literals and snprintf are not supported; but math is.
* Also, because we exclude such types when choosing MAXIMUM_ALIGNOF,
* it must be possible to coerce the compiler to allocate them on no
* more than MAXALIGN boundaries.
*/
#if defined(PG_INT128_TYPE)
#if defined(pg_attribute_aligned) || ALIGNOF_PG_INT128_TYPE <= MAXIMUM_ALIGNOF
#define HAVE_INT128 1
typedef PG_INT128_TYPE int128
#if defined(pg_attribute_aligned)
pg_attribute_aligned(MAXIMUM_ALIGNOF)
#endif
;
typedef unsigned PG_INT128_TYPE uint128
#if defined(pg_attribute_aligned)
pg_attribute_aligned(MAXIMUM_ALIGNOF)
#endif
;
#endif
#endif
/*
* stdint.h limits aren't guaranteed to be present and aren't guaranteed to
* have compatible types with our fixed width types. So just define our own.
*/
#define PG_INT8_MIN (-0x7F-1)
#define PG_INT8_MAX (0x7F)
#define PG_UINT8_MAX (0xFF)
#define PG_INT16_MIN (-0x7FFF-1)
#define PG_INT16_MAX (0x7FFF)
#define PG_UINT16_MAX (0xFFFF)
#define PG_INT32_MIN (-0x7FFFFFFF-1)
#define PG_INT32_MAX (0x7FFFFFFF)
#define PG_UINT32_MAX (0xFFFFFFFFU)
#define PG_INT64_MIN (-INT64CONST(0x7FFFFFFFFFFFFFFF) - 1)
#define PG_INT64_MAX INT64CONST(0x7FFFFFFFFFFFFFFF)
#define PG_UINT64_MAX UINT64CONST(0xFFFFFFFFFFFFFFFF)
/* Max value of size_t might also be missing if we don't have stdint.h */
#ifndef SIZE_MAX
#if SIZEOF_SIZE_T == 8
#define SIZE_MAX PG_UINT64_MAX
#else
#define SIZE_MAX PG_UINT32_MAX
#endif
#endif
/*
* We now always use int64 timestamps, but keep this symbol defined for the
* benefit of external code that might test it.
*/
#define HAVE_INT64_TIMESTAMP
/*
* 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 float float4;
typedef double float8;
/*
* Oid, RegProcedure, TransactionId, SubTransactionId, MultiXactId,
* CommandId
*/
/* typedef Oid is in postgres_ext.h */
/*
* regproc is the type name used in the include/catalog headers, but
* RegProcedure is the preferred name in C code.
*/
typedef Oid regproc;
typedef regproc RegProcedure;
typedef uint32 TransactionId;
typedef uint32 LocalTransactionId;
typedef uint32 SubTransactionId;
#define InvalidSubTransactionId ((SubTransactionId) 0)
#define TopSubTransactionId ((SubTransactionId) 1)
/* MultiXactId must be equivalent to TransactionId, to fit in t_xmax */
typedef TransactionId MultiXactId;
typedef uint32 MultiXactOffset;
typedef uint32 CommandId;
#define FirstCommandId ((CommandId) 0)
#define InvalidCommandId (~(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. 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 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
{
char vl_len_[4]; /* Do not touch this field directly! */
char vl_dat[FLEXIBLE_ARRAY_MEMBER]; /* Data content is here */
};
#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_ANY_EXHDR(ptr).
*/
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) */
/*
* Specialized array types. These are physically laid out just the same
* as regular arrays (so that the regular array subscripting code works
* with them). They exist as distinct types mostly for historical reasons:
* they have nonstandard I/O behavior which we don't want to change for fear
* of breaking applications that look at the system catalogs. There is also
* an implementation issue for oidvector: it's part of the primary key for
* pg_proc, and we can't use the normal btree array support routines for that
* without circularity.
*/
typedef struct
{
int32 vl_len_; /* these fields must match ArrayType! */
int ndim; /* always 1 for int2vector */
int32 dataoffset; /* always 0 for int2vector */
Oid elemtype;
int dim1;
int lbound1;
int16 values[FLEXIBLE_ARRAY_MEMBER];
} int2vector;
typedef struct
{
int32 vl_len_; /* these fields must match ArrayType! */
int ndim; /* always 1 for oidvector */
int32 dataoffset; /* always 0 for oidvector */
Oid elemtype;
int dim1;
int lbound1;
Oid values[FLEXIBLE_ARRAY_MEMBER];
} oidvector;
/*
* Representation of a Name: effectively just a C string, but null-padded to
* exactly NAMEDATALEN bytes. The use of a struct is historical.
