Programming Forums > Application Development > C++

Scrag · Dec 13th, 2004, 8:27 AM

I've been trying to figure this one out for a while and my brain is fried. Basically, Im trying to write a function that will remove the "%20" thats represents a space in html and relace it with "\ ". Im trying this using the strstr() function, but I really dont know how to start this, or what I need for a basic algorithm. Any thoughts or ideas would be greatly appreciated, or even just a point in the starting direction.

THANKS!
Scrag

plox · Dec 13th, 2004, 2:49 PM

Sounds like a fun function. One question and then I would LOVE to help you. Will you be reading an external file or is the user going to be inputing the text into the command line? I might still be able to help if it is with the external file, that just makes things a tad harder. Only because I have not done much with external files, and so I don't have the most experience.

Benoit · Dec 13th, 2004, 3:05 PM

It would be easy with an external file...Just use fgets and read one line at a time

Scrag · Dec 13th, 2004, 3:32 PM

I am writing a web server, I got the web server part pretty much done, but Im adding the ability for the web server to list a directory for downloading files if needed. This will be a function that will be passed a string variable. For example, it gets passed the http string "Cool%20File.mpg", then I need to replace the http space "%20" with "\ " so the unix file system can read the file/cd to the dir. So after the function gets passed the string "Cool%20File.mpg", it should return the string "Cool\ File.mpg"

Thanks for the help!!

tempest · Dec 13th, 2004, 3:41 PM

If you're writing a webserver than you need to do more than convert just %20. You have to convert every number that appears after a % to its hexadecimal -> character value. Not just 20 for space..

amado · Dec 13th, 2004, 6:59 PM

Don't know what platform u're writing the program in but there is a function in msdn that does this for you ::: InternetCanonicalizeUrl

Scrag · Dec 13th, 2004, 9:05 PM

Yeah, i knoiw I need to convert all number values, but I figured this would be a good start

I am using C and compiling with gcc, under linux. Im think in gonna write the function to read each char of the string to a new buffer string, then when strstr(httpGET_PATH, "%20), wite out a `\` and a ' ' char, skip 3 chars, continue etc. Any suggestions on a better way would be cool.

Thanks again,
Scrag

tempest · Dec 13th, 2004, 9:33 PM

There may or may not be a better way to do the if evals... but heres code for %20 that could be easily adapted....

(Toggle Plain Text)

void convertURL(char *blah) {
  char url[1024]; // If you have URLs bigger than 1024, you have problems...
  strcpy(url, blah);

  for(int len=0;len<1024;len++) if(url[len] == NULL) break; 

  char newStr[1024];
  int pos = 0;
  for(int i=0;i<len - 3;i++) {
    if(url[i] == '%' &&
      url[i+1] == '2' &&
      url[i+2] == '0') {
      newStr[pos++] = ' ';
      i += 2;
    } else
      newStr[pos++] = url[i];
  }

  strcpy(blah, newStr);
}

Scrag · Dec 13th, 2004, 10:50 PM

Thanks a lot tempest!!! Definetly gets me going in the right direction

I've been struggling with this for a while now, and other forums didnt seem to help.

Thanks again!

:rock:

Scrag · Dec 13th, 2004, 11:27 PM

On second thought/compile, it works flawlessly,

Thanks again!

Dec 13th, 2004, 2:49 PM	#2
plox Newbie Join Date: Dec 2004 Posts: 6 Rep Power: 0	Sounds like a fun function. One question and then I would LOVE to help you. Will you be reading an external file or is the user going to be inputing the text into the command line? I might still be able to help if it is with the external file, that just makes things a tad harder. Only because I have not done much with external files, and so I don't have the most experience. __________________ <span style='color:green'>Some people are afraid of the net. I'm afraid of what's outside it.</span>

Dec 13th, 2004, 3:05 PM	#3
Benoit Expert Programmer Join Date: Sep 2004 Location: Ontario, Canada Posts: 550 Rep Power: 4	It would be easy with an external file...Just use fgets and read one line at a time __________________ Johnny was a chemist's son but Johnny is no more, for what Johnny thought was H2O was H2SO4

