Re: [PHP] How to get a string from C library into PHP via SWIG?
On Tue, 2010-01-05 at 13:29 -0800, Eric Fowler wrote: I have a need to call a C language function from a PHP script. The function, which I wrote, looks like this: /* * foo(): Takes a string in sIn and writes another string into sOut according to what is passed in, and the * value at *pcch. Will not write more than *pcch bytes to output, including null terminator. * Upon return, *pcch contains number of chars written to sOut. */ void foo(const char * sIn, char * sOut, size_t * pcch); So basically I need to pass down a string, and get back a string. I have been using swig but clearly I ain't getting it (I am good in C but new to PHP). Lots of warnings, crashes, and so on. No happiness. The swig docs show how to pass strings between python, java, etc., and C, but nothing on C --- PHP. Can anyone help me with a fragment of sample code, or a link? Thanks Eric Can't you just compile the C into an executable and call it from a shell? There are several ways to retrieve input from shell programs. Thanks, Ash http://www.ashleysheridan.co.uk
Re: [PHP] How to get a string from C library into PHP via SWIG?
Hm, that could work, but it does produce overhead. Thank you. Eric On Tue, Jan 5, 2010 at 1:29 PM, Ashley Sheridan a...@ashleysheridan.co.uk wrote: On Tue, 2010-01-05 at 13:29 -0800, Eric Fowler wrote: I have a need to call a C language function from a PHP script. The function, which I wrote, looks like this: /* * foo(): Takes a string in sIn and writes another string into sOut according to what is passed in, and the * value at *pcch. Will not write more than *pcch bytes to output, including null terminator. * Upon return, *pcch contains number of chars written to sOut. */ void foo(const char * sIn, char * sOut, size_t * pcch); So basically I need to pass down a string, and get back a string. I have been using swig but clearly I ain't getting it (I am good in C but new to PHP). Lots of warnings, crashes, and so on. No happiness. The swig docs show how to pass strings between python, java, etc., and C, but nothing on C --- PHP. Can anyone help me with a fragment of sample code, or a link? Thanks Eric Can't you just compile the C into an executable and call it from a shell? There are several ways to retrieve input from shell programs. Thanks, Ash http://www.ashleysheridan.co.uk -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] How to get a string from C library into PHP via SWIG?
On Tue, Jan 5, 2010 at 3:42 PM, Eric Fowler eric.fow...@gmail.com wrote: Hm, that could work, but it does produce overhead. you should consider your overall communication paradigm. im very loosely familiar w/ swig, basically ive heard of it ... anyways, you have a few options for communication, . shell (call php from C or the other way around) . php extension, this may not make sense depending on what your C is doing and is by far the most complex . network protocol, socket, http or other.. can you tell us a little bit more about what youre trying to accomplish and specifically how C and php are communicating in general in your application? -nathan
Re: [PHP] How to get a string from C library into PHP via SWIG?
On Tue, Jan 5, 2010 at 4:05 PM, Eric Fowler eric.fow...@gmail.com wrote: I have a software library that parses strings into a C language structure. It is a utility for C programmers. It contains a utility function that takes the output structure and formats it as a string for display. The goal is to demonstrate the functionality by permitting users to enter strings into a text box and press a button. The string will be passed into my code, parsed, formatted as a different kind of string, and returned, where it will be displayed on the web site. The code is being shipped as a Windows DLL but for the web site I am working with Linux dynamic libraries (*.so). I am able to call functions within the binary from PHP now, but pointers within PHP are not working far less crossing the PHP/C Line Of Death without dying. Eric please keep the responses on list for the benefit of others. well, if you have an .so, honestly i might spend the effort to wrap it up in a simple extension. but if you want to roll something out quickly, i would probly just invoke it over the shell via shell_exec() or similar. i cant imagine what sort of noticeable impact you would see in performance going over the shell in this case. honestly, i think the question is how much work do you want to do. also, do you intend to share this functionality w/ other php programers, that might be an argument for an extension. do you already have a C based program that loads up the library from the cli and uses STDIN / STDOUT, if so i think going over the shell is a no-brainer.. -nathan
Re: [PHP] How to get a string from C library into PHP via SWIG?
