├── .gitignore ├── LICENSE ├── Makefile ├── README.md ├── c_src ├── emmap.cpp └── erl_nif_compat.h ├── doc ├── README.md ├── emmap.md └── overview.edoc ├── ebin └── emmap.app ├── rebar ├── rebar.config └── src └── emmap.erl /.gitignore: -------------------------------------------------------------------------------- 1 | .eunit 2 | *~ 3 | *.so 4 | *.beam 5 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | 2 | Apache License 3 | Version 2.0, January 2004 4 | http://www.apache.org/licenses/ 5 | 6 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 7 | 8 | 1. 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While redistributing 167 | the Work or Derivative Works thereof, You may choose to offer, 168 | and charge a fee for, acceptance of support, warranty, indemnity, 169 | or other liability obligations and/or rights consistent with this 170 | License. However, in accepting such obligations, You may act only 171 | on Your own behalf and on Your sole responsibility, not on behalf 172 | of any other Contributor, and only if You agree to indemnify, 173 | defend, and hold each Contributor harmless for any liability 174 | incurred by, or claims asserted against, such Contributor by reason 175 | of your accepting any such warranty or additional liability. 176 | 177 | END OF TERMS AND CONDITIONS 178 | 179 | -------------------------------------------------------------------------------- /Makefile: -------------------------------------------------------------------------------- 1 | 2 | all: 3 | ./rebar compile eunit 4 | 5 | clean: 6 | ./rebar clean -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Erlang MMAP `emmap` 2 | 3 | This Erlang library provides a wrapper that allows you to memory map files into the Erlang memory space. 4 | 5 | 6 | ## Basic Usage 7 | 8 | The basic usage is 9 | 10 | {ok, Mem} = emmap:open("filename", [read, shared, direct]), 11 | {ok, Binary} = file:pread(Mem, 100, 40), 12 | ... 13 | ok = file:close(Mem). 14 | 15 | The open options is a list containing zero or more of these: 16 | 17 | - `read`, `write`: Open for reading and/or writing (you can specify both). 18 | - `private`, `shared`: The file is opened with copy-on-write semantics, or sharing memory with the underlying file. 19 | - `direct`: read/pread operations do not copy memory, but rather use "resource binaries" that can change content if the underlying data is changed. This is the most performant, but also has other implications. 20 | - `lock`, `nolock` do (or do not) use a semaphore to control state changes internally in the NIF library. 21 | 22 | From this point, `Mem` can be used with the `file` operations 23 | 24 | - `{ok, Binary} = file:pread(Mem, Position, Length)` read Length bytes at Position in the file. 25 | - `ok = file:pwrite(Mem, Position, Binary)` writes to the given position. 26 | - `{ok, Binary} = file:read(Mem, Length)` read 1..Length bytes from current position, or return `eof` if pointer is at end of file. 27 | - `{ok, Pos} = file:position(Mem, Where)` see file:position/2 documentation. 28 | - `ok = file:close(Mem)` 29 | 30 | ## Notes 31 | 32 | Using the option `direct` has the effect that the mmap file is not closed until all references to binaries coming out of read/pread have been garbage collected. This is a consequence of that such binaries are referring directly to the mmap'ed memory. 