Implementation of the '1027' encoding mode used by Brother printers. More...

Macros
#define	pDEBUG(x, ...)

#define	WHITE_BYTE 0x00

Functions
static void	hl_c1027_line_append (struct cm1027_line *c, uint16_t word)

static void	hl_c1027_sequence_append (struct cm1027_line c, const uint16_t pattern, size_t cnt)

static uint16_t	hl_encoding_vertical (unsigned count)

static uint16_t	hl_encoding_repeat_word (unsigned count)

static uint16_t	hl_encoding_repeat_byte (unsigned count, unsigned data)

static uint16_t	hl_encoding_repeat_nibble (unsigned count, unsigned data)

static uint16_t	hl_encoding_copy (unsigned count)

bool	hl_c1027_line_check_if_empty (unsigned cnt, const uint16_t line[cnt])

static bool	c1027_upper_lower_byte_match (uint16_t data)

static bool	c1027_all_nibbles_match (uint16_t data)

static void	hl_1027_plain_data_copy (struct cm1027_line cline, const uint16_t pattern, unsigned start, unsigned cnt)

void	hl_c1027_line_encode (struct cm1027_line cline, unsigned cnt, const uint16_t line[cnt], const uint16_t prev)

int	hl_c1027_block_flush (struct cm1027_block block, FILE outstream)

int	hl_c1027_block_line_add (struct cm1027_block block, const struct cm1027_line line, FILE *outstream)

int	hl_c1027_block_line_twin_add (struct cm1027_block block, const struct cm1027_line line, unsigned cnt, FILE *outstream)

void	hl_c1027_block_init (struct cm1027_block *block, unsigned llength)

void	hl_c1027_block_exit (struct cm1027_block *block)

Detailed Description

Read the corresponding header file for further information about this encoding method.

The printer wants the data to be print as:

a bit is '0': this dot isn't printed, the paper colour is still visible at this position
a bit is '1': this dot is printed, a black dot is visible at this position

Macro Definition Documentation

◆ pDEBUG

#define pDEBUG	(	x,
		...
	)

◆ WHITE_BYTE

#define WHITE_BYTE 0x00

Define the byte value of eight white dots (e.g. not to print)

Function Documentation

◆ hl_c1027_line_append()

static void hl_c1027_line_append	(	struct cm1027_line *	c,
		uint16_t	word
	)

static

Append a single word to the end of the line data buffer

Parameters

[in,out]	c	Compression output buffer
[in]	word	The word to append to the end of the line data buffer

◆ hl_c1027_sequence_append()

static void hl_c1027_sequence_append	(	struct cm1027_line *	c,
		const uint16_t *	pattern,
		size_t	cnt
	)

static

Append a pattern to the encoded output buffer

Parameters

[in,out]	c	The buffer to add the pattern to
[in]	pattern	The pattern to copy
[in]	cnt	Count of words to copy

Todo:: Do we need to keep the pattern as is? Or do we need to honor the endianess here as well?

◆ hl_encoding_vertical()

static uint16_t hl_encoding_vertical ( unsigned count )

static

Generate a vertical copy entry

Parameters

[in] count Copy counter

Returns: The encoded compression code word

Copy count words from the previous line

The generated entry is defined to (MSB left):

76543210 76543210 111ccccc cccccccc

With:

ccccccccccccc 13 bit of count

Precondition: count < 8192

Todo:: What does count == 0x00 mean?

◆ hl_encoding_repeat_word()

static uint16_t hl_encoding_repeat_word ( unsigned count )

static

Generate a horizontal word repeat entry

Parameters

[in] count Repeat counter

Returns: The encoded compression code word

Repeat the next 16 bit word count times

The generated entry is defined to (MSB left):

76543210 76543210 100ccccc cccccccc <word>

With:

ccccccccccccc 13 bit of count

Precondition: count < 8192

Todo:: What does count == 0x00 mean?

◆ hl_encoding_repeat_byte()

static uint16_t hl_encoding_repeat_byte	(	unsigned	count,
		unsigned	data
	)

static

Generate a horizontal byte repeat entry

Parameters

[in]	count	Repeat counter
[in]	data	Repeat byte twice `count` times

Returns: The encoded compression code word

Repeat 8 bit data count * 2 times

The generated entry is defined to (MSB left):

76543210 76543210 110ccccc dddddddd

With:

dddddddd data ccccc 6 bit of count

Precondition: count < 32

Todo:: What does a count == 0 mean?

◆ hl_encoding_repeat_nibble()

static uint16_t hl_encoding_repeat_nibble	(	unsigned	count,
		unsigned	data
	)

static

Generate a horizontal nibble repeat entry

Parameters

[in]	count	Repeat counter
[in]	data	Repeat lower nibble quad `count` times

Returns: The encoded compression code word

Repeat data nibble count * 4 times

The generated entry is defined to (MSB left):

76543210 76543210 101ddddc cccccccc

With:

dddd lower nibble of data ccccccccc 9 bit of count

Precondition: count < 512

◆ hl_encoding_copy()

static uint16_t hl_encoding_copy ( unsigned count )

static

No compression, count words of data follow

Parameters

[in] count Count of data words follows

Returns: The encoded compression code word

The generated entry is defined to (MSB left):

76543210 76543210 000ccccc ccccxxxx <word>…

With:

ccccccccc 9 bit of count

Precondition: count < 512

◆ hl_c1027_line_check_if_empty()

bool hl_c1027_line_check_if_empty	(	unsigned	cnt,
		const uint16_t	line[cnt]
	)

Check if a line is empty, e.g. nothing to print

Parameters

[in]	line	The line data to check
[in]	cnt	Count of words in `*line`

Return values

true	Nothing to print
false	Line contains something to print

If all bits in the line are '0' the line contains nothing to print and can be skipped instead. Empty lines can maybe skipped entirely if they are leading a block.

