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METALINK_PARSE_UPDATE(3)       libmetalink Manual	METALINK_PARSE_UPDATE(3)

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(),  met-
     alink_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 met-
     alink_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.  met-
     alink_parse_final() takes the pointer of metalink_t(3)  pointer  and  allo-
     cates 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 met-
     alink_parser_context_t() and returns the pointer to it.  In case  of  fail-
     ure, 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)

libmetalink 0.1.0		    July 2012		METALINK_PARSE_UPDATE(3)

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