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1113 discussions

Need foreign string method for translate-into-foreign-memory?
by Liam Healy 20 Oct '13

20 Oct '13

Based on this report http://paste.lisp.org/display/139232 it seems like we need a method translate-into-foreign-memory for foreign-string in order that cffi-libffi works when there are both structures by value and strings in the arguments (or return). I looked at the code for translate-to-foreign for inspiration, but I'm not clear on how strings work. Is this simply a memcpy? Liam

4 24

[cffi-devel] Illegal :UTF-8 character starting at position
by Joeish W 18 Oct '13

18 Oct '13

Im refferring to this OpenCV function on this post IplImage* cvLoadImage(const char* filename, int iscolor=CV_LOAD_IMAGE_COLOR ) I'm tring to get the c functionality where i can access the imageData struct member of IplImage with the below statement (more info here http://docs.opencv.org/modules/core/doc/old_basic_structures.html?highlight…) IplImage* converted_image= cvLoadImage("c:\\box_in_scene.png",0):converted_image->imageData when i try with this (dp converted-image (Load-image "/home/w/Documents/opencv- 2.4.6.1/samples/c/box_in_scene.png" 0)) (cffi:with-foreign-slots ((image-data) converted-image (:struct ipl-image)) (cffi:foreign-string-to-lisp image-data)) I get the post title error message. I also get message when i try to setf IMAGE-DATA to another variable or list it .....i get same thing with foreign-slot-value here is sampling of the more than 6 pages of converted_image->imageData that was cout'ed in C P1']}stqouqwruM/./22330/00+1)/+%+8S~sx{zzx|x~|x~y{~Y(&&''()+,%(%$%! $l~

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[cffi-devel] wrapping opencv's cvError
by Joeish W 16 Oct '13

16 Oct '13

I wrapped opencv's cvError like this ;; void cvError(int status, const char* func_name, const char* err_msg, const char* file_name, int line) (cffi:defcfun ("cvError" cv-error) :void (status :int) (func-name :string) (err-msg :string) (file-name :string) (line :int)) but the whole purpose of the function is to cause an error in c which it does perfectly when i run this at the repl (cv-error +stsoutofrange+ "SCALAR" "error" "/home/w/Documents/opencv-2.4.6.1/modules/calib3d/src/epnp.cpp" 1) here is the error OpenCV Error: One of arguments' values is out of range (bew!) in SCALAR, file /home/w/Documents/opencv-2.4.6.1/modules/calib3d/src/epnp.cpp, line 1 terminate called after throwing an instance of 'cv::Exception' but the thing is it causes the error in c on the inferior-lisp buffer in emacs on the repl buffer the repl just hangs....how would i go about getting this error(above) to show up on the lisp side

2 1

Help wrapping this struct?
by Joeish W 15 Oct '13

15 Oct '13

not sure of the wording on this so pls bear with me in OpenCV when you want to create an image you do this IplImage* img=cvCreateImage(cvGetSize(imgHSV),IPL_DEPTH_8U, 1); or you can do this img=cvCreateImage(cvGetSize(imgHSV),IPL_DEPTH_8U, 1); if you've already called the below first IplImage* img; my question is...since i already wrapped cvCreateImage with this successfully ;; IplImage* cvCreateImage(CvSize size, int depth, int channels) (cffi:defcfun ("cvCreateImage" %create-image) (:pointer (:struct ipl-image)) (size :int64) (depth :int) (channels :int)) (defun create-image (size depth channels) "Create an image with dimensions given by SIZE, DEPTH bits per channel, and CHANNELS number of channels." (let ((nsize (size->int64 size))) (%create-image nsize depth channels))) and i use it all the time successfully, converting c opencv code into lisp in many programs...and have never once did this IplImage* img; I always call it in a let like this (img (create-image sz +ipl-depth-8u+ 3)) but if i wanted to expose this kind of functionality in lisp where i would call i/e (ipl-image img) first before calling(img (create-image sz +ipl-depth-8u+ 3)) how would i do that I tried writing a glue wrapper in c IplImage* IplImage_glue(int img) { return (IplImage *) img; } here is my repl history after that was compiled into a .so(ubuntu raring) CL-OPENCV> ;; IplImage* IplImage_glue(IplImage* img); (cffi:defcfun ("IplImage_glue" ipl-image) (:pointer (:struct ipl-image)) (img (:pointer (:struct ipl-image)))) IPL-IMAGE CL-OPENCV> (dp img (cffi:null-pointer)) IMG CL-OPENCV> (ipl-image img) #.(SB-SYS:INT-SAP #X00000000) CL-OPENCV> (cffi:with-foreign-slots ((n-size) img (:struct ipl-image)) (format t "n-size = ~a~%" n-size)) every thing runs up until the with-foreign-slots then.. Unhandled memory fault at #x0. [Condition of type SB-SYS:MEMORY-FAULT-ERROR] ..i assume because im not accessing a ipl-image struct pointer but maybe i am.....any help is appreciated

