stream/stream.c

   1 /*
   2  * This file is part of MPlayer.
   3  *
   4  * MPlayer is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * MPlayer is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <unistd.h>
  22
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #ifndef __MINGW32__
  26 #include <sys/ioctl.h>
  27 #include <sys/wait.h>
  28 #endif
  29 #include <fcntl.h>
  30 #include <strings.h>
  31
  32 #include "config.h"
  33
  34 #if HAVE_WINSOCK2_H
  35 #include <winsock2.h>
  36 #endif
  37
  38 #include <libavutil/common.h>
  39
  40 #include "mp_msg.h"
  41 #include "osdep/shmem.h"
  42 #include "osdep/timer.h"
  43 #include "network.h"
  44 #include "stream.h"
  45 #include "libmpdemux/demuxer.h"
  46 #include "ffmpeg_files/intreadwrite.h"
  47
  48 #include "m_option.h"
  49 #include "m_struct.h"
  50
  51 #include "cache2.h"
  52
  53 struct input_ctx;
  54 static int (*stream_check_interrupt_cb)(struct input_ctx *ctx, int time);
  55 static struct input_ctx *stream_check_interrupt_ctx;
  56
  57 extern const stream_info_t stream_info_vcd;
  58 extern const stream_info_t stream_info_cdda;
  59 extern const stream_info_t stream_info_netstream;
  60 extern const stream_info_t stream_info_pnm;
  61 extern const stream_info_t stream_info_asf;
  62 extern const stream_info_t stream_info_rtsp;
  63 extern const stream_info_t stream_info_rtp;
  64 extern const stream_info_t stream_info_udp;
  65 extern const stream_info_t stream_info_http1;
  66 extern const stream_info_t stream_info_http2;
  67 extern const stream_info_t stream_info_dvb;
  68 extern const stream_info_t stream_info_tv;
  69 extern const stream_info_t stream_info_radio;
  70 extern const stream_info_t stream_info_pvr;
  71 extern const stream_info_t stream_info_ftp;
  72 extern const stream_info_t stream_info_vstream;
  73 extern const stream_info_t stream_info_dvdnav;
  74 extern const stream_info_t stream_info_smb;
  75 extern const stream_info_t stream_info_sdp;
  76 extern const stream_info_t stream_info_rtsp_sip;
  77
  78 extern const stream_info_t stream_info_cue;
  79 extern const stream_info_t stream_info_null;
  80 extern const stream_info_t stream_info_mf;
  81 extern const stream_info_t stream_info_ffmpeg;
  82 extern const stream_info_t stream_info_file;
  83 extern const stream_info_t stream_info_ifo;
  84 extern const stream_info_t stream_info_dvd;
  85 extern const stream_info_t stream_info_bluray;
  86
  87 static const stream_info_t* const auto_open_streams[] = {
  88 #ifdef CONFIG_VCD
  89   &stream_info_vcd,
  90 #endif
  91 #ifdef CONFIG_CDDA
  92   &stream_info_cdda,
  93 #endif
  94 #ifdef CONFIG_NETWORKING
  95   &stream_info_netstream,
  96   &stream_info_http1,
  97   &stream_info_asf,
  98   &stream_info_pnm,
  99   &stream_info_rtsp,
 100 #ifdef CONFIG_LIVE555
 101   &stream_info_sdp,
 102   &stream_info_rtsp_sip,
 103 #endif
 104   &stream_info_rtp,
 105   &stream_info_udp,
 106   &stream_info_http2,
 107 #endif
 108 #ifdef CONFIG_DVBIN
 109   &stream_info_dvb,
 110 #endif
 111 #ifdef CONFIG_TV
 112   &stream_info_tv,
 113 #endif
 114 #ifdef CONFIG_RADIO
 115   &stream_info_radio,
 116 #endif
 117 #ifdef CONFIG_PVR
 118   &stream_info_pvr,
 119 #endif
 120 #ifdef CONFIG_FTP
 121   &stream_info_ftp,
 122 #endif
 123 #ifdef CONFIG_VSTREAM
 124   &stream_info_vstream,
 125 #endif
 126 #ifdef CONFIG_LIBSMBCLIENT
 127   &stream_info_smb,
 128 #endif
 129   &stream_info_cue,
 130 #ifdef CONFIG_DVDREAD
 131   &stream_info_ifo,
 132   &stream_info_dvd,
 133 #endif
