ucar.unidata.io.RandomAccessFile.searchForward()方法的使用及代码示例

x33g5p2x  于2022-01-29 转载在 其他  
字(7.0k)|赞(0)|评价(0)|浏览(195)

本文整理了Java中ucar.unidata.io.RandomAccessFile.searchForward方法的一些代码示例，展示了RandomAccessFile.searchForward的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。RandomAccessFile.searchForward方法的具体详情如下：
包路径：ucar.unidata.io.RandomAccessFile
类名称：RandomAccessFile
方法名：searchForward

RandomAccessFile.searchForward介绍

[英]Search forward from the current pos, looking for a match.
[中]从当前pos向前搜索，寻找匹配项。

代码示例

代码示例来源：origin: edu.ucar/cdm

  1. public static boolean failFast(RandomAccessFile raf) throws IOException {
  2.  return !raf.searchForward(matcher, 1000); // look in first 1K
  3. }

代码示例来源：origin: Unidata/thredds

  1. public static boolean failFast(RandomAccessFile raf) throws IOException {
  2.  raf.seek(0);
  3.  boolean ok = raf.searchForward(matchDSET, 1000); // look in first 1K
  4.  if (!ok) {
  5.   raf.seek(0);
  6.   ok = raf.searchForward(matchdset, 1000); // look in first 1K
  7.   if (!ok) return true;
  8.  }
  9.  long pos = raf.getFilePointer();
  10.  ok = raf.searchForward(matchENDVARS, 20000); // look in next 20K
  11.  if (!ok) {
  12.   raf.seek(pos);
  13.   ok = raf.searchForward(matchendvars, 20000); // look in next 20K
  14.  }
  15.  return !ok;
  16. }

代码示例来源：origin: Unidata/thredds

  1. public static void main2(String[] args) throws IOException {
  2.  String filename = (args.length > 0 && args[0] != null) ? args[0] : "Q:/cdmUnitTest/formats/grib2/LMPEF_CLM_050518_1200.grb";
  3.  System.out.printf("Scan %s%n", filename);
  4.  try (RandomAccessFile raf = new RandomAccessFile(filename, "r")) {
  5.   raf.seek(0);
  6.   while (!raf.isAtEndOfFile()) {
  7.    boolean found = raf.searchForward(matcher, -1);
  8.    if (found) {
  9.     raf.skipBytes(7); // will be positioned on byte 0 of indicator section
  10.     int edition = raf.read(); // read at byte 8
  11.     System.out.printf(" GRIB edition %d found at pos %d%n", edition, raf.getFilePointer());
  12.     break;
  13.    }
  14.   }
  15.  } catch (IOException e) {
  16.   e.printStackTrace();
  17.  }
  18. }

代码示例来源：origin: Unidata/thredds

  1. public boolean hasNext() throws IOException {
  2.  if (lastPos >= raf.length()) return false;
  3.  raf.seek(lastPos);
  4.  boolean more = raf.searchForward(matcher, -1); // will scan to end for another BUFR header
  5.  if (more) {
  6.   long stop = raf.getFilePointer();
  7.   int sizeHeader = (int) (stop - lastPos);
  8.   if (sizeHeader > 30) sizeHeader = 30;
  9.   header = new byte[sizeHeader];
  10.   startPos = stop-sizeHeader;
  11.   raf.seek(startPos);
  12.   int nRead = raf.read(header);
  13.   if (nRead != header.length) {
  14.     log.warn("Unable to read full BUFR header. Got " + nRead +
  15.         " but expected " + header.length);
  16.     return false;
  17.   }
  18.  }
  19.  if (debug && countMsgs % 100 == 0) System.out.printf("%d ", countMsgs);
  20.  return more;
  21. }