◆ c1027_upper_lower_byte_match()

static bool c1027_upper_lower_byte_match ( uint16_t data )

static

Check if upper and lower bytes are the same

Parameters

[in] data Word to check

Return values

true	If the upper and lower byte of the word matches (e.g. 0xfefe for example)
false	If they don't match

◆ c1027_all_nibbles_match()

static bool c1027_all_nibbles_match ( uint16_t data )

static

Check if all four nibbles are the same

Parameters

[in] data Word to check

Return values

true	if all nibbles in the word are equal (e.g. 0xeeee for example)
false	if not equal

This function works correctly, if the word has two equal bytes. The algorithm ensure this, by first calling c1027_upper_lower_byte_match() and in the next step this function to check in more detail.

◆ hl_1027_plain_data_copy()

static void hl_1027_plain_data_copy	(	struct cm1027_line *	cline,
		const uint16_t *	pattern,
		unsigned	start,
		unsigned	cnt
	)

static

Append plain pattern to the encoded output buffer

Parameters

[in,out]	cline	The buffer to add the pattern to
[in]	pattern	Where to copy the plain pattern from
[in]	start	Index where to start copy plain data from `pattern`
[in]	cnt	Word count to copy beginning with `start` from `pattern`

◆ hl_c1027_line_encode()

void hl_c1027_line_encode	(	struct cm1027_line *	cline,
		unsigned	cnt,
		const uint16_t	line[cnt],
		const uint16_t *	prev
	)

Encode one line into the printer's wire format according to the 1027 method

Parameters

[in,out]	cline	Where to store the encoded result
[in]	cnt	Count of words in `line`
[in]	line	The current line to encode
[in]	prev	The previous line for reference (can be NULL)

Precondition: line and prev must be independent

◆ hl_c1027_block_flush()

int hl_c1027_block_flush	(	struct cm1027_block *	block,
		FILE *	outstream
	)

Flush out the current block and prepare for the next block

Parameters

[in]	block	Printer data block info
[in,out]	outstream	The stream to send the printer data to

Return values

0	on success
-errno	if the data flushing to the printer has failed

This flushes the data out to the printer's tream with a leading PCL command of the form:

the ESC char
"*b"
'block->bused_cnt * 2 + header length' as an integer ASCII number (variable length)
the char 'W' (one byte)
the c0127_band_header structure content
and then appends the whole block data at once.

Attention: The block, e.g. cm1027_block::block_started gets cleared if called!

Note: 'Flushing' here means only to write the accumulated line encoding data including the required data header into the printer's stream. Then everything gets prepared to start the next block. It doesn't mean, the printer receives this data immediately (but it can, if the stream's buffer is already full). The real stream flush should happen when processing of the current page finishes.

◆ hl_c1027_block_line_add()

int hl_c1027_block_line_add	(	struct cm1027_block *	block,
		const struct cm1027_line *	line,
		FILE *	outstream
	)

Precondition: A block should never cross a band's boundaries

◆ hl_c1027_block_line_twin_add()

int hl_c1027_block_line_twin_add	(	struct cm1027_block *	block,
		const struct cm1027_line *	line,
		unsigned	cnt,
		FILE *	outstream
	)

Add one line and a twin of it to the encoded data

Parameters

[in,out]	block	Block info
[in]	line	The line to add to this block
[in]	cnt	Final length in words of one fully decoded line
[in]	outstream	The IO stream to send the printer data to (on demand)

This function adds two lines to the block for the HQ1200 mode, where the vertical resolution is still 600 DPI but the printer expects the lines for 1200 DPI.

The first line is the line and the second one is a twin of it, encoded as a reuse of the full line content.

◆ hl_c1027_block_init()

void hl_c1027_block_init	(	struct cm1027_block *	block,
		unsigned	llength
	)

Init the printer data block as a preparation of hl_c1027_block_line_add()

Parameters

[in,out]	block	Printer data block info
[in]	llength	Max line length in count of words

◆ hl_c1027_block_exit()

void hl_c1027_block_exit ( struct cm1027_block * block )

Free resources allocated when processing

Parameters

[in] block Printer data block info

Macros

Functions

Detailed Description

Macro Definition Documentation

◆ pDEBUG

◆ WHITE_BYTE

Function Documentation

◆ hl_c1027_line_append()

◆ hl_c1027_sequence_append()

◆ hl_encoding_vertical()

◆ hl_encoding_repeat_word()

◆ hl_encoding_repeat_byte()

◆ hl_encoding_repeat_nibble()

◆ hl_encoding_copy()

◆ hl_c1027_line_check_if_empty()

◆ c1027_upper_lower_byte_match()

◆ c1027_all_nibbles_match()

◆ hl_1027_plain_data_copy()

◆ hl_c1027_line_encode()

◆ hl_c1027_block_flush()

◆ hl_c1027_block_line_add()

◆ hl_c1027_block_line_twin_add()

◆ hl_c1027_block_init()

◆ hl_c1027_block_exit()