lws-upng.h File Reference

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Typedefs
typedef enum lws_upng_format_t	lws_upng_format_t
typedef struct lws_upng_t	lws_upng_t

Enumerations
enum	lws_upng_format_t {   LWS_UPNG_BADFORMAT , LWS_UPNG_RGB8 , LWS_UPNG_RGB16 , LWS_UPNG_RGBA8 ,   LWS_UPNG_RGBA16 , LWS_UPNG_LUMINANCE1 , LWS_UPNG_LUMINANCE2 , LWS_UPNG_LUMINANCE4 ,   LWS_UPNG_LUMINANCE8 , LWS_UPNG_LUMINANCE_ALPHA1 , LWS_UPNG_LUMINANCE_ALPHA2 , LWS_UPNG_LUMINANCE_ALPHA4 ,   LWS_UPNG_LUMINANCE_ALPHA8 }

Functions
LWS_VISIBLE LWS_EXTERN lws_upng_t *	lws_upng_new (void)
LWS_VISIBLE LWS_EXTERN void	lws_upng_free (lws_upng_t **upng)
LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t	lws_upng_emit_next_line (lws_upng_t *upng, const uint8_t **ppix, const uint8_t **buf, size_t *size, char hold_at_metadata)
LWS_VISIBLE LWS_EXTERN unsigned int	lws_upng_get_width (const lws_upng_t *upng)
LWS_VISIBLE LWS_EXTERN unsigned int	lws_upng_get_height (const lws_upng_t *upng)
LWS_VISIBLE LWS_EXTERN unsigned int	lws_upng_get_bpp (const lws_upng_t *upng)
LWS_VISIBLE LWS_EXTERN unsigned int	lws_upng_get_bitdepth (const lws_upng_t *upng)
LWS_VISIBLE LWS_EXTERN unsigned int	lws_upng_get_components (const lws_upng_t *upng)
LWS_VISIBLE LWS_EXTERN unsigned int	lws_upng_get_pixelsize (const lws_upng_t *upng)
LWS_VISIBLE LWS_EXTERN lws_upng_format_t	lws_upng_get_format (const lws_upng_t *upng)
LWS_VISIBLE LWS_EXTERN struct inflator_ctx *	lws_upng_inflator_create (const uint8_t **outring, size_t *outringlen, size_t **opl, size_t **cl)
LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t	lws_upng_inflate_data (struct inflator_ctx *inf, const void *buf, size_t len)
LWS_VISIBLE LWS_EXTERN void	lws_upng_inflator_destroy (struct inflator_ctx **inf)

Typedef Documentation

lws_upng_format_t

typedef enum lws_upng_format_t lws_upng_format_t

lws_upng_t

typedef struct lws_upng_t lws_upng_t

Definition at line 1 of file lws-upng.h.

Enumeration Type Documentation

lws_upng_format_t

enum lws_upng_format_t

Enumerator
LWS_UPNG_BADFORMAT
LWS_UPNG_RGB8
LWS_UPNG_RGB16
LWS_UPNG_RGBA8
LWS_UPNG_RGBA16
LWS_UPNG_LUMINANCE1
LWS_UPNG_LUMINANCE2
LWS_UPNG_LUMINANCE4
LWS_UPNG_LUMINANCE8
LWS_UPNG_LUMINANCE_ALPHA1
LWS_UPNG_LUMINANCE_ALPHA2
LWS_UPNG_LUMINANCE_ALPHA4
LWS_UPNG_LUMINANCE_ALPHA8

Definition at line 34 of file lws-upng.h.

                               {
        LWS_UPNG_BADFORMAT,
        LWS_UPNG_RGB8,
        LWS_UPNG_RGB16,
        LWS_UPNG_RGBA8,
        LWS_UPNG_RGBA16,
        LWS_UPNG_LUMINANCE1,
        LWS_UPNG_LUMINANCE2,
        LWS_UPNG_LUMINANCE4,
        LWS_UPNG_LUMINANCE8,
        LWS_UPNG_LUMINANCE_ALPHA1,
        LWS_UPNG_LUMINANCE_ALPHA2,
        LWS_UPNG_LUMINANCE_ALPHA4,
        LWS_UPNG_LUMINANCE_ALPHA8
} lws_upng_format_t;

Function Documentation

lws_upng_new()

LWS_VISIBLE LWS_EXTERN lws_upng_t* lws_upng_new

(

void

)

lws_upng_new() - Create new UPNG decode object

Returns a new PNG decoding object, which should be destroyed with lws_upng_free() when done with, or NULL if OOM.

