lz4_wrapper.c
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/*
* 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;
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;
}