 134 #ifdef CONFIG_DVDNAV
 135   &stream_info_dvdnav,
 136 #endif
 137 #ifdef CONFIG_LIBBLURAY
 138   &stream_info_bluray,
 139 #endif
 140 #ifdef CONFIG_FFMPEG
 141   &stream_info_ffmpeg,
 142 #endif
 143
 144   &stream_info_null,
 145   &stream_info_mf,
 146   &stream_info_file,
 147   NULL
 148 };
 149
 150 static stream_t *open_stream_plugin(const stream_info_t *sinfo,
 151                                     const char *filename,
 152                                     int mode, struct MPOpts *options,
 153                                     int *file_format, int *ret,
 154                                     char **redirected_url)
 155 {
 156   void* arg = NULL;
 157   stream_t* s;
 158   m_struct_t* desc = (m_struct_t*)sinfo->opts;
 159
 160   // Parse options
 161   if(desc) {
 162     arg = m_struct_alloc(desc);
 163     if(sinfo->opts_url) {
 164       m_option_t url_opt =
 165         { "stream url", arg , CONF_TYPE_CUSTOM_URL, 0, 0 ,0, sinfo->opts };
 166       if(m_option_parse(&url_opt,"stream url",filename,arg,M_CONFIG_FILE) < 0) {
 167         mp_msg(MSGT_OPEN,MSGL_ERR, "URL parsing failed on url %s\n",filename);
 168         m_struct_free(desc,arg);
 169         return NULL;
 170       }
 171     }
 172   }
 173   s = new_stream(-2,-2);
 174   s->opts = options;
 175   s->url=strdup(filename);
 176   s->flags |= mode;
 177   *ret = sinfo->open(s,mode,arg,file_format);
 178   if((*ret) != STREAM_OK) {
 179 #ifdef CONFIG_NETWORKING
 180     if (*ret == STREAM_REDIRECTED && redirected_url) {
 181         if (s->streaming_ctrl && s->streaming_ctrl->url
 182             && s->streaming_ctrl->url->url)
 183           *redirected_url = strdup(s->streaming_ctrl->url->url);
 184         else
 185           *redirected_url = NULL;
 186     }
 187     streaming_ctrl_free(s->streaming_ctrl);
 188 #endif
 189     free(s->url);
 190     free(s);
 191     return NULL;
 192   }
 193   if(s->type <= -2)
 194     mp_msg(MSGT_OPEN,MSGL_WARN, "Warning streams need a type !!!!\n");
 195   if(s->flags & MP_STREAM_SEEK && !s->seek)
 196     s->flags &= ~MP_STREAM_SEEK;
 197   if(s->seek && !(s->flags & MP_STREAM_SEEK))
 198     s->flags |= MP_STREAM_SEEK;
 199
 200   s->mode = mode;
 201
 202   mp_msg(MSGT_OPEN,MSGL_V, "STREAM: [%s] %s\n",sinfo->name,filename);
 203   mp_msg(MSGT_OPEN,MSGL_V, "STREAM: Description: %s\n",sinfo->info);
 204   mp_msg(MSGT_OPEN,MSGL_V, "STREAM: Author: %s\n", sinfo->author);
 205   mp_msg(MSGT_OPEN,MSGL_V, "STREAM: Comment: %s\n", sinfo->comment);
 206
 207   return s;
 208 }
 209
 210
 211 stream_t *open_stream_full(const char *filename, int mode,
 212                            struct MPOpts *options, int *file_format)
 213 {
 214   int i,j,l,r;
 215   const stream_info_t* sinfo;
 216   stream_t* s;
 217   char *redirected_url = NULL;
 218
 219   for(i = 0 ; auto_open_streams[i] ; i++) {
 220     sinfo = auto_open_streams[i];
 221     if(!sinfo->protocols) {
 222       mp_msg(MSGT_OPEN,MSGL_WARN, "Stream type %s has protocols == NULL, it's a bug\n", sinfo->name);
 223       continue;
 224     }
 225     for(j = 0 ; sinfo->protocols[j] ; j++) {
 226       l = strlen(sinfo->protocols[j]);
 227       // l == 0 => Don't do protocol matching (ie network and filenames)
 228       if((l == 0 && !strstr(filename, "://")) ||
 229          ((strncasecmp(sinfo->protocols[j],filename,l) == 0) &&
 230                       (strncmp("://",filename+l,3) == 0))) {
 231         *file_format = DEMUXER_TYPE_UNKNOWN;
 232         s = open_stream_plugin(sinfo,filename,mode,options,file_format,&r,