33 | 34 | -------------------------------------------------------------------------------- /c_src/emmap.cpp: -------------------------------------------------------------------------------- 1 | 2 | 3 | #include "erl_nif_compat.h" 4 | #include 5 | #include 6 | #include 7 | #include 8 | #include 9 | 10 | static ErlNifResourceType* MMAP_RESOURCE; 11 | 12 | #ifndef MAP_NOCACHE 13 | /* No MAP_NOCACHE on Linux - just bypass this option */ 14 | #define MAP_NOCACHE (0) 15 | #endif 16 | 17 | typedef struct 18 | { 19 | size_t position; 20 | int direct; 21 | int prot; 22 | bool closed; 23 | ErlNifRWLock* rwlock; 24 | void* mem; 25 | size_t len; 26 | } mhandle; 27 | 28 | static int on_load(ErlNifEnv*, void**, ERL_NIF_TERM); 29 | 30 | static int emmap_unmap(mhandle *handle, bool from_dtor) 31 | { 32 | if (handle->mem != 0) { 33 | if (from_dtor || !handle->direct) { 34 | int result = munmap(handle->mem, handle->len); 35 | handle->mem = 0; 36 | return result; 37 | } else { 38 | handle->closed = true; 39 | } 40 | } 41 | return 0; 42 | } 43 | 44 | void emmap_dtor(ErlNifEnv* env, void* arg) 45 | { 46 | mhandle* handle = (mhandle*)arg; 47 | emmap_unmap(handle, true); 48 | 49 | // only the destructor destroys the rwlock 50 | if (handle->rwlock != 0) enif_rwlock_destroy(handle->rwlock); 51 | } 52 | 53 | #define RW_UNLOCK if (handle->rwlock != 0) enif_rwlock_rwunlock(handle->rwlock) 54 | #define RW_LOCK if (handle->rwlock != 0) enif_rwlock_rwlock(handle->rwlock) 55 | #define R_UNLOCK if (handle->rwlock != 0) enif_rwlock_runlock(handle->rwlock) 56 | #define R_LOCK if (handle->rwlock != 0) enif_rwlock_rlock(handle->rwlock) 57 | 58 | static ERL_NIF_TERM ATOM_OK; 59 | static ERL_NIF_TERM ATOM_TRUE; 60 | static ERL_NIF_TERM ATOM_FALSE; 61 | static ERL_NIF_TERM ATOM_ERROR; 62 | static ERL_NIF_TERM ATOM_LOCK; 63 | static ERL_NIF_TERM ATOM_NOLOCK; 64 | static ERL_NIF_TERM ATOM_DIRECT; 65 | static ERL_NIF_TERM ATOM_READ; 66 | static ERL_NIF_TERM ATOM_WRITE; 67 | static ERL_NIF_TERM ATOM_NONE; 68 | static ERL_NIF_TERM ATOM_PRIVATE; 69 | static ERL_NIF_TERM ATOM_SHARED; 70 | static ERL_NIF_TERM ATOM_ANON; 71 | static ERL_NIF_TERM ATOM_FILE; 72 | static ERL_NIF_TERM ATOM_FIXED; 73 | static ERL_NIF_TERM ATOM_NOCACHE; 74 | 75 | static ERL_NIF_TERM ATOM_BOF; 76 | static ERL_NIF_TERM ATOM_CUR; 77 | static ERL_NIF_TERM ATOM_EOF; 78 | 79 | static ERL_NIF_TERM emmap_open(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]); 80 | static ERL_NIF_TERM emmap_read(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]); 81 | static ERL_NIF_TERM emmap_read_line(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]); 82 | static ERL_NIF_TERM emmap_close(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]); 83 | static ERL_NIF_TERM emmap_pread(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]); 84 | static ERL_NIF_TERM emmap_pwrite(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]); 85 | static ERL_NIF_TERM emmap_position(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]); 86 | 87 | extern "C" { 88 | 89 | static ErlNifFunc nif_funcs[] = 90 | { 91 | {"open_nif", 4, emmap_open}, 92 | {"close_nif", 1, emmap_close}, 93 | {"pread_nif", 3, emmap_pread}, 94 | {"pwrite_nif", 3, emmap_pwrite}, 95 | {"position_nif", 3, emmap_position}, 96 | {"read_nif", 2, emmap_read}, 97 | {"read_line_nif", 1, emmap_read_line}, 98 | }; 99 | 100 | ERL_NIF_INIT(emmap, nif_funcs, &on_load, NULL, NULL, NULL); 101 | }; 102 | 103 | static int on_load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info) 104 | { 105 | ErlNifResourceFlags flags = (ErlNifResourceFlags)(ERL_NIF_RT_CREATE | ERL_NIF_RT_TAKEOVER); 106 | MMAP_RESOURCE = enif_open_resource_type_compat(env, "mmap_resource", &emmap_dtor, flags, 0); 107 | 108 | ATOM_OK = enif_make_atom(env, "ok"); 109 | ATOM_TRUE = enif_make_atom(env, "true"); 110 | ATOM_FALSE = enif_make_atom(env, "false"); 111 | ATOM_ERROR = enif_make_atom(env, "error"); 112 | 113 | ATOM_DIRECT = enif_make_atom(env, "direct"); 114 | ATOM_READ = enif_make_atom(env, "read"); 115 | ATOM_WRITE = enif_make_atom(env, "write"); 116 | ATOM_NONE = enif_make_atom(env, "none"); 117 | ATOM_PRIVATE = enif_make_atom(env, "private"); 118 | ATOM_SHARED = enif_make_atom(env, "shared"); 119 | ATOM_ANON = enif_make_atom(env, "anon"); 120 | ATOM_FILE = enif_make_atom(env, "file"); 121 | ATOM_FIXED = enif_make_atom(env, "fixed"); 122 | ATOM_NOCACHE = enif_make_atom(env, "nocache"); 123 | 124 | ATOM_BOF = enif_make_atom(env, "bof"); 