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/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2006-2016. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*/
/*
* Purpose: A driver using libpq to connect to Postgres
* from erlang, a sample for the driver documentation
*/
#include <erl_driver.h>
#include <algorithm>
#include <vector>
using namespace std;
#include <iostream>
#define L cerr << __LINE__ << "\r\n";
/* Driver interface declarations */
static ErlDrvData start(ErlDrvPort port, char*);
static void output(ErlDrvData drv_data, char *buf, int len);
static void ready_async(ErlDrvData, ErlDrvThreadData);
static ErlDrvEntry next_perm_driver_entry = {
NULL, /* init */
start,
NULL, /* stop */
output,
NULL, /* ready_input */
NULL, /* ready_output */
"next_perm", /* the name of the driver */
NULL, /* finish */
NULL, /* handle */
NULL, /* control */
NULL, /* timeout */
NULL, /* outputv */
ready_async,
NULL, /* flush */
NULL, /* call */
NULL /* event */
};
/* INITIALIZATION AFTER LOADING */
/*
* This is the init function called after this driver has been loaded.
* It must *not* be declared static. Must return the address to
* the driver entry.
*/
#ifdef __cplusplus
extern "C" { // shouldn't this be in the DRIVER_INIT macro?
#endif
DRIVER_INIT(next_perm)
{
return &next_perm_driver_entry;
}
#ifdef __cplusplus
}
#endif
/* DRIVER INTERFACE */
static ErlDrvData start(ErlDrvPort port, char *)
{
if (port == NULL)
return ERL_DRV_ERROR_GENERAL;
return (ErlDrvData)port;
}
struct our_async_data {
bool prev;
vector<int> data;
our_async_data(ErlDrvPort p, int command, const char* buf, int len);
};
our_async_data::our_async_data(ErlDrvPort p, int command,
const char* buf, int len)
: prev(command == 2),
data((int*)buf, (int*)buf + len / sizeof(int))
{
}
static void do_perm(void* async_data);
static void output(ErlDrvData drv_data, char *buf, int len)
{
if (*buf < 1 || *buf > 2) return;
ErlDrvPort port = reinterpret_cast<ErlDrvPort>(drv_data);
void* async_data = new our_async_data(port, *buf, buf+1, len);
driver_async(port, NULL, do_perm, async_data, NULL);
}
static void do_perm(void* async_data)
{
our_async_data* d = reinterpret_cast<our_async_data*>(async_data);
if (d->prev)
prev_permutation(d->data.begin(), d->data.end());
else
next_permutation(d->data.begin(), d->data.end());
}
static void ready_async(ErlDrvData drv_data, ErlDrvThreadData async_data)
{
ErlDrvPort port = reinterpret_cast<ErlDrvPort>(drv_data);
our_async_data* d = reinterpret_cast<our_async_data*>(async_data);
int n = d->data.size(), result_n = n*2 + 5;
ErlDrvTermData *result = new ErlDrvTermData[result_n], *rp = result;
*rp++ = ERL_DRV_PORT;
*rp++ = driver_mk_port(port);
for (vector<int>::iterator i = d->data.begin();
i != d->data.end(); ++i) {
*rp++ = ERL_DRV_INT;
*rp++ = *i;
}
*rp++ = ERL_DRV_NIL;
*rp++ = ERL_DRV_LIST;
*rp++ = n+2;
driver_output_term(port, result, result_n);
delete[] result;
delete d;
}
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