[0aec496] | 1 | #include "filecache.hfa" |
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| 2 | |
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| 3 | #include <assert.h> |
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| 4 | #include <string.h> |
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| 5 | |
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| 6 | #include <stdlib.hfa> |
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| 7 | |
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| 8 | #include <errno.h> |
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| 9 | #include <unistd.h> |
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| 10 | extern "C" { |
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| 11 | #include <fcntl.h> |
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| 12 | #include <ftw.h> |
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| 13 | } |
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| 14 | |
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| 15 | #include "options.hfa" |
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| 16 | |
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| 17 | static inline uint32_t murmur_32_scramble(uint32_t k) { |
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| 18 | k *= 0xcc9e2d51; |
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| 19 | k = (k << 15) | (k >> 17); |
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| 20 | k *= 0x1b873593; |
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| 21 | return k; |
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| 22 | } |
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| 23 | |
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| 24 | uint32_t murmur3_32(const uint8_t* key, size_t len, uint32_t seed) |
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| 25 | { |
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| 26 | uint32_t h = seed; |
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| 27 | uint32_t k; |
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| 28 | /* Read in groups of 4. */ |
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| 29 | for (size_t i = len >> 2; i; i--) { |
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| 30 | // Here is a source of differing results across endiannesses. |
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| 31 | // A swap here has no effects on hash properties though. |
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| 32 | memcpy(&k, key, sizeof(uint32_t)); |
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| 33 | key += sizeof(uint32_t); |
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| 34 | h ^= murmur_32_scramble(k); |
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| 35 | h = (h << 13) | (h >> 19); |
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| 36 | h = h * 5 + 0xe6546b64; |
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| 37 | } |
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| 38 | /* Read the rest. */ |
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| 39 | k = 0; |
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| 40 | for (size_t i = len & 3; i; i--) { |
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| 41 | k <<= 8; |
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| 42 | k |= key[i - 1]; |
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| 43 | } |
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| 44 | // A swap is *not* necessary here because the preceding loop already |
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| 45 | // places the low bytes in the low places according to whatever endianness |
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| 46 | // we use. Swaps only apply when the memory is copied in a chunk. |
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| 47 | h ^= murmur_32_scramble(k); |
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| 48 | /* Finalize. */ |
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| 49 | h ^= len; |
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| 50 | h ^= h >> 16; |
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| 51 | h *= 0x85ebca6b; |
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| 52 | h ^= h >> 13; |
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| 53 | h *= 0xc2b2ae35; |
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| 54 | h ^= h >> 16; |
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| 55 | return h; |
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| 56 | } |
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| 57 | |
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| 58 | |
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| 59 | struct { |
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| 60 | cache_line * entries; |
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| 61 | size_t size; |
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| 62 | } file_cache; |
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| 63 | |
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| 64 | void ?{}( cache_line & this ) with( this ) { |
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| 65 | file = 0p; |
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| 66 | size = 0; |
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| 67 | fd = 0; |
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| 68 | } |
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| 69 | |
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| 70 | [int fd, size_t size] get_file( * const char file, size_t len ) { |
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| 71 | uint32_t idx = murmur3_32( (const uint8_t *)file, len, options.hash_seed ) % file_cache.size; |
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| 72 | |
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| 73 | for(int i = 0;; i++) { |
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| 74 | assert( i < file_cache.size ); |
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| 75 | cache_line & entry = file_cache.entries[idx]; |
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| 76 | if( !entry.file ) return [-1, 0]; |
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| 77 | #if !defined(REJECT_CONFLICTS) |
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| 78 | if( strncmp(entry.file, file, len) != 0 ) { |
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| 79 | idx = (idx + 1) % file_cache.size; |
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| 80 | continue; |
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| 81 | } |
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| 82 | #endif |
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| 83 | return [entry.fd, entry.size]; |
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| 84 | } |
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| 85 | } |
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| 86 | |
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| 87 | int put_file( cache_line & entry ) { |
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| 88 | uint32_t idx = murmur3_32( (const uint8_t *)entry.file, strlen(entry.file), options.hash_seed ) % file_cache.size; |