 233                                 &redirected_url);
 234         if(s) return s;
 235         if(r == STREAM_REDIRECTED && redirected_url) {
 236           mp_msg(MSGT_OPEN,MSGL_V, "[%s] open %s redirected to %s\n",
 237                  sinfo->info, filename, redirected_url);
 238           s = open_stream_full(redirected_url, mode, options, file_format);
 239           free(redirected_url);
 240           return s;
 241         }
 242         else if(r != STREAM_UNSUPPORTED) {
 243           mp_tmsg(MSGT_OPEN,MSGL_ERR, "Failed to open %s.\n",filename);
 244           return NULL;
 245         }
 246         break;
 247       }
 248     }
 249   }
 250
 251   mp_msg(MSGT_OPEN,MSGL_ERR, "No stream found to handle url %s\n",filename);
 252   return NULL;
 253 }
 254
 255 stream_t *open_output_stream(const char *filename, struct MPOpts *options)
 256 {
 257   int file_format; //unused
 258   if(!filename) {
 259     mp_msg(MSGT_OPEN,MSGL_ERR,"open_output_stream(), NULL filename, report this bug\n");
 260     return NULL;
 261   }
 262
 263   return open_stream_full(filename,STREAM_WRITE,options,&file_format);
 264 }
 265
 266 //=================== STREAMER =========================
 267
 268 void stream_capture_do(stream_t *s)
 269 {
 270   if (fwrite(s->buffer, s->buf_len, 1, s->capture_file) < 1) {
 271     mp_tmsg(MSGT_GLOBAL, MSGL_ERR, "Error writing capture file: %s\n",
 272             strerror(errno));
 273     fclose(s->capture_file);
 274     s->capture_file = NULL;
 275   }
 276 }
 277
 278 int stream_read_internal(stream_t *s, void *buf, int len)
 279 {
 280   // we will retry even if we already reached EOF previously.
 281   switch(s->type){
 282   case STREAMTYPE_STREAM:
 283 #ifdef CONFIG_NETWORKING
 284     if( s->streaming_ctrl!=NULL && s->streaming_ctrl->streaming_read ) {
 285       len=s->streaming_ctrl->streaming_read(s->fd, buf, len, s->streaming_ctrl);
 286     } else
 287 #endif
 288     if (s->fill_buffer)
 289       len = s->fill_buffer(s, buf, len);
 290     else
 291       len = read(s->fd, buf, len);
 292     break;
 293   case STREAMTYPE_DS:
 294     len = demux_read_data((demux_stream_t*)s->priv, buf, len);
 295     break;
 296
 297
 298   default:
 299     len= s->fill_buffer ? s->fill_buffer(s, buf, len) : 0;
 300   }
 301   if(len<=0){ s->eof=1; return 0; }
 302   // When reading succeeded we are obviously not at eof.
 303   // This e.g. avoids issues with eof getting stuck when lavf seeks in MPEG-TS
 304   s->eof=0;
 305   s->pos+=len;
 306   return len;
 307 }
 308
 309 int stream_fill_buffer(stream_t *s){
 310   int len = stream_read_internal(s, s->buffer, STREAM_BUFFER_SIZE);
 311   if (len <= 0)
 312     return 0;
 313   s->buf_pos=0;
 314   s->buf_len=len;
 315 //  printf("[%d]",len);fflush(stdout);
 316   if (s->capture_file)
 317     stream_capture_do(s);
 318   return len;
 319 }
 320
 321 int stream_write_buffer(stream_t *s, unsigned char *buf, int len) {
 322   int rd;
 323   if(!s->write_buffer)
 324     return -1;
 325   rd = s->write_buffer(s, buf, len);
 326   if(rd < 0)
 327     return -1;
 328   s->pos += rd;
 329   return rd;
 330 }
 331
 332 int stream_seek_internal(stream_t *s, off_t newpos)
 333 {
 334 if(newpos==0 || newpos!=s->pos){
 335   switch(s->type){
 336   case STREAMTYPE_STREAM:
 337     //s->pos=newpos; // real seek
 338     // Some streaming protocol allow to seek backward and forward
 339     // A function call that return -1 can tell that the protocol
 340     // doesn't support seeking.
