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