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heatshrink_decoder.h
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heatshrink_decoder.h
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#ifndef HEATSHRINK_DECODER_H
#define HEATSHRINK_DECODER_H
#include <stdint.h>
#include <stddef.h>
#include "heatshrink_common.h"
#include "heatshrink_config.h"
typedef enum {
HSDR_SINK_OK, /* data sunk, ready to poll */
HSDR_SINK_FULL, /* out of space in internal buffer */
HSDR_SINK_ERROR_NULL=-1, /* NULL argument */
} HSD_sink_res;
typedef enum {
HSDR_POLL_EMPTY, /* input exhausted */
HSDR_POLL_MORE, /* more data remaining, call again w/ fresh output buffer */
HSDR_POLL_ERROR_NULL=-1, /* NULL arguments */
HSDR_POLL_ERROR_UNKNOWN=-2,
} HSD_poll_res;
typedef enum {
HSDR_FINISH_DONE, /* output is done */
HSDR_FINISH_MORE, /* more output remains */
HSDR_FINISH_ERROR_NULL=-1, /* NULL arguments */
} HSD_finish_res;
#if HEATSHRINK_DYNAMIC_ALLOC
#define HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(BUF) \
((BUF)->input_buffer_size)
#define HEATSHRINK_DECODER_WINDOW_BITS(BUF) \
((BUF)->window_sz2)
#define HEATSHRINK_DECODER_LOOKAHEAD_BITS(BUF) \
((BUF)->lookahead_sz2)
#else
#define HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(_) \
HEATSHRINK_STATIC_INPUT_BUFFER_SIZE
#define HEATSHRINK_DECODER_WINDOW_BITS(_) \
(HEATSHRINK_STATIC_WINDOW_BITS)
#define HEATSHRINK_DECODER_LOOKAHEAD_BITS(BUF) \
(HEATSHRINK_STATIC_LOOKAHEAD_BITS)
#endif
typedef struct {
uint16_t input_size; /* bytes in input buffer */
uint16_t input_index; /* offset to next unprocessed input byte */
uint16_t output_count; /* how many bytes to output */
uint16_t output_index; /* index for bytes to output */
uint16_t head_index; /* head of window buffer */
uint16_t bit_accumulator;
uint8_t state; /* current state machine node */
uint8_t current_byte; /* current byte of input */
uint8_t bit_index; /* current bit index */
#if HEATSHRINK_DYNAMIC_ALLOC
/* Fields that are only used if dynamically allocated. */
uint8_t window_sz2; /* window buffer bits */
uint8_t lookahead_sz2; /* lookahead bits */
uint16_t input_buffer_size; /* input buffer size */
/* Input buffer, then expansion window buffer */
uint8_t buffers[];
#else
/* Input buffer, then expansion window buffer */
uint8_t buffers[(1 << HEATSHRINK_DECODER_WINDOW_BITS(_))
+ HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(_)];
#endif
} heatshrink_decoder;
#if HEATSHRINK_DYNAMIC_ALLOC
/* Allocate a decoder with an input buffer of INPUT_BUFFER_SIZE bytes,
* an expansion buffer size of 2^WINDOW_SZ2, and a lookahead
* size of 2^lookahead_sz2. (The window buffer and lookahead sizes
* must match the settings used when the data was compressed.)
* Returns NULL on error. */
heatshrink_decoder *heatshrink_decoder_alloc(uint16_t input_buffer_size,
uint8_t expansion_buffer_sz2, uint8_t lookahead_sz2);
/* Free a decoder. */
void heatshrink_decoder_free(heatshrink_decoder *hsd);
#endif
/* Reset a decoder. */
void heatshrink_decoder_reset(heatshrink_decoder *hsd);
/* Sink at most SIZE bytes from IN_BUF into the decoder. *INPUT_SIZE is set to
* indicate how many bytes were actually sunk (in case a buffer was filled). */
HSD_sink_res heatshrink_decoder_sink(heatshrink_decoder *hsd,
uint8_t *in_buf, size_t size, size_t *input_size);
/* Poll for output from the decoder, copying at most OUT_BUF_SIZE bytes into
* OUT_BUF (setting *OUTPUT_SIZE to the actual amount copied). */
HSD_poll_res heatshrink_decoder_poll(heatshrink_decoder *hsd,
uint8_t *out_buf, size_t out_buf_size, size_t *output_size);
/* Notify the dencoder that the input stream is finished.
* If the return value is HSDR_FINISH_MORE, there is still more output, so
* call heatshrink_decoder_poll and repeat. */
HSD_finish_res heatshrink_decoder_finish(heatshrink_decoder *hsd);
#endif