diff options
Diffstat (limited to 'src/include/postgres.h')
| -rw-r--r-- | src/include/postgres.h | 89 |
1 files changed, 73 insertions, 16 deletions
diff --git a/src/include/postgres.h b/src/include/postgres.h index 3b93f7b3bb..87df7844f4 100644 --- a/src/include/postgres.h +++ b/src/include/postgres.h @@ -7,7 +7,7 @@ * Client-side code should include postgres_fe.h instead. * * - * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group + * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group * Portions Copyright (c) 1995, Regents of the University of California * Portions Copyright (c) 2010-2012 Postgres-XC Development Group * @@ -297,20 +297,18 @@ typedef struct /* 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! + * 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 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. + * Code assembling a new datum should call VARDATA() and SET_VARSIZE(). + * (Datums begin life untoasted.) * - * 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. + * 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) @@ -610,7 +608,7 @@ typedef Datum *DatumPtr; * value has adequate lifetime. */ -#define NameGetDatum(X) PointerGetDatum(X) +#define NameGetDatum(X) CStringGetDatum(NameStr(*(X))) /* * DatumGetInt64 @@ -667,6 +665,14 @@ extern Datum Int64GetDatum(int64 X); #endif /* + * Float <-> Datum conversions + * + * These have to be implemented as inline functions rather than macros, when + * passing by value, because many machines pass int and float function + * parameters/results differently; so we need to play weird games with unions. + */ + +/* * DatumGetFloat4 * Returns 4-byte floating point value of a datum. * @@ -674,7 +680,18 @@ extern Datum Int64GetDatum(int64 X); */ #ifdef USE_FLOAT4_BYVAL -extern float4 DatumGetFloat4(Datum X); +static inline float4 +DatumGetFloat4(Datum X) +{ + union + { + int32 value; + float4 retval; + } myunion; + + myunion.value = GET_4_BYTES(X); + return myunion.retval; +} #else #define DatumGetFloat4(X) (* ((float4 *) DatumGetPointer(X))) #endif @@ -686,8 +703,22 @@ extern float4 DatumGetFloat4(Datum X); * Note: if float4 is pass by reference, this function returns a reference * to palloc'd space. */ +#ifdef USE_FLOAT4_BYVAL +static inline Datum +Float4GetDatum(float4 X) +{ + union + { + float4 value; + int32 retval; + } myunion; + myunion.value = X; + return SET_4_BYTES(myunion.retval); +} +#else extern Datum Float4GetDatum(float4 X); +#endif /* * DatumGetFloat8 @@ -697,7 +728,18 @@ extern Datum Float4GetDatum(float4 X); */ #ifdef USE_FLOAT8_BYVAL -extern float8 DatumGetFloat8(Datum X); +static inline float8 +DatumGetFloat8(Datum X) +{ + union + { + int64 value; + float8 retval; + } myunion; + + myunion.value = GET_8_BYTES(X); + return myunion.retval; +} #else #define DatumGetFloat8(X) (* ((float8 *) DatumGetPointer(X))) #endif @@ -710,7 +752,22 @@ extern float8 DatumGetFloat8(Datum X); * to palloc'd space. */ +#ifdef USE_FLOAT8_BYVAL +static inline Datum +Float8GetDatum(float8 X) +{ + union + { + float8 value; + int64 retval; + } myunion; + + myunion.value = X; + return SET_8_BYTES(myunion.retval); +} +#else extern Datum Float8GetDatum(float8 X); +#endif /* |