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@@ -9,6 +9,7 @@
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#include <lz4.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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+#include <asm/unaligned.h>
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static u16 LZ4_readLE16(const void *src) { return le16_to_cpu(*(u16 *)src); }
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static void LZ4_copy4(void *dst, const void *src) { *(u32 *)dst = *(u32 *)src; }
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@@ -22,45 +23,10 @@ typedef uint64_t U64;
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#define FORCE_INLINE static inline __attribute__((always_inline))
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-/* Unaltered (except removing unrelated code) from github.com/Cyan4973/lz4. */
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+/* lz4.c is unaltered (except removing unrelated code) from github.com/Cyan4973/lz4. */
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#include "lz4.c" /* #include for inlining, do not link! */
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-struct lz4_frame_header {
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- u32 magic;
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- union {
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- u8 flags;
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- struct {
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- u8 reserved0:2;
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- u8 has_content_checksum:1;
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- u8 has_content_size:1;
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- u8 has_block_checksum:1;
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- u8 independent_blocks:1;
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- u8 version:2;
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- };
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- };
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- union {
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- u8 block_descriptor;
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- struct {
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- u8 reserved1:4;
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- u8 max_block_size:3;
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- u8 reserved2:1;
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- };
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- };
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- /* + u64 content_size iff has_content_size is set */
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- /* + u8 header_checksum */
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-} __packed;
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-
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-struct lz4_block_header {
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- union {
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- u32 raw;
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- struct {
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- u32 size:31;
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- u32 not_compressed:1;
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- };
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- };
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- /* + size bytes of data */
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- /* + u32 block_checksum iff has_block_checksum is set */
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-} __packed;
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+#define LZ4F_BLOCKUNCOMPRESSED_FLAG 0x80000000U
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int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
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{
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@@ -72,53 +38,70 @@ int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
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*dstn = 0;
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{ /* With in-place decompression the header may become invalid later. */
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- const struct lz4_frame_header *h = in;
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+ u32 magic;
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+ u8 flags, version, independent_blocks, has_content_size;
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+ u8 block_desc;
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- if (srcn < sizeof(*h) + sizeof(u64) + sizeof(u8))
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+ if (srcn < sizeof(u32) + 3*sizeof(u8))
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return -EINVAL; /* input overrun */
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+ magic = get_unaligned_le32(in);
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+ in += sizeof(u32);
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+ flags = *(u8 *)in;
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+ in += sizeof(u8);
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+ block_desc = *(u8 *)in;
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+ in += sizeof(u8);
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+
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+ version = (flags >> 6) & 0x3;
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+ independent_blocks = (flags >> 5) & 0x1;
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+ has_block_checksum = (flags >> 4) & 0x1;
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+ has_content_size = (flags >> 3) & 0x1;
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+
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/* We assume there's always only a single, standard frame. */
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- if (le32_to_cpu(h->magic) != LZ4F_MAGIC || h->version != 1)
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+ if (magic != LZ4F_MAGIC || version != 1)
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return -EPROTONOSUPPORT; /* unknown format */
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- if (h->reserved0 || h->reserved1 || h->reserved2)
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- return -EINVAL; /* reserved must be zero */
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- if (!h->independent_blocks)
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+ if ((flags & 0x03) || (block_desc & 0x8f))
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+ return -EINVAL; /* reserved bits must be zero */
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+ if (!independent_blocks)
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return -EPROTONOSUPPORT; /* we can't support this yet */
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- has_block_checksum = h->has_block_checksum;
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- in += sizeof(*h);
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- if (h->has_content_size)
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+ if (has_content_size) {
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+ if (srcn < sizeof(u32) + 3*sizeof(u8) + sizeof(u64))
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+ return -EINVAL; /* input overrun */
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in += sizeof(u64);
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+ }
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+ /* Header checksum byte */
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in += sizeof(u8);
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}
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while (1) {
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- struct lz4_block_header b;
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+ u32 block_header, block_size;
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- b.raw = le32_to_cpu(*(u32 *)in);
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- in += sizeof(struct lz4_block_header);
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+ block_header = get_unaligned_le32(in);
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+ in += sizeof(u32);
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+ block_size = block_header & ~LZ4F_BLOCKUNCOMPRESSED_FLAG;
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- if (in - src + b.size > srcn) {
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+ if (in - src + block_size > srcn) {
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ret = -EINVAL; /* input overrun */
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break;
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}
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- if (!b.size) {
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+ if (!block_size) {
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ret = 0; /* decompression successful */
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break;
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}
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- if (b.not_compressed) {
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- size_t size = min((ptrdiff_t)b.size, end - out);
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+ if (block_header & LZ4F_BLOCKUNCOMPRESSED_FLAG) {
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+ size_t size = min((ptrdiff_t)block_size, end - out);
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memcpy(out, in, size);
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out += size;
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- if (size < b.size) {
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+ if (size < block_size) {
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ret = -ENOBUFS; /* output overrun */
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break;
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}
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} else {
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/* constant folding essential, do not touch params! */
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- ret = LZ4_decompress_generic(in, out, b.size,
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+ ret = LZ4_decompress_generic(in, out, block_size,
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end - out, endOnInputSize,
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full, 0, noDict, out, NULL, 0);
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if (ret < 0) {
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@@ -128,7 +111,7 @@ int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
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out += ret;
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}
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- in += b.size;
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+ in += block_size;
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if (has_block_checksum)
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in += sizeof(u32);
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}
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