lib/bitio.c

   1 /*  bitio.c
   2     part of swftools
   3     implementation of bitio.h.
   4
   5     Copyright (C) 2003 Matthias Kramm <kramm@quiss.org>
   6
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License
  18     along with this program; if not, write to the Free Software
  19     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #ifdef HAVE_UNISTD_H
  24 #include <unistd.h>
  25 #endif
  26 #ifdef HAVE_IO_H
  27 #include <io.h>
  28 #endif
  29 #include <string.h>
  30 #include <memory.h>
  31 #include <fcntl.h>
  32
  33 #include "../config.h"
  34
  35 #ifdef HAVE_ZLIB
  36 #include <zlib.h>
  37 #define ZLIB_BUFFER_SIZE 16384
  38 #endif
  39 #include "./bitio.h"
  40
  41 /* ---------------------------- null reader ------------------------------- */
  42
  43 static int reader_nullread(reader_t*r, void* data, int len)
  44 {
  45     memset(data, 0, len);
  46     return len;
  47 }
  48 static void reader_nullread_dealloc(reader_t*r)
  49 {
  50     memset(r, 0, sizeof(reader_t));
  51 }
  52 void reader_init_nullreader(reader_t*r)
  53 {
  54     r->read = reader_nullread;
  55     r->dealloc = reader_nullread_dealloc;
  56     r->internal = 0;
  57     r->type = READER_TYPE_NULL;
  58     r->mybyte = 0;
  59     r->bitpos = 8;
  60     r->pos = 0;
  61 }
  62 /* ---------------------------- file reader ------------------------------- */
  63
  64 static int reader_fileread(reader_t*reader, void* data, int len)
  65 {
  66     int ret = read((int)reader->internal, data, len);
  67     if(ret>=0)
  68         reader->pos += ret;
  69     return ret;
  70 }
  71 void reader_init_filereader(reader_t*r, int handle)
  72 {
  73     r->read = reader_fileread;
  74     r->internal = (void*)handle;
  75     r->type = READER_TYPE_FILE;
  76     r->mybyte = 0;
  77     r->bitpos = 8;
  78     r->pos = 0;
  79 }
  80
  81 /* ---------------------------- mem reader ------------------------------- */
  82
  83 struct memread_t
  84 {
  85     unsigned char*data;
  86     int length;
  87 };
  88 static int reader_memread(reader_t*reader, void* data, int len)
  89 {
  90     struct memread_t*mr = (struct memread_t*)reader->internal;
  91
  92     if(mr->length - reader->pos > len) {
  93         memcpy(data, &mr->data[reader->pos], len);
  94         reader->pos += len;
  95         return len;
  96     } else {
  97         memcpy(data, &mr->data[reader->pos], mr->length - reader->pos);
  98         reader->pos += mr->length;
  99         return mr->length - reader->pos;
 100     }
 101 }
 102 static void reader_memread_dealloc(reader_t*reader)
 103 {
 104     if(reader->internal)
 105         free(reader->internal);
 106     memset(reader, 0, sizeof(reader_t));
 107 }
 108 void reader_init_memreader(reader_t*r, void*newdata, int newlength)
 109 {
 110     struct memread_t*mr = (struct memread_t*)malloc(sizeof(struct memread_t));
 111     mr->data = (unsigned char*)newdata;
 112     mr->length = newlength;
 113     r->read = reader_memread;
 114     r->dealloc = reader_memread_dealloc;
 115     r->internal = (void*)mr;
 116     r->type = READER_TYPE_MEM;
 117     r->mybyte = 0;
 118     r->bitpos = 8;
 119     r->pos = 0;
 120 }
 121
