/* src/common/tutorial/funcs.cpp */

/******************************************************************************
  These are user-defined functions that can be bound to a openGauss backend
  and called by openGauss to execute SQL functions of the same name.

  The calling format for these functions is defined by the CREATE FUNCTION
  SQL statement that binds them to the backend.

  NOTE: this file shows examples of "old style" function call conventions.
  See funcs_new.c for examples of "new style".
*****************************************************************************/

#include "postgres.h"
#include "knl/knl_variable.h" /* general openGauss declarations */

#include "executor/executor.h" /* for GetAttributeByName() */
#include "utils/geo_decls.h"   /* for point type */

PG_MODULE_MAGIC;

/* These prototypes just prevent possible warnings from gcc. */

int add_one(int arg);
float8* add_one_float8(float8* arg);
Point* makepoint(Point* pointx, Point* pointy);
text* copytext(text* t);
text* concat_text(text* arg1, text* arg2);
bool c_overpaid(HeapTupleHeader t, /* the current instance of EMP */
    int32 limit);

/* By Value */
int add_one(int arg)
{
    return arg + 1;
}

/* By Reference, Fixed Length */
float8* add_one_float8(float8* arg)
{
    float8* result = (float8*)palloc(sizeof(float8));

    *result = *arg + 1.0;

    return result;
}

Point* makepoint(Point* pointx, Point* pointy)
{
    Point* new_point = (Point*)palloc(sizeof(Point));

    new_point->x = pointx->x;
    new_point->y = pointy->y;

    return new_point;
}

/* By Reference, Variable Length */
text* copytext(text* t)
{
    /*
     * VARSIZE is the total size of the struct in bytes.
     */
    text* new_t = (text*)palloc(VARSIZE(t));

    SET_VARSIZE(new_t, VARSIZE(t));

    /*
     * VARDATA is a pointer to the data region of the struct.
     */
    errno_t errorno = EOK;
    errorno = memcpy_s((void *) VARDATA(new_t), /* destination */
        VARSIZE(t) - VARHDRSZ),                 /* how many bytes */
        (void *) VARDATA(t),                    /* source */
        VARSIZE(t) - VARHDRSZ);                 /* how many bytes */
    securec_check(errorno, "\0", "\0");
    return new_t;
}

text* concat_text(text* arg1, text* arg2)
{
    int32 arg1_size = VARSIZE(arg1) - VARHDRSZ;
    int32 arg2_size = VARSIZE(arg2) - VARHDRSZ;
    int32 new_text_size = arg1_size + arg2_size + VARHDRSZ;
    text* new_text = (text*)palloc(new_text_size);
    errno_t errorno = EOK;

    SET_VARSIZE(new_text, new_text_size);
    errorno = memcpy_s(VARDATA(new_text), arg1_size, VARDATA(arg1), arg1_size);
    securec_check(errorno, "\0", "\0");
    errorno = memcpy_s(VARDATA(new_text) + arg1_size, arg2_size, VARDATA(arg2), arg2_size);
    securec_check(errorno, "\0", "\0");

    return new_text;
}

/* Composite types */
bool c_overpaid(HeapTupleHeader t, /* the current instance of EMP */
    int32 limit)
{
    bool isnull = false;
    int32 salary;

    salary = DatumGetInt32(GetAttributeByName(t, "salary", &isnull));
    if (isnull) {
        return false;
    }
    return salary > limit;
}