lzw.cpp.hpp File Reference

Detailed Description

LZW decompression (implementation)

Decoder for GIF LZW data.

Definition in file lzw.cpp.hpp.

#include "fl/stl/cstddef.h"
#include "fl/stl/assert.h"
#include "fl/stl/int.h"
#include "fl/stl/allocator.h"
#include "fl/stl/noexcept.h"
#include "lzw.h"

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Classes
struct	fl::third_party::lzw_ctx
	LZW decompression context. More...
struct	fl::third_party::lzw_read_ctx
	Context for reading LZW data. More...
struct	fl::third_party::lzw_table_entry
	LZW table entry. More...

Namespaces
namespace	fl
	Base definition for an LED controller.
namespace	fl::third_party

Macros
#define	LZW_TABLE_ENTRY_MAX   (1u << LZW_CODE_MAX)
	Maximum number of lzw table entries.

Typedefs
typedef fl::u32(*	fl::third_party::lzw_writer_fn) (struct lzw_ctx *ctx, void *output_data, fl::u32 output_length, fl::u32 output_pos, fl::u16 code, fl::u16 left)

Functions
static lzw_result	fl::third_party::lzw__block_advance (struct lzw_read_ctx *ctx) FL_NOEXCEPT
	Advance the context to the next sub-block in the input data.
static lzw_result	fl::third_party::lzw__decode (struct lzw_ctx *ctx, lzw_writer_fn write_fn, void *output_data, fl::u32 output_length, fl::u32 *output_written) FL_NOEXCEPT
	Get the next LZW code and write its value(s) to output buffer.
static lzw_result	fl::third_party::lzw__handle_clear (struct lzw_ctx *ctx, fl::u16 *code_out) FL_NOEXCEPT
	Handle clear code.
static fl::u32	fl::third_party::lzw__map_write_fn (struct lzw_ctx *ctx, void *output_data, fl::u32 output_length, fl::u32 output_used, fl::u16 code, fl::u16 left) FL_NOEXCEPT
	Write colour mapped values for this code to the output.
static lzw_result	fl::third_party::lzw__read_code (struct lzw_read_ctx *ctx, fl::u16 code_size, fl::u16 *code_out) FL_NOEXCEPT
	Get the next LZW code of given size from the raw input data.
static void	fl::third_party::lzw__table_add_entry (struct lzw_ctx *ctx, fl::u16 code) FL_NOEXCEPT
	Create new table entry.
static fl::u32	fl::third_party::lzw__write_fn (struct lzw_ctx *ctx, void *output_data, fl::u32 output_length, fl::u32 output_used, fl::u16 code, fl::u16 left) FL_NOEXCEPT
	Write values for this code to the output stack.
lzw_result	fl::third_party::lzw_context_create (struct lzw_ctx **ctx) FL_NOEXCEPT
	Create an LZW decompression context.
void	fl::third_party::lzw_context_destroy (struct lzw_ctx *ctx) FL_NOEXCEPT
	Destroy an LZW decompression context.
lzw_result	fl::third_party::lzw_decode (struct lzw_ctx *ctx, const fl::u8 **const output_data, fl::u32 *output_written) FL_NOEXCEPT
	Read input codes until end of LZW context owned output buffer.
lzw_result	fl::third_party::lzw_decode_init (struct lzw_ctx *ctx, fl::u8 minimum_code_size, const fl::u8 *input_data, fl::size input_length, fl::size input_pos) FL_NOEXCEPT
	Initialise an LZW decompression context for decoding.
lzw_result	fl::third_party::lzw_decode_init_map (struct lzw_ctx *ctx, fl::u8 minimum_code_size, fl::u32 transparency_idx, const fl::u32 *colour_table, const fl::u8 *input_data, fl::size input_length, fl::size input_pos) FL_NOEXCEPT
	Initialise an LZW decompression context for decoding to colour map values.
lzw_result	fl::third_party::lzw_decode_map (struct lzw_ctx *ctx, fl::u32 *output_data, fl::u32 output_length, fl::u32 *output_written) FL_NOEXCEPT
	Read LZW codes into client buffer, mapping output to colours.

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Class Documentation

fl::third_party::lzw_ctx

struct fl::third_party::lzw_ctx

Collaboration diagram for fl::third_party::lzw_ctx:

Class Members
u16	clear_code	Special Clear code value.
u16	code_max	Max code value for current code size.
u8	code_size	Current LZW code size.
const u32 *	colour_map	Index to colour mapping.
u16	eoi_code	Special End of Information code value.
bool	has_transparency	Whether the image is opaque.
u8	initial_code_size	Starting LZW code size.
struct lzw_read_ctx	input	Input reading context.
u16	output_code	Code that has been partially output.
u16	output_left	Number of values left for output_code.
u16	prev_code	Code read from input previously.
u16	prev_code_count	Total values for previous code.
u16	prev_code_first	First value of previous code.
u8	stack_base[LZW_TABLE_ENTRY_MAX]	Output value stack.
struct lzw_table_entry	table[LZW_TABLE_ENTRY_MAX]	LZW code table. Generated during decode.
u16	table_size	Next position in table to fill.
u8	transparency_idx	Index representing transparency.

fl::third_party::lzw_read_ctx

struct fl::third_party::lzw_read_ctx

Class Members
const u8 *	data	Pointer to start of input data.
size	data_len	Input data length.
size	data_sb_next	Offset to sub-block size.
size	sb_bit	Current bit offset in sub-block.
u32	sb_bit_count	Bit count in sub-block.
const u8 *	sb_data	Pointer to current sub-block in data.

fl::third_party::lzw_table_entry

struct fl::third_party::lzw_table_entry

Class Members
u16	count	Count of values in this entry's record.
u16	extends	Offset in table to previous entry.
u8	first	First value in entry's entire record.
u8	value	Last value for record ending at entry.