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| 27 | I have no idea wether any patents in any countries apply to this |
27 | I have no idea wether any patents in any countries apply to this |
| 28 | algorithm, but at the moment it is believed that it is free from any |
28 | algorithm, but at the moment it is believed that it is free from any |
| 29 | patents. |
29 | patents. |
| 30 | |
30 | |
| 31 | FUNCTIONS |
31 | FUNCTIONS |
| 32 | $compressed = compress $uncompressed |
32 | $compressed = compress $uncompressed |
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33 | $compressed = compress_best $uncompressed |
| 33 | Try to compress the given string as quickly and as much as possible. In |
34 | Try to compress the given string as quickly and as much as possible. |
| 34 | the worst case, the string can enlarge by 1 byte, but that should be the |
35 | In the worst case, the string can enlarge by 1 byte, but that should |
| 35 | absolute exception. You can expect a 45% compression ratio on large, |
36 | be the absolute exception. You can expect a 45% compression ratio on |
| 36 | binary strings. |
37 | large, binary strings. |
| 37 | |
38 | |
| 38 | $decompressed = decompress $compressed |
39 | The "compress_best" function uses a different algorithm that is |
| 39 | Uncompress the string (compressed by "compress") and return the original |
40 | slower but usually achieves better compression. |
| 40 | data. Decompression errors can result in either broken data (there is no |
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| 41 | checksum kept) or a runtime error. |
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| 42 | |
41 | |
| 43 | $serialized = sfreeze $value (simplified freeze) |
42 | $decompressed = decompress $compressed |
| 44 | Often there is the need to serialize data into a string. This function |
43 | Uncompress the string (compressed by "compress") and return the |
| 45 | does that, by using the Storable module. It does the following |
44 | original data. Decompression errors can result in either broken data |
| 46 | transforms: |
45 | (there is no checksum kept) or a runtime error. |
| 47 | |
46 | |
| 48 | undef (the perl undefined value) |
47 | $serialized = sfreeze $value (simplified freeze) |
| 49 | => a special cookie (undef'ness is being preserved) |
48 | $serialized = sfreeze_best $value |
| 50 | IV, NV, PV (i.e. a _plain_ perl scalar): |
49 | Often there is the need to serialize data into a string. This |
| 51 | => stays as is when it contains normal text/numbers |
50 | function does that, by using the Storable module. It does the |
| 52 | => gets serialized into a string |
51 | following transforms: |
| 53 | RV, undef, other funny objects (magical ones for example): |
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| 54 | => data structure is freeze'd into a string. |
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| 55 | |
52 | |
| 56 | That is, it tries to leave "normal", human-readable data untouched but |
53 | undef (the perl undefined value) |
| 57 | still serializes complex data structures into strings. The idea is to |
54 | => a special cookie (undef'ness is being preserved) |
| 58 | keep readability as high as possible, and in cases readability can't be |
55 | IV, NV, PV (i.e. a _plain_ perl scalar): |
| 59 | helped anyways, it tries to compress the string. |
56 | => stays as is when it contains normal text/numbers |
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57 | => gets serialized into a string |
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58 | RV, undef, other funny objects (magical ones for example): |
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59 | => data structure is freeze'd into a string. |
| 60 | |
60 | |
| 61 | The "sfreeze" functions will enlarge the original data one byte at most |
61 | That is, it tries to leave "normal", human-readable data untouched |
| 62 | and will only load the Storable method when neccessary. |
62 | but still serializes complex data structures into strings. The idea |
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63 | is to keep readability as high as possible, and in cases readability |
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64 | can't be helped anyways, it tries to compress the string. |
| 63 | |
65 | |
| 64 | $serialized = sfreeze_c $value (sfreeze and compress) |
66 | The "sfreeze" functions will enlarge the original data one byte at |
| 65 | Similar to "sfreeze", but always tries to "c"ompress the resulting |
67 | most and will only load the Storable method when neccessary. |
| 66 | string. This still leaves most small objects (most numbers) untouched. |
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| 67 | |
68 | |
| 68 | $serialized = sfreeze_cr $value (sfreeze and compress references) |
69 | The "sfreeze_best" function uses a different algorithm that is |
| 69 | Similar to "sfreeze", but tries to "c"ompress the resulting string |
70 | slower but usually achieves better compression. |
| 70 | unless it's a "simple" string. References for example are not "simple" |
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| 71 | and as such are being compressed. |
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| 72 | |
71 | |
| 73 | $original_data = sthaw $serialized |
72 | $serialized = sfreeze_c $value (sfreeze and compress) |
| 74 | Recreate the original object from it's serialized representation. This |
73 | $serialized = sfreeze_c_best $value |
| 75 | function automatically detects all the different sfreeze formats. |
74 | Similar to "sfreeze", but always tries to "c"ompress the resulting |
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75 | string. This still leaves most small objects (most numbers) |
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76 | untouched. |
| 76 | |
77 | |
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78 | The "sfreeze_c" function uses a different algorithm that is slower |
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79 | but usually achieves better compression. |
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80 | |
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81 | $serialized = sfreeze_cr $value (sfreeze and compress references) |
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82 | $serialized = sfreeze_cr_best $value |
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83 | Similar to "sfreeze", but tries to "c"ompress the resulting string |
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84 | unless it's a "simple" string. References for example are not |
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85 | "simple" and as such are being compressed. |
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86 | |
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87 | The "sfreeze_cr_best" function uses a different algorithm that is |
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88 | slower but usually achieves better compression. |
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89 | |
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90 | $original_data = sthaw $serialized |
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91 | Recreate the original object from it's serialized representation. |
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92 | This function automatically detects all the different sfreeze |
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93 | formats. |
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94 | |
| 77 | Compress::LZF::set_serializer $package, $freeze, $thaw |
95 | Compress::LZF::set_serializer $package, $freeze, $thaw |
| 78 | Set the serialize module and functions to use. The default is |
96 | Set the serialize module and functions to use. The default is |
| 79 | "Storable", "Storable::net_mstore" and "Storable::mretrieve", which |
97 | "Storable", "Storable::net_mstore" and "Storable::mretrieve", which |
| 80 | should be fine for most purposes. |
98 | should be fine for most purposes. |
| 81 | |
99 | |
| 82 | SEE ALSO |
100 | SEE ALSO |
| 83 | Other Compress::* modules, especially Compress::LZV1 (an older, less |
101 | Other Compress::* modules, especially Compress::LZV1 (an older, less |
| 84 | speedy module that guarentees only 1 byte overhead worst case) and |
102 | speedy module that guarentees only 1 byte overhead worst case) and |
| 85 | Compress::Zlib. |
103 | Compress::Zlib. |
