NAME¶

metalink_parse_update, metalink_parse_final, metalink_parser_context_new, metalink_parser_context_delete - Parse Metalink file and create metalink_t object.

SYNOPSIS¶

#include <metalink/metalink.h>

metalink_error_t metalink_parse_update(metalink_parser_context_t *ctx, const char *buf, size_t len);
metalink_error_t metalink_parse_final(metalink_parser_context_t *ctx, const char *buf, size_t len, metalink_t **res);

metalink_parser_context_t* metalink_parser_context_new();
void metalink_parser_context_delete(metalink_parser_context_t *ctx);

DESCRIPTION¶

These functions provide a push interface for parsing Metalink XML files.

Before calling metalink_parse_update() and metalink_parse_final(), metalink_parse_context_t has to be created by metalink_parser_context_new().

In each call of metalink_parse_update(), len bytes of buf are processed. At the last piece of data, call metalink_parse_final() to get metalink_t(3) structure as a result. Giving 0 as len is permitted.

metalink_parse_final() calls metalink_parser_context_delete() internally to deallocate the memory for passed metalink_parser_context_t. Therefore you don't have to call metlaink_parser_context_delete() if you call metalink_parse_final(). Otherwise call metalink_parser_context_delete() to free the allocated resource.

You don't have to allocate memory for metalink_t(3) structure. metalink_parse_final() takes the pointer of metalink_t(3) pointer and allocates memory for that pointer.

The caller must free the memory allocated for metalink_t(3) structure using metalink_delete(3) if it is no longer used.

RETURN VALUE¶

metalink_parse_update(), metalink_parse_final() return 0 for success. When error occurred, non-zero value error code is returned. If error occurred, metalink_parse_final() does not allocate memory for metalink_t. The error codes are described in metalink_error.h.

In case of success, metalink_parser_context_new() allocates memory for metalink_parser_context_t() and returns the pointer to it. In case of failure, metalink_parser_context_new() returns NULL.

metalink_parser_context_delete() returns no value.

EXAMPLE¶

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <metalink/metalink.h>
int main(int argc, char** argv)
{


  metalink_error_t r;


  metalink_t* metalink;


  metalink_file_t* file;


  metalink_checksum_t** checksums;


  metalink_parser_context_t* context;


  int fd;


  char buf[BUFSIZ];


  ssize_t length;


  context = metalink_parser_context_new();


  if(context == NULL) {


    fprintf(stderr,


            "ERROR: failed to create metalink_parser_context_t\n");


    exit(EXIT_FAILURE);


  }


  fd = open("sample.metalink", O_RDONLY);


  if(fd == -1) {


    fprintf(stderr, "ERROR: open():%s\n", strerror(errno));


    exit(EXIT_FAILURE);


  }


  while((length = TEMP_FAILURE_RETRY(read(fd, buf, sizeof(buf)))) != 0){


    r = metalink_parse_update(context, buf, length);


    if(r != 0) {


      fprintf(stderr, "ERROR: code=%d\n", r);


      metalink_parser_context_delete(context);


      exit(EXIT_FAILURE);


    }


  }


  if(length == -1) {


    fprintf(stderr, "ERROR: read():%s\n", strerror(errno));


    metalink_parser_context_delete(context);


    exit(EXIT_FAILURE);    


  }


  


  r = metalink_parse_final(context, NULL, 0, &metalink);


  if(r != 0) {


    fprintf(stderr, "ERROR: code=%d\n", r);


    exit(EXIT_FAILURE);


  }


  TEMP_FAILURE_RETRY(close(fd));


 


  file = metalink->files[0];


  printf("name: %s\n", file->name);


  printf("size: %lld\n", file->size);


  printf("os  : %s\n", file->os);


  if(file->checksums) {


    checksums = file->checksums;


    while(*checksums) {


      printf("hash: %s %s\n", (*checksums)->type, (*checksums)->hash);


      ++checksums;


    }


  }


  if(file->chunk_checksum) {


    size_t count = 0;


    metalink_piece_hash_t** piece_hashes;


    printf("chunk checksum: size=%d, type=%s\n",


           file->chunk_checksum->length,


           file->chunk_checksum->type);


    printf("first 5 piece hashes...\n");


    piece_hashes = file->chunk_checksum->piece_hashes;


    while(*piece_hashes && count < 5) {


      printf("piece=%d, hash=%s\n", (*piece_hashes)->piece,


                                     (*piece_hashes)->hash);


      ++piece_hashes;


      ++count;


    }


    printf("...\n");


  }


  if(file->resources) {


    size_t count = 0;


    metalink_resource_t** resources;


    printf("first 5 resources...\n");


    resources = file->resources;


    while(*resources && count < 5) {


      printf("type=%s, location=%s, preference=%d, url=%s\n",


             (*resources)->type, (*resources)->location,


             (*resources)->preference, (*resources)->url);


      ++resources;


      ++count;


    }


    printf("...\n");


  }


  /* delete metalink_t */


  metalink_delete(metalink);


  return EXIT_SUCCESS;
}

SEE ALSO¶

metalink_delete(3), metalink_parse_file(3), metalink_t(3)