125 | ATOM_CUR = enif_make_atom(env, "cur"); 126 | ATOM_EOF = enif_make_atom(env, "eof"); 127 | 128 | ATOM_LOCK = enif_make_atom(env, "lock"); 129 | ATOM_NOLOCK = enif_make_atom(env, "nolock"); 130 | 131 | return 0; 132 | } 133 | 134 | static ERL_NIF_TERM describe_error(ErlNifEnv* env, int err) { 135 | switch (err) { 136 | case EAGAIN: 137 | return enif_make_atom(env, "eagain"); 138 | case EINVAL: 139 | return enif_make_atom(env, "einval"); 140 | case ENOSPC: 141 | return enif_make_atom(env, "enospc"); 142 | case ENOENT: 143 | return enif_make_atom(env, "enoent"); 144 | case ENOMEM: 145 | return enif_make_atom(env, "enomem"); 146 | case EACCES: 147 | return enif_make_atom(env, "eacces"); 148 | case EBADF: 149 | return enif_make_atom(env, "ebadf"); 150 | case ENODEV: 151 | return enif_make_atom(env, "enodev"); 152 | case ENXIO: 153 | return enif_make_atom(env, "enxio"); 154 | case EOVERFLOW: 155 | return enif_make_atom(env, "eoverflow"); 156 | } 157 | return enif_make_tuple2(env, 158 | enif_make_atom(env, "errno"), 159 | enif_make_int(env, err)); 160 | } 161 | 162 | static ERL_NIF_TERM make_error_tuple(ErlNifEnv* env, int err) { 163 | return enif_make_tuple2(env, ATOM_ERROR, describe_error(env, err)); 164 | } 165 | 166 | 167 | int decode_flags(ErlNifEnv* env, ERL_NIF_TERM list, int *prot, int *flags, bool *direct, bool *lock) 168 | { 169 | bool l = true; 170 | bool d = false; 171 | int f = MAP_FILE; 172 | int p = 0; 173 | ERL_NIF_TERM head; 174 | while (enif_get_list_cell(env, list, &head, &list)) { 175 | 176 | if (enif_is_identical(head, ATOM_READ)) { 177 | p |= PROT_READ; 178 | } else if (enif_is_identical(head, ATOM_DIRECT)) { 179 | d = true; 180 | } else if (enif_is_identical(head, ATOM_LOCK)) { 181 | l = true; 182 | } else if (enif_is_identical(head, ATOM_NOLOCK)) { 183 | l = false; 184 | } else if (enif_is_identical(head, ATOM_WRITE)) { 185 | p |= PROT_WRITE; 186 | // } else if (enif_is_identical(head, ATOM_NONE)) { 187 | // p |= PROT_NONE; 188 | 189 | } else if (enif_is_identical(head, ATOM_PRIVATE)) { 190 | f |= MAP_PRIVATE; 191 | } else if (enif_is_identical(head, ATOM_SHARED)) { 192 | f |= MAP_SHARED; 193 | // } else if (enif_is_identical(head, ATOM_ANON)) { 194 | // f |= MAP_ANON; 195 | // } else if (enif_is_identical(head, ATOM_FILE)) { 196 | // f |= MAP_FILE; 197 | // } else if (enif_is_identical(head, ATOM_FIXED)) { 198 | // f |= MAP_FIXED; 199 | } else if (enif_is_identical(head, ATOM_NOCACHE)) { 200 | f |= MAP_NOCACHE; 201 | 202 | } else { 203 | return 0; 204 | } 205 | } 206 | 207 | // direct cannot be write 208 | if (d & ((p & PROT_WRITE) != 0)) 209 | return 0; 210 | 211 | // default to private 212 | if ((f & (MAP_SHARED|MAP_PRIVATE)) == 0) 213 | f |= MAP_PRIVATE; 214 | 215 | // default to read-only 216 | if ((p & (PROT_READ|PROT_WRITE)) == 0) 217 | p |= PROT_READ; 218 | 219 | *flags = f; 220 | *prot = p; 221 | *direct = d; 222 | *lock = l; 223 | 224 | return 1; 225 | } 226 | 227 | static ERL_NIF_TERM emmap_open(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) 228 | { 229 | int flags; 230 | int prot; 231 | bool direct, lock; 232 | unsigned long int len; 233 | unsigned long int offset; 234 | char buf[1024]; 235 | 236 | #ifndef NDEBUG 237 | if ( sizeof(long int) != sizeof(size_t) ) { 238 | abort(); 239 | } 240 | #endif 241 | 242 | if (argc == 4 243 | && enif_get_string(env, argv[0], buf, 1024, ERL_NIF_LATIN1) 244 | && enif_get_ulong(env, argv[1], &offset) 245 | && enif_get_ulong(env, argv[2], &len) 246 | && decode_flags(env, argv[3], &prot, &flags, &direct, &lock)) { 247 | 248 | int mode = (((prot & PROT_WRITE)==PROT_WRITE) ? O_RDWR : O_RDONLY); 249 | 250 | int fd = open(buf, mode); 251 | if (fd < 0) { 252 | return make_error_tuple(env, errno); 253 | } 254 | 255 | void * res = mmap(0, (size_t) len, prot, flags, fd, (size_t) offset); 256 | if (res == MAP_FAILED) { 257 | return make_error_tuple(env, errno); 