From 84adefa331c4159d432d22840663c38f155cd4c1 Mon Sep 17 00:00:00 2001
From: Erlang/OTP <otp@erlang.org>
Date: Fri, 20 Nov 2009 14:54:40 +0000
Subject: The R13B03 release.

---
 erts/example/next_perm.cc | 137 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 137 insertions(+)
 create mode 100644 erts/example/next_perm.cc

(limited to 'erts/example/next_perm.cc')

diff --git a/erts/example/next_perm.cc b/erts/example/next_perm.cc
new file mode 100644
index 0000000000..ee81cb0404
--- /dev/null
+++ b/erts/example/next_perm.cc
@@ -0,0 +1,137 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 2006-2009. All Rights Reserved.
+ * 
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ * 
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights 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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