Dec 13th, 2004, 3:41 PM	#5
tempest Programming Guru Join Date: Oct 2004 Posts: 1,041 Rep Power: 5	If you're writing a webserver than you need to do more than convert just %20. You have to convert every number that appears after a % to its hexadecimal -> character value. Not just 20 for space.. __________________

Dec 13th, 2004, 9:33 PM	#8
tempest Programming Guru Join Date: Oct 2004 Posts: 1,041 Rep Power: 5	There may or may not be a better way to do the if evals... but heres code for %20 that could be easily adapted.... (Toggle Plain Text) void convertURL(char blah) { char url[1024]; // If you have URLs bigger than 1024, you have problems... strcpy(url, blah); for(int len=0;len<1024;len++) if(url[len] == NULL) break; char newStr[1024]; int pos = 0; for(int i=0;i<len - 3;i++) { if(url[i] == '%' && url[i+1] == '2' && url[i+2] == '0') { newStr[pos++] = ' '; i += 2; } else newStr[pos++] = url[i]; } strcpy(blah, newStr); } void convertURL(char blah) { char url[1024]; // If you have URLs bigger than 1024, you have problems... strcpy(url, blah); for(int len=0;len<1024;len++) if(url[len] == NULL) break; char newStr[1024]; int pos = 0; for(int i=0;i<len - 3;i++) { if(url[i] == '%' && url[i+1] == '2' && url[i+2] == '0') { newStr[pos++] = ' '; i += 2; } else newStr[pos++] = url[i]; } strcpy(blah, newStr); } __________________

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Dec 13th, 2004, 8:27 AM	#1
Scrag Newbie Join Date: Dec 2004 Posts: 8 Rep Power: 0	I've been trying to figure this one out for a while and my brain is fried. Basically, Im trying to write a function that will remove the "%20" thats represents a space in html and relace it with "\ ". Im trying this using the strstr() function, but I really dont know how to start this, or what I need for a basic algorithm. Any thoughts or ideas would be greatly appreciated, or even just a point in the starting direction. THANKS! Scrag

Dec 13th, 2004, 3:32 PM	#4
Scrag Newbie Join Date: Dec 2004 Posts: 8 Rep Power: 0	I am writing a web server, I got the web server part pretty much done, but Im adding the ability for the web server to list a directory for downloading files if needed. This will be a function that will be passed a string variable. For example, it gets passed the http string "Cool%20File.mpg", then I need to replace the http space "%20" with "\ " so the unix file system can read the file/cd to the dir. So after the function gets passed the string "Cool%20File.mpg", it should return the string "Cool\ File.mpg" Thanks for the help!!

Dec 13th, 2004, 6:59 PM	#6
amado Newbie Join Date: Dec 2004 Posts: 3 Rep Power: 0	Don't know what platform u're writing the program in but there is a function in msdn that does this for you ::: InternetCanonicalizeUrl

Dec 13th, 2004, 9:05 PM	#7
Scrag Newbie Join Date: Dec 2004 Posts: 8 Rep Power: 0	Yeah, i knoiw I need to convert all number values, but I figured this would be a good start I am using C and compiling with gcc, under linux. Im think in gonna write the function to read each char of the string to a new buffer string, then when strstr(httpGET_PATH, "%20), wite out a `\` and a ' ' char, skip 3 chars, continue etc. Any suggestions on a better way would be cool. Thanks again, Scrag

Dec 13th, 2004, 10:50 PM	#9
Scrag Newbie Join Date: Dec 2004 Posts: 8 Rep Power: 0	Thanks a lot tempest!!! Definetly gets me going in the right direction I've been struggling with this for a while now, and other forums didnt seem to help. Thanks again! :rock:

Dec 13th, 2004, 11:27 PM	#10
Scrag Newbie Join Date: Dec 2004 Posts: 8 Rep Power: 0	On second thought/compile, it works flawlessly, Thanks again!

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Programming Forums > Application Development > C++

C Function To Replace A String In A String.