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44 | * don't play with this unless you benchmark! |
44 | * don't play with this unless you benchmark! |
45 | * decompression is not dependent on the hash function |
45 | * decompression is not dependent on the hash function |
46 | * the hashing function might seem strange, just believe me |
46 | * the hashing function might seem strange, just believe me |
47 | * it works ;) |
47 | * it works ;) |
48 | */ |
48 | */ |
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49 | #ifndef FRST |
49 | #define FRST(p) (((p[0]) << 8) | p[1]) |
50 | # define FRST(p) (((p[0]) << 8) | p[1]) |
50 | #define NEXT(v,p) (((v) << 8) | p[2]) |
51 | # define NEXT(v,p) (((v) << 8) | p[2]) |
51 | #define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
52 | # define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
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53 | //# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1)) |
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54 | #endif |
52 | /* |
55 | /* |
53 | * IDX works because it is very similar to a multiplicative hash, e.g. |
56 | * IDX works because it is very similar to a multiplicative hash, e.g. |
54 | * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) |
57 | * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) |
55 | * the latter is also quite fast on newer CPUs, and sligthly better |
58 | * the latter is also quite fast on newer CPUs, and compresses similarly. |
56 | * |
59 | * |
57 | * the next one is also quite good, albeit slow ;) |
60 | * the next one is also quite good, albeit slow ;) |
58 | * (int)(cos(h & 0xffffff) * 1e6) |
61 | * (int)(cos(h & 0xffffff) * 1e6) |
59 | */ |
62 | */ |
60 | |
63 | |
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65 | # define IDX(h) ((h) & (HSIZE - 1)) |
68 | # define IDX(h) ((h) & (HSIZE - 1)) |
66 | #endif |
69 | #endif |
67 | |
70 | |
68 | #define MAX_LIT (1 << 5) |
71 | #define MAX_LIT (1 << 5) |
69 | #define MAX_OFF (1 << 13) |
72 | #define MAX_OFF (1 << 13) |
70 | #define MAX_REF ((1 << 8) + (1 << 3)) |
73 | #define MAX_REF ((1 << 8) + (1 << 3)) |
71 | |
74 | |
72 | /* |
75 | /* |
73 | * compressed format |
76 | * compressed format |
74 | * |
77 | * |
75 | * 000LLLLL <L+1> ; literal |
78 | * 000LLLLL <L+1> ; literal |
76 | * LLLOOOOO oooooooo ; backref L |
79 | * LLLooooo oooooooo ; backref L |
77 | * 111OOOOO LLLLLLLL oooooooo ; backref L+7 |
80 | * 111ooooo LLLLLLLL oooooooo ; backref L+7 |
78 | * |
81 | * |
79 | */ |
82 | */ |
80 | |
83 | |
81 | unsigned int |
84 | unsigned int |
82 | lzf_compress (const void *const in_data, unsigned int in_len, |
85 | lzf_compress (const void *const in_data, unsigned int in_len, |
83 | void *out_data, unsigned int out_len |
86 | void *out_data, unsigned int out_len |
84 | #if LZF_STATE_ARG |
87 | #if LZF_STATE_ARG |
85 | , LZF_STATE *htab |
88 | , LZF_STATE htab |
86 | #endif |
89 | #endif |
87 | ) |
90 | ) |
88 | { |
91 | { |
89 | #if !LZF_STATE_ARG |
92 | #if !LZF_STATE_ARG |
90 | LZF_STATE htab; |
93 | LZF_STATE htab; |