1 // SPDX-License-Identifier: 0BSD
27 	uint64_t low;  member
32 	/// Number of bytes written out by rc_encode() -> rc_shift_low()
59 	rc->low = 0;  in rc_reset()
60 	rc->cache_size = 1;  in rc_reset()
61 	rc->range = UINT32_MAX;  in rc_reset()
62 	rc->cache = 0;  in rc_reset()
63 	rc->out_total = 0;  in rc_reset()
64 	rc->count = 0;  in rc_reset()
65 	rc->pos = 0;  in rc_reset()
73 	assert(rc->pos == 0);  in rc_forget()
74 	rc->count = 0;  in rc_forget()
81 	rc->symbols[rc->count] = bit;  in rc_bit()
82 	rc->probs[rc->count] = prob;  in rc_bit()
83 	++rc->count;  in rc_bit()
94 		const uint32_t bit = (symbol >> --bit_count) & 1;  in rc_bittree()
112 	} while (--bit_count != 0);  in rc_bittree_reverse()
121 		rc->symbols[rc->count++]  in rc_direct()
122 				= RC_DIRECT_0 + ((value >> --bit_count) & 1);  in rc_direct()
131 		rc->symbols[rc->count++] = RC_FLUSH;  in rc_flush()
139 	if ((uint32_t)(rc->low) < (uint32_t)(0xFF000000)  in rc_shift_low()
140 			|| (uint32_t)(rc->low >> 32) != 0) {  in rc_shift_low()
145 			out[*out_pos] = rc->cache + (uint8_t)(rc->low >> 32);  in rc_shift_low()
147 			++rc->out_total;  in rc_shift_low()
148 			rc->cache = 0xFF;  in rc_shift_low()
150 		} while (--rc->cache_size != 0);  in rc_shift_low()
152 		rc->cache = (rc->low >> 24) & 0xFF;  in rc_shift_low()
155 	++rc->cache_size;  in rc_shift_low()
156 	rc->low = (rc->low & 0x00FFFFFF) << RC_SHIFT_BITS;  in rc_shift_low()
163 // the dummy version these refer to the size of the whole range-encoded
166 rc_shift_low_dummy(uint64_t *low, uint64_t *cache_size, uint8_t *cache,  in rc_shift_low_dummy()  argument
169 	if ((uint32_t)(*low) < (uint32_t)(0xFF000000)  in rc_shift_low_dummy()
170 			|| (uint32_t)(*low >> 32) != 0) {  in rc_shift_low_dummy()
178 		} while (--*cache_size != 0);  in rc_shift_low_dummy()
180 		*cache = (*low >> 24) & 0xFF;  in rc_shift_low_dummy()
184 	*low = (*low & 0x00FFFFFF) << RC_SHIFT_BITS;  in rc_shift_low_dummy()
194 	assert(rc->count <= RC_SYMBOLS_MAX);  in rc_encode()
196 	while (rc->pos < rc->count) {  in rc_encode()
198 		if (rc->range < RC_TOP_VALUE) {  in rc_encode()
202 			rc->range <<= RC_SHIFT_BITS;  in rc_encode()
206 		switch (rc->symbols[rc->pos]) {  in rc_encode()
208 			probability prob = *rc->probs[rc->pos];  in rc_encode()
209 			rc->range = (rc->range >> RC_BIT_MODEL_TOTAL_BITS)  in rc_encode()
211 			prob += (RC_BIT_MODEL_TOTAL - prob) >> RC_MOVE_BITS;  in rc_encode()
212 			*rc->probs[rc->pos] = prob;  in rc_encode()
217 			probability prob = *rc->probs[rc->pos];  in rc_encode()
218 			const uint32_t bound = prob * (rc->range  in rc_encode()
220 			rc->low += bound;  in rc_encode()
221 			rc->range -= bound;  in rc_encode()
222 			prob -= prob >> RC_MOVE_BITS;  in rc_encode()
223 			*rc->probs[rc->pos] = prob;  in rc_encode()
228 			rc->range >>= 1;  in rc_encode()
232 			rc->range >>= 1;  in rc_encode()
233 			rc->low += rc->range;  in rc_encode()
238 			rc->range = UINT32_MAX;  in rc_encode()
244 			} while (++rc->pos < rc->count);  in rc_encode()
256 		++rc->pos;  in rc_encode()
259 	rc->count = 0;  in rc_encode()
260 	rc->pos = 0;  in rc_encode()
269 	assert(rc->count <= RC_SYMBOLS_MAX);  in rc_encode_dummy()
271 	uint64_t low = rc->low;  in rc_encode_dummy()  local
272 	uint64_t cache_size = rc->cache_size;  in rc_encode_dummy()
273 	uint32_t range = rc->range;  in rc_encode_dummy()
274 	uint8_t cache = rc->cache;  in rc_encode_dummy()
275 	uint64_t out_pos = rc->out_total;  in rc_encode_dummy()
277 	size_t pos = rc->pos;  in rc_encode_dummy()
282 			if (rc_shift_low_dummy(&low, &cache_size, &cache,  in rc_encode_dummy()
291 		if (pos == rc->count)  in rc_encode_dummy()
295 		switch (rc->symbols[pos]) {  in rc_encode_dummy()
297 			probability prob = *rc->probs[pos];  in rc_encode_dummy()
304 			probability prob = *rc->probs[pos];  in rc_encode_dummy()
307 			low += bound;  in rc_encode_dummy()
308 			range -= bound;  in rc_encode_dummy()
318 			low += range;  in rc_encode_dummy()
330 	// Flush the last bytes. This isn't in rc->symbols[] so we do  in rc_encode_dummy()
334 		if (rc_shift_low_dummy(&low, &cache_size,  in rc_encode_dummy()
346 	return rc->cache_size + 5 - 1;  in rc_pending()