static HSD_state st_yield_backref(heatshrink_decoder *hsd,
output_info *oi) {
size_t count = oi->buf_size - *oi->output_size;
if (count > 0) {
size_t i = 0;
if (hsd->output_count < count) count = hsd->output_count;
uint8_t *buf = &hsd->buffers[HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(hsd)];
uint16_t mask = (1 << HEATSHRINK_DECODER_WINDOW_BITS(hsd)) - 1;
uint16_t neg_offset = hsd->output_index;
LOG("-- emitting %zu bytes from -%u bytes back\n", count, neg_offset);
ASSERT(neg_offset <= mask + 1);
ASSERT(count <= (size_t)(1 << BACKREF_COUNT_BITS(hsd)));
for (i=0; i<count; i++) {
uint8_t c = buf[(hsd->head_index - neg_offset) & mask];
push_byte(hsd, oi, c);
buf[hsd->head_index & mask] = c;
hsd->head_index++;
LOG(" -- ++ 0x%02x\n", c);
}
hsd->output_count -= count;
if (hsd->output_count == 0) { return HSDS_TAG_BIT; }
}
return HSDS_YIELD_BACKREF;
}
static HSD_state st_backref_count_lsb(heatshrink_decoder *hsd) {
uint8_t br_bit_ct = BACKREF_COUNT_BITS(hsd);
uint32_t bits = get_bits(hsd, br_bit_ct < 8 ? br_bit_ct : 8);
LOG("-- backref count (lsb), got 0x%04x (+1)\n", bits);
if (bits == NO_BITS) { return HSDS_BACKREF_COUNT_LSB; }
hsd->output_count |= bits;
hsd->output_count++;
return HSDS_YIELD_BACKREF;
}
static HSD_state st_backref_count_msb(heatshrink_decoder *hsd) {
uint8_t br_bit_ct = BACKREF_COUNT_BITS(hsd);
ASSERT(br_bit_ct > 8);
uint32_t bits = get_bits(hsd, br_bit_ct - 8);
LOG("-- backref count (msb), got 0x%04x (+1)\n", bits);
if (bits == NO_BITS) { return HSDS_BACKREF_COUNT_MSB; }
hsd->output_count = bits << 8;
return HSDS_BACKREF_COUNT_LSB;
}
static HSD_state st_backref_index_lsb(heatshrink_decoder *hsd) {
uint8_t bit_ct = BACKREF_INDEX_BITS(hsd);
uint32_t bits = get_bits(hsd, bit_ct < 8 ? bit_ct : 8);
LOG("-- backref index (lsb), got 0x%04x (+1)\n", bits);
if (bits == NO_BITS) { return HSDS_BACKREF_INDEX_LSB; }
hsd->output_index |= bits;
hsd->output_index++;
uint8_t br_bit_ct = BACKREF_COUNT_BITS(hsd);
hsd->output_count = 0;
return (br_bit_ct > 8) ? HSDS_BACKREF_COUNT_MSB : HSDS_BACKREF_COUNT_LSB;
}