258 | } 259 | 260 | close(fd); 261 | 262 | mhandle* handle = (mhandle*)enif_alloc_resource_compat(env, MMAP_RESOURCE, 263 | sizeof(mhandle)); 264 | 265 | if (lock) 266 | handle->rwlock = enif_rwlock_create((char*)"mmap"); 267 | else 268 | handle->rwlock = 0; 269 | 270 | handle->prot = prot; 271 | handle->mem = res; 272 | handle->len = len; 273 | handle->closed = false; 274 | handle->direct = direct; 275 | handle->position = 0; 276 | 277 | ERL_NIF_TERM resource = enif_make_resource(env, handle); 278 | enif_release_resource_compat(env, handle); 279 | 280 | return enif_make_tuple2(env, 281 | enif_make_atom(env, "ok"), 282 | resource); 283 | 284 | } else { 285 | return enif_make_badarg(env); 286 | } 287 | } 288 | 289 | static ERL_NIF_TERM emmap_close(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) 290 | { 291 | mhandle *handle; 292 | if (argc==1 && enif_get_resource(env, argv[0], MMAP_RESOURCE, (void**)&handle)) 293 | { 294 | int res; 295 | RW_LOCK; 296 | res = emmap_unmap(handle, false); 297 | RW_UNLOCK; 298 | 299 | if (res == 0) { 300 | return ATOM_OK; 301 | } 302 | 303 | return make_error_tuple(env, errno); 304 | } 305 | else 306 | { 307 | return enif_make_badarg(env); 308 | } 309 | } 310 | 311 | static ERL_NIF_TERM emmap_pread(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) 312 | { 313 | unsigned long pos, bytes; 314 | mhandle *handle; 315 | if (argc==3 316 | && enif_get_resource(env, argv[0], MMAP_RESOURCE, (void**)&handle) 317 | && enif_get_ulong(env, argv[1], &pos) 318 | && enif_get_ulong(env, argv[2], &bytes) 319 | && pos >= 0 320 | && bytes >= 0 321 | && pos <= handle->len 322 | ) 323 | { 324 | // Adjust bytes to behave like original file:pread/3 325 | if (pos + bytes > handle->len) bytes = handle->len - pos; 326 | 327 | ErlNifBinary bin; 328 | 329 | if ((handle->prot & PROT_READ) == 0) { 330 | return make_error_tuple(env, EACCES); 331 | } 332 | 333 | // if this mmap is direct, use a resource binary 334 | if (handle->direct) { 335 | 336 | ERL_NIF_TERM res = enif_make_resource_binary 337 | (env, handle, (void*) (((char*)handle->mem) + pos), bytes); 338 | 339 | return enif_make_tuple2(env, ATOM_OK, res); 340 | 341 | } else { 342 | 343 | // When it is non-direct, we have to allocate the binary 344 | if (!enif_alloc_binary((size_t) bytes, &bin)) { 345 | return make_error_tuple(env, ENOMEM); 346 | } 347 | 348 | R_LOCK; 349 | if (handle->closed) { 350 | R_UNLOCK; 351 | return enif_make_badarg(env); 352 | } 353 | memcpy(bin.data, (void*) (((char*)handle->mem) + pos), bytes); 354 | R_UNLOCK; 355 | 356 | ERL_NIF_TERM res = enif_make_binary(env, &bin); 357 | return enif_make_tuple2(env, ATOM_OK, res); 358 | } 359 | } 360 | else 361 | { 362 | return enif_make_badarg(env); 363 | } 364 | } 365 | 366 | static ERL_NIF_TERM emmap_pwrite(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) 367 | { 368 | ErlNifBinary bin; 369 | unsigned long pos; 370 | mhandle *handle; 371 | if (argc==3 372 | && enif_get_resource(env, argv[0], MMAP_RESOURCE, (void**)&handle) 373 | && enif_get_ulong(env, argv[1], &pos) 374 | && enif_inspect_binary(env, argv[2], &bin) 375 | && pos >= 0 376 | && (pos + bin.size) <= handle->len 377 | ) 378 | { 379 | 380 | if ((handle->prot & PROT_WRITE) == 0) { 381 | return make_error_tuple(env, EACCES); 382 | } 383 | 384 | RW_LOCK; 385 | if (handle->closed) { 386 | RW_UNLOCK; 387 | return enif_make_badarg(env); 388 | } else { 389 | memcpy((void*) (((char*)handle->mem) + pos), bin.data, bin.size); 390 | RW_UNLOCK; 391 | } 392 | 393 | return ATOM_OK; 394 | } 395 | else 396 | { 397 | return enif_make_badarg(env); 398 | } 399 | } 400 | 401 | static ERL_NIF_TERM emmap_read(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) 402 | { 403 | mhandle *handle; 404 | unsigned long bytes; 405 | 406 | if (enif_get_resource(env, argv[0], MMAP_RESOURCE, (void**)&handle) 407 | && enif_get_ulong(env, argv[1], &bytes)) { 408 | 