 122 /* ---------------------------- mem writer ------------------------------- */
 123
 124 struct memwrite_t
 125 {
 126     unsigned char*data;
 127     int length;
 128 };
 129
 130 static int writer_memwrite_write(writer_t*w, void* data, int len)
 131 {
 132     struct memwrite_t*mw = (struct memwrite_t*)w->internal;
 133     if(mw->length - w->pos > len) {
 134         memcpy(&mw->data[w->pos], data, len);
 135         w->pos += len;
 136         return len;
 137     } else {
 138         memcpy(&mw->data[w->pos], data, mw->length - w->pos);
 139         w->pos = mw->length;
 140         return mw->length - w->pos;
 141     }
 142 }
 143 static void writer_memwrite_finish(writer_t*w)
 144 {
 145     if(w->internal)
 146         free(w->internal);
 147     w->internal = 0;
 148 }
 149 void writer_init_memwriter(writer_t*w, void*data, int len)
 150 {
 151     struct memwrite_t *mr;
 152     mr = (struct memwrite_t*)malloc(sizeof(struct memwrite_t));
 153     mr->data = (unsigned char *)data;
 154     mr->length = len;
 155     memset(w, 0, sizeof(writer_t));
 156     w->write = writer_memwrite_write;
 157     w->finish = writer_memwrite_finish;
 158     w->internal = (void*)mr;
 159     w->type = WRITER_TYPE_MEM;
 160     w->bitpos = 0;
 161     w->mybyte = 0;
 162     w->pos = 0;
 163 }
 164
 165 /* ------------------------- growing mem writer ------------------------------- */
 166
 167 struct growmemwrite_t
 168 {
 169     unsigned char*data;
 170     int length;
 171     U32 grow;
 172 };
 173 static int writer_growmemwrite_write(writer_t*w, void* data, int len)
 174 {
 175     struct growmemwrite_t*mw = (struct growmemwrite_t*)w->internal;
 176     if(!mw->data) {
 177         fprintf(stderr, "Illegal write operation: data already given away");
 178         exit(1);
 179     }
 180     if(mw->length - w->pos < len) {
 181         int newlength = mw->length;
 182         while(newlength - w->pos < len) {
 183             newlength += mw->grow;
 184         }
 185 #ifdef NO_REALLOC
 186         unsigned char*newmem = (unsigned char*)malloc(newlength);
 187         memcpy(newmem, mw->data, mw->length);
 188         free(mw->data);
 189         mw->data = newmem;
 190 #else
 191         mw->data = (unsigned char*)realloc(mw->data, newlength);
 192 #endif
 193         mw->length = newlength;
 194     }
 195     memcpy(&mw->data[w->pos], data, len);
 196     w->pos += len;
 197     return len;
 198 }
 199 static void writer_growmemwrite_finish(writer_t*w)
 200 {
 201     struct growmemwrite_t*mw = (struct growmemwrite_t*)w->internal;
 202     if(mw->data)
 203         free(mw->data);
 204     mw->data = 0;
 205     mw->length = 0;
 206     free(w->internal);mw=0;
 207     memset(w, 0, sizeof(writer_t));
 208 }
 209 void* writer_growmemwrite_memptr(writer_t*w, int*len)
 210 {
 211     struct growmemwrite_t*mw = (struct growmemwrite_t*)w->internal;
 212     if(len) {
 213         *len = w->pos;
 214     }
 215     return mw->data;
 216 }
 217 void* writer_growmemwrite_getmem(writer_t*w)
 218 {
 219     struct growmemwrite_t*mw = (struct growmemwrite_t*)w->internal;
 220     void*ret = mw->data;
 221     /* remove own reference so that neither write() nor finish() can free it.