*/
typedef struct nameData
{
char data[NAMEDATALEN];
} 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) ((const void*)(pointer) != NULL)
/*
* PointerIsAligned
* True iff pointer is properly aligned to point to the given type.
*/
#define PointerIsAligned(pointer, type) \
(((uintptr_t)(pointer) % (sizeof (type))) == 0)
#define OffsetToPointer(base, offset) \
((void *)((char *) base + offset))
#define OidIsValid(objectId) ((bool) ((objectId) != InvalidOid))
#define RegProcedureIsValid(p) OidIsValid(p)
/* ----------------------------------------------------------------
* Section 5: offsetof, lengthof, 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]))
/* ----------------
* Alignment macros: align a length or address appropriately for a given type.
* The fooALIGN() macros round up to a multiple of the required alignment,
* while the fooALIGN_DOWN() macros round down. The latter are more useful
* for problems like "how many X-sized structures will fit in a page?".
*
* NOTE: TYPEALIGN[_DOWN] will not work if ALIGNVAL is not a power of 2.
* That case seems extremely unlikely to be needed in practice, however.
*
* NOTE: MAXIMUM_ALIGNOF, and hence MAXALIGN(), intentionally exclude any
* larger-than-8-byte types the compiler might have.
* ----------------
*/
#define TYPEALIGN(ALIGNVAL,LEN) \
(((uintptr_t) (LEN) + ((ALIGNVAL) - 1)) & ~((uintptr_t) ((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))
/* MAXALIGN covers only built-in types, not buffers */
#define BUFFERALIGN(LEN) TYPEALIGN(ALIGNOF_BUFFER, (LEN))
#define CACHELINEALIGN(LEN) TYPEALIGN(PG_CACHE_LINE_SIZE, (LEN))
#define TYPEALIGN_DOWN(ALIGNVAL,LEN) \
(((uintptr_t) (LEN)) & ~((uintptr_t) ((ALIGNVAL) - 1)))
#define SHORTALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_SHORT, (LEN))
#define INTALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_INT, (LEN))
#define LONGALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_LONG, (LEN))
#define DOUBLEALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_DOUBLE, (LEN))
#define MAXALIGN_DOWN(LEN) TYPEALIGN_DOWN(MAXIMUM_ALIGNOF, (LEN))
#define BUFFERALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_BUFFER, (LEN))
/*
* The above macros will not work with types wider than uintptr_t, like with
* uint64 on 32-bit platforms. That's not problem for the usual use where a
* pointer or a length is aligned, but for the odd case that you need to
* align something (potentially) wider, use TYPEALIGN64.
*/
#define TYPEALIGN64(ALIGNVAL,LEN) \
(((uint64) (LEN) + ((ALIGNVAL) - 1)) & ~((uint64) ((ALIGNVAL) - 1)))
/* we don't currently need wider versions of the other ALIGN macros */
#define MAXALIGN64(LEN) TYPEALIGN64(MAXIMUM_ALIGNOF, (LEN))
/* ----------------------------------------------------------------
* Section 6: assertions
* ----------------------------------------------------------------
*/
/*
* USE_ASSERT_CHECKING, if defined, turns on all the assertions.
* - plai 9/5/90
*
* It should _NOT_ be defined in releases or in benchmark copies
*/
/*
* Assert() can be used in both frontend and backend code. In frontend code it
* just calls the standard assert, if it's available. If use of assertions is
* not configured, it does nothing.
*/
#ifndef USE_ASSERT_CHECKING
#define Assert(condition) ((void)true)
#define AssertMacro(condition) ((void)true)
#define AssertArg(condition) ((void)true)
#define AssertState(condition) ((void)true)
#define AssertPointerAlignment(ptr, bndr) ((void)true)
#define Trap(condition, errorType) ((void)true)
#define TrapMacro(condition, errorType) (true)
#elif defined(FRONTEND)
#include <assert.h>
#define Assert(p) assert(p)
#define AssertMacro(p) ((void) assert(p))
#define AssertArg(condition) assert(condition)
#define AssertState(condition) assert(condition)
#define AssertPointerAlignment(ptr, bndr) ((void)true)
#else /* USE_ASSERT_CHECKING && !FRONTEND */
/*
* Trap
* Generates an exception if the given condition is true.
