1 // SPDX-License-Identifier: GPL-2.0-only
7  * Implementation of the LZ77 "plain" compression algorithm, as per MS-XCA spec.
22 #define LZ77_HASH_LOG		15
36 static __always_inline void lz77_write8(u8 *ptr, u8 v)  in lz77_write8()  argument
38 	put_unaligned(v, ptr);  in lz77_write8()
41 static __always_inline void lz77_write16(u16 *ptr, u16 v)  in lz77_write16()  argument
43 	put_unaligned_le16(v, ptr);  in lz77_write16()
46 static __always_inline void lz77_write32(u32 *ptr, u32 v)  in lz77_write32()  argument
48 	put_unaligned_le32(v, ptr);  in lz77_write32()
69 		return (cur - start);  in lz77_match_len()
75 	return (cur - start);  in lz77_match_len()
80 	len -= 3;  in lz77_write_match()
81 	dist--;  in lz77_write_match()
93 	len -= 7;  in lz77_write_match()
96 		lz77_write8(dst, umin(len, 15));  in lz77_write_match()
102 		lz77_write8(b, *b | umin(len, 15) << 4);  in lz77_write_match()
106 	if (len < 15)  in lz77_write_match()
109 	len -= 15;  in lz77_write_match()
118 	len += 7 + 15;  in lz77_write_match()
149 		return -ENOMEM;  in lz77_compress()
157 		hash = ((lz77_read64(srcp) << 24) * 889523592379ULL) >> (64 - LZ77_HASH_LOG);  in lz77_compress()
159 		htable[hash] = srcp - src;  in lz77_compress()
160 		dist = srcp - wnd;  in lz77_compress()
184 		 * Bail out if @dstp reached >= 7/8 of @slen -- already compressed badly, not worth  in lz77_compress()
187 		if (unlikely(dstp - dst >= slen - (slen >> 3))) {  in lz77_compress()
206 		u32 c = umin(end - srcp, 32 - flag_count);  in lz77_compress()
223 	flag <<= (32 - flag_count);  in lz77_compress()
224 	flag |= (1 << (32 - flag_count)) - 1;  in lz77_compress()
227 	*dlen = dstp - dst;  in lz77_compress()
234 	return -EMSGSIZE;  in lz77_compress()