 222        It's property of the caller now.
 223     */
 224     mw->data = 0;
 225     return ret;
 226 }
 227 void writer_growmemwrite_reset(writer_t*w)
 228 {
 229     struct growmemwrite_t*mw = (struct growmemwrite_t*)w->internal;
 230     w->pos = 0;
 231     w->bitpos = 0;
 232     w->mybyte = 0;
 233 }
 234 void writer_init_growingmemwriter(writer_t*w, U32 grow)
 235 {
 236     struct growmemwrite_t *mr;
 237     mr = (struct growmemwrite_t *)malloc(sizeof(struct growmemwrite_t));
 238     mr->length = 4096;
 239     mr->data = (unsigned char *)malloc(mr->length);
 240     mr->grow = grow;
 241     memset(w, 0, sizeof(writer_t));
 242     w->write = writer_growmemwrite_write;
 243     w->finish = writer_growmemwrite_finish;
 244     w->internal = (void*)mr;
 245     w->type = WRITER_TYPE_GROWING_MEM;
 246     w->bitpos = 0;
 247     w->mybyte = 0;
 248     w->pos = 0;
 249 }
 250
 251 /* ---------------------------- file writer ------------------------------- */
 252
 253 struct filewrite_t
 254 {
 255     int handle;
 256     char free_handle;
 257 };
 258
 259 static int writer_filewrite_write(writer_t*w, void* data, int len)
 260 {
 261     struct filewrite_t * fw= (struct filewrite_t*)w->internal;
 262     return write(fw->handle, data, len);
 263 }
 264 static void writer_filewrite_finish(writer_t*w)
 265 {
 266     struct filewrite_t *mr = (struct filewrite_t*)w->internal;
 267     if(mr->free_handle)
 268         close(mr->handle);
 269     free(w->internal);
 270     memset(w, 0, sizeof(writer_t));
 271 }
 272 void writer_init_filewriter(writer_t*w, int handle)
 273 {
 274     struct filewrite_t *mr = (struct filewrite_t *)malloc(sizeof(struct filewrite_t));
 275     mr->handle = handle;
 276     mr->free_handle = 0;
 277     memset(w, 0, sizeof(writer_t));
 278     w->write = writer_filewrite_write;
 279     w->finish = writer_filewrite_finish;
 280     w->internal = mr;
 281     w->type = WRITER_TYPE_FILE;
 282     w->bitpos = 0;
 283     w->mybyte = 0;
 284     w->pos = 0;
 285 }
 286 void writer_init_filewriter2(writer_t*w, char*filename)
 287 {
 288     int fi = open("movie.swf",
 289 #ifdef O_BINARY
 290             O_BINARY|
 291 #endif
 292             O_WRONLY|O_CREAT|O_TRUNC, 0644);
 293     writer_init_filewriter(w, fi);
 294     ((struct filewrite_t*)w->internal)->free_handle = 1;
 295 }
 296
 297 /* ---------------------------- null writer ------------------------------- */
 298
 299 static int writer_nullwrite_write(writer_t*w, void* data, int len)
 300 {
 301     w->pos += len;
 302     return len;
 303 }
 304 static void writer_nullwrite_finish(writer_t*w)
 305 {
 306     memset(w, 0, sizeof(writer_t));
 307 }
 308 void writer_init_nullwriter(writer_t*w)
 309 {
 310     memset(w, 0, sizeof(writer_t));
 311     w->write = writer_nullwrite_write;
 312     w->finish = writer_nullwrite_finish;
 313     w->internal = 0;
 314     w->type = WRITER_TYPE_NULL;
 315     w->bitpos = 0;
 316     w->mybyte = 0;
 317     w->pos = 0;
 318 }
 319 /* ---------------------------- zlibinflate reader -------------------------- */
 320
 321 struct zlibinflate_t
 322 {
 323 #ifdef HAVE_ZLIB