409 | 410 | RW_LOCK; 411 | 412 | if (handle->position == handle->len) { 413 | RW_UNLOCK; 414 | return ATOM_EOF; 415 | } 416 | 417 | unsigned long new_pos = handle->position + bytes; 418 | if (new_pos > handle->len) { new_pos = handle->len; } 419 | long size = new_pos - handle->position; 420 | long start = handle->position; 421 | handle->position = new_pos; 422 | RW_UNLOCK; 423 | 424 | if (handle->direct) { 425 | 426 | ERL_NIF_TERM res = enif_make_resource_binary 427 | (env, handle, (void*) (((char*)handle->mem) + start), size); 428 | 429 | return enif_make_tuple2(env, ATOM_OK, res); 430 | 431 | } else { 432 | 433 | ErlNifBinary bin; 434 | // When it is non-direct, we have to allocate the binary 435 | if (!enif_alloc_binary((size_t) size, &bin)) { 436 | return make_error_tuple(env, ENOMEM); 437 | } 438 | 439 | memcpy(bin.data, (void*) (((char*)handle->mem) + start), size); 440 | 441 | ERL_NIF_TERM res = enif_make_binary(env, &bin); 442 | return enif_make_tuple2(env, ATOM_OK, res); 443 | } 444 | 445 | } else { 446 | return enif_make_badarg(env); 447 | } 448 | } 449 | 450 | static ERL_NIF_TERM emmap_read_line(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) 451 | { 452 | mhandle *handle; 453 | 454 | if (enif_get_resource(env, argv[0], MMAP_RESOURCE, (void**)&handle)) { 455 | 456 | RW_LOCK; 457 | 458 | if (handle->position == handle->len) { 459 | RW_UNLOCK; 460 | return ATOM_EOF; 461 | } 462 | 463 | long start = handle->position; 464 | char *current = ((char*)handle->mem) + handle->position; 465 | long linelen = 0; // Length of line without trailing \n 466 | long no_crlf_len = 0; 467 | bool have_cr = false; 468 | bool got_eof = false; 469 | 470 | // Read buffer until \n or EOF is reached 471 | while (*current != '\n') { 472 | handle->position ++; 473 | current ++; 474 | if (handle->position == handle->len) { 475 | got_eof = true; 476 | break; 477 | } 478 | } 479 | // Step to next byte if EOF is not reached 480 | if (not got_eof) { 481 | handle->position ++; 482 | } 483 | 484 | no_crlf_len = linelen = handle->position - start; 485 | 486 | if (not got_eof) { 487 | // Found LF -- exclude it from line 488 | no_crlf_len --; 489 | // If line length before \n is non-zero check if we have \r before \n 490 | if ((no_crlf_len > 0) && (*(current - 1) == '\r')) { 491 | have_cr = true; 492 | no_crlf_len --; 493 | } 494 | } 495 | 496 | RW_UNLOCK; 497 | 498 | // We must not include CR before LF in result, so use direct only without CR 499 | if ((handle->direct) && (not have_cr)) { 500 | 501 | // Include trailing LF if we have it 502 | ERL_NIF_TERM res = enif_make_resource_binary 503 | (env, handle, (void*) (((char*)handle->mem) + start), linelen); 504 | 505 | return enif_make_tuple2(env, ATOM_OK, res); 506 | 507 | } else { 508 | if (not got_eof) linelen = no_crlf_len + 1; 509 | 510 | ErlNifBinary bin; 511 | // When it is non-direct, we have to allocate the binary 512 | if (!enif_alloc_binary((size_t) linelen, &bin)) { 513 | return make_error_tuple(env, ENOMEM); 514 | } 515 | 516 | memcpy(bin.data, (void*) (((char*)handle->mem) + start), no_crlf_len); 517 | // Set trailing \n if needed 518 | if (not got_eof) *(((char*)bin.data) + no_crlf_len) = '\n'; 519 | 520 | ERL_NIF_TERM res = enif_make_binary(env, &bin); 521 | return enif_make_tuple2(env, ATOM_OK, res); 522 | } 523 | 524 | } else { 525 | return enif_make_badarg(env); 526 | } 527 | } 528 | 529 | static ERL_NIF_TERM emmap_position(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) 530 | { 531 | mhandle *handle; 532 | long position; 533 | long relpos; 534 | if (argc==3 535 | && enif_get_resource(env, argv[0], MMAP_RESOURCE, (void**)&handle) 536 | && enif_get_long(env, argv[2], &relpos) 537 | && (argv[1] == ATOM_CUR || argv[1] == ATOM_BOF || argv[1] == ATOM_EOF)) 538 | { 539 | RW_LOCK; 540 | 541 | if (argv[1] == ATOM_BOF) { 542 | position = 0L + relpos; 543 | } else if (argv[1] == ATOM_CUR) { 