代码示例来源：origin: edu.ucar/grib

  1. /**
  2.  * returns Grib file type, 1 or 2, or 0 not a Grib file.
  3.  *
  4.  * @return GribFileType
  5.  * @throws IOException           on data read
  6.  * @throws NotSupportedException NotSupportedException
  7.  */
  8. public final int getEdition() throws IOException {
  9.  raf.seek(0);
  10.  if (!raf.searchForward(matcher, 8000)) return 0; // must find "GRIB" in first 8k
  11.  raf.skipBytes(4);
  12.  //  Read Section 0 Indicator Section to get Edition number
  13.  Grib2IndicatorSection is = new Grib2IndicatorSection(raf);  // section 0
  14.  return is.getGribEdition();
  15. }

代码示例来源：origin: edu.ucar/bufr

  1. public boolean hasNext() throws IOException {
  2.  if (lastPos >= raf.length()) return false;
  3.  raf.seek(lastPos);
  4.  boolean more = raf.searchForward(matcher, -1); // will scan to end for another BUFR header
  5.  if (more) {
  6.   long stop = raf.getFilePointer();
  7.   int sizeHeader = (int) (stop - lastPos);
  8.   if (sizeHeader > 30) sizeHeader = 30;
  9.   header = new byte[sizeHeader];
  10.   startPos = stop-sizeHeader;
  11.   raf.seek(startPos);
  12.   raf.read(header);
  13.  }
  14.  // System.out.println(" more "+more+" at "+startPos+" lastPos "+ lastPos+" nbytes= "+nbytes+ " msg "+countMsgs);
  15.  return more;
  16. }

代码示例来源：origin: edu.ucar/grib

  1. static public boolean isValidFile(RandomAccessFile raf) throws IOException {
  2.  raf.seek(0);
  3.  if (!raf.searchForward(matcher, 8000)) return false; // must find "GRIB" in first 8k
  4.  raf.skipBytes(4);
  5.  //  Read Section 0 Indicator Section to get Edition number
  6.  Grib2IndicatorSection is = new Grib2IndicatorSection(raf);  // section 0
  7.  if (is.getGribEdition() != 1 && is.getGribEdition() != 2)
  8.   return false;
  9.  if (is.getGribLength() > raf.length())
  10.   return false;
  11.  return true;
  12. }

代码示例来源：origin: Unidata/thredds

  1. /**
  2.  * is this a valid BUFR file.
  3.  *
  4.  * @param raf check this file
  5.  * @return true if its a BUFR file
  6.  * @throws IOException on read error
  7.  */
  8. static public boolean isValidFile(ucar.unidata.io.RandomAccessFile raf) throws IOException {
  9.  raf.seek(0);
  10.  if (!raf.searchForward(matcher, 40 * 1000)) return false; // must find "BUFR" in first 40k
  11.  raf.skipBytes(4);
  12.  BufrIndicatorSection is = new BufrIndicatorSection(raf);
  13.  if (is.getBufrEdition() > 4) return false;
  14.  // if(is.getBufrLength() > MAX_MESSAGE_SIZE) return false;
  15.  return !(is.getBufrLength() > raf.length());
  16. }

代码示例来源：origin: edu.ucar/bufr

  1. /**
  2.  * is this a valid BUFR file.
  3.  *
  4.  * @param raf check this file
  5.  * @return true if its a BUFR file
  6.  * @throws IOException on read error
  7.  */
  8. static public boolean isValidFile(ucar.unidata.io.RandomAccessFile raf) throws IOException {
  9.  raf.seek(0);
  10.  if (!raf.searchForward(matcher, 8000)) return false; // must find "BUFR" in first 8k
  11.  raf.skipBytes(4);
  12.  BufrIndicatorSection is = new BufrIndicatorSection(raf);
  13.  if (is.getBufrEdition() > 4) return false;
  14.  // if(is.getBufrLength() > MAX_MESSAGE_SIZE) return false;
  15.  if (is.getBufrLength() > raf.length()) return false;
  16.  return true;
  17. }

