1 | /* |
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2 | * JFFS2 -- Journalling Flash File System, Version 2. |
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3 | * |
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4 | * Copyright © 2001-2007 Red Hat, Inc. |
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5 | * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org> |
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6 | * Copyright © 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>, |
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7 | * University of Szeged, Hungary |
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8 | * Copyright © 2013 embedded brains GmbH <rtems@embedded-brains.de> |
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9 | * |
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10 | * Created by Arjan van de Ven <arjan@infradead.org> |
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11 | * |
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12 | * For licensing information, see the file 'LICENCE' in this directory. |
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13 | * |
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14 | */ |
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15 | |
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16 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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17 | |
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18 | #include "compr.h" |
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19 | |
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20 | /* jffs2_compress: |
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21 | * @data_in: Pointer to uncompressed data |
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22 | * @cpage_out: Pointer to returned pointer to buffer for compressed data |
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23 | * @datalen: On entry, holds the amount of data available for compression. |
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24 | * On exit, expected to hold the amount of data actually compressed. |
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25 | * @cdatalen: On entry, holds the amount of space available for compressed |
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26 | * data. On exit, expected to hold the actual size of the compressed |
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27 | * data. |
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28 | * |
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29 | * Returns: Lower byte to be stored with data indicating compression type used. |
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30 | * Zero is used to show that the data could not be compressed - the |
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31 | * compressed version was actually larger than the original. |
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32 | * Upper byte will be used later. (soon) |
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33 | * |
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34 | * If the cdata buffer isn't large enough to hold all the uncompressed data, |
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35 | * jffs2_compress should compress as much as will fit, and should set |
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36 | * *datalen accordingly to show the amount of data which were compressed. |
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37 | */ |
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38 | uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f, |
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39 | unsigned char *data_in, unsigned char **cpage_out, |
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40 | uint32_t *datalen, uint32_t *cdatalen) |
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41 | { |
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42 | struct super_block *sb = OFNI_BS_2SFFJ(c); |
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43 | rtems_jffs2_compressor_control *cc = sb->s_compressor_control; |
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44 | int ret; |
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45 | |
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46 | if (cc != NULL) { |
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47 | *cpage_out = &cc->buffer[0]; |
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48 | ret = (*cc->compress)(cc, data_in, *cpage_out, datalen, cdatalen); |
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49 | } else { |
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50 | ret = JFFS2_COMPR_NONE; |
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51 | } |
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52 | |
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53 | if (ret == JFFS2_COMPR_NONE) { |
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54 | *cpage_out = data_in; |
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55 | *datalen = *cdatalen; |
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56 | } |
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57 | return ret; |
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58 | } |
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59 | |
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60 | int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f, |
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61 | uint16_t comprtype, unsigned char *cdata_in, |
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62 | unsigned char *data_out, uint32_t cdatalen, uint32_t datalen) |
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63 | { |
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64 | struct super_block *sb = OFNI_BS_2SFFJ(c); |
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65 | rtems_jffs2_compressor_control *cc = sb->s_compressor_control; |
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66 | |
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67 | /* Older code had a bug where it would write non-zero 'usercompr' |
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68 | fields. Deal with it. */ |
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69 | if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB) |
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70 | comprtype &= 0xff; |
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71 | |
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72 | switch (comprtype & 0xff) { |
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73 | case JFFS2_COMPR_NONE: |
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74 | /* This should be special-cased elsewhere, but we might as well deal with it */ |
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75 | memcpy(data_out, cdata_in, datalen); |
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76 | break; |
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77 | case JFFS2_COMPR_ZERO: |
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78 | memset(data_out, 0, datalen); |
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79 | break; |
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80 | default: |
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81 | if (cc != NULL) { |
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82 | return (*cc->decompress)(cc, comprtype, cdata_in, data_out, cdatalen, datalen); |
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83 | } else { |
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84 | return -EIO; |
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85 | } |
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86 | } |
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87 | return 0; |
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88 | } |
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