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/*
* MOC - music on console
* Copyright (C) 2005 Damian Pietras <daper@daper.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stddef.h>
#include <sys/types.h>
#include <assert.h>
#include <string.h>
#include "common.h"
#include "fifo_buf.h"
struct fifo_buf
{
int size; /* Size of the buffer */
int pos; /* Current position */
int fill; /* Current fill */
char buf[]; /* The buffer content */
};
/* Initialize and return a new fifo_buf structure of the size requested. */
struct fifo_buf *fifo_buf_new (const size_t size)
{
struct fifo_buf *b;
assert (size > 0);
b = xmalloc (offsetof (struct fifo_buf, buf) + size);
b->size = size;
b->pos = 0;
b->fill = 0;
return b;
}
/* Destroy the buffer object. */
void fifo_buf_free (struct fifo_buf *b)
{
assert (b != NULL);
free (b);
}
/* Put data into the buffer. Returns number of bytes actually put. */
size_t fifo_buf_put (struct fifo_buf *b, const char *data, size_t size)
{
size_t written = 0;
assert (b != NULL);
assert (b->buf != NULL);
while (b->fill < b->size && written < size) {
size_t write_from;
size_t to_write;
if (b->pos + b->fill < b->size) {
write_from = b->pos + b->fill;
to_write = b->size - (b->pos + b->fill);
}
else {
write_from = b->fill - b->size + b->pos;
to_write = b->size - b->fill;
}
if (to_write > size - written)
to_write = size - written;
memcpy (b->buf + write_from, data + written, to_write);
b->fill += to_write;
written += to_write;
}
return written;
}
/* Copy data from the beginning of the buffer to the user buffer. Returns the
* number of bytes copied. */
size_t fifo_buf_peek (struct fifo_buf *b, char *user_buf, size_t user_buf_size)
{
size_t user_buf_pos = 0, written = 0;
ssize_t left, pos;
assert (b != NULL);
assert (b->buf != NULL);
left = b->fill;
pos = b->pos;
while (left && written < user_buf_size) {
size_t to_copy = pos + left <= b->size
? left : b->size - pos;
if (to_copy > user_buf_size - written)
to_copy = user_buf_size - written;
memcpy (user_buf + user_buf_pos, b->buf + pos, to_copy);
user_buf_pos += to_copy;
written += to_copy;
left -= to_copy;
pos += to_copy;
if (pos == b->size)
pos = 0;
}
return written;
}
size_t fifo_buf_get (struct fifo_buf *b, char *user_buf, size_t user_buf_size)
{
size_t user_buf_pos = 0, written = 0;
assert (b != NULL);
assert (b->buf != NULL);
while (b->fill && written < user_buf_size) {
size_t to_copy = b->pos + b->fill <= b->size
? b->fill : b->size - b->pos;
if (to_copy > user_buf_size - written)
to_copy = user_buf_size - written;
memcpy (user_buf + user_buf_pos, b->buf + b->pos, to_copy);
user_buf_pos += to_copy;
written += to_copy;
b->fill -= to_copy;
b->pos += to_copy;
if (b->pos == b->size)
b->pos = 0;
}
return written;
}
/* Get the amount of free space in the buffer. */
size_t fifo_buf_get_space (const struct fifo_buf *b)
{
assert (b != NULL);
assert (b->buf != NULL);
return b->size - b->fill;
}
size_t fifo_buf_get_fill (const struct fifo_buf *b)
{
assert (b != NULL);
return b->fill;
}
size_t fifo_buf_get_size (const struct fifo_buf *b)
{
assert (b != NULL);
return b->size;
}
void fifo_buf_clear (struct fifo_buf *b)
{
assert (b != NULL);
b->fill = 0;
}
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