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/*
* Copyright (c) 2004-2005 Sergey Lyubka <valenok@gmail.com>
* All rights reserved
*
* "THE BEER-WARE LICENSE" (Revision 42):
* Sergey Lyubka wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return.
*/
#ifndef IO_HEADER_INCLUDED
#define IO_HEADER_INCLUDED
#include <assert.h>
#include <stddef.h>
/*
* I/O buffer descriptor
*/
struct io {
char *buf; /* IO Buffer */
size_t size; /* IO buffer size */
size_t head; /* Bytes read */
size_t tail; /* Bytes written */
size_t total; /* Total bytes read */
};
static __inline void
io_clear(struct io *io)
{
assert(io->buf != NULL);
assert(io->size > 0);
io->total = io->tail = io->head = 0;
}
static __inline char *
io_space(struct io *io)
{
assert(io->buf != NULL);
assert(io->size > 0);
assert(io->head <= io->size);
return (io->buf + io->head);
}
static __inline char *
io_data(struct io *io)
{
assert(io->buf != NULL);
assert(io->size > 0);
assert(io->tail <= io->size);
return (io->buf + io->tail);
}
static __inline size_t
io_space_len(const struct io *io)
{
assert(io->buf != NULL);
assert(io->size > 0);
assert(io->head <= io->size);
return (io->size - io->head);
}
static __inline size_t
io_data_len(const struct io *io)
{
assert(io->buf != NULL);
assert(io->size > 0);
assert(io->head <= io->size);
assert(io->tail <= io->head);
return (io->head - io->tail);
}
static __inline void
io_inc_tail(struct io *io, size_t n)
{
assert(io->buf != NULL);
assert(io->size > 0);
assert(io->tail <= io->head);
assert(io->head <= io->size);
io->tail += n;
assert(io->tail <= io->head);
if (io->tail == io->head)
io->head = io->tail = 0;
}
static __inline void
io_inc_head(struct io *io, size_t n)
{
assert(io->buf != NULL);
assert(io->size > 0);
assert(io->tail <= io->head);
io->head += n;
io->total += n;
assert(io->head <= io->size);
}
#endif /* IO_HEADER_INCLUDED */
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