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/*------------------------------------------------------------------------- * * postgres.h * Primary include file for PostgreSQL server .c files * * This should be the first file included by PostgreSQL backend modules. * Client-side code should include postgres_fe.h instead. * * * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group * Portions Copyright (c) 1995, Regents of the University of California * * src/include/postgres.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 * ------- ------------------------------------------------ * 1) variable-length datatypes (TOAST support) * 2) datum type + support macros * 3) exception handling definitions * * NOTES * * In general, this file should contain declarations that are widely needed * in the backend environment, but are of no interest outside the backend. * * Simple type definitions live in c.h, where they are shared with * postgres_fe.h. We do that since those type definitions are needed by * frontend modules that want to deal with binary data transmission to or * from the backend. Type definitions in this file should be for * representations that never escape the backend, such as Datum or * TOASTed varlena objects. * *---------------------------------------------------------------- */ #ifndef POSTGRES_H #define POSTGRES_H #include "c.h" #include "utils/elog.h" #include "utils/palloc.h" /* ---------------------------------------------------------------- * Section 1: variable-length datatypes (TOAST support) * ---------------------------------------------------------------- */ /* * struct varatt_external is a "TOAST pointer", that is, the information * needed to fetch a stored-out-of-line Datum. The data is compressed * if and only if va_extsize < va_rawsize - VARHDRSZ. This struct must not * contain any padding, because we sometimes compare pointers using memcmp. * * Note that this information is stored unaligned within actual tuples, so * you need to memcpy from the tuple into a local struct variable before * you can look at these fields! (The reason we use memcmp is to avoid * having to do that just to detect equality of two TOAST pointers...) */ struct varatt_external { int32 va_rawsize; /* Original data size (includes header) */ int32 va_extsize; /* External saved size (doesn't) */ Oid va_valueid; /* Unique ID of value within TOAST table */ Oid va_toastrelid; /* RelID of TOAST table containing it */ }; /* * These structs describe the header of a varlena object that may have been * TOASTed. Generally, don't reference these structs directly, but use the * macros below. * * We use separate structs for the aligned and unaligned cases because the * compiler might otherwise think it could generate code that assumes * alignment while touching fields of a 1-byte-header varlena. */ typedef union { struct /* Normal varlena (4-byte length) */ { uint32 va_header; char va_data[1]; } va_4byte; struct /* Compressed-in-line format */ { uint32 va_header; uint32 va_rawsize; /* Original data size (excludes header) */ char va_data[1]; /* Compressed data */ } va_compressed; } varattrib_4b; typedef struct { uint8 va_header; char va_data[1]; /* Data begins here */ } varattrib_1b; typedef struct { uint8 va_header; /* Always 0x80 or 0x01 */ uint8 va_len_1be; /* Physical length of datum */ char va_data[1]; /* Data (for now always a TOAST pointer) */ } varattrib_1b_e; /* * Bit layouts for varlena headers on big-endian machines: * * 00xxxxxx 4-byte length word, aligned, uncompressed data (up to 1G) * 01xxxxxx 4-byte length word, aligned, *compressed* data (up to 1G) * 10000000 1-byte length word, unaligned, TOAST