110 lines
3.5 KiB
C
110 lines
3.5 KiB
C
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#ifndef HEATSHRINK_ENCODER_H
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#define HEATSHRINK_ENCODER_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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HSER_SINK_OK, /* data sunk into input buffer */
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HSER_SINK_ERROR_NULL=-1, /* NULL argument */
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HSER_SINK_ERROR_MISUSE=-2, /* API misuse */
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} HSE_sink_res;
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typedef enum {
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HSER_POLL_EMPTY, /* input exhausted */
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HSER_POLL_MORE, /* poll again for more output */
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HSER_POLL_ERROR_NULL=-1, /* NULL argument */
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HSER_POLL_ERROR_MISUSE=-2, /* API misuse */
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} HSE_poll_res;
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typedef enum {
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HSER_FINISH_DONE, /* encoding is complete */
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HSER_FINISH_MORE, /* more output remaining; use poll */
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HSER_FINISH_ERROR_NULL=-1, /* NULL argument */
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} HSE_finish_res;
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#if HEATSHRINK_DYNAMIC_ALLOC
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#define HEATSHRINK_ENCODER_WINDOW_BITS(HSE) \
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((HSE)->window_sz2)
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#define HEATSHRINK_ENCODER_LOOKAHEAD_BITS(HSE) \
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((HSE)->lookahead_sz2)
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#define HEATSHRINK_ENCODER_INDEX(HSE) \
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((HSE)->search_index)
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struct hs_index {
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uint16_t size;
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int16_t index[];
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};
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#else
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#define HEATSHRINK_ENCODER_WINDOW_BITS(_) \
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(HEATSHRINK_STATIC_WINDOW_BITS)
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#define HEATSHRINK_ENCODER_LOOKAHEAD_BITS(_) \
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(HEATSHRINK_STATIC_LOOKAHEAD_BITS)
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#define HEATSHRINK_ENCODER_INDEX(HSE) \
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(&(HSE)->search_index)
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struct hs_index {
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uint16_t size;
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int16_t index[2 << HEATSHRINK_STATIC_WINDOW_BITS];
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};
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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 match_scan_index;
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uint16_t match_length;
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uint16_t match_pos;
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uint16_t outgoing_bits; /* enqueued outgoing bits */
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uint8_t outgoing_bits_count;
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uint8_t flags;
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uint8_t state; /* current state machine node */
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uint8_t current_byte; /* current byte of output */
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uint8_t bit_index; /* current bit index */
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#if HEATSHRINK_DYNAMIC_ALLOC
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uint8_t window_sz2; /* 2^n size of window */
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uint8_t lookahead_sz2; /* 2^n size of lookahead */
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#if HEATSHRINK_USE_INDEX
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struct hs_index *search_index;
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#endif
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/* input buffer and / sliding window for expansion */
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uint8_t buffer[];
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#else
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#if HEATSHRINK_USE_INDEX
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struct hs_index search_index;
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#endif
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/* input buffer and / sliding window for expansion */
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uint8_t buffer[2 << HEATSHRINK_ENCODER_WINDOW_BITS(_)];
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#endif
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} heatshrink_encoder;
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#if HEATSHRINK_DYNAMIC_ALLOC
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/* Allocate a new encoder struct and its buffers.
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* Returns NULL on error. */
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heatshrink_encoder *heatshrink_encoder_alloc(uint8_t window_sz2,
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uint8_t lookahead_sz2);
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/* Free an encoder. */
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void heatshrink_encoder_free(heatshrink_encoder *hse);
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#endif
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/* Reset an encoder. */
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void heatshrink_encoder_reset(heatshrink_encoder *hse);
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/* Sink up to SIZE bytes from IN_BUF into the encoder.
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* INPUT_SIZE is set to the number of bytes actually sunk (in case a
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* buffer was filled.). */
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HSE_sink_res heatshrink_encoder_sink(heatshrink_encoder *hse,
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uint8_t *in_buf, size_t size, size_t *input_size);
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/* Poll for output from the encoder, 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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HSE_poll_res heatshrink_encoder_poll(heatshrink_encoder *hse,
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uint8_t *out_buf, size_t out_buf_size, size_t *output_size);
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/* Notify the encoder that the input stream is finished.
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* If the return value is HSER_FINISH_MORE, there is still more output, so
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* call heatshrink_encoder_poll and repeat. */
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HSE_finish_res heatshrink_encoder_finish(heatshrink_encoder *hse);
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#endif
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