 324     z_stream zs;
 325     reader_t*input;
 326     unsigned char readbuffer[ZLIB_BUFFER_SIZE];
 327 #endif
 328 };
 329
 330 #ifdef HAVE_ZLIB
 331 static void zlib_error(int ret, char* msg, z_stream*zs)
 332 {
 333     fprintf(stderr, "%s: zlib error (%d): last zlib error: %s\n",
 334           msg,
 335           ret,
 336           zs->msg?zs->msg:"unknown");
 337     perror("errno:");
 338     exit(1);
 339 }
 340 #endif
 341
 342 static int reader_zlibinflate(reader_t*reader, void* data, int len)
 343 {
 344 #ifdef HAVE_ZLIB
 345     struct zlibinflate_t*z = (struct zlibinflate_t*)reader->internal;
 346     int ret;
 347     if(!z) {
 348         return 0;
 349     }
 350     if(!len)
 351         return 0;
 352
 353     z->zs.next_out = (Bytef *)data;
 354     z->zs.avail_out = len;
 355
 356     while(1) {
 357         if(!z->zs.avail_in) {
 358             z->zs.avail_in = z->input->read(z->input, z->readbuffer, ZLIB_BUFFER_SIZE);
 359             z->zs.next_in = z->readbuffer;
 360         }
 361         if(z->zs.avail_in)
 362             ret = inflate(&z->zs, Z_NO_FLUSH);
 363         else
 364             ret = inflate(&z->zs, Z_FINISH);
 365
 366         if (ret != Z_OK &&
 367             ret != Z_STREAM_END) zlib_error(ret, "bitio:inflate_inflate", &z->zs);
 368
 369         if (ret == Z_STREAM_END) {
 370                 int pos = z->zs.next_out - (Bytef*)data;
 371                 ret = inflateEnd(&z->zs);
 372                 if (ret != Z_OK) zlib_error(ret, "bitio:inflate_end", &z->zs);
 373                 free(reader->internal);
 374                 reader->internal = 0;
 375                 reader->pos += pos;
 376                 return pos;
 377         }
 378         if(!z->zs.avail_out) {
 379             break;
 380         }
 381     }
 382     reader->pos += len;
 383     return len;
 384 #else
 385     fprintf(stderr, "Error: swftools was compiled without zlib support");
 386     exit(1);
 387 #endif
 388 }
 389 static void reader_zlibinflate_dealloc(reader_t*reader)
 390 {
 391 #ifdef HAVE_ZLIB
 392     struct zlibinflate_t*z = (struct zlibinflate_t*)reader->internal;
 393     /* test whether read() already did basic deallocation */
 394     if(reader->internal) {
 395         inflateEnd(&z->zs);
 396         free(reader->internal);
 397     }
 398     memset(reader, 0, sizeof(reader_t));
 399 #endif
 400 }
 401 void reader_init_zlibinflate(reader_t*r, reader_t*input)
 402 {
 403 #ifdef HAVE_ZLIB
 404     struct zlibinflate_t*z;
 405     int ret;
 406     memset(r, 0, sizeof(reader_t));
 407     z = (struct zlibinflate_t*)malloc(sizeof(struct zlibinflate_t));
 408     memset(z, 0, sizeof(struct zlibinflate_t));
 409     r->internal = z;
 410     r->read = reader_zlibinflate;
 411     r->dealloc = reader_zlibinflate_dealloc;
 412     r->type = READER_TYPE_ZLIB;
 413     r->pos = 0;
 414     z->input = input;
 415     memset(&z->zs,0,sizeof(z_stream));
 416     z->zs.zalloc = Z_NULL;
 417     z->zs.zfree  = Z_NULL;
 418     z->zs.opaque = Z_NULL;
 419     ret = inflateInit(&z->zs);
 420     if (ret != Z_OK) zlib_error(ret, "bitio:inflate_init", &z->zs);
 421     reader_resetbits(r);