pointer * 1xxxxxxx 1-byte length word, unaligned, uncompressed data (up to 126b) * * Bit layouts for varlena headers on little-endian machines: * * xxxxxx00 4-byte length word, aligned, uncompressed data (up to 1G) * xxxxxx10 4-byte length word, aligned, *compressed* data (up to 1G) * 00000001 1-byte length word, unaligned, TOAST pointer * xxxxxxx1 1-byte length word, unaligned, uncompressed data (up to 126b) * * The "xxx" bits are the length field (which includes itself in all cases). * In the big-endian case we mask to extract the length, in the little-endian * case we shift. Note that in both cases the flag bits are in the physically * first byte. Also, it is not possible for a 1-byte length word to be zero; * this lets us disambiguate alignment padding bytes from the start of an * unaligned datum. (We now *require* pad bytes to be filled with zero!) */ /* * Endian-dependent macros. These are considered internal --- use the * external macros below instead of using these directly. * * Note: IS_1B is true for external toast records but VARSIZE_1B will return 0 * for such records. Hence you should usually check for IS_EXTERNAL before * checking for IS_1B. */ #ifdef WORDS_BIGENDIAN #define VARATT_IS_4B(PTR) \ ((((varattrib_1b *) (PTR))->va_header & 0x80) == 0x00) #define VARATT_IS_4B_U(PTR) \ ((((varattrib_1b *) (PTR))->va_header & 0xC0) == 0x00) #define VARATT_IS_4B_C(PTR) \ ((((varattrib_1b *) (PTR))->va_header & 0xC0) == 0x40) #define VARATT_IS_1B(PTR) \ ((((varattrib_1b *) (PTR))->va_header & 0x80) == 0x80) #define VARATT_IS_1B_E(PTR) \ ((((varattrib_1b *) (PTR))->va_header) == 0x80) #define VARATT_NOT_PAD_BYTE(PTR) \ (*((uint8 *) (PTR)) != 0) /* VARSIZE_4B() should only be used on known-aligned data */ #define VARSIZE_4B(PTR) \ (((varattrib_4b *) (PTR))->va_4byte.va_header & 0x3FFFFFFF) #define VARSIZE_1B(PTR) \ (((varattrib_1b *) (PTR))->va_header & 0x7F) #define VARSIZE_1B_E(PTR) \ (((varattrib_1b_e *) (PTR))->va_len_1be) #define SET_VARSIZE_4B(PTR,len) \ (((varattrib_4b *) (PTR))->va_4byte.va_header = (len) & 0x3FFFFFFF) #define SET_VARSIZE_4B_C(PTR,len) \ (((varattrib_4b *) (PTR))->va_4byte.va_header = ((len) & 0x3FFFFFFF) | 0x40000000) #define SET_VARSIZE_1B(PTR,len) \ (((varattrib_1b *) (PTR))->va_header = (len) | 0x80) #define SET_VARSIZE_1B_E(PTR,len) \ (((varattrib_1b_e *) (PTR))->va_header = 0x80, \ ((varattrib_1b_e *) (PTR))->va_len_1be = (len)) #else /* !WORDS_BIGENDIAN */ #define VARATT_IS_4B(PTR) \ ((((varattrib_1b *) (PTR))->va_header & 0x01) == 0x00) #define VARATT_IS_4B_U(PTR) \ ((((varattrib_1b *) (PTR))->va_header & 0x03) == 0x00) #define VARATT_IS_4B_C(PTR) \ ((((varattrib_1b *) (PTR))->va_header & 0x03) == 0x02) #define VARATT_IS_1B(PTR) \ ((((varattrib_1b *) (PTR))->va_header & 0x01) == 0x01) #define VARATT_IS_1B_E(PTR) \ ((((varattrib_1b *) (PTR))->va_header) == 0x01) #define VARATT_NOT_PAD_BYTE(PTR) \ (*((uint8 *) (PTR)) != 0) /* VARSIZE_4B() should only be used on known-aligned data */ #define VARSIZE_4B(PTR) \ ((((varattrib_4b *) (PTR))->va_4byte.va_header >> 2) & 0x3FFFFFFF) #define VARSIZE_1B(PTR) \ ((((varattrib_1b *) (PTR))->va_header >> 1) & 0x7F) #define VARSIZE_1B_E(PTR) \ (((varattrib_1b_e *) (PTR))->va_len_1be) #define SET_VARSIZE_4B(PTR,len) \ (((varattrib_4b *) (PTR))->va_4byte.va_header = (((uint32) (len)) << 2)) #define SET_VARSIZE_4B_C(PTR,len) \ (((varattrib_4b *) (PTR))->va_4byte.va_header = (((uint32) (len)) << 2) | 0x02) #define SET_VARSIZE_1B(PTR,len) \ (((varattrib_1b *) (PTR))->va_header = (((uint8) (len)) << 1) | 0x01) #define SET_VARSIZE_1B_E(PTR,len) \ (((varattrib_1b_e *) (PTR))->va_header = 0x01, \ ((varattrib_1b_e *) (PTR))->va_len_1be = (len)) #endif /* WORDS_BIGENDIAN */ #define VARHDRSZ_SHORT 1 #define VARATT_SHORT_MAX 0x7F #define VARATT_CAN_MAKE_SHORT(PTR) \ (VARATT_IS_4B_U(PTR) && \ (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT) <= VARATT_SHORT_MAX) #define VARATT_CONVERTED_SHORT_SIZE(PTR) \ (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT) #define VARHDRSZ_EXTERNAL 2 #define VARDATA_4B(PTR) (((varattrib_4b *) (PTR))->va_4byte.va_data) #define VARDATA_4B_C(PTR) (((varattrib_4b *) (PTR))->va_compressed.va_data) #define VARDATA_1B(PTR) (((varattrib_1b *) (PTR))->va_data) #define VARDATA_1B_E(PTR) (((varattrib_1b_e *) (PTR))->va_data) #define VARRAWSIZE_4B_C(PTR) \ (((varattrib_4b *) (PTR))->va_compressed.va_rawsize) /* 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. */ #define VARDATA(PTR) VARDATA_4B(PTR) #define VARSIZE(PTR) VARSIZE_4B(PTR) #define VARSIZE_SHORT(PTR) VARSIZE_1B(PTR) #define VARDATA_SHORT(PTR) VARDATA_1B(PTR) #define VARSIZE_EXTERNAL(PTR) VARSIZE_1B_E(PTR) #define VARDATA_EXTERNAL(PTR) VARDATA_1B_E(PTR) #define VARATT_IS_COMPRESSED(PTR) VARATT_IS_4B_C(PTR) #define VARATT_IS_EXTERNAL(PTR) VARATT_IS_1B_E(PTR) #define VARATT_IS_SHORT(PTR) VARATT_IS_1B(PTR) #define VARATT_IS_EXTENDED(PTR) (!VARATT_IS_4B_U(PTR)) #define SET_VARSIZE(PTR, len) SET_VARSIZE_4B(PTR, len) #define SET_VARSIZE_SHORT(PTR, len) SET_VARSIZE_1B(PTR, len) #define SET_VARSIZE_COMPRESSED(PTR, len) SET_VARSIZE_4B_C(PTR, len) #define SET_VARSIZE_EXTERNAL(PTR, len) SET_VARSIZE_1B_E(PTR, len) #define VARSIZE_ANY(PTR) \ (VARATT_IS_1B_E(PTR) ? VARSIZE_1B_E(PTR) : \ (VARATT_IS_1B(PTR) ? VARSIZE_1B(PTR) : \ VARSIZE_4B(PTR))) #define VARSIZE_ANY_EXHDR(PTR) \ (VARATT_IS_1B_E(PTR) ? VARSIZE_1B_E(PTR)-VARHDRSZ_EXTERNAL : \ (VARATT_IS_1B(PTR) ? VARSIZE_1B(PTR)-VARHDRSZ_SHORT : \ VARSIZE_4B(PTR)-VARHDRSZ)) /* caution: this will not work on an external or compressed-in-line Datum */ /* caution: this will return a possibly unaligned pointer */ #define VARDATA_ANY(PTR) \ (VARATT_IS_1B(PTR) ? VARDATA_1B(PTR) : VARDATA_4B(PTR)) /* ---------------------------------------------------------------- * Section 2: datum type + support macros * ---------------------------------------------------------------- */ /* * Port Notes: * Postgres makes the following assumptions about datatype sizes: * * sizeof(Datum) == sizeof(void *) == 4 or 8 * sizeof(char) == 1 * sizeof(short) == 2 * * When a type narrower than Datum is stored in a Datum, we place it in the * low-order bits and are careful that the DatumGetXXX macro for it discards * the unused high-order bits (as opposed to, say, assuming they are zero). * This is needed to support old-style user-defined functions, since depending * on architecture and compiler, the return value of a function returning char * or short may contain garbage when called as if it returned Datum. */ typedef uintptr_t Datum; #define SIZEOF_DATUM SIZEOF_VOID_P typedef Datum *DatumPtr; #define GET_1_BYTE(datum) (((Datum) (datum)) & 0x000000ff) #define GET_2_BYTES(datum) (((Datum) (datum)) & 0x0000ffff) #define GET_4_BYTES(datum) (((Datum) (datum)) & 0xffffffff) #if SIZEOF_DATUM == 8 #define GET_8_BYTES(datum) ((Datum) (datum)) #endif #define SET_1_BYTE(value) (((Datum) (value)) & 0x000000ff) #define SET_2_BYTES(value) (((Datum) (value)) & 0x0000ffff) #define SET_4_BYTES(value) (((Datum) (value)) & 0xffffffff) #if SIZEOF_DATUM == 8 #define SET_8_BYTES(value) ((Datum) (value)) #endif /* * DatumGetBool * Returns boolean value of a datum. * * Note: any nonzero value will be considered TRUE, but we ignore bits to * the left of the width of bool, per comment above. */ #define DatumGetBool(X) ((bool) (GET_1_BYTE(X) != 0)) /* * BoolGetDatum * Returns datum representation for a boolean. * * Note: any nonzero value will be considered TRUE. */ #define BoolGetDatum(X) ((Datum) ((X) ? 