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Add timestamp and timestamptz versions of generate_series().

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Hitoshi Harada
This commit is contained in:
Tom Lane
2008-05-04 23:19:24 +00:00
parent 600da67fbe
commit b6d15590f7
5 changed files with 229 additions and 15 deletions
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181
src/backend/utils/adt/timestamp.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.188 2008/05/04 21:13:35 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.189 2008/05/04 23:19:23 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -24,6 +24,7 @@
#include "access/hash.h"
#include "access/xact.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "libpq/pqformat.h"
#include "miscadmin.h"
#include "parser/scansup.h"
@ -45,6 +46,22 @@ TimestampTz PgStartTime;
/* Set at configuration reload */
TimestampTz PgReloadTime;
typedef struct
{
Timestamp current;
Timestamp finish;
Interval step;
int step_sign;
} generate_series_timestamp_fctx;
typedef struct
{
TimestampTz current;
TimestampTz finish;
Interval step;
int step_sign;
} generate_series_timestamptz_fctx;
static TimeOffset time2t(const int hour, const int min, const int sec, const fsec_t fsec);
static int EncodeSpecialTimestamp(Timestamp dt, char *str);
@ -4651,3 +4668,165 @@ timestamptz_izone(PG_FUNCTION_ARGS)
PG_RETURN_TIMESTAMP(result);
}
/* generate_series_timestamp()
* Generate the set of timestamps from start to finish by step
*/
Datum
generate_series_timestamp(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
generate_series_timestamp_fctx *fctx;
Timestamp result;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
Timestamp start = PG_GETARG_TIMESTAMP(0);
Timestamp finish = PG_GETARG_TIMESTAMP(1);
Interval *step = PG_GETARG_INTERVAL_P(2);
MemoryContext oldcontext;
Interval interval_zero;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/*
* switch to memory context appropriate for multiple function calls
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* allocate memory for user context */
fctx = (generate_series_timestamp_fctx *)
palloc(sizeof(generate_series_timestamp_fctx));
/*
* Use fctx to keep state from call to call. Seed current with the
* original start value
*/
fctx->current = start;
fctx->finish = finish;
fctx->step = *step;
/* Determine sign of the interval */
MemSet(&interval_zero, 0, sizeof(Interval));
fctx->step_sign = interval_cmp_internal(&fctx->step, &interval_zero);
if (fctx->step_sign == 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("step size cannot equal zero")));
funcctx->user_fctx = fctx;
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
/*
* get the saved state and use current as the result for this iteration
*/
fctx = funcctx->user_fctx;
result = fctx->current;
if (fctx->step_sign > 0 ?
timestamp_cmp_internal(result, fctx->finish) <= 0 :
timestamp_cmp_internal(result, fctx->finish) >= 0)
{
/* increment current in preparation for next iteration */
fctx->current = DatumGetTimestamp(
DirectFunctionCall2(timestamp_pl_interval,
TimestampGetDatum(fctx->current),
PointerGetDatum(&fctx->step)));
/* do when there is more left to send */
SRF_RETURN_NEXT(funcctx, TimestampGetDatum(result));
}
else
{
/* do when there is no more left */
SRF_RETURN_DONE(funcctx);
}
}
/* generate_series_timestamptz()
* Generate the set of timestamps from start to finish by step
*/
Datum
generate_series_timestamptz(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
generate_series_timestamptz_fctx *fctx;
TimestampTz result;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
TimestampTz start = PG_GETARG_TIMESTAMPTZ(0);
TimestampTz finish = PG_GETARG_TIMESTAMPTZ(1);
Interval *step = PG_GETARG_INTERVAL_P(2);
MemoryContext oldcontext;
Interval interval_zero;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/*
* switch to memory context appropriate for multiple function calls
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* allocate memory for user context */
fctx = (generate_series_timestamptz_fctx *)
palloc(sizeof(generate_series_timestamptz_fctx));
/*
* Use fctx to keep state from call to call. Seed current with the
* original start value
*/
fctx->current = start;
fctx->finish = finish;
fctx->step = *step;
/* Determine sign of the interval */
MemSet(&interval_zero, 0, sizeof(Interval));
fctx->step_sign = interval_cmp_internal(&fctx->step, &interval_zero);
if (fctx->step_sign == 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("step size cannot equal zero")));
funcctx->user_fctx = fctx;
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
/*
* get the saved state and use current as the result for this iteration
*/
fctx = funcctx->user_fctx;
result = fctx->current;
if (fctx->step_sign > 0 ?
timestamp_cmp_internal(result, fctx->finish) <= 0 :
timestamp_cmp_internal(result, fctx->finish) >= 0)
{
/* increment current in preparation for next iteration */
fctx->current = DatumGetTimestampTz(
DirectFunctionCall2(timestamptz_pl_interval,
TimestampTzGetDatum(fctx->current),
PointerGetDatum(&fctx->step)));
/* do when there is more left to send */
SRF_RETURN_NEXT(funcctx, TimestampTzGetDatum(result));
}
else
{
/* do when there is no more left */
SRF_RETURN_DONE(funcctx);
}
}