*/
#define Trap(condition, errorType) \
do { \
if (condition) \
ExceptionalCondition(CppAsString(condition), (errorType), \
__FILE__, __LINE__); \
} while (0)
/*
* TrapMacro is the same as Trap but it's intended for use in macros:
*
* #define foo(x) (AssertMacro(x != 0), bar(x))
*
* Isn't CPP fun?
*/
#define TrapMacro(condition, errorType) \
((bool) (! (condition) || \
(ExceptionalCondition(CppAsString(condition), (errorType), \
__FILE__, __LINE__), 0)))
#define Assert(condition) \
Trap(!(condition), "FailedAssertion")
#define AssertMacro(condition) \
((void) TrapMacro(!(condition), "FailedAssertion"))
#define AssertArg(condition) \
Trap(!(condition), "BadArgument")
#define AssertState(condition) \
Trap(!(condition), "BadState")
/*
* Check that `ptr' is `bndr' aligned.
*/
#define AssertPointerAlignment(ptr, bndr) \
Trap(TYPEALIGN(bndr, (uintptr_t)(ptr)) != (uintptr_t)(ptr), \
"UnalignedPointer")
#endif /* USE_ASSERT_CHECKING && !FRONTEND */
/*
* ExceptionalCondition is compiled into the backend whether or not
* USE_ASSERT_CHECKING is defined, so as to support use of extensions
* that are built with that #define with a backend that isn't. Hence,
* we should declare it as long as !FRONTEND.
*/
#ifndef FRONTEND
extern void ExceptionalCondition(const char *conditionName,
const char *errorType,
const char *fileName, int lineNumber) pg_attribute_noreturn();
#endif
/*
* Macros to support compile-time assertion checks.
*
* If the "condition" (a compile-time-constant expression) evaluates to false,
* throw a compile error using the "errmessage" (a string literal).
*
* gcc 4.6 and up supports _Static_assert(), but there are bizarre syntactic
* placement restrictions. These macros make it safe to use as a statement
* or in an expression, respectively.
*
* Otherwise we fall back on a kluge that assumes the compiler will complain
* about a negative width for a struct bit-field. This will not include a
* helpful error message, but it beats not getting an error at all.
*/
#ifndef __cplusplus
#ifdef HAVE__STATIC_ASSERT
#define StaticAssertStmt(condition, errmessage) \
do { _Static_assert(condition, errmessage); } while(0)
#define StaticAssertExpr(condition, errmessage) \
((void) ({ StaticAssertStmt(condition, errmessage); true; }))
#else /* !HAVE__STATIC_ASSERT */
#define StaticAssertStmt(condition, errmessage) \
((void) sizeof(struct { int static_assert_failure : (condition) ? 1 : -1; }))
#define StaticAssertExpr(condition, errmessage) \
StaticAssertStmt(condition, errmessage)
#endif /* HAVE__STATIC_ASSERT */
#else /* C++ */
#if defined(__cpp_static_assert) && __cpp_static_assert >= 200410
#define StaticAssertStmt(condition, errmessage) \
static_assert(condition, errmessage)
#define StaticAssertExpr(condition, errmessage) \
({ static_assert(condition, errmessage); })
#else
#define StaticAssertStmt(condition, errmessage) \
do { struct static_assert_struct { int static_assert_failure : (condition) ? 1 : -1; }; } while(0)
#define StaticAssertExpr(condition, errmessage) \
((void) ({ StaticAssertStmt(condition, errmessage); }))
#endif
#endif /* C++ */
/*
* Compile-time checks that a variable (or expression) has the specified type.
*
* AssertVariableIsOfType() can be used as a statement.
* AssertVariableIsOfTypeMacro() is intended for use in macros, eg
* #define foo(x) (AssertVariableIsOfTypeMacro(x, int), bar(x))
*
* If we don't have __builtin_types_compatible_p, we can still assert that
* the types have the same size. This is far from ideal (especially on 32-bit
* platforms) but it provides at least some coverage.