 341 #ifdef CONFIG_NETWORKING
 342     if(s->seek) { // new stream seek is much cleaner than streaming_ctrl one
 343       if(!s->seek(s,newpos)) {
 344         mp_msg(MSGT_STREAM,MSGL_ERR, "Seek failed\n");
 345         return 0;
 346       }
 347       break;
 348     }
 349
 350     if( s->streaming_ctrl!=NULL && s->streaming_ctrl->streaming_seek ) {
 351       if( s->streaming_ctrl->streaming_seek( s->fd, newpos, s->streaming_ctrl )<0 ) {
 352         mp_msg(MSGT_STREAM,MSGL_INFO,"Stream not seekable!\n");
 353         return 1;
 354       }
 355       break;
 356     }
 357 #endif
 358     if(newpos<s->pos){
 359       mp_msg(MSGT_STREAM,MSGL_INFO,"Cannot seek backward in linear streams!\n");
 360       return 1;
 361     }
 362     break;
 363   default:
 364     // This should at the beginning as soon as all streams are converted
 365     if(!s->seek)
 366       return 0;
 367     // Now seek
 368     if(!s->seek(s,newpos)) {
 369       mp_msg(MSGT_STREAM,MSGL_ERR, "Seek failed\n");
 370       return 0;
 371     }
 372   }
 373 //   putchar('.');fflush(stdout);
 374 //} else {
 375 //   putchar('%');fflush(stdout);
 376 }
 377   return -1;
 378 }
 379
 380 int stream_seek_long(stream_t *s,off_t pos){
 381   int res;
 382 off_t newpos=0;
 383
 384 //  if( mp_msg_test(MSGT_STREAM,MSGL_DBG3) ) printf("seek_long to 0x%X\n",(unsigned int)pos);
 385
 386   s->buf_pos=s->buf_len=0;
 387
 388   if(s->mode == STREAM_WRITE) {
 389     if(!s->seek || !s->seek(s,pos))
 390       return 0;
 391     return 1;
 392   }
 393
 394   if(s->sector_size)
 395       newpos = (pos/s->sector_size)*s->sector_size;
 396   else
 397       newpos = pos&(~((off_t)STREAM_BUFFER_SIZE-1));
 398
 399 if( mp_msg_test(MSGT_STREAM,MSGL_DBG3) ){
 400   mp_msg(MSGT_STREAM,MSGL_DBG3, "s->pos=%"PRIX64"  newpos=%"PRIX64"  new_bufpos=%"PRIX64"  buflen=%X  \n",
 401     (int64_t)s->pos,(int64_t)newpos,(int64_t)pos,s->buf_len);
 402 }
 403   pos-=newpos;
 404
 405   res = stream_seek_internal(s, newpos);
 406   if (res >= 0)
 407     return res;
 408
 409   while(s->pos<newpos){
 410     if(stream_fill_buffer(s)<=0) break; // EOF
 411   }
 412
 413 s->eof = 0; // EOF reset when seek succeeds.
 414 while (stream_fill_buffer(s) > 0) {
 415   if(pos<=s->buf_len){
 416     s->buf_pos=pos; // byte position in sector
 417     return 1;
 418   }
 419   pos -= s->buf_len;
 420 }
 421 // Fill failed, but seek still is a success.
