update

2026-08-14 12:01:38 +02:00
commit 0bbc249155
21 changed files with 6786 additions and 0 deletions
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/* Minimal LZ4 decompressor for EROFS FreeBSD */
+#include <sys/param.h>
+#include <sys/systm.h>
+
+#include "erofs_defs.h"
+#include "internal.h"
+
+static int
+lz4_finish(const uint8_t *ip, const uint8_t *iend, int partial)
+{
+	if (partial)
+		return (0);
+	while (ip < iend) {
+		if (*ip++ != 0)
+			return (-1);
+	}
+	return (0);
+}
+
+int
+lz4_decompress(void *src, void *dst, size_t srclen, size_t dstlen, int partial)
+{
+	const uint8_t *ip, *iend;
+	uint8_t *op, *oend;
+	unsigned int token;
+	size_t length, copylen;
+	size_t offset;
+
+	ip = src;
+	iend = ip + srclen;
+	op = dst;
+	oend = op + dstlen;
+	if (iend < ip || oend < op)
+		return (-1);
+
+	while (ip < iend) {
+		token = *ip++;
+		length = token >> EROFS_LZ4_TOKEN_LITERAL_SHIFT;
+		if (length == EROFS_LZ4_MAX_RUN) {
+			unsigned int value;
+			do {
+				if (ip >= iend)
+					return (-1);
+				value = *ip++;
+				if (length > SIZE_MAX - value)
+					return (-1);
+				length += value;
+			} while (value == EROFS_LZ4_EXT_SENTINEL);
+		}
+		if (length > (size_t)(iend - ip))
+			return (-1);
+		if (!partial && length > (size_t)(oend - op))
+			return (-1);
+		copylen = MIN(length, (size_t)(oend - op));
+		memcpy(op, ip, copylen);
+		ip += length;
+		op += copylen;
+		if (op == oend)
+			return (lz4_finish(ip, iend, partial));
+		if (ip >= iend)
+			break;
+		if (ip + EROFS_LZ4_OFFSET_BYTES > iend)
+			return (-1);
+		offset = ip[0] | (ip[1] << 8);
+		ip += EROFS_LZ4_OFFSET_BYTES;
+		if (offset == 0 || offset > (size_t)(op - (uint8_t *)dst))
+			return (-1);
+		length = token & EROFS_LZ4_TOKEN_MATCH_MASK;
+		if (length == EROFS_LZ4_MAX_RUN) {
+			unsigned int value;
+			do {
+				if (ip >= iend)
+					return (-1);
+				value = *ip++;
+				if (length > SIZE_MAX - value)
+					return (-1);
+				length += value;
+			} while (value == EROFS_LZ4_EXT_SENTINEL);
+		}
+		if (length > SIZE_MAX - EROFS_LZ4_MIN_MATCH)
+			return (-1);
+		length += EROFS_LZ4_MIN_MATCH;
+		if (!partial && length > (size_t)(oend - op))
+			return (-1);
+		copylen = MIN(length, (size_t)(oend - op));
+		while (copylen-- != 0) {
+			*op = *(op - offset);
+			++op;
+		}
+		if (op == oend)
+			return (lz4_finish(ip, iend, partial));
+	}
+	return (op == oend ? lz4_finish(ip, iend, partial) : -1);
+}