Re: [xml] about xmlReadMemory()

[nicolas bats <sl1200mk2 gmail com>]

thank you so much Nick,

it's crystal clear now :)

++

nicolas

Le mer. 3 mars 2021 à 11:12, Nick Wellnhofer <wellnhofer aevum de> a écrit :

On 03/03/2021 09:30, nicolas bats wrote:
> Hi Nick,
> I've experimented with xmlReadIO and it's cool.
> this message just to check I'm doing right:
> -I register an xmlInputReadCallback of type: size_t myCallback(void* context,
> char* buffer, int length)
> -I do my stuff in the callback and if data I use exceed the length of the
> buffer, I realloc it.
> Is this schema good?
> Do I need to set size_t as the return type of myCallback?

No, the read callback is supposed to fill the buffer with up to 'length'
bytes. Try something like:

typedef struct {
     const char *ptr;
     size_t remaining;
} myContext;

static int
myReadCallback(void *vcontext, char *buffer, int len) {
     myContext *context = vcontext;

     if (context->remaining < len)
         len = context->remaining;
     memcpy(buffer, context->ptr, len);
     context->ptr += len;
     context->remaining -= len;

     return len;
}

xmlDocPtr
myReadMemory(const char *buffer, size_t size, const char *URL,
              const char *encoding, int options) {
     myContext context;

     context.ptr = buffer;
     context.remaining = size;

     return xmlReadIO(myReadCallback, NULL, &context, URL, encoding, options);
}