*/
#ifdef HAVE__BUILTIN_TYPES_COMPATIBLE_P
#define AssertVariableIsOfType(varname, typename) \
StaticAssertStmt(__builtin_types_compatible_p(__typeof__(varname), typename), \
CppAsString(varname) " does not have type " CppAsString(typename))
#define AssertVariableIsOfTypeMacro(varname, typename) \
(StaticAssertExpr(__builtin_types_compatible_p(__typeof__(varname), typename), \
CppAsString(varname) " does not have type " CppAsString(typename)))
#else /* !HAVE__BUILTIN_TYPES_COMPATIBLE_P */
#define AssertVariableIsOfType(varname, typename) \
StaticAssertStmt(sizeof(varname) == sizeof(typename), \
CppAsString(varname) " does not have type " CppAsString(typename))
#define AssertVariableIsOfTypeMacro(varname, typename) \
(StaticAssertExpr(sizeof(varname) == sizeof(typename), \
CppAsString(varname) " does not have type " CppAsString(typename)))
#endif /* HAVE__BUILTIN_TYPES_COMPATIBLE_P */
/* ----------------------------------------------------------------
* Section 7: 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-long aligned addresses */
#define LONG_ALIGN_MASK (sizeof(long) - 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. However, we have also found that the loop is faster than
* native libc memset() on some platforms, even those with assembler
* memset() functions. More research needs to be done, perhaps with
* MEMSET_LOOP_LIMIT tests in configure.
*/
#define MemSet(start, val, len) \
do \
{ \
/* must be void* because we don't know if it is integer aligned yet */ \
void *_vstart = (void *) (start); \
int _val = (val); \
Size _len = (len); \
\
if ((((uintptr_t) _vstart) & LONG_ALIGN_MASK) == 0 && \
(_len & LONG_ALIGN_MASK) == 0 && \
_val == 0 && \
_len <= MEMSET_LOOP_LIMIT && \
/* \
* If MEMSET_LOOP_LIMIT == 0, optimizer should find \
* the whole "if" false at compile time. \
*/ \
MEMSET_LOOP_LIMIT != 0) \
{ \
long *_start = (long *) _vstart; \
long *_stop = (long *) ((char *) _start + _len); \
while (_start < _stop) \
*_start++ = 0; \
} \
else \
memset(_vstart, _val, _len); \
} while (0)
/*
* MemSetAligned is the same as MemSet except it omits the test to see if
* "start" is word-aligned. This is okay to use if the caller knows a-priori
* that the pointer is suitably aligned (typically, because he just got it
* from palloc(), which always delivers a max-aligned pointer).
*/
#define MemSetAligned(start, val, len) \
do \
{ \
long *_start = (long *) (start); \
int _val = (val); \
Size _len = (len); \
\
if ((_len & LONG_ALIGN_MASK) == 0 && \
_val == 0 && \
_len <= MEMSET_LOOP_LIMIT && \
MEMSET_LOOP_LIMIT != 0) \
{ \
long *_stop = (long *) ((char *) _start + _len); \
while (_start < _stop) \
*_start++ = 0; \
} \
else \
memset(_start, _val, _len); \
} while (0)
/*
* MemSetTest/MemSetLoop are a variant version that allow all the tests in
* MemSet to be done at compile time in cases where "val" and "len" are
* constants *and* we know the "start" pointer must be word-aligned.
* If MemSetTest succeeds, then it is okay to use MemSetLoop, otherwise use
* MemSetAligned. Beware of multiple evaluations of the arguments when using
* this approach.
*/
#define MemSetTest(val, len) \
( ((len) & LONG_ALIGN_MASK) == 0 && \
(len) <= MEMSET_LOOP_LIMIT && \
MEMSET_LOOP_LIMIT != 0 && \
(val) == 0 )
#define MemSetLoop(start, val, len) \
do \
{ \
long * _start = (long *) (start); \
long * _stop = (long *) ((char *) _start + (Size) (len)); \
\
while (_start < _stop) \
*_start++ = 0; \
} while (0)
/* ----------------------------------------------------------------
* Section 8: random stuff
* ----------------------------------------------------------------
*/
/*
* Use this, not "char buf[BLCKSZ]", to declare a field or local variable
* holding a page buffer, if that page might be accessed as a page and not
* just a string of bytes. Otherwise the variable might be under-aligned,
* causing problems on alignment-picky hardware. (In some places, we use
* this to declare buffers even though we only pass them to read() and
* write(), because copying to/from aligned buffers is usually faster than
* using unaligned buffers.) We include both "double" and "int64" in the
* union to ensure that the compiler knows the value must be MAXALIGN'ed