This is going to the list per Nathan's suggestion. I confess I am doing this the hard way because I want to get a handle on how to pass across that boundary. My current angle of attack is to use the malloc.i functions in swig to handle those strings. I will keep you all posted. I know you care. :-) Eric I have a software library that parses strings into a C language structure. It is a utility for C programmers. It contains a utility function that takes the output structure and formats it as a string for display. The goal is to demonstrate the functionality by permitting users to enter strings into a text box and press a button. The string will be passed into my code, parsed, formatted as a different kind of string, and returned, where it will be displayed on the web site. The code is being shipped as a Windows DLL but for the web site I am working with Linux dynamic libraries (*.so). I am able to call functions within the binary from PHP now, but pointers within PHP are not working far less crossing the PHP/C Line Of Death without dying. please keep the responses on list for the benefit of others. well, if you have an .so, honestly i might spend the effort to wrap it up in a simple extension. but if you want to roll something out quickly, i would probly just invoke it over the shell via shell_exec() or similar. i cant imagine what sort of noticeable impact you would see in performance going over the shell in this case. honestly, i think the question is how much work do you want to do. also, do you intend to share this functionality w/ other php programers, that might be an argument for an extension. do you already have a C based program that loads up the library from the cli and uses STDIN / STDOUT, if so i think going over the shell is a no-brainer.. On Tue, Jan 5, 2010 at 2:56 PM, Nathan Nobbe quickshif...@gmail.com wrote: On Tue, Jan 5, 2010 at 3:42 PM, Eric Fowler eric.fow...@gmail.com wrote: Hm, that could work, but it does produce overhead. you should consider your overall communication paradigm. im very loosely familiar w/ swig, basically ive heard of it ... anyways, you have a few options for communication, . shell (call php from C or the other way around) . php extension, this may not make sense depending on what your C is doing and is by far the most complex . network protocol, socket, http or other.. can you tell us a little bit more about what youre trying to accomplish and specifically how C and php are communicating in general in your application? -nathan -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] How to get a string from C library into PHP via SWIG?
A little more information: my crashes all relate to handling the char datatype. Floats and ints are happy. I suspect that a char type in PHP is not the same as a char type in C. But I am not sure at all. More recently I have used cmalloc.i to allocate arrays of chars and floats. The floats are happy, the chars crash upon allocation. Weird. Eric On Tue, Jan 5, 2010 at 2:56 PM, Nathan Nobbe quickshif...@gmail.com wrote: On Tue, Jan 5, 2010 at 3:42 PM, Eric Fowler eric.fow...@gmail.com wrote: Hm, that could work, but it does produce overhead. you should consider your overall communication paradigm. im very loosely familiar w/ swig, basically ive heard of it ... anyways, you have a few options for communication, . shell (call php from C or the other way around) . php extension, this may not make sense depending on what your C is doing and is by far the most complex . network protocol, socket, http or other.. can you tell us a little bit more about what youre trying to accomplish and specifically how C and php are communicating in general in your application? -nathan -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] How to get a string from C library into PHP via SWIG?
On Tue, Jan 5, 2010 at 4:38 PM, Eric Fowler eric.fow...@gmail.com wrote: A little more information: my crashes all relate to handling the char datatype. Floats and ints are happy. I suspect that a char type in PHP is not the same as a char type in C. But I am not sure at all. More recently I have used cmalloc.i to allocate arrays of chars and floats. The floats are happy, the chars crash upon allocation. neat, swig generates php extensions. i wonder Eric, how much functionality you intend to expose to php, a series of functions, classes? from the sounds of your earlier description i would imagine maybe one class or a single set of functions to operate on a single string variable, with additional parameters for metadata. im curious, if youre sold on the generator, or if youre interested to just try your hand writing an extension. if youre strong w/ C you could probly crank it out quickly. another option would be to version the generated (swig) C, and repair it by hand, putting those changes in a branch. during subsequent generations, you could merge the work from said branch and iterate on that. of course the other option is to figure out swig, lol. anyways, is this C of yours for a private project or is it something i could take a peak at; im halfway curious what youre working w/. o, and guess what, reading through the swig php page, i discovered you can write php extensions 'in c++', by creating a thin C wrapper - wow, i had never thought of that, lol. -nathan
Re: [PHP] How to get a string from C library into PHP via SWIG?
I will expose only one function, prototyped like the foo() example I described. cstring.i is not implemented for a PHP target (wah). I think I will go the shell approach. I have enough time in this already. Eric On Tue, Jan 5, 2010 at 6:26 PM, Nathan Nobbe quickshif...@gmail.com wrote: On Tue, Jan 5, 2010 at 4:38 PM, Eric Fowler eric.fow...@gmail.com wrote: A little more information: my crashes all relate to handling the char datatype. Floats and ints are happy. I suspect that a char type in PHP is not the same as a char type in C. But I am not sure at all. More recently I have used cmalloc.i to allocate arrays of chars and floats. The floats are happy, the chars crash upon allocation. neat, swig generates php extensions. i wonder Eric, how much functionality you intend to expose to php, a series of functions, classes? from the sounds of your earlier description i would imagine maybe one class or a single set of functions to operate on a single string variable, with additional parameters for metadata. im curious, if youre sold on the generator, or if youre interested to just try your hand writing an extension. if youre strong w/ C you could probly crank it out quickly. another option would be to version the generated (swig) C, and repair it by hand, putting those changes in a branch. during subsequent generations, you could merge the work from said branch and iterate on that. of course the other option is to figure out swig, lol. anyways, is this C of yours for a private project or is it something i could take a peak at; im halfway curious what youre working w/. o, and guess what, reading through the swig php page, i discovered you can write php extensions 'in c++', by creating a thin C wrapper - wow, i had never thought of that, lol. -nathan -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