 422 #else
 423     fprintf(stderr, "Error: swftools was compiled without zlib support");
 424     exit(1);
 425 #endif
 426 }
 427
 428 /* ---------------------------- zlibdeflate writer -------------------------- */
 429
 430 struct zlibdeflate_t
 431 {
 432 #ifdef HAVE_ZLIB
 433     z_stream zs;
 434     writer_t*output;
 435     unsigned char writebuffer[ZLIB_BUFFER_SIZE];
 436 #endif
 437 };
 438
 439 static int writer_zlibdeflate_write(writer_t*writer, void* data, int len)
 440 {
 441 #ifdef HAVE_ZLIB
 442     struct zlibdeflate_t*z = (struct zlibdeflate_t*)writer->internal;
 443     int ret;
 444     if(writer->type != WRITER_TYPE_ZLIB) {
 445         fprintf(stderr, "Wrong writer ID (writer not initialized?)\n");
 446         return 0;
 447     }
 448     if(!z) {
 449         fprintf(stderr, "zlib not initialized!\n");
 450         return 0;
 451     }
 452     if(!len)
 453         return 0;
 454
 455     z->zs.next_in = (Bytef *)data;
 456     z->zs.avail_in = len;
 457
 458     while(1) {
 459         ret = deflate(&z->zs, Z_NO_FLUSH);
 460
 461         if (ret != Z_OK) zlib_error(ret, "bitio:deflate_deflate", &z->zs);
 462
 463         if(z->zs.next_out != z->writebuffer) {
 464             z->output->write(z->output, z->writebuffer, z->zs.next_out - (Bytef*)z->writebuffer);
 465             z->zs.next_out = z->writebuffer;
 466             z->zs.avail_out = ZLIB_BUFFER_SIZE;
 467         }
 468
 469         if(!z->zs.avail_in) {
 470             break;
 471         }
 472     }
 473     writer->pos += len;
 474     return len;
 475 #else
 476     fprintf(stderr, "Error: swftools was compiled without zlib support");
 477     exit(1);
 478 #endif
 479 }
 480 static void writer_zlibdeflate_finish(writer_t*writer)
 481 {
 482 #ifdef HAVE_ZLIB
 483     struct zlibdeflate_t*z = (struct zlibdeflate_t*)writer->internal;
 484     writer_t*output;
 485     int ret;
 486     if(writer->type != WRITER_TYPE_ZLIB) {
 487         fprintf(stderr, "Wrong writer ID (writer not initialized?)\n");
 488         return;
 489     }
 490     if(!z)
 491         return;
 492     output= z->output;
 493     while(1) {
 494         ret = deflate(&z->zs, Z_FINISH);
 495         if (ret != Z_OK &&
 496             ret != Z_STREAM_END) zlib_error(ret, "bitio:deflate_finish", &z->zs);
 497
 498         if(z->zs.next_out != z->writebuffer) {
 499             z->output->write(z->output, z->writebuffer, z->zs.next_out - (Bytef*)z->writebuffer);
 500             z->zs.next_out = z->writebuffer;
 501             z->zs.avail_out = ZLIB_BUFFER_SIZE;
 502         }
 503
 504         if (ret == Z_STREAM_END) {
 505             break;
 506
 507         }
 508     }
 509     ret = deflateEnd(&z->zs);
 510     if (ret != Z_OK) zlib_error(ret, "bitio:deflate_end", &z->zs);
 511     free(writer->internal);
 512     memset(writer, 0, sizeof(writer_t));
 513     //output->finish(output);
 514 #else
 515     fprintf(stderr, "Error: swftools was compiled without zlib support");
 516     exit(1);
 517 #endif
 518 }
 519 void writer_init_zlibdeflate(writer_t*w, writer_t*output)
 520 {
 521 #ifdef HAVE_ZLIB
 522     struct zlibdeflate_t*z;