544 | position = handle->position + relpos; 545 | } else if (argv[1] == ATOM_EOF) { 546 | position = handle->len - relpos; 547 | } 548 | 549 | if (position < 0L || ((unsigned long)position) > handle->len) { 550 | RW_UNLOCK; 551 | return enif_make_badarg(env); 552 | } 553 | 554 | handle->position = position; 555 | RW_UNLOCK; 556 | 557 | return enif_make_tuple2(env, ATOM_OK, enif_make_ulong(env, position)); 558 | } 559 | else 560 | { 561 | return enif_make_badarg(env); 562 | } 563 | } 564 | -------------------------------------------------------------------------------- /c_src/erl_nif_compat.h: -------------------------------------------------------------------------------- 1 | /* Copyright (c) 2010-2011 Basho Technologies, Inc. 2 | * 3 | * This file is provided to you under the Apache License, 4 | * Version 2.0 (the "License"); you may not use this file 5 | * except in compliance with the License. You may obtain 6 | * a copy of the License at 7 | * 8 | * http://www.apache.org/licenses/LICENSE-2.0 9 | * 10 | * Unless required by applicable law or agreed to in writing, 11 | * software distributed under the License is distributed on an 12 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 13 | * KIND, either express or implied. See the License for the 14 | * specific language governing permissions and limitations 15 | * under the License. 16 | */ 17 | 18 | #ifndef ERL_NIF_COMPAT_H_ 19 | #define ERL_NIF_COMPAT_H_ 20 | 21 | #ifdef __cplusplus 22 | extern "C" { 23 | #endif /* __cplusplus */ 24 | 25 | #include "erl_nif.h" 26 | 27 | #if ERL_NIF_MAJOR_VERSION == 1 && ERL_NIF_MINOR_VERSION == 0 28 | 29 | #define enif_open_resource_type_compat enif_open_resource_type 30 | #define enif_alloc_resource_compat enif_alloc_resource 31 | #define enif_release_resource_compat enif_release_resource 32 | #define enif_alloc_binary_compat enif_alloc_binary 33 | #define enif_alloc_compat enif_alloc 34 | #define enif_free_compat enif_free 35 | #define enif_cond_create erl_drv_cond_create 36 | #define enif_cond_destroy erl_drv_cond_destroy 37 | #define enif_cond_signal erl_drv_cond_signal 38 | #define enif_cond_broadcast erl_drv_cond_broadcast 39 | #define enif_cond_wait erl_drv_cond_wait 40 | #define ErlNifCond ErlDrvCond 41 | #endif /* R13B04 */ 42 | 43 | #if ERL_NIF_MAJOR_VERSION == 2 && ERL_NIF_MINOR_VERSION >= 0 44 | 45 | #define enif_open_resource_type_compat(E, N, D, F, T) \ 46 | enif_open_resource_type(E, NULL, N, D, F, T) 47 | 48 | #define enif_alloc_resource_compat(E, T, S) \ 49 | enif_alloc_resource(T, S) 50 | 51 | #define enif_release_resource_compat(E, H) \ 52 | enif_release_resource(H) 53 | 54 | #define enif_alloc_binary_compat(E, S, B) \ 55 | enif_alloc_binary(S, B) 56 | 57 | #define enif_alloc_compat(E, S) \ 58 | enif_alloc(S) 59 | 60 | #define enif_free_compat(E, P) \ 61 | enif_free(P) 62 | 63 | #endif /* R14 */ 64 | 65 | 66 | 67 | #ifdef __cplusplus 68 | } 69 | #endif /* __cplusplus */ 70 | 71 | #endif /* ERL_NIF_COMPAT_H_ */ 72 | -------------------------------------------------------------------------------- /doc/README.md: -------------------------------------------------------------------------------- 1 | 2 | 3 | #mmap - memory mapping files for erlang# 4 | 5 | 6 | Copyright (c) 2012 Trifork 7 | 8 | 9 | __Authors:__ Kresten Krab Thorup ([`krab@trifork.com`](mailto:krab@trifork.com)). 10 | 11 | 12 | Status: 13 | ------ 14 | 15 | 16 | 17 | ##Modules## 18 | 19 | 20 | 21 |
emmap
22 | 23 | -------------------------------------------------------------------------------- /doc/emmap.md: -------------------------------------------------------------------------------- 1 | 2 | 3 | #Module emmap# 4 | * [Data Types](#types) 5 | * [Function Index](#index) 6 | * [Function Details](#functions) 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | ##Data Types## 15 | 16 | 17 | 18 | 19 | ###mmap_file()## 20 | 21 | 22 | 23 | 
mmap_file() = #file_descriptor{}
