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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/lib/decompress.c
10811 views
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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/types.h>

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#include <linux/string.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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static const 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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} compressed_formats[] = {

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	{ {037, 0213}, "gzip", gunzip },

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	{ {037, 0236}, "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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	{ {0, 0}, NULL, NULL }

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};

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decompress_fn decompress_method(const unsigned char *inbuf, int 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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		return NULL;	/* Need at least this much... */

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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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