 523     int ret;
 524     memset(w, 0, sizeof(writer_t));
 525     z = (struct zlibdeflate_t*)malloc(sizeof(struct zlibdeflate_t));
 526     memset(z, 0, sizeof(struct zlibdeflate_t));
 527     w->internal = z;
 528     w->write = writer_zlibdeflate_write;
 529     w->finish = writer_zlibdeflate_finish;
 530     w->type = WRITER_TYPE_ZLIB;
 531     w->pos = 0;
 532     z->output = output;
 533     memset(&z->zs,0,sizeof(z_stream));
 534     z->zs.zalloc = Z_NULL;
 535     z->zs.zfree  = Z_NULL;
 536     z->zs.opaque = Z_NULL;
 537     ret = deflateInit(&z->zs, 9);
 538     if (ret != Z_OK) zlib_error(ret, "bitio:deflate_init", &z->zs);
 539     w->bitpos = 0;
 540     w->mybyte = 0;
 541     z->zs.next_out = z->writebuffer;
 542     z->zs.avail_out = ZLIB_BUFFER_SIZE;
 543 #else
 544     fprintf(stderr, "Error: swftools was compiled without zlib support");
 545     exit(1);
 546 #endif
 547 }
 548
 549 /* ----------------------- bit handling routines -------------------------- */
 550
 551 void writer_writebit(writer_t*w, int bit)
 552 {
 553     if(w->bitpos==8)
 554     {
 555         w->write(w, &w->mybyte, 1);
 556         w->bitpos = 0;
 557         w->mybyte = 0;
 558     }
 559     if(bit&1)
 560         w->mybyte |= 1 << (7 - w->bitpos);
 561     w->bitpos ++;
 562 }
 563 void writer_writebits(writer_t*w, unsigned int data, int bits)
 564 {
 565     int t;
 566     for(t=0;t<bits;t++)
 567     {
 568         writer_writebit(w, (data >> (bits-t-1))&1);
 569     }
 570 }
 571 void writer_resetbits(writer_t*w)
 572 {
 573     if(w->bitpos)
 574         w->write(w, &w->mybyte, 1);
 575     w->bitpos = 0;
 576     w->mybyte = 0;
 577 }
 578
 579 unsigned int reader_readbit(reader_t*r)
 580 {
 581     if(r->bitpos==8)
 582     {
 583         r->bitpos=0;
 584         r->read(r, &r->mybyte, 1);
 585     }
 586     return (r->mybyte>>(7-r->bitpos++))&1;
 587 }
 588 unsigned int reader_readbits(reader_t*r, int num)
 589 {
 590     int t;
 591     int val = 0;
 592     for(t=0;t<num;t++)
 593     {
 594         val<<=1;
 595         val|=reader_readbit(r);
 596     }
 597     return val;
 598 }
 599 void reader_resetbits(reader_t*r)
 600 {
 601     r->mybyte = 0;
 602     r->bitpos = 8;
 603
 604 }
 605
 606 U8 reader_readU8(reader_t*r)
 607 {
 608     U8 b = 0;
 609     if(r->read(r, &b, 1)<1) {
 610         fprintf(stderr, "bitio.c:reader_readU8: Read over end of memory region\n");
 611     }
 612     return b;
 613 }
 614 U16 reader_readU16(reader_t*r)
 615 {
 616     U8 b1=0,b2=0;
 617     if(r->read(r, &b1, 1)<1) {
 618         fprintf(stderr, "bitio.c:reader_readU16: Read over end of memory region\n");
 619     }
 620     if(r->read(r, &b2, 1)<1) {
 621         fprintf(stderr, "bitio.c:reader_readU16: Read over end of memory region\n");
 622     }
 623     return b1|b2<<8;
 624 }
 625 U32 reader_readU32(reader_t*r)
 626 {
 627     U8 b1=0,b2=0,b3=0,b4=0;
 628     if(r->read(r, &b1, 1)<1)
 629         fprintf(stderr, "bitio.c:reader_readU32: Read over end of memory region\n");
 630     if(r->read(r, &b2, 1)<1)
 631         fprintf(stderr, "bitio.c:reader_readU32: Read over end of memory region\n");