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| 89 | |
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| 90 | int i = 0; |
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| 91 | for(;file_cache.entries[idx].file; i++ ) { |
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| 92 | assert( i < file_cache.size ); |
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| 93 | idx = (idx + 1) % file_cache.size; |
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| 94 | } |
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| 95 | |
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| 96 | file_cache.entries[idx] = entry; |
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| 97 | return i > 0 ? 1 : 0; |
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| 98 | } |
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| 99 | |
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| 100 | // int ftw(const char *dirpath, int (*fn) (const char *fpath, const struct stat *sb, int typeflag), int nopenfd) |
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| 101 | void fill_cache( const char * path ) { |
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| 102 | int ret; |
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| 103 | size_t fcount = 0; |
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| 104 | size_t fsize = 16; |
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| 105 | cache_line * raw = 0p; |
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| 106 | raw = alloc(raw, fsize, true); |
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| 107 | // Step 1 get a dense array of all files |
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| 108 | int walk(const char *fpath, const struct stat *sb, int typeflag) { |
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| 109 | if(typeflag != FTW_F) return 0; |
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| 110 | |
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| 111 | int idx = fcount; |
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| 112 | fcount++; |
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| 113 | if(fcount > fsize) { |
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| 114 | fsize *= 2; |
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| 115 | raw = alloc(raw, fsize, true); |
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| 116 | } |
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| 117 | |
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| 118 | raw[idx].file = strdup(fpath+2); |
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| 119 | raw[idx].size = sb->st_size; |
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| 120 | raw[idx].fd = open( fpath, options.open_flags ); |
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| 121 | if(raw[idx].fd < 0) { |
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| 122 | abort( "open file error: (%d) %s\n", (int)errno, strerror(errno) ); |
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| 123 | } |
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| 124 | return 0; |
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| 125 | } |
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| 126 | |
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| 127 | ret = ftw(path, walk, 10); |
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| 128 | if(ret < 0) { |
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| 129 | abort( "ftw error: (%d) %s\n", (int)errno, strerror(errno) ); |
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| 130 | } |
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| 131 | |
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| 132 | if(fcount == 0) { |
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| 133 | abort("No file found in path %s\n", path); |
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| 134 | } |
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| 135 | |
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| 136 | // Step 2 create the cache |
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| 137 | file_cache.size = options.file_cache_size > 0 ? options.file_cache_size : fsize; |
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| 138 | if( file_cache.size < fcount ) { |
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| 139 | abort("File Cache too small\n"); |
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| 140 | } |
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| 141 | |
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| 142 | file_cache.entries = anew(fsize); |
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| 143 | |
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| 144 | // Step 3 fill the cache |
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| 145 | int conflicts = 0; |
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| 146 | for(i; fcount) { |
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| 147 | printf("Added file %s\n", raw[i].file); |
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| 148 | conflicts += put_file( raw[i] ); |
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| 149 | } |
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| 150 | printf("Filled cache from path \"%s\" with %zu files\n", path, fcount); |
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| 151 | if( conflicts > 0 ) { |
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| 152 | printf("Found %d conflicts (seed: %u)\n", conflicts, options.hash_seed); |
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| 153 | #if defined(REJECT_CONFLICTS) |
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| 154 | abort("Conflicts found in the cache"); |
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| 155 | #endif |
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| 156 | } |
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| 157 | |
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| 158 | // Step 4 clean up |
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| 159 | free( raw ); |
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| 160 | } |
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| 161 | |
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| 162 | void close_cache() { |
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| 163 | for(idx; file_cache.size) { |
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| 164 | cache_line & entry = file_cache.entries[idx]; |
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| 165 | if( !entry.file ) continue; |
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| 166 | |
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| 167 | int ret = close( entry.fd ); |
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| 168 | if(ret < 0) { |
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| 169 | abort( "close file error: (%d) %s\n", (int)errno, strerror(errno) ); |
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| 170 | } |
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| 171 | } |
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| 172 | |
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| 173 | delete( file_cache.entries ); |
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| 174 | } |
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