24 | 25 | 26 | 27 | ###open_option()## 28 | 29 | 30 | 31 | 
open_option() = read | write | direct | lock | nolock | private | shared | nocache
32 | 33 | 34 | ##Function Index## 35 | 36 | 37 |
close/1
open/2
open/4
position/2
pread/3
pwrite/3
read/2
simple_test/0
38 | 39 | 40 | 41 | 42 | ##Function Details## 43 | 44 | 45 | 46 | ###close/1## 47 | 48 | 49 | 50 | 51 | 
close(File::mmap_file()) -> ok
52 |

53 | 54 | 55 | 56 | 57 | ###open/2## 58 | 59 | 60 | 61 | 62 | `open(FileName, Options) -> any()` 63 | 64 | 65 | 66 | ###open/4## 67 | 68 | 69 | 70 | 71 | 
open(File::string(), Offset::pos_integer(), Length::pos_integer(), Options::[open_option()]) -> {ok, mmap_file()} | {error, term()}
72 |

73 | 74 | 75 | 76 | 77 | ###position/2## 78 | 79 | 80 | 81 | 82 | 
position(File::mmap_file(), Position::pos_integer() | {bof | cur | eof, Position::integer()}) -> {ok, pos_integer()} | {error, term()}
83 |

84 | 85 | 86 | 87 | 88 | ###pread/3## 89 | 90 | 91 | 92 | 93 | 
pread(File::mmap_file(), Offset::pos_integer(), Length::pos_integer()) -> {ok, binary()} | {error, term()} | eof
94 |

95 | 96 | 97 | 98 | 99 | ###pwrite/3## 100 | 101 | 102 | 103 | 104 | 
pwrite(File::mmap_file(), Position::pos_integer(), Data::binary()) -> ok | {error, term()}
105 |

106 | 107 | 108 | 109 | 110 | ###read/2## 111 | 112 | 113 | 114 | 115 | 
read(File::mmap_file(), Length::pos_integer()) -> {ok, binary()} | {error, term()} | eof
116 |

117 | 118 | 119 | 120 | 121 | ###simple_test/0## 122 | 123 | 124 | 125 | 126 | `simple_test() -> any()` 127 | 128 | -------------------------------------------------------------------------------- /doc/overview.edoc: -------------------------------------------------------------------------------- 1 | @author Kresten Krab Thorup 2 | @copyright 2012 Trifork 3 | 4 | @title mmap - memory mapping files for erlang 5 | 6 | @doc 7 | Status: 8 | ------ 9 | 10 | 11 | @end 12 | -------------------------------------------------------------------------------- /ebin/emmap.app: -------------------------------------------------------------------------------- 1 | {application, emmap, 2 | [ 3 | {description, ""}, 4 | {vsn, "1.0.0"}, 5 | {modules, [ 6 | emmap 7 | ]}, 8 | {registered, []}, 9 | {applications, [ 10 | kernel, 11 | stdlib 12 | ]}, 13 | {env, []} 14 | ]}. 15 | -------------------------------------------------------------------------------- /rebar: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/krestenkrab/emmap/05ae1bbc8b9b584473483023643fdc3f329a7698/rebar -------------------------------------------------------------------------------- /rebar.config: -------------------------------------------------------------------------------- 1 | {port_specs, [{"priv/emmap_nifs.so", ["c_src/*.cpp"]}]}. 2 | 3 | {port_env, [ 4 | %% Make sure to link -lstdc++ 5 | {"(linux|solaris|freebsd|netbsd|openbsd|dragonfly|darwin)", 6 | "LDFLAGS", "$LDFLAGS -lstdc++"}, 7 | {"(linux|solaris|freebsd|netbsd|openbsd|dragonfly|darwin)", 8 | "CFLAGS", "$CFLAGS -DNDEBUG"} 9 | ]}. 10 | 11 | {deps, [{edown, ".*", {git, "https://github.com/uwiger/edown.git", "HEAD"}}]}. 12 | 13 | {edoc_opts, [{doclet, edown_doclet}, 14 | {source_path, ["src", "test"]}, 15 | {stylesheet, ""}, 16 | {image, ""}, 17 | {app_default,"http://www.erlang.org/doc/man"}]}. 18 | -------------------------------------------------------------------------------- /src/emmap.erl: -------------------------------------------------------------------------------- 1 | -module(emmap). 2 | 3 | -export([open/2, open/4, close/1, pread/3, pwrite/3, read/2, read_line/1, position/2]). 4 | -on_load(init/0). 5 | 6 | -ifdef(TEST). 7 | -export([simple_test/0]). 8 | -endif. 9 | 10 | -include_lib("kernel/include/file.hrl"). 11 | 12 | -type open_option() :: 13 | read | write 14 | | direct 15 | | lock | nolock 16 | | private | shared 17 | | nocache 18 | . 19 | 20 | -type mmap_file() :: #file_descriptor{}. 