cobs.c File Reference

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Detailed Description

Consistant Overhead Byte Stuffing (COBS).

COBS is an escaping algorithm, taking input in the [0,255] range and producing output in the [1,255] range. In other words, it escapes all NUL bytes.

Author:

Raphael Manfredi

Date:

2002-2004

#include "common.h"
#include "cobs.h"
#include "walloc.h"
#include "override.h"

Defines
#define	FINISH(x)
#define	FINISH()
Functions
gchar *	cobs_encodev (struct iovec *iov, gint iovcnt, size_t *retlen)
	Encode vector `iov' of `iovcnt' elements, whose size is held in `retlen'.
gchar *	cobs_encode (gchar *buf, size_t len, size_t *retlen)
	Encode `len' bytes starting at `buf' into new allocated buffer.
gboolean	cobs_decode_into (const gchar *buf, size_t len, gchar *out, size_t outlen, size_t *retlen)
	Decode `len' bytes starting at `buf' into decoding buffer `out', which is `outlen' bytes long.
gboolean	cobs_is_valid (const gchar *buf, size_t len)
	Check whether supplied buffer forms a valid COBS encoding.
gchar *	cobs_decode (gchar *buf, size_t len, size_t *retlen, gboolean inplace)
	Decode `len' bytes starting at `buf' into new allocated buffer, unless `inplace' is true in which case decoding is done inplace.
void	cobs_stream_init (cobs_stream_t *cs, gpointer data, size_t len)
	Initialize an incremental COBS context, where data will be written in the supplied buffer.
gboolean	cobs_stream_write (cobs_stream_t *cs, gpointer data, size_t len)
	Add data to the COBS stream.
size_t	cobs_stream_close (cobs_stream_t *cs, gboolean *saw_nul)
	Close COBS stream: we have no more data to write.
void	cobs_stream_invalidate (cobs_stream_t *cs)
	Empty the descriptor, making it invalid.
gboolean	cobs_stream_is_valid (cobs_stream_t *cs)
	Check whether the stream descriptor is valid, for assertions.

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Define Documentation

#define FINISH (   )

Value: do { \ g_assert(cs->cp < cs->end); \ *cs->cp = cs->last_code = cs->code; \ cs->cp = cs->o++; \ cs->code = 0x1; \ } while (0)

#define FINISH (  x   )

Value: do { \ *cp = last_code = (x); \ cp = o++; \ code = 0x1; \ } while (0)

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Function Documentation

gchar* cobs_decode (  gchar *  buf, size_t  len, size_t *  retlen, gboolean  inplace )

Decode `len' bytes starting at `buf' into new allocated buffer, unless `inplace' is true in which case decoding is done inplace. Returns: the new decoded buffer, or NULL if the input was not valid COBS encoding. The length of the decoded buffer is in `retlen'.

gboolean cobs_decode_into (  const gchar *  buf, size_t  len, gchar *  out, size_t  outlen, size_t *  retlen )

Decode `len' bytes starting at `buf' into decoding buffer `out', which is `outlen' bytes long. Returns: whether the input was valid COBS encoding. The length of the decoded buffer is returned in `retlen'.

gchar* cobs_encode (  gchar *  buf, size_t  len, size_t *  retlen )

Encode `len' bytes starting at `buf' into new allocated buffer. Returns: the new encoded buffer, and its length in `retlen'.

gchar* cobs_encodev (  struct iovec *  iov, gint  iovcnt, size_t *  retlen )

Encode vector `iov' of `iovcnt' elements, whose size is held in `retlen'. Returns: the new encoded buffer, and its length in `retlen'. Attention: NB: the output is a linear buffer, not a vector.

gboolean cobs_is_valid (  const gchar *  buf, size_t  len )

Check whether supplied buffer forms a valid COBS encoding.

size_t cobs_stream_close (  cobs_stream_t *  cs, gboolean *  saw_nul )

Close COBS stream: we have no more data to write. Parameters: cs  the stream to close saw_nul  if non-NULL, writes whether we saw a NUL in the input Returns: the final length of the stream on success, 0 on error.

void cobs_stream_init (  cobs_stream_t *  cs, gpointer  data, size_t  len )

Initialize an incremental COBS context, where data will be written in the supplied buffer. Parameters: cs  the COBS stream to initialize. data  start of buffer where data will be written len  length of supplied buffer

void cobs_stream_invalidate (  cobs_stream_t *  cs  )

Empty the descriptor, making it invalid.

gboolean cobs_stream_is_valid (  cobs_stream_t *  cs  )

Check whether the stream descriptor is valid, for assertions.

gboolean cobs_stream_write (  cobs_stream_t *  cs, gpointer  data, size_t  len )

Add data to the COBS stream. Returns: TRUE if OK, FALSE if we cannot put the data any more.

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