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