 632     if(r->read(r, &b3, 1)<1)
 633         fprintf(stderr, "bitio.c:reader_readU32: Read over end of memory region\n");
 634     if(r->read(r, &b4, 1)<1)
 635         fprintf(stderr, "bitio.c:reader_readU32: Read over end of memory region\n");
 636     return b1|b2<<8|b3<<16|b4<<24;
 637 }
 638 float reader_readFloat(reader_t*r)
 639 {
 640     U8 b1=0,b2=0,b3=0,b4=0;
 641     r->read(r, &b1, 1);
 642     r->read(r, &b2, 1);
 643     r->read(r, &b3, 1);
 644     r->read(r, &b4, 1);
 645     U32 w = (b1|b2<<8|b3<<16|b4<<24);
 646     return *(float*)&w;
 647 }
 648 double reader_readDouble(reader_t*r)
 649 {
 650     double f;
 651     r->read(r, &f, 8);
 652     return f;
 653
 654     U8 b[8];
 655     r->read(r, b, 8);
 656     U64 w = ((U64)b[0]|(U64)b[1]<<8|(U64)b[2]<<16|(U64)b[3]<<24|(U64)b[4]<<32|(U64)b[5]<<40|(U64)b[6]<<48|(U64)b[7]<<56);
 657     return *(double*)&w;
 658 }
 659 char*reader_readString(reader_t*r)
 660 {
 661     writer_t g;
 662     writer_init_growingmemwriter(&g, 16);
 663     while(1) {
 664         U8 b = reader_readU8(r);
 665         writer_writeU8(&g, b);
 666         if(!b)
 667             break;
 668     }
 669     char*string = (char*)writer_growmemwrite_getmem(&g);
 670     writer_growmemwrite_finish(&g);
 671     return string;
 672 }
 673
 674 void writer_writeString(writer_t*w, const char*s)
 675 {
 676     int l = strlen(s);
 677     char zero = 0;
 678     w->write(w, (void*)s, l);
 679     w->write(w, &zero, 1);
 680 }
 681 void writer_writeU8(writer_t*w, unsigned char b)
 682 {
 683     w->write(w, &b, 1);
 684 }
 685 void writer_writeU16(writer_t*w, unsigned short v)
 686 {
 687     unsigned char b1 = v;
 688     unsigned char b2 = v>>8;
 689     w->write(w, &b1, 1);
 690     w->write(w, &b2, 1);
 691 }
 692 void writer_writeU32(writer_t*w, unsigned long v)
 693 {
 694     unsigned char b1 = v;
 695     unsigned char b2 = v>>8;
 696     unsigned char b3 = v>>16;
 697     unsigned char b4 = v>>24;
 698     w->write(w, &b1, 1);
 699     w->write(w, &b2, 1);
 700     w->write(w, &b3, 1);
 701     w->write(w, &b4, 1);
 702 }
 703 void writer_writeFloat(writer_t*w, float f)
 704 {
 705     unsigned long v = *(unsigned long*)&f;
 706     unsigned char b1 = v;
 707     unsigned char b2 = v>>8;
 708     unsigned char b3 = v>>16;
 709     unsigned char b4 = v>>24;
 710     w->write(w, &b1, 1);
 711     w->write(w, &b2, 1);
 712     w->write(w, &b3, 1);
 713     w->write(w, &b4, 1);
 714 }
 715 void writer_writeDouble(writer_t*w, double f)
 716 {
 717     w->write(w, &f, 8);
 718     return;
 719
 720     unsigned long long v = *(unsigned long long*)&f;
 721     unsigned char b1 = v;
 722     unsigned char b2 = v>>8;
 723     unsigned char b3 = v>>16;
 724     unsigned char b4 = v>>24;
 725     unsigned char b5 = v>>32;
 726     unsigned char b6 = v>>40;
 727     unsigned char b7 = v>>48;
 728     unsigned char b8 = v>>56;
 729     w->write(w, &b1, 1);
 730     w->write(w, &b2, 1);
 731     w->write(w, &b3, 1);
 732     w->write(w, &b4, 1);
 733     w->write(w, &b5, 1);
 734     w->write(w, &b6, 1);
 735     w->write(w, &b7, 1);
 736     w->write(w, &b8, 1);
 737 }