1 : 0)) /* * DatumGetChar * Returns character value of a datum. */ #define DatumGetChar(X) ((char) GET_1_BYTE(X)) /* * CharGetDatum * Returns datum representation for a character. */ #define CharGetDatum(X) ((Datum) SET_1_BYTE(X)) /* * Int8GetDatum * Returns datum representation for an 8-bit integer. */ #define Int8GetDatum(X) ((Datum) SET_1_BYTE(X)) /* * DatumGetUInt8 * Returns 8-bit unsigned integer value of a datum. */ #define DatumGetUInt8(X) ((uint8) GET_1_BYTE(X)) /* * UInt8GetDatum * Returns datum representation for an 8-bit unsigned integer. */ #define UInt8GetDatum(X) ((Datum) SET_1_BYTE(X)) /* * DatumGetInt16 * Returns 16-bit integer value of a datum. */ #define DatumGetInt16(X) ((int16) GET_2_BYTES(X)) /* * Int16GetDatum * Returns datum representation for a 16-bit integer. */ #define Int16GetDatum(X) ((Datum) SET_2_BYTES(X)) /* * DatumGetUInt16 * Returns 16-bit unsigned integer value of a datum. */ #define DatumGetUInt16(X) ((uint16) GET_2_BYTES(X)) /* * UInt16GetDatum * Returns datum representation for a 16-bit unsigned integer. */ #define UInt16GetDatum(X) ((Datum) SET_2_BYTES(X)) /* * DatumGetInt32 * Returns 32-bit integer value of a datum. */ #define DatumGetInt32(X) ((int32) GET_4_BYTES(X)) /* * Int32GetDatum * Returns datum representation for a 32-bit integer. */ #define Int32GetDatum(X) ((Datum) SET_4_BYTES(X)) /* * DatumGetUInt32 * Returns 32-bit unsigned integer value of a datum. */ #define DatumGetUInt32(X) ((uint32) GET_4_BYTES(X)) /* * UInt32GetDatum * Returns datum representation for a 32-bit unsigned integer. */ #define UInt32GetDatum(X) ((Datum) SET_4_BYTES(X)) /* * DatumGetObjectId * Returns object identifier value of a datum. */ #define DatumGetObjectId(X) ((Oid) GET_4_BYTES(X)) /* * ObjectIdGetDatum * Returns datum representation for an object identifier. */ #define ObjectIdGetDatum(X) ((Datum) SET_4_BYTES(X)) /* * DatumGetTransactionId * Returns transaction identifier value of a datum. */ #define DatumGetTransactionId(X) ((TransactionId) GET_4_BYTES(X)) /* * TransactionIdGetDatum * Returns datum representation for a transaction identifier. */ #define TransactionIdGetDatum(X) ((Datum) SET_4_BYTES((X))) /* * DatumGetCommandId * Returns command identifier value of a datum. */ #define DatumGetCommandId(X) ((CommandId) GET_4_BYTES(X)) /* * CommandIdGetDatum * Returns datum representation for a command identifier. */ #define CommandIdGetDatum(X) ((Datum) SET_4_BYTES(X)) /* * DatumGetPointer * Returns pointer value of a datum. */ #define DatumGetPointer(X) ((Pointer) (X)) /* * PointerGetDatum * Returns datum representation for a pointer. */ #define PointerGetDatum(X) ((Datum) (X)) /* * DatumGetCString * Returns C string (null-terminated string) value of a datum. * * Note: C string is not a full-fledged Postgres type at present, * but type input functions use this conversion for their inputs. */ #define DatumGetCString(X) ((char *) DatumGetPointer(X)) /* * CStringGetDatum * Returns datum representation for a C string (null-terminated string). * * Note: C string is not a full-fledged Postgres type at present, * but type output functions use this conversion for their outputs. * Note: CString is pass-by-reference; caller must ensure the pointed-to * value has adequate lifetime. */ #define CStringGetDatum(X) PointerGetDatum(X) /* * DatumGetName * Returns name value of a datum. */ #define DatumGetName(X) ((Name) DatumGetPointer(X)) /* * NameGetDatum * Returns datum representation for a name. * * Note: Name is pass-by-reference; caller must