1 0

CFFI-UFFI incompatibility: LOOKUP-FOREIGN-ENCODING function
by Victor 09 Oct '13

09 Oct '13

Hi all, there seems to be a minor incompatibility between the latest UFFI and CFFI-UFFI-COMPAT: the LOOKUP-FOREIGN-ENCODING function is missing in the compat package. It is easy to fix by copy-pasting this function implementation from the UFFI i18n.lisp sources (see the attached patch). Could you please include it into the next CFFI release? Thanks, Victor

2 3

accessing defcstruct members as in c
by Joeish W 09 Oct '13

09 Oct '13

Here is the opencv code i'm trying to convert to lisp int size[] = { 5, 5, 5 }; CvMatND* b = cvCreateMatND(3, size, CV_32F); cvSetZero(b); int a=0; for (int x = 0; x < b->dim[0].size; x++) { for (int y = 0; y < b->dim[1].size; y++) { for (int z = 0; z < b->dim[2].size; z++) { a++; cvSet3D(b, x,y,z, cvScalar(a)); } } } in the code above it creates a 3 dimensional matrix and adds data to it in the for loop in the loop the code accesses the sizes of each dimension of the 3d matrix with dim[0].size dim[1].size and dim[2].size I'm trying to do the same in lisp....I created wrappers for the structs and the c function below and tried everything i could from nested with-foreign-slots to access the members of dim to mem-reffing and mem-areffing the out put of dims....the most i got was a plist for dim (STEP 100 SIZE 5) when i accessed the cv-mat-nd-dim struct with with-foreign-slots inside a with-foreign-slots for MATRIX i set with this (defparameter matrix (create-mat-nd 3 '(5 5 5 ) +32fc1+)) but it has only 1 item in it, in c you can access an infinite number because its an nd matrix (cffi:defcunion cv-mat-nd-data (ptr :pointer) (fl :pointer) (db :pointer) (i :pointer) (s :pointer)) (cffi:defcstruct cv-mat-nd-dim (size :int) (step :int)) ;; ;(cffi:foreign-type-size '(:struct cv-mat-nd)) = todo - doesn't work cv-mat-nd = 40 opencv's = 288 (cffi:defcstruct cv-mat-nd (type :int) (dims :int) (refcount :pointer) (hdr-refcount :int) (data (:union cv-mat-nd-data)) (dim (:pointer (:struct cv-mat-nd-dim)))) ;; CvMatND* cvCreateMatND(int dims, const int* sizes, int type) (cffi:defcfun ("cvCreateMatND" %create-mat-nd) (:pointer (:struct cv-mat-nd)) "Creates the header and allocates the data for a multi-dimensional dense array." (dims :int) (sizes :pointer) (type :int)) (defun create-mat-nd (dims sizes type) "Return a specific element of single-channel nD array." (%create-mat-nd dims (cffi:foreign-alloc :int :initial-contents sizes) type))

