rtspcommon.cpp

linux下的rtsp/rtp/rtcp协议栈源代码； c++写的

/**********
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)

This library is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
more details.

You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
**********/
// "liveMedia"
// Copyright (c) 1996-2006 Live Networks, Inc.  All rights reserved.
// Common routines used by both RTSP clients and servers
// Implementation

#include "RTSPCommon.hh"

Boolean parseRTSPRequestString(char const* reqStr,
			       unsigned reqStrSize,
			       char* resultCmdName,
			       unsigned resultCmdNameMaxSize,
			       char* resultURLPreSuffix,
			       unsigned resultURLPreSuffixMaxSize,
			       char* resultURLSuffix,
			       unsigned resultURLSuffixMaxSize,
			       char* resultCSeq,
			       unsigned resultCSeqMaxSize) {
  // This parser is currently rather dumb; it should be made smarter #####

  // Read everything up to the first space as the command name:
  Boolean parseSucceeded = False;
  unsigned i;
  for (i = 0; i < resultCmdNameMaxSize-1 && i < reqStrSize; ++i) {
    char c = reqStr[i];
    if (c == ' ' || c == '\t') {
      parseSucceeded = True;
      break;
    }

    resultCmdName[i] = c;
  }
  resultCmdName[i] = '\0';
  if (!parseSucceeded) return False;
      
  // Skip over the prefix of any "rtsp://" or "rtsp:/" URL that follows:
  unsigned j = i+1;
  while (j < reqStrSize && (reqStr[j] == ' ' || reqStr[j] == '\t')) ++j; // skip over any additional white space
  for (j = i+1; j < reqStrSize-8; ++j) {
    if ((reqStr[j] == 'r' || reqStr[j] == 'R')
	&& (reqStr[j+1] == 't' || reqStr[j+1] == 'T')
	&& (reqStr[j+2] == 's' || reqStr[j+2] == 'S')
	&& (reqStr[j+3] == 'p' || reqStr[j+3] == 'P')
	&& reqStr[j+4] == ':' && reqStr[j+5] == '/') {
      j += 6;
      if (reqStr[j] == '/') {
	// This is a "rtsp://" URL; skip over the host:port part that follows:
	++j;
	while (j < reqStrSize && reqStr[j] != '/' && reqStr[j] != ' ') ++j;
      } else {
	// This is a "rtsp:/" URL; back up to the "/":
	--j;
      }
      i = j;
      break;
    }
  }

  // Look for the URL suffix (before the following "RTSP/"):
  parseSucceeded = False;
  for (unsigned k = i+1; k < reqStrSize-5; ++k) {
    if (reqStr[k] == 'R' && reqStr[k+1] == 'T' &&
	reqStr[k+2] == 'S' && reqStr[k+3] == 'P' && reqStr[k+4] == '/') {
      while (--k >= i && reqStr[k] == ' ') {} // go back over all spaces before "RTSP/"
      unsigned k1 = k;
      while (k1 > i && reqStr[k1] != '/' && reqStr[k1] != ' ') --k1;
      // the URL suffix comes from [k1+1,k]

      // Copy "resultURLSuffix":
      if (k - k1 + 1 > resultURLSuffixMaxSize) return False; // there's no room
      unsigned n = 0, k2 = k1+1;
      while (k2 <= k) resultURLSuffix[n++] = reqStr[k2++];
      resultURLSuffix[n] = '\0';

      // Also look for the URL 'pre-suffix' before this:
      unsigned k3 = --k1;
      while (k3 > i && reqStr[k3] != '/' && reqStr[k3] != ' ') --k3;
      // the URL pre-suffix comes from [k3+1,k1]

      // Copy "resultURLPreSuffix":
      if (k1 - k3 + 1 > resultURLPreSuffixMaxSize) return False; // there's no room
      n = 0; k2 = k3+1;
      while (k2 <= k1) resultURLPreSuffix[n++] = reqStr[k2++];
      resultURLPreSuffix[n] = '\0';

      i = k + 7; // to go past " RTSP/"
      parseSucceeded = True;
      break;
    }
  }
  if (!parseSucceeded) return False;

  // Look for "CSeq:", skip whitespace,
  // then read everything up to the next \r or \n as 'CSeq':
  parseSucceeded = False;
  for (j = i; j < reqStrSize-5; ++j) {
    if (reqStr[j] == 'C' && reqStr[j+1] == 'S' && reqStr[j+2] == 'e' &&
	reqStr[j+3] == 'q' && reqStr[j+4] == ':') {
      j += 5;
      unsigned n;
      while (j < reqStrSize && (reqStr[j] ==  ' ' || reqStr[j] == '\t')) ++j;
      for (n = 0; n < resultCSeqMaxSize-1 && j < reqStrSize; ++n,++j) {
	char c = reqStr[j];
	if (c == '\r' || c == '\n') {
	  parseSucceeded = True;
	  break;
	}

	resultCSeq[n] = c;
      }
      resultCSeq[n] = '\0';
      break;
    }
  }
  if (!parseSucceeded) return False;

  return True;
}