ensure the pointed-to * value has adequate lifetime. */ #define NameGetDatum(X) PointerGetDatum(X) /* * DatumGetInt64 * Returns 64-bit integer value of a datum. * * Note: this macro hides whether int64 is pass by value or by reference. */ #ifdef USE_FLOAT8_BYVAL #define DatumGetInt64(X) ((int64) GET_8_BYTES(X)) #else #define DatumGetInt64(X) (* ((int64 *) DatumGetPointer(X))) #endif /* * Int64GetDatum * Returns datum representation for a 64-bit integer. * * Note: if int64 is pass by reference, this function returns a reference * to palloc'd space. */ #ifdef USE_FLOAT8_BYVAL #define Int64GetDatum(X) ((Datum) SET_8_BYTES(X)) #else extern Datum Int64GetDatum(int64 X); #endif /* * DatumGetFloat4 * Returns 4-byte floating point value of a datum. * * Note: this macro hides whether float4 is pass by value or by reference. */ #ifdef USE_FLOAT4_BYVAL extern float4 DatumGetFloat4(Datum X); #else #define DatumGetFloat4(X) (* ((float4 *) DatumGetPointer(X))) #endif /* * Float4GetDatum * Returns datum representation for a 4-byte floating point number. * * Note: if float4 is pass by reference, this function returns a reference * to palloc'd space. */ extern Datum Float4GetDatum(float4 X); /* * DatumGetFloat8 * Returns 8-byte floating point value of a datum. * * Note: this macro hides whether float8 is pass by value or by reference. */ #ifdef USE_FLOAT8_BYVAL extern float8 DatumGetFloat8(Datum X); #else #define DatumGetFloat8(X) (* ((float8 *) DatumGetPointer(X))) #endif /* * Float8GetDatum * Returns datum representation for an 8-byte floating point number. * * Note: if float8 is pass by reference, this function returns a reference * to palloc'd space. */ extern Datum Float8GetDatum(float8 X); /* * Int64GetDatumFast * Float8GetDatumFast * Float4GetDatumFast * * These macros are intended to allow writing code that does not depend on * whether int64, float8, float4 are pass-by-reference types, while not * sacrificing performance when they are. The argument must be a variable * that will exist and have the same value for as long as the Datum is needed. * In the pass-by-ref case, the address of the variable is taken to use as * the Datum. In the pass-by-val case, these will be the same as the non-Fast * macros. */ #ifdef USE_FLOAT8_BYVAL #define Int64GetDatumFast(X) Int64GetDatum(X) #define Float8GetDatumFast(X) Float8GetDatum(X) #else #define Int64GetDatumFast(X) PointerGetDatum(&(X)) #define Float8GetDatumFast(X) PointerGetDatum(&(X)) #endif #ifdef USE_FLOAT4_BYVAL #define Float4GetDatumFast(X) Float4GetDatum(X) #else #define Float4GetDatumFast(X) PointerGetDatum(&(X)) #endif /* ---------------------------------------------------------------- * Section 3: exception handling definitions * Assert, Trap, etc macros * ---------------------------------------------------------------- */ extern PGDLLIMPORT bool assert_enabled; /* * 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 */ /* * Trap * Generates an exception if the given condition is true. */ #define Trap(condition, errorType) \ do { \ if ((assert_enabled) && (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) ((! assert_enabled) || ! (condition) || \ (ExceptionalCondition(CppAsString(condition), (errorType), \ __FILE__, __LINE__), 0))) #ifndef USE_ASSERT_CHECKING #define Assert(condition) #define AssertMacro(condition) ((void)true) #define AssertArg(condition) #define AssertState(condition) #else #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") #endif /* USE_ASSERT_CHECKING */ extern void ExceptionalCondition(const char *conditionName, const char *errorType, const char *fileName, int lineNumber) __attribute__((noreturn)); #endif /* POSTGRES_H */