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2023-12-08 01573e231f18eb2d99162747186f59511f56b64d

 kernel/lib/lzo/lzo1x_compress.c
..
..
@@ -1,3 +1,4 @@
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+// SPDX-License-Identifier: GPL-2.0-only
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 /*
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  *  LZO1X Compressor from LZO
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  *
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..
@@ -20,7 +21,8 @@
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 static noinline size_t
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 lzo1x_1_do_compress(const unsigned char *in, size_t in_len,
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 		    unsigned char *out, size_t *out_len,
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-		    size_t ti, void *wrkmem)
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+		    size_t ti, void *wrkmem, signed char *state_offset,
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+		    const unsigned char bitstream_version)
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 {
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 	const unsigned char *ip;
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 	unsigned char *op;
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@@ -35,27 +37,87 @@
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 	ip += ti < 4 ? 4 - ti : 0;
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38
 
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 	for (;;) {
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-		const unsigned char *m_pos;
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+		const unsigned char *m_pos = NULL;
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 		size_t t, m_len, m_off;
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 		u32 dv;
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+		u32 run_length = 0;
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 literal:
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 		ip += 1 + ((ip - ii) >> 5);
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 next:
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 		if (unlikely(ip >= ip_end))
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 			break;
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 		dv = get_unaligned_le32(ip);
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-		t = ((dv * 0x1824429d) >> (32 - D_BITS)) & D_MASK;
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-		m_pos = in + dict[t];
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-		dict[t] = (lzo_dict_t) (ip - in);
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-		if (unlikely(dv != get_unaligned_le32(m_pos)))
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-			goto literal;
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+
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+		if (dv == 0 && bitstream_version) {
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+			const unsigned char *ir = ip + 4;
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+			const unsigned char *limit = ip_end
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+				< (ip + MAX_ZERO_RUN_LENGTH + 1)
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+				? ip_end : ip + MAX_ZERO_RUN_LENGTH + 1;
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+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && \
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+	defined(LZO_FAST_64BIT_MEMORY_ACCESS)
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+			u64 dv64;
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+
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+			for (; (ir + 32) <= limit; ir += 32) {
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+				dv64 = get_unaligned((u64 *)ir);
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+				dv64 |= get_unaligned((u64 *)ir + 1);
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+				dv64 |= get_unaligned((u64 *)ir + 2);
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+				dv64 |= get_unaligned((u64 *)ir + 3);
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+				if (dv64)
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+					break;
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+			}
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+			for (; (ir + 8) <= limit; ir += 8) {
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+				dv64 = get_unaligned((u64 *)ir);
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+				if (dv64) {
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+#  if defined(__LITTLE_ENDIAN)
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+					ir += __builtin_ctzll(dv64) >> 3;
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+#  elif defined(__BIG_ENDIAN)
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+					ir += __builtin_clzll(dv64) >> 3;
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+#  else
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+#    error "missing endian definition"
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+#  endif
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+					break;
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+				}
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+			}
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+#else
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+			while ((ir < (const unsigned char *)
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+					ALIGN((uintptr_t)ir, 4)) &&
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+					(ir < limit) && (*ir == 0))
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+				ir++;
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+			if (IS_ALIGNED((uintptr_t)ir, 4)) {
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+				for (; (ir + 4) <= limit; ir += 4) {
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+					dv = *((u32 *)ir);
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+					if (dv) {
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+#  if defined(__LITTLE_ENDIAN)
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+						ir += __builtin_ctz(dv) >> 3;
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+#  elif defined(__BIG_ENDIAN)
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+						ir += __builtin_clz(dv) >> 3;
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+#  else
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+#    error "missing endian definition"
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+#  endif
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+						break;
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+					}
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+				}
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+			}
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+#endif
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+			while (likely(ir < limit) && unlikely(*ir == 0))
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+				ir++;
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+			run_length = ir - ip;
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+			if (run_length > MAX_ZERO_RUN_LENGTH)
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+				run_length = MAX_ZERO_RUN_LENGTH;
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+		} else {
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+			t = ((dv * 0x1824429d) >> (32 - D_BITS)) & D_MASK;
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+			m_pos = in + dict[t];
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+			dict[t] = (lzo_dict_t) (ip - in);
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+			if (unlikely(dv != get_unaligned_le32(m_pos)))
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+				goto literal;
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+		}
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 		ii -= ti;
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 		ti = 0;
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 		t = ip - ii;
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 		if (t != 0) {
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 			if (t <= 3) {
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-				op[-2] |= t;
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+				op[*state_offset] |= t;
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 				COPY4(op, ii);
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 				op += t;
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 			} else if (t <= 16) {
..
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@@ -86,6 +148,17 @@
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 					*op++ = *ii++;
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 				} while (--t > 0);
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 			}
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+		}
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+
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+		if (unlikely(run_length)) {
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+			ip += run_length;
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+			run_length -= MIN_ZERO_RUN_LENGTH;
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+			put_unaligned_le32((run_length << 21) | 0xfffc18
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+					   | (run_length & 0x7), op);
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+			op += 4;
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+			run_length = 0;
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+			*state_offset = -3;
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+			goto finished_writing_instruction;
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 		}
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163
 