21 | 22 | init() -> 23 | case code:priv_dir(emmap) of 24 | {error, bad_name} -> 25 | case code:which(?MODULE) of 26 | Filename when is_list(Filename) -> 27 | SoName = filename:join([filename:dirname(Filename),"../priv", "emmap_nifs"]); 28 | _ -> 29 | SoName = filename:join("../priv", "emmap_nifs") 30 | end; 31 | Dir -> 32 | SoName = filename:join(Dir, "emmap_nifs") 33 | end, 34 | erlang:load_nif(SoName, 0). 35 | 36 | 37 | open(FileName, Options) -> 38 | case file:read_file_info(FileName) of 39 | {ok, FileInfo} -> 40 | open(FileName, 0, FileInfo#file_info.size, Options); 41 | Error -> 42 | Error 43 | end. 44 | 45 | -spec open(File::string(), 46 | Offset::pos_integer(), 47 | Length::pos_integer(), 48 | Options::[ open_option() ]) -> 49 | {ok, mmap_file()} | {error, term()}. 50 | 51 | open(FileName, Off, Len, Options) -> 52 | case open_nif(FileName, Off, Len, Options) of 53 | {ok, Mem} -> 54 | {ok, #file_descriptor{ module=?MODULE, data=Mem }}; 55 | Error -> 56 | Error 57 | end. 58 | 59 | open_nif(_,_,_,_) -> 60 | {ok, <<>>}. 61 | 62 | -spec close(File::mmap_file()) -> ok. 63 | 64 | close(#file_descriptor{ module=?MODULE, data=Mem }) -> 65 | close_nif(Mem). 66 | 67 | close_nif(_) -> 68 | ok. 69 | 70 | -spec pread(File::mmap_file(), Offset::pos_integer(), Length::pos_integer()) -> 71 | {ok, binary()} | {error, term()} | eof. 72 | 73 | pread(#file_descriptor{ module=?MODULE, data=Mem }, Off, Len) -> 74 | pread_nif(Mem, Off, Len). 75 | 76 | pread_nif(_,_,_) -> 77 | {ok, <<>>}. 78 | 79 | -spec read(File::mmap_file(), Length::pos_integer()) -> 80 | {ok, binary()} | {error, term()} | eof. 81 | 82 | read(#file_descriptor{ module=?MODULE, data=Mem }, Len) -> 83 | read_nif(Mem, Len). 84 | 85 | read_nif(_,_) -> 86 | {ok, <<>>}. 87 | 88 | 89 | -spec read_line(File::mmap_file()) -> 90 | {ok, binary()} | {error, term()} | eof. 91 | 92 | read_line(#file_descriptor{ module=?MODULE, data=Mem }) -> 93 | read_line_nif(Mem). 94 | 95 | read_line_nif(_) -> 96 | {ok, <<>>}. 97 | 98 | 99 | -spec pwrite(File::mmap_file(), Position::pos_integer(), Data::binary()) -> 100 | ok | {error, term()}. 101 | 102 | pwrite(#file_descriptor{ module=?MODULE, data=Mem }, Off, Data) -> 103 | pwrite_nif(Mem, Off, Data). 104 | 105 | pwrite_nif(_,_,_) -> 106 | ok. 107 | 108 | -spec position(File::mmap_file(), 109 | Position::pos_integer() | {bof|cur|eof, Position::integer()} ) -> 110 | {ok, pos_integer()} | {error, term()}. 111 | position(#file_descriptor{ module=?MODULE, data=Mem}, At) 112 | when is_integer(At) -> 113 | position_nif(Mem, bof, At); 114 | position(#file_descriptor{ module=?MODULE, data=Mem}, From) 115 | when From == 'bof'; From == 'cur'; From == 'eof' -> 116 | position_nif(Mem, From, 0); 117 | position(#file_descriptor{ module=?MODULE, data=Mem}, {From, Off}) 118 | when From == 'bof'; From == 'cur'; From == 'eof' -> 119 | position_nif(Mem, From, Off). 120 | 121 | position_nif(_,_From,_Off) -> 122 | {ok, 0}. 123 | 124 | 125 | -ifdef(TEST). 126 | 127 | simple_test() -> 128 | {ok, File} = file:open("test.data", [raw, write]), 129 | ok = file:write(File, <<"abcd">>), 130 | ok = file:close(File), 131 | 132 | %% with direct+shared, the contents of a binary may change 133 | {ok, MFile} = emmap:open("test.data", 0, 4, [direct, shared, nolock]), 134 | {ok, Mem} = file:pread(MFile, 2, 2), 135 | <<"cd">> = Mem, 136 | {error, eacces} = file:pwrite(MFile, 2, <<"xx">>), 137 | 138 | {ok, MFile2} = emmap:open("test.data", 0, 4, [read, write, shared]), 139 | ok = file:pwrite(MFile2, 2, <<"xx">>), 140 | {ok, <<"xx">>} = file:pread(MFile, 2, 2), 141 | 142 | %% Woot! 143 | <<"xx">> = Mem, 144 | 145 | {ok, 0} = file:position(MFile, {cur, 0}), 146 | {ok, <<"ab">>} = file:read(MFile, 2), 147 | {ok, <<"xx">>} = file:read(MFile, 2), 148 | 149 | file:close(MFile), 150 | file:close(MFile2) . 151 | 152 | 153 | -endif. 154 | --------------------------------------------------------------------------------