2 1

[cff-devel] ….
by Marco Antoniotti 09 Oct '13

09 Oct '13

Hi apologies for the not-so-hidden-sarcasm. Subject says it all. As we know, the CLNET mail server is not Mailman, but could it be possible to customize the subject line in the "proper way"? There are tons of "old men tricks" out there that depend on certain Subject formatting conventions. cffi-devel is one of the best and more active fora in the CL community and I enjoy reading it… as long as it is nicely advertised in my mailbox :) All the best -- Marco Antoniotti

5 7

Need help accessing a nested struct member?
by Joeish W 07 Oct '13

07 Oct '13

I do apoligize if i added to much code on this....it just seems difficult to explain without showing all the code involve. pls let me know if this isnt worded right to community guidelines and i'll edit it....pls be precise so i know what to change.. here is how the struct CvSeq is defined #define CV_TREE_NODE_FIELDS(node_type) \ int flags; /* Miscellaneous flags. */ \ int header_size; /* Size of sequence header. */ \ struct node_type* h_prev; /* Previous sequence. */ \ struct node_type* h_next; /* Next sequence. */ \ struct node_type* v_prev; /* 2nd previous sequence. */ \ struct node_type* v_next /* 2nd next sequence. */ /* Read/Write sequence. Elements can be dynamically inserted to or deleted from the sequence. */ #define CV_SEQUENCE_FIELDS() \ CV_TREE_NODE_FIELDS(CvSeq); \ int total; /* Total number of elements. */ \ int elem_size; /* Size of sequence element in bytes. */ \ schar* block_max; /* Maximal bound of the last block. */ \ schar* ptr; /* Current write pointer. */ \ int delta_elems; /* Grow seq this many at a time. */ \ CvMemStorage* storage; /* Where the seq is stored. */ \ CvSeqBlock* free_blocks; /* Free blocks list. */ \ CvSeqBlock* first; /* Pointer to the first sequence block. */ typedef struct CvSeq { CV_SEQUENCE_FIELDS() } CvSeq; and here is how i ended up wrapping it. ;; (cffi:foreign-type-size '(:struct cv-seq)) = 96 (cffi:defcstruct cv-seq (flags :int) (header-size :int) (h-prev :pointer) (h-next :pointer) (v-prev :pointer) (v-next :pointer) (total :int) (elem-size :int) (block-max :pointer) (ptr :pointer) (delta-elems :int) (storage :pointer) (free-blocks :pointer) (first :pointer)) I was curious what to do with the h_next h_prev and v_prev and v_next, they seem to be recursive and they are not working or i am not using them right normally when a struct contains a member like CvMemStorage* storage; I wrap it like this (:pointer (:struct cv-mem-storage)) and it works but h_next i/e seems to point back to itself this is the way the h_next struct member works in c. in the below code while contours is not null it iterates though a while loop and through every iteration it sets the variable contours to the next pointer stored in h_next which is set by the cvFindContours function. the cvFindContours fubction in c adds a pointer to the h_next member of the CvSeq struct for every item in the picture it finds...pls see below link for more details and example picture (trying 2 keep this short) ... the code i got the below snippet from is the first program on this page.....http://opencv-srf.blogspot.com/2011/09/object-detection-tracking-u… (i broke it down so it would be easier to understand) int main() { IplImage* img = cvLoadImage("/home/w/quicklisp/dists/quicklisp/software/cl-opencv-master/images/FindingContours.png"); //converting the original image into grayscale IplImage* imgGrayScale = cvCreateImage(cvGetSize(img), 8, 1); CvMemStorage *storage = cvCreateMemStorage(0); //storage area for all contours CvSeq* contours= cvCreateSeq(CV_SEQ_ELTYPE_POINT, sizeof(CvSeq), sizeof(CvPoint), storage); //finding all contours in the image cvFindContours(imgGrayScale, storage, &contours, sizeof(CvContour), CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE, cvPoint(0,0)); //iterating through each contour while(contours) {cout << "contours = " << endl << " " << contours << endl << endl; //obtain a sequence of points of contour, pointed by the variable 'contour' contours = contours->h_next; } cout << "contours end = " << endl << " " << contours << endl << endl; return 0; } when i convert to lisp(below ...i didnt add while loop because h-next is null), i use nested with-foreign-slots to access the h-next member for debugging. it is a null pointer where in the c code above the h_next member is full of data...the function does work though....it works as good as it does in c (let* ((img (load-image "/home/w/quicklisp/dists/quicklisp/software/cl-opencv-master/images/FindingContours.png" 1)) (img-size (get-size img)) (img-grayscale (create-image img-size +ipl-depth-8u+ 1)) (storage (create-mem-storage 0)) ( contours (create-seq +seq-eltype-point+ (cffi:foreign-type-size '(:struct cv-seq)) (cffi:foreign-type-size '(:struct cv-point)) storage))) (find-contours img-grayscale storage contours (cffi:foreign-type-size '(:struct cv-contour)) +retr-list+ +chain-approx-simple+ (make-cv-point :x 0 :y 0)) (cffi:with-foreign-slots ((h-next) contours (:struct cv-seq)) (cffi:with-foreign-slots ((h-next) h-next (:struct cv-seq)) h-next) )) just outputs a null-pointer>> #.(SB-SYS:INT-SAP #X00000000) any help on this would be appreciated?