 422 s->pos += pos;
 423 s->buf_pos = 0;
 424 s->buf_len = 0;
 425
 426 mp_msg(MSGT_STREAM,MSGL_V,
 427        "stream_seek: Seek to/past EOF: no buffer preloaded.\n");
 428 return 1;
 429 }
 430
 431
 432 void stream_reset(stream_t *s){
 433   if(s->eof){
 434     s->pos=0;
 435     s->buf_pos=s->buf_len=0;
 436     s->eof=0;
 437   }
 438   if(s->control) s->control(s,STREAM_CTRL_RESET,NULL);
 439   //stream_seek(s,0);
 440 }
 441
 442 int stream_control(stream_t *s, int cmd, void *arg){
 443   if(!s->control) return STREAM_UNSUPPORTED;
 444 #ifdef CONFIG_STREAM_CACHE
 445   if (s->cache_pid)
 446     return cache_do_control(s, cmd, arg);
 447 #endif
 448   return s->control(s, cmd, arg);
 449 }
 450
 451 stream_t* new_memory_stream(unsigned char* data,int len){
 452   stream_t *s;
 453
 454   if(len < 0)
 455     return NULL;
 456   s=calloc(1, sizeof(stream_t)+len);
 457   s->fd=-1;
 458   s->type=STREAMTYPE_MEMORY;
 459   s->buf_pos=0; s->buf_len=len;
 460   s->start_pos=0; s->end_pos=len;
 461   stream_reset(s);
 462   s->pos=len;
 463   memcpy(s->buffer,data,len);
 464   return s;
 465 }
 466
 467 stream_t* new_stream(int fd,int type){
 468   stream_t *s=calloc(1, sizeof(stream_t));
 469   if(s==NULL) return NULL;
 470
 471 #if HAVE_WINSOCK2_H
 472   {
 473     WSADATA wsdata;
 474     int temp = WSAStartup(0x0202, &wsdata); // there might be a better place for this (-> later)
 475     mp_msg(MSGT_STREAM,MSGL_V,"WINSOCK2 init: %i\n", temp);
 476   }
 477 #endif
 478
 479   s->fd=fd;
 480   s->type=type;
 481   s->buf_pos=s->buf_len=0;
 482   s->start_pos=s->end_pos=0;
 483   s->priv=NULL;
 484   s->url=NULL;
 485   s->cache_pid=0;
 486   stream_reset(s);
 487   return s;
 488 }
 489
 490 void free_stream(stream_t *s){
 491 //  printf("\n*** free_stream() called ***\n");
 492 #ifdef CONFIG_STREAM_CACHE
 493     cache_uninit(s);
 494 #endif
 495   if (s->capture_file) {
 496     fclose(s->capture_file);
 497     s->capture_file = NULL;
 498   }
 499
 500   if(s->close) s->close(s);
 501   if(s->fd>0){
 502     /* on unix we define closesocket to close
 503        on windows however we have to distinguish between
 504        network socket and file */
 505     if(s->url && strstr(s->url,"://"))
 506       closesocket(s->fd);
 507     else close(s->fd);
 508   }
 509 #if HAVE_WINSOCK2_H
 510   mp_msg(MSGT_STREAM,MSGL_V,"WINSOCK2 uninit\n");
 511   WSACleanup(); // there might be a better place for this (-> later)
 512 #endif
 513   // Disabled atm, i don't like that. s->priv can be anything after all
 514   // streams should destroy their priv on close
 515   //free(s->priv);
 516   free(s->url);
 517   free(s);
 518 }
 519
 520 stream_t* new_ds_stream(demux_stream_t *ds) {
 521   stream_t* s = new_stream(-1,STREAMTYPE_DS);
 522   s->priv = ds;
 523   return s;
 524 }
 525
 526 void stream_set_interrupt_callback(int (*cb)(struct input_ctx *, int),
 527                                    struct input_ctx *ctx)
 528 {
 529     stream_check_interrupt_cb = cb;
 530     stream_check_interrupt_ctx = ctx;
 531 }
 532
 533 int stream_check_interrupt(int time) {
 534     if(!stream_check_interrupt_cb) {
 535         usec_sleep(time * 1000);
 536         return 0;
 537     }
 538     return stream_check_interrupt_cb(stream_check_interrupt_ctx, time);
 539 }
 540
 541 /**
 542  * Helper function to read 16 bits little-endian and advance pointer
 543  */
 544 static uint16_t get_le16_inc(const uint8_t **buf)
 545 {
 546   uint16_t v = AV_RL16(*buf);
 547   *buf += 2;
 548   return v;
 549 }
 550
 551 /**
