// SPDX-License-Identifier: GPL-2.0
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/*
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* decompress.c
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*
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* Detect the decompression method based on magic number
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*/
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#include <linux/decompress/generic.h>
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#include <linux/decompress/bunzip2.h>
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#include <linux/decompress/unlzma.h>
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#include <linux/decompress/unxz.h>
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#include <linux/decompress/inflate.h>
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#include <linux/decompress/unlzo.h>
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#include <linux/decompress/unlz4.h>
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#include <linux/decompress/unzstd.h>
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/init.h>
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#include <linux/printk.h>
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#ifndef CONFIG_DECOMPRESS_GZIP
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# define gunzip NULL
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#endif
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#ifndef CONFIG_DECOMPRESS_BZIP2
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# define bunzip2 NULL
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#endif
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#ifndef CONFIG_DECOMPRESS_LZMA
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# define unlzma NULL
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#endif
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#ifndef CONFIG_DECOMPRESS_XZ
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# define unxz NULL
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#endif
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#ifndef CONFIG_DECOMPRESS_LZO
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# define unlzo NULL
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#endif
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#ifndef CONFIG_DECOMPRESS_LZ4
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# define unlz4 NULL
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#endif
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#ifndef CONFIG_DECOMPRESS_ZSTD
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# define unzstd NULL
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#endif
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struct compress_format {
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unsigned char magic[2];
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const char *name;
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decompress_fn decompressor;
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};
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static const struct compress_format compressed_formats[] __initconst = {
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{ {0x1f, 0x8b}, "gzip", gunzip },
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{ {0x1f, 0x9e}, "gzip", gunzip },
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{ {0x42, 0x5a}, "bzip2", bunzip2 },
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{ {0x5d, 0x00}, "lzma", unlzma },
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{ {0xfd, 0x37}, "xz", unxz },
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{ {0x89, 0x4c}, "lzo", unlzo },
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{ {0x02, 0x21}, "lz4", unlz4 },
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{ {0x28, 0xb5}, "zstd", unzstd },
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{ {0, 0}, NULL, NULL }
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};
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decompress_fn __init decompress_method(const unsigned char *inbuf, long len,
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const char **name)
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{
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const struct compress_format *cf;
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if (len < 2) {
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if (name)
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*name = NULL;
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return NULL; /* Need at least this much... */
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}
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pr_debug("Compressed data magic: %#.2x %#.2x\n", inbuf[0], inbuf[1]);
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for (cf = compressed_formats; cf->name; cf++) {
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if (!memcmp(inbuf, cf->magic, 2))
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break;
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}
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if (name)
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*name = cf->name;
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return cf->decompressor;
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}
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