1 0

Fwd: Could use help wrapping opencv function?
by Attila Lendvai 07 Oct '13

07 Oct '13

[this time to the list also] > CV_INLINE CvPoint cvPoint( int x, int y ) > { > CvPoint p; > > p.x = x; > p.y = y; > > return p; > } it's been a while since i was fooling around with C... but 'p' is a local variable on the stack, and if you return its address, then it will point into nowhere when the C function's stack frame is unwound. for that code you should receive a scary warning from any sane C compiler. and a bit of meta re your emails... read this: http://www.catb.org/esr/faqs/smart-questions.html -- • attila lendvai • PGP: 963F 5D5F 45C7 DFCD 0A39 -- “Most people think they need a ruler. Perhaps we should give them a fake one that doesn't actually do anything, and then they won't think about it. It is sort of like giving an infant a pacifier.” — Perry Metzger

2 1

Could use help wrapping opencv function?
by Joeish W 05 Oct '13

05 Oct '13

the function I'm trying to wrap is here CV_INLINE CvPoint cvPoint( int x, int y ) { CvPoint p; p.x = x; p.y = y; return p; } and here is the related struct typedef struct CvPoint { int x; int y; } CvPoint; I wrap it like this like I normally do ; this is how swig wrapped the defcstruct (cffi:defcstruct cv-point (x :int) (y :int)) ;; CvPoint cvPoint(int x, int y) (cffi:defcfun ("cvPoint" pointy) (:struct cv-point) "constructs CvPoint structure." (x :int) (y :int)) the wrapper i made runs at the repl but when i call the function i get error CL-OPENCV> (point 7 7) The value NIL is not of type SB-SYS:SYSTEM-AREA-POINTER. [Condition of type TYPE-ERROR] Backtrace: 0: (CFFI::CALL #.(SB-SYS:INT-SAP #X7FFFE0000E10) NIL #.(SB-SYS:INT-SAP #X7FFFE5427FD0) #.(SB-SYS:INT-SAP #X7FFFE5427FD8)) Locals: SB-DEBUG::ARG-0 = #.(SB-SYS:INT-SAP #X7FFFE0000E10) SB-DEBUG::ARG-1 = NIL SB-DEBUG::ARG-2 = #.(SB-SYS:INT-SAP #X7FFFE5427FD0) SB-DEBUG::ARG-3 = #.(SB-SYS:INT-SAP #X7FFFE5427FD8) in the backtrace it appears to be linking 4 parameters and i think its because of this CV_INLINE CvPoint cvPoint( int x, int y ) { CvPoint p; p.x = x; p.y = y; return p; } because their are 4 items in the CV_INLINE I was hoping someone could help me get by this error message

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