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metalink_parse_update

NAME

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

SYNOPSIS

#include <metalink/metalink_parser.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 privide 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() take the pointer of metalink_t(3) pointer and allocate 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_parser.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)