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 		m_len = 4;
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@@ -170,7 +243,6 @@
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 		m_off = ip - m_pos;
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 		ip += m_len;
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-		ii = ip;
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 		if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) {
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 			m_off -= 1;
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 			*op++ = (((m_len - 1) << 5) | ((m_off & 7) << 2));
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@@ -196,6 +268,19 @@
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 				*op++ = (M4_MARKER | ((m_off >> 11) & 8)
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 						| (m_len - 2));
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 			else {
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+				if (unlikely(((m_off & 0x403f) == 0x403f)
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+						&& (m_len >= 261)
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+						&& (m_len <= 264))
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+						&& likely(bitstream_version)) {
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+					// Under lzo-rle, block copies
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+					// for 261 <= length <= 264 and
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+					// (distance & 0x80f3) == 0x80f3
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+					// can result in ambiguous
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+					// output. Adjust length
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+					// to 260 to prevent ambiguity.
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+					ip -= m_len - 260;
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+					m_len = 260;
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+				}
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 				m_len -= M4_MAX_LEN;
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 				*op++ = (M4_MARKER | ((m_off >> 11) & 8));
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 				while (unlikely(m_len > 255)) {
..
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@@ -207,29 +292,48 @@
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 			*op++ = (m_off << 2);
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 			*op++ = (m_off >> 6);
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 		}
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+		*state_offset = -2;
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+finished_writing_instruction:
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+		ii = ip;
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 		goto next;
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 	}
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 	*out_len = op - out;
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 	return in_end - (ii - ti);
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 }
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303
 
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-int lzo1x_1_compress(const unsigned char *in, size_t in_len,
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+int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
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 		     unsigned char *out, size_t *out_len,
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-		     void *wrkmem)
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+		     void *wrkmem, const unsigned char bitstream_version)
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307
 {
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 	const unsigned char *ip = in;
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 	unsigned char *op = out;
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+	unsigned char *data_start;
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 	size_t l = in_len;
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 	size_t t = 0;
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+	signed char state_offset = -2;
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+	unsigned int m4_max_offset;
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+
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+	// LZO v0 will never write 17 as first byte (except for zero-length
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+	// input), so this is used to version the bitstream
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+	if (bitstream_version > 0) {
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+		*op++ = 17;
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+		*op++ = bitstream_version;
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+		m4_max_offset = M4_MAX_OFFSET_V1;
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+	} else {
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+		m4_max_offset = M4_MAX_OFFSET_V0;
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+	}
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+
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+	data_start = op;
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 	while (l > 20) {
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-		size_t ll = l <= (M4_MAX_OFFSET + 1) ? l : (M4_MAX_OFFSET + 1);
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+		size_t ll = l <= (m4_max_offset + 1) ? l : (m4_max_offset + 1);
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 		uintptr_t ll_end = (uintptr_t) ip + ll;
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 		if ((ll_end + ((t + ll) >> 5)) <= ll_end)
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 			break;
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 		BUILD_BUG_ON(D_SIZE * sizeof(lzo_dict_t) > LZO1X_1_MEM_COMPRESS);
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 		memset(wrkmem, 0, D_SIZE * sizeof(lzo_dict_t));
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-		t = lzo1x_1_do_compress(ip, ll, op, out_len, t, wrkmem);
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+		t = lzo1x_1_do_compress(ip, ll, op, out_len, t, wrkmem,
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+					&state_offset, bitstream_version);
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 		ip += ll;
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 		op += *out_len;
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 		l  -= ll;
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..
@@ -239,10 +343,10 @@
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 	if (t > 0) {
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 		const unsigned char *ii = in + in_len - t;
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345
 
242
-		if (op == out && t <= 238) {
346
+		if (op == data_start && t <= 238) {
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 			*op++ = (17 + t);
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 		} else if (t <= 3) {
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-			op[-2] |= t;
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+			op[state_offset] |= t;
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 		} else if (t <= 18) {
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 			*op++ = (t - 3);
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 		} else {
..
..
@@ -273,7 +377,24 @@
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 	*out_len = op - out;
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 	return LZO_E_OK;
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379
 }
380
+
381
+int lzo1x_1_compress(const unsigned char *in, size_t in_len,
382
+		     unsigned char *out, size_t *out_len,
383
+		     void *wrkmem)
384
+{
385
+	return lzogeneric1x_1_compress(in, in_len, out, out_len, wrkmem, 0);
386
+}
387
+
388
+int lzorle1x_1_compress(const unsigned char *in, size_t in_len,
389
+		     unsigned char *out, size_t *out_len,
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+		     void *wrkmem)
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+{
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+	return lzogeneric1x_1_compress(in, in_len, out, out_len,
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+				       wrkmem, LZO_VERSION);
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+}
395
+
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 EXPORT_SYMBOL_GPL(lzo1x_1_compress);
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+EXPORT_SYMBOL_GPL(lzorle1x_1_compress);
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398
 
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 MODULE_LICENSE("GPL");
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 MODULE_DESCRIPTION("LZO1X-1 Compressor");