代码示例来源：origin: Unidata/thredds

  1. static public boolean isValidFile(RandomAccessFile raf) {
  2.  try {
  3.   raf.seek(0);
  4.   boolean found = raf.searchForward(matcher, maxScan); // look in first 16K
  5.   if (!found) return false;
  6.   raf.skipBytes(7); // will be positioned on byte 0 of indicator section
  7.   int edition = raf.read(); // read at byte 8
  8.   if (edition != 2) return false;
  9.   // check ending = 7777
  10.   long len = GribNumbers.int8(raf);
  11.   if (len > raf.length()) return false;
  12.   raf.skipBytes(len-20);
  13.   for (int i = 0; i < 4; i++) {
  14.    if (raf.read() != 55) return false;
  15.   }
  16.   return true;
  17.  } catch (IOException e) {
  18.   return false;
  19.  }
  20. }

代码示例来源：origin: Unidata/thredds

  1. static public boolean isValidFile(RandomAccessFile raf) {
  2.  try {
  3.   raf.seek(0);
  4.   boolean found = raf.searchForward(matcher, maxScan); // look in first 16K
  5.   if (!found) return false;
  6.   raf.skipBytes(4); // will be positioned on byte 0 of indicator section
  7.   int len = GribNumbers.uint3(raf);
  8.   int edition = raf.read(); // read at byte 8
  9.   if (edition != 1) return false;
  10.   
  11.   /* Due to a trick done by ECMWF's GRIBEX to support large GRIBs, we need a special treatment
  12.    * to fix the length of the GRIB message. See:
  13.    * https://software.ecmwf.int/wiki/display/EMOS/Changes+in+cycle+000281
  14.    * https://github.com/Unidata/thredds/issues/445
  15.   */
  16.   len = getFixedTotalLengthEcmwfLargeGrib(raf,len);
  17.   
  18.   // check ending = 7777
  19.   if (len > raf.length()) return false;
  20.   if (allowBadIsLength) return true;
  21.   raf.skipBytes(len-12);
  22.   for (int i = 0; i < 4; i++) {
  23.    if (raf.read() != 55) return false;
  24.   }
  25.   return true;
  26.  } catch (IOException e) {
  27.   return false;
  28.  }
  29. }

代码示例来源：origin: Unidata/thredds

  1. more = raf.searchForward(matcher, -1); // will scan to end for a 'GRIB' string
  2. if (!more) break;

代码示例来源：origin: Unidata/thredds

  1. public boolean hasNext() throws IOException {
  2.  if (lastPos >= raf.length()) return false;
  3.  boolean more;
  4.  long foundAt = 0;
  5.  while (true) { // scan until we get a GRIB-1 or more is false
  6.   raf.seek(lastPos);
  7.   more = raf.searchForward(matcher, -1); // will scan to end for a 'GRIB' string
  8.   if (!more) break;
  9.   foundAt = raf.getFilePointer();
  10.   // see if its GRIB-1
  11.   raf.skipBytes(7);
  12.   int edition = raf.read();
  13.   if (edition == 1) break;
  14.   lastPos = raf.getFilePointer(); // not edition 1 ! could terminate ??
  15.  }
  16.  if (more) {
  17.   // read the header - stuff between the records
  18.   int sizeHeader = (int) (foundAt - lastPos);
  19.   if (sizeHeader > 100) sizeHeader = 100;   // maximum 100 bytes, more likely to be garbage
  20.   long startPos = foundAt-sizeHeader;
  21.   header = new byte[sizeHeader];
  22.   raf.seek(startPos);
  23.   raf.readFully(header);
  24.   raf.seek(foundAt);
  25.   this.lastPos = foundAt; // ok start from here next time
  26.  }
  27.  return more;
  28. }

内容来源于网络，如有侵权，请联系作者删除！

randomaccessfile

相关文章

    查看更多

    热门标签

    更多
    JavaquerypythonNode开发语言requestUtil数据库Table后端算法LoggerMessageElementParser

    最新文章

    更多

    RandomAccessFile类方法

    • 蜀ICP备13028337号-1 大数据知识库 https://www.saoniuhuo.com © All rights reserved
    • 本站内容来源互联网,如果侵犯您的权益请联系我们删除, 联系方式：448109455@qq.com