lws_upng_free()

LWS_VISIBLE LWS_EXTERN void lws_upng_free

(

lws_upng_t **

upng

)

lws_upng_free() - Destroy a PNG decode object

Parameters

upng	Pointer to the decode object to destroy and set to NULL

This also frees any sub-allocations in the object.

lws_upng_emit_next_line()

LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t lws_upng_emit_next_line	(	lws_upng_t *	upng,
		const uint8_t **	ppix,
		const uint8_t **	buf,
		size_t *	size,
		char	hold_at_metadata
	)

lws_upng_emit_next_line() - deocde the next line

Parameters

upng	the decode object
ppix	pointer to a pointer set to the line's decoded pixel data
buf	pointer to a const uint8_t array of PNG input
size	pointer to the count of bytes available at *buf
hold_at_metadata	true if we should not advance to decode

Make PNG input available to the decoder so it can issue the next line's worth of pixels. If the call consumed any input, *buf and *size are adjusted accordingly.

The decoder is stateful so it is not sensitive to the chunk size for the input.

If hold_at_metadata is set, then the decoder will only go as far as picking out the metadata like image dimensions, but not start the decode, which requires the >30KB heap allocation. This lets you put off for as long as possible committing to the decode allocation... this only helps overall if you have flow controlled the incoming PNG data.

Return will be one of LWS_SRET_WANT_INPUT is the decoder is stalled waiting for more input to be provided, LWS_SRET_WANT_OUTPUT is the decoder stopped because it had produced a whole line of output pixels (which can be found starting at *ppix), LWS_SRET_OK is it completed and LWS_SRET_FATAL or larger if the decode failed.

lws_upng_get_width()

LWS_VISIBLE LWS_EXTERN unsigned int lws_upng_get_width

(

const lws_upng_t *

upng

)

lws_upng_get_height()

LWS_VISIBLE LWS_EXTERN unsigned int lws_upng_get_height

(

const lws_upng_t *

upng

)

lws_upng_get_bpp()

LWS_VISIBLE LWS_EXTERN unsigned int lws_upng_get_bpp

(

const lws_upng_t *

upng

)

lws_upng_get_bitdepth()

LWS_VISIBLE LWS_EXTERN unsigned int lws_upng_get_bitdepth

(

const lws_upng_t *

upng

)

lws_upng_get_components()

LWS_VISIBLE LWS_EXTERN unsigned int lws_upng_get_components

(

const lws_upng_t *

upng

)

lws_upng_get_pixelsize()

LWS_VISIBLE LWS_EXTERN unsigned int lws_upng_get_pixelsize

(

const lws_upng_t *

upng

)

lws_upng_get_format()

LWS_VISIBLE LWS_EXTERN lws_upng_format_t lws_upng_get_format

(

const lws_upng_t *

upng

)

lws_upng_inflator_create()

LWS_VISIBLE LWS_EXTERN struct inflator_ctx* lws_upng_inflator_create	(	const uint8_t **	outring,
		size_t *	outringlen,
		size_t **	opl,
		size_t **	cl
	)

lws_upng_inflator_create() - create a gzip inflator context

Parameters

outring	pointer set to the output ringbuffer on exit
outringlen	size of the output ringbuffer set on exit
opl	pointer to set to point to ctx outpos_linear
cl	pointer to set to point to ctx consumed_linear

Creates an opaque gzip inflator object.

lws_upng_inflate_data()

LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t lws_upng_inflate_data	(	struct inflator_ctx *	inf,
		const void *	buf,
		size_t	len
	)

lws_upng_inflate_data() - inflate compressed data statefully

Parameters

inf	inflator context created with lws_upng_inflator_create()
buf	NULL to continue consumption of existing input, or new input
len	ignored if buf is NULL, else amount of new input at buf

Tries to progress the inflation. If output is available, *opl will be further along than before it was called. *cl should be set to opl to consume the available output data.

Output is into a ringfuffer, typically sized at 32KB. opl and cl are "linear", that is extend beyond the ringbuffer. They should be modulo outringlen (given when the inflator was created) when accessing outring.

lws_upng_inflator_destroy()

LWS_VISIBLE LWS_EXTERN void lws_upng_inflator_destroy

(

struct inflator_ctx **

inf

)

lws_upng_inflator_destroy() - destroys the inflation context and ringbuffer

inf: pointer to pointer to inflation context

Frees the inflation context and its allocations, and sets *inf to NULL.