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/**
* xrdp: A Remote Desktop Protocol server.
*
* Copyright (C) Laxmikant Rashinkar 2013 LK.Rashinkar@gmail.com
*
* 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.
*/
/* FIFO implementation to store a pointer to a user struct */
/* module based logging */
#define MODULE_NAME "FIFO "
#define LOCAL_DEBUG
#include "fifo.h"
#include "mlog.h"
#include "os_calls.h"
/**
* Initialize a FIFO that grows as required
*
* @param fp pointer to a FIFO
* @param num_entries initial size
*
* @return 0 on success, -1 on failure
*****************************************************************************/
int
fifo_init(FIFO* fp, int num_entries)
{
log_debug_high("entered");
/* validate params */
if (!fp)
{
log_debug_high("invalid parameters");
return -1;
}
if (num_entries < 1)
num_entries = 10;
fp->rd_ptr = 0;
fp->wr_ptr = 0;
fp->user_data = (long *) g_malloc(sizeof(long) * num_entries, 1);
if (fp->user_data)
{
fp->entries = num_entries;
log_debug_low("FIFO created; rd_ptr=%d wr_ptr=%d entries=%d",
fp->rd_ptr, fp->wr_ptr, fp->entries);
return 0;
}
else
{
log_error("FIFO create error; system out of memory");
fp->entries = 0;
return -1;
}
}
/**
* Deinit FIFO and release resources
*
* @param fp FIFO to deinit
*
* @return 0 on success, -1 on error
*****************************************************************************/
int
fifo_deinit(FIFO* fp)
{
log_debug_high("entered");
if (!fp)
{
log_debug_high("FIFO is null");
return -1;
}
if (fp->user_data)
{
g_free(fp->user_data);
fp->user_data = 0;
}
fp->rd_ptr = 0;
fp->wr_ptr = 0;
fp->entries = 0;
return 0;
}
/**
* Check if FIFO is empty
*
* @param fp FIFO
*
* @return 1 if FIFO is empty, 0 otherwise
*****************************************************************************/
int
fifo_is_empty(FIFO* fp)
{
log_debug_high("entered");
if (!fp)
{
log_debug_high("FIFO is null");
return 0;
}
return (fp->rd_ptr == fp->wr_ptr) ? 1 : 0;
}
/**
* Insert an item at the end
*
* @param fp FIFO
* @param data data to insert into FIFO
*
* @param 0 on success, -1 on error
*****************************************************************************/
int
fifo_insert(FIFO* fp, void* data)
{
long* lp;
int next_val; /* next value for wr_ptr */
int i;
log_debug_high("entered");
if (!fp)
{
log_debug_high("FIFO is null");
return -1;
}
next_val = fp->wr_ptr + 1;
if (next_val >= fp->entries)
next_val = 0;
if (next_val == fp->rd_ptr)
{
/* FIFO is full, expand it by 10 entries */
lp = (long *) g_malloc(sizeof(long) * (fp->entries + 10), 1);
if (!lp)
{
log_debug_low("FIFO full; cannot expand, no memory");
return -1;
}
log_debug_low("FIFO full, expanding by 10 entries");
/* copy old data new location */
for (i = 0; i < (fp->entries - 1); i++)
{
lp[i] = fp->user_data[fp->rd_ptr++];
if (fp->rd_ptr >= fp->entries)
fp->rd_ptr = 0;
}
/* update pointers */
fp->rd_ptr = 0;
fp->wr_ptr = fp->entries - 1;
next_val = fp->entries;
fp->entries += 10;
/* free old data */
g_free(fp->user_data);
fp->user_data = lp;
}
log_debug_low("inserting data at index %d", fp->wr_ptr);
fp->user_data[fp->wr_ptr] = (long) data;
fp->wr_ptr = next_val;
return 0;
}
/**
* Remove an item from the head
*
* @param fp FIFO
*
* @param data on success, NULL on error
*****************************************************************************/
void*
fifo_remove(FIFO* fp)
{
long data;
log_debug_high("entered");
if (!fp)
{
log_debug_high("FIFO is null");
return 0;
}
if (fp->rd_ptr == fp->wr_ptr)
{
log_debug_high("FIFO is empty");
return 0;
}
log_debug_low("removing data at index %d", fp->rd_ptr);
data = fp->user_data[fp->rd_ptr++];
if (fp->rd_ptr >= fp->entries)
{
log_debug_high("FIFO rd_ptr wrapped around");
fp->rd_ptr = 0;
}
return (void *) data;
}
/**
* Return item from head, but do not remove it
*
* @param fp FIFO
*
* @param data on success, NULL on error
*****************************************************************************/
void*
fifo_peek(FIFO* fp)
{
log_debug_high("entered\n");
if (!fp)
{
log_debug_high("FIFO is null\n");
return 0;
}
if (fp->rd_ptr == fp->wr_ptr)
{
log_debug_high("FIFO is empty\n");
return 0;
}
log_debug_low("peeking data at index %d\n", fp->rd_ptr);
return (void *) fp->user_data[fp->rd_ptr];
}
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