 552  * Helper function to read 16 bits big-endian and advance pointer
 553  */
 554 static uint16_t get_be16_inc(const uint8_t **buf)
 555 {
 556   uint16_t v = AV_RB16(*buf);
 557   *buf += 2;
 558   return v;
 559 }
 560
 561 /**
 562  * Find a newline character in buffer
 563  * \param buf buffer to search
 564  * \param len amount of bytes to search in buffer, may not overread
 565  * \param utf16 chose between UTF-8/ASCII/other and LE and BE UTF-16
 566  *              0 = UTF-8/ASCII/other, 1 = UTF-16-LE, 2 = UTF-16-BE
 567  */
 568 static const uint8_t *find_newline(const uint8_t *buf, int len, int utf16)
 569 {
 570   uint32_t c;
 571   const uint8_t *end = buf + len;
 572   switch (utf16) {
 573   case 0:
 574     return (uint8_t *)memchr(buf, '\n', len);
 575   case 1:
 576     while (buf < end - 1) {
 577       GET_UTF16(c, buf < end - 1 ? get_le16_inc(&buf) : 0, return NULL;)
 578       if (buf <= end && c == '\n')
 579         return buf - 1;
 580     }
 581     break;
 582   case 2:
 583     while (buf < end - 1) {
 584       GET_UTF16(c, buf < end - 1 ? get_be16_inc(&buf) : 0, return NULL;)
 585       if (buf <= end && c == '\n')
 586         return buf - 1;
 587     }
 588     break;
 589   }
 590   return NULL;
 591 }
 592
 593 /**
 594  * Copy a number of bytes, converting to UTF-8 if input is UTF-16
 595  * \param dst buffer to copy to
 596  * \param dstsize size of dst buffer
 597  * \param src buffer to copy from
 598  * \param len amount of bytes to copy from src
 599  * \param utf16 chose between UTF-8/ASCII/other and LE and BE UTF-16
 600  *              0 = UTF-8/ASCII/other, 1 = UTF-16-LE, 2 = UTF-16-BE
 601  */
 602 static int copy_characters(uint8_t *dst, int dstsize,
 603                            const uint8_t *src, int *len, int utf16)
 604 {
 605   uint32_t c;
 606   uint8_t *dst_end = dst + dstsize;
 607   const uint8_t *end = src + *len;
 608   switch (utf16) {
 609   case 0:
 610     if (*len > dstsize)
 611       *len = dstsize;
 612     memcpy(dst, src, *len);
 613     return *len;
 614   case 1:
 615     while (src < end - 1 && dst_end - dst > 8) {
 616       uint8_t tmp;
 617       GET_UTF16(c, src < end - 1 ? get_le16_inc(&src) : 0, ;)
 618       PUT_UTF8(c, tmp, *dst++ = tmp;)
 619     }
 620     *len -= end - src;
 621     return dstsize - (dst_end - dst);
 622   case 2:
 623     while (src < end - 1 && dst_end - dst > 8) {
 624       uint8_t tmp;
 625       GET_UTF16(c, src < end - 1 ? get_be16_inc(&src) : 0, ;)
 626       PUT_UTF8(c, tmp, *dst++ = tmp;)
 627     }
 628     *len -= end - src;
 629     return dstsize - (dst_end - dst);
 630   }
 631   return 0;
 632 }
 633
 634 unsigned char* stream_read_line(stream_t *s,unsigned char* mem, int max, int utf16) {
 635   int len;
 636   const unsigned char *end;
 637   unsigned char *ptr = mem;
 638   if (max < 1) return NULL;
 639   max--; // reserve one for 0-termination
 640   do {
 641     len = s->buf_len-s->buf_pos;
 642     // try to fill the buffer
 643     if(len <= 0 &&
 644        (!cache_stream_fill_buffer(s) ||
 645         (len = s->buf_len-s->buf_pos) <= 0)) break;
 646     end = find_newline(s->buffer+s->buf_pos, len, utf16);
 647     if(end) len = end - (s->buffer+s->buf_pos) + 1;
 648     if(len > 0 && max > 0) {
 649       int l = copy_characters(ptr, max, s->buffer+s->buf_pos, &len, utf16);
 650       max -= l;
 651       ptr += l;
 652       if (!len)
 653         break;
 654     }
 655     s->buf_pos += len;
 656   } while(!end);
 657   ptr[0] = 0;
 658   if(s->eof && ptr == mem) return NULL;
 659   return mem;
 660 }