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Added select_buf.[ch]

Michal Matyska authored on 21/06/2006 21:08:48
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select_buf.c
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+/*
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+ * $Id$
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+ *
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+ * Copyright (C) 2005-2006 iptelorg GmbH
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+ *
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+ * This file is part of ser, a free SIP server.
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+ *
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+ * ser is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License as published by
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+ * the Free Software Foundation; either version 2 of the License, or
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+ * (at your option) any later version
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+ *
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+ * For a license to use the ser software under conditions
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+ * other than those described here, or to purchase support for this
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+ * software, please contact iptel.org by e-mail at the following addresses:
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+ *    info@iptel.org
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+ *
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+ * ser is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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+ * GNU General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU General Public License
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+ * along with this program; if not, write to the Free Software
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+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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+ *
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+ * History:
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+ * --------
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+ *	2006-06-16  static buffer for select results (mma)
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+ *	            each process owns a separate space
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+ *	            each request starts using the buffer from the start
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+ *
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+ */
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+
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+#include <stdio.h>
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+#include <stdlib.h>
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+#include <string.h>
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+#include <unistd.h>
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+#include <ctype.h>
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+
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+#include "dprint.h"
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+#include "mem/mem.h"
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+
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+/*
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+ * Placeholder for the buffer
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+ *
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+ * two buffers are actually used to cover the different size requests
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+ * assuming that resize can move the result to newly allocated space
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+ * and comparing two selects from the script could require two static buffers
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+ *
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+ * if more static buffers need to be valid at the same time change
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+ * the following constant
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+ */
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+
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+#define MAX_BUFFERS 2
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+#define BUFFER_GRANULARITY 256
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+
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+typedef struct stat_buffer_ {
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+	char *b;
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+	int size;
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+	int offset;
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+} stat_buffer_t;
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+
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+static stat_buffer_t buffer[MAX_BUFFERS];
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+static int active_buffer=-1;
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+
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+#define ALLOC_SIZE(req_size) (((req_size/BUFFER_GRANULARITY)+1)*BUFFER_GRANULARITY)
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+
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+int allocate_buffer(int req_size) {
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+	int size=ALLOC_SIZE(req_size);
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+
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+	if (buffer[active_buffer].b == NULL) {
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+		if ((buffer[active_buffer].b=pkg_malloc(size))==NULL)
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+			return 0;
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+		buffer[active_buffer].size=size;
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+		buffer[active_buffer].offset=0;
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+		return 1;
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+	}
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+
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+	active_buffer = (active_buffer?active_buffer:MAX_BUFFERS)-1;
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+	if (buffer[active_buffer].size >= req_size) {
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+		buffer[active_buffer].offset = 0;
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+		return 1;
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+	}
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+
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+	if (pkg_realloc(buffer[active_buffer].b,size)) {
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+		buffer[active_buffer].size=size;
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+		buffer[active_buffer].offset=0;
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+		return 1;
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+	}
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+
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+	return 0;
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+}
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+
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+/*
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+ * Request for space from buffer
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+ *
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+ * Returns:  NULL  memory allocation failure (no more space)
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+ *           pointer to the space on success
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+ */
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+
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+char* get_static_buffer(int req_size) {
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+	char *p = NULL;
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+	if ((buffer[active_buffer].size >= buffer[active_buffer].offset + req_size)
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+			|| (allocate_buffer(req_size))) {
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+		/* enough space in current buffer or allocation successful */
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+		p = buffer[active_buffer].b+buffer[active_buffer].offset;
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+		buffer[active_buffer].offset += req_size;
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+		return p;
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+	}
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+	return NULL;
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+}
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+
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+/* Internal function - called before request is going to be processed
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+ *
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+ * Reset offset to unused space
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+ */
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+
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+int reset_static_buffer() {
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+	int i;
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+
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+	if (active_buffer == -1) {
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+		memset(buffer, 0, sizeof(buffer));
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+	} else {
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+		for (i=0; i<MAX_BUFFERS; i++)
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+			buffer[i].offset=0;
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+	}
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+	active_buffer=0;
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+	return 0;
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+}
select_buf.h
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+/*
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+ * $Id$
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+ *
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+ * Copyright (C) 2005-2006 iptelorg GmbH
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+ *
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+ * This file is part of ser, a free SIP server.
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+ *
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+ * ser is free software; you can redistribute it and/or modify
8 
+ * it under the terms of the GNU General Public License as published by
9 
+ * the Free Software Foundation; either version 2 of the License, or
10 
+ * (at your option) any later version
11 
+ *
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+ * For a license to use the ser software under conditions
13 
+ * other than those described here, or to purchase support for this
14 
+ * software, please contact iptel.org by e-mail at the following addresses:
15 
+ *    info@iptel.org
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+ *
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+ * ser is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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+ * GNU General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU General Public License
23 
+ * along with this program; if not, write to the Free Software
24 
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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+ *
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+ * History:
27 
+ * --------
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+ *	2006-06-16  static buffer for select results (mma)
29 
+ *	            each process owns a separate space
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+ *	            each request starts using the buffer from the start
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+ *
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+ */
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+
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+#ifndef SELECT_BUFFER_H
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+#define SELECT_BUFFER_H
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+
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+/*
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+ * Request for space from buffer
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+ *
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+ * Returns:  NULL  memory allocation failure (no more space)
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+ *           pointer to the space on success
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+ */
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+
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+char* get_static_buffer(int req_size);
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+
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+/* Internal function - called before request is going to be processed
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+ *
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+ * Reset offset to unused space
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+ */
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+
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+int reset_static_buffer();
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+
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+#endif /* SELECT_BUFFER_H */