1 files changed, 137 insertions, 0 deletions
diff --git a/lib/lz4_wrapper.c b/lib/lz4_wrapper.c
new file mode 100644
index 0000000000..0739663fca
--- /dev/null
+++ b/lib/lz4_wrapper.c
@@ -0,0 +1,137 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * SPDX-License-Identifier: GPL 2.0+ BSD-3-Clause
+ */
+
+#include <common.h>
+#include <compiler.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+static u16 LZ4_readLE16(const void *src) { return le16_to_cpu(*(u16 *)src); }
+static void LZ4_copy4(void *dst, const void *src) { *(u32 *)dst = *(u32 *)src; }
+static void LZ4_copy8(void *dst, const void *src) { *(u64 *)dst = *(u64 *)src; }
+
+typedef  uint8_t BYTE;
+typedef uint16_t U16;
+typedef uint32_t U32;
+typedef  int32_t S32;
+typedef uint64_t U64;
+
+#define FORCE_INLINE static inline __attribute__((always_inline))
+
+/* Unaltered (except removing unrelated code) from github.com/Cyan4973/lz4. */
+#include "lz4.c"	/* #include for inlining, do not link! */
+
+#define LZ4F_MAGIC 0x184D2204
+
+struct lz4_frame_header {
+	u32 magic;
+	union {
+		u8 flags;
+		struct {
+			u8 reserved0:2;
+			u8 has_content_checksum:1;
+			u8 has_content_size:1;
+			u8 has_block_checksum:1;
+			u8 independent_blocks:1;
+			u8 version:2;
+		};
+	};
+	union {
+		u8 block_descriptor;
+		struct {
+			u8 reserved1:4;
+			u8 max_block_size:3;
+			u8 reserved2:1;
+		};
+	};
+	/* + u64 content_size iff has_content_size is set */
+	/* + u8 header_checksum */
+} __packed;
+
+struct lz4_block_header {
+	union {
+		u32 raw;
+		struct {
+			u32 size:31;
+			u32 not_compressed:1;
+		};
+	};
+	/* + size bytes of data */
+	/* + u32 block_checksum iff has_block_checksum is set */
+} __packed;
+
+int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
+{
+	const void *end = dst + *dstn;
+	const void *in = src;
+	void *out = dst;
+	int has_block_checksum;
+	int ret;
+	*dstn = 0;
+
+	{ /* With in-place decompression the header may become invalid later. */
+		const struct lz4_frame_header *h = in;
+
+		if (srcn < sizeof(*h) + sizeof(u64) + sizeof(u8))
+			return -EINVAL;	/* input overrun */
+
+		/* We assume there's always only a single, standard frame. */
+		if (le32_to_cpu(h->magic) != LZ4F_MAGIC || h->version != 1)
+			return -EPROTONOSUPPORT;	/* unknown format */
+		if (h->reserved0 || h->reserved1 || h->reserved2)
+			return -EINVAL;	/* reserved must be zero */
+		if (!h->independent_blocks)
+			return -EPROTONOSUPPORT; /* we can't support this yet */
+		has_block_checksum = h->has_block_checksum;
+
+		in += sizeof(*h);
+		if (h->has_content_size)
+			in += sizeof(u64);
+		in += sizeof(u8);
+	}
+
+	while (1) {
+		struct lz4_block_header b = { .raw = le32_to_cpu(*(u32 *)in) };
+		in += sizeof(struct lz4_block_header);
+
+		if (in - src + b.size > srcn) {
+			ret = -EINVAL;		/* input overrun */
+			break;
+		}
+
+		if (!b.size) {
+			ret = 0;	/* decompression successful */
+			break;
+		}
+
+		if (b.not_compressed) {
+			size_t size = min((ptrdiff_t)b.size, end - out);
+			memcpy(out, in, size);
+			out += size;
+			if (size < b.size) {
+				ret = -ENOBUFS;	/* output overrun */
+				break;
+			}
+		} else {
+			/* constant folding essential, do not touch params! */
+			ret = LZ4_decompress_generic(in, out, b.size,
+					end - out, endOnInputSize,
+					full, 0, noDict, out, NULL, 0);
+			if (ret < 0) {
+				ret = -EPROTO;	/* decompression error */
+				break;
+			}
+			out += ret;
+		}
+
+		in += b.size;
+		if (has_block_checksum)
+			in += sizeof(u32);
+	}
+
+	*dstn = out - dst;
+	return ret;
+}