message_state.h File Reference

private message structures More...

#include "node.h"

Include dependency graph for message_state.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Classes
struct	message_state_t
	holds callbacks and associated variables More...

Typedefs
typedef struct message_t	message_t
typedef struct message_state_t	message_state_t
	holds callbacks and associated variables

Functions
message_state_t *	message_state_new ()
	initializes an message_state_t structure
void	message_state_free (message_state_t *ms)
	frees an messate_state_t structure

Detailed Description

private message structures

This file describes a structure that is used to keep the state of the parser while parsing a hl7 file. It is primarely used for registering callback functions.

If you want to analyze parts of the document while the parser is still running or you are using it in a multi-threaded environment, then there is the possibility to add callback functions. The following callback hooks are available:

• void (*cb_progress)(message_t *message, size_t total, size_t current);
• void (*cb_start)(message_t *message)
• void (*cb_end)(message_t *message, size_t max, size_t current, int exit_code)
• void (*cb_segment)(message_t *message, size_t num, char name[3])

Also, you can controll how often the cb_progress() callback is fired, default is every 1% of progress (does not fire on files smaller than 100 bytes).

You may register callbacks as follows:

#include <stdio.h>
#include "decode.h" // or lib7.h which is the combined header for lib7.so

static void cb_progress(message_t *message, size_t total, size_t current) {
    printf("Parsing: %02d%%\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", (current*100/total)+1);
    fflush(stdout);
}

static void cb_end(message_t *message, size_t max, size_t current, int exit_code) {
    // clear progress line in terminal
    printf("\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b");
    if (exit_code != 0) {
        printf("Parser failed with exit code: %02d\n", exit_code);
    } 
}

int main() {
    char *filename "some_file.hl7";
    FILE *fd = fopen(filename, "rb");
    message_t root = create_message_t(NULL);

    // example of a progress callback, it will show on very large files
    size_t fd_pos = ftell(fd);
    fseek(fd, 0, SEEK_END);
    size_t file_size = ftell(fd);
    fseek(fd, fd_pos, SEEK_SET); // reset

    // register callback progress
    root->state->cb_progress = cb_progress;
    // call progress every 5%
    root->state->progress_every = file_size / 20;
    // add a callback at the end of paring, which will clear the progress line
    root->state->cb_end = cb_end;


    // start the parser
    int ret = hl7_decode(fd, &root);

    fclose(fd); // no need for fd anymore, all data in memory
    if (ret != 0) {
      // whoopsie
      free_message_t(root);
    }

    // do something with the data in root

    // cleanup
    free_message_t(root);
}