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/*
*
* AT chat library with GLib integration
*
* Copyright (C) 2008-2011 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <string.h>
#include <glib.h>
#include "ringbuffer.h"
#define MAX_SIZE 262144
struct ring_buffer {
unsigned char *buffer;
unsigned int size;
unsigned int mask;
unsigned int in;
unsigned int out;
};
struct ring_buffer *ring_buffer_new(unsigned int size)
{
unsigned int real_size = 1;
struct ring_buffer *buffer;
/* Find the next power of two for size */
while (real_size < size && real_size < MAX_SIZE)
real_size = real_size << 1;
if (real_size > MAX_SIZE)
return NULL;
buffer = g_slice_new(struct ring_buffer);
if (buffer == NULL)
return NULL;
buffer->buffer = g_slice_alloc(real_size);
if (buffer->buffer == NULL) {
g_free(buffer);
return NULL;
}
buffer->size = real_size;
buffer->mask = real_size - 1;
buffer->in = 0;
buffer->out = 0;
return buffer;
}
int ring_buffer_write(struct ring_buffer *buf, const void *data,
unsigned int len)
{
unsigned int end;
unsigned int offset;
const unsigned char *d = data; /* Needed to satisfy non-gcc compilers */
/* Determine how much we can actually write */
len = MIN(len, buf->size - buf->in + buf->out);
/* Determine how much to write before wrapping */
offset = buf->in & buf->mask;
end = MIN(len, buf->size - offset);
memcpy(buf->buffer+offset, d, end);
/* Now put the remainder on the beginning of the buffer */
memcpy(buf->buffer, d + end, len - end);
buf->in += len;
return len;
}
unsigned char *ring_buffer_write_ptr(struct ring_buffer *buf,
unsigned int offset)
{
return buf->buffer + ((buf->in + offset) & buf->mask);
}
int ring_buffer_avail_no_wrap(struct ring_buffer *buf)
{
unsigned int offset = buf->in & buf->mask;
unsigned int len = buf->size - buf->in + buf->out;
return MIN(len, buf->size - offset);
}
int ring_buffer_write_advance(struct ring_buffer *buf, unsigned int len)
{
len = MIN(len, buf->size - buf->in + buf->out);
buf->in += len;
return len;
}
int ring_buffer_read(struct ring_buffer *buf, void *data, unsigned int len)
{
unsigned int end;
unsigned int offset;
unsigned char *d = data;
len = MIN(len, buf->in - buf->out);
/* Grab data from buffer starting at offset until the end */
offset = buf->out & buf->mask;
end = MIN(len, buf->size - offset);
memcpy(d, buf->buffer + offset, end);
/* Now grab remainder from the beginning */
memcpy(d + end, buf->buffer, len - end);
buf->out += len;
if (buf->out == buf->in)
buf->out = buf->in = 0;
return len;
}
int ring_buffer_drain(struct ring_buffer *buf, unsigned int len)
{
len = MIN(len, buf->in - buf->out);
buf->out += len;
if (buf->out == buf->in)
buf->out = buf->in = 0;
return len;
}
int ring_buffer_len_no_wrap(struct ring_buffer *buf)
{
unsigned int offset = buf->out & buf->mask;
unsigned int len = buf->in - buf->out;
return MIN(len, buf->size - offset);
}
unsigned char *ring_buffer_read_ptr(struct ring_buffer *buf,
unsigned int offset)
{
return buf->buffer + ((buf->out + offset) & buf->mask);
}
int ring_buffer_len(struct ring_buffer *buf)
{
if (buf == NULL)
return -1;
return buf->in - buf->out;
}
void ring_buffer_reset(struct ring_buffer *buf)
{
if (buf == NULL)
return;
buf->in = 0;
buf->out = 0;
}
int ring_buffer_avail(struct ring_buffer *buf)
{
if (buf == NULL)
return -1;
return buf->size - buf->in + buf->out;
}
int ring_buffer_capacity(struct ring_buffer *buf)
{
if (buf == NULL)
return -1;
return buf->size;
}
void ring_buffer_free(struct ring_buffer *buf)
{
if (buf == NULL)
return;
g_slice_free1(buf->size, buf->buffer);
g_slice_free1(sizeof(struct ring_buffer), buf);
}
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