/*
* url.c
*
* doi_to_url()
* Handle outputing DOI as a URL (Endnote and RIS formats)
* 1) Append https://doi.org as necessary
* 2) Check for overlap with pre-existing URL for the DOI
*
* is_doi()
* Check for DOI buried in another field.
*
* Copyright (c) Chris Putnam 2008-2018
*
* Source code released under the GPL version 2
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "bibutils.h"
#include "url.h"
static void
construct_url( char *prefix, str *id, str *id_url, char sep )
{
if ( !strncasecmp( str_cstr( id ), "http:", 5 ) )
str_strcpy( id_url, id );
else {
str_strcpyc( id_url, prefix );
if ( sep!='\0' ) {
if ( id->data[0]!=sep ) str_addchar( id_url, sep );
}
str_strcat( id_url, id );
}
}
static int
url_exists( fields *f, char *urltag, str *doi_url )
{
int i, n;
if ( urltag ) {
n = fields_num( f );
for ( i=0; i<n; ++i ) {
if ( strcmp( fields_tag( f, i, FIELDS_CHRP ), urltag ) ) continue;
if ( strcmp( fields_value( f, i, FIELDS_CHRP ), str_cstr( doi_url ) ) ) continue;
return 1;
}
}
return 0;
}
static void
xxx_to_url( fields *f, int n, char *http_prefix, char *urltag, str *xxx_url, char sep )
{
str_empty( xxx_url );
construct_url( http_prefix, fields_value( f, n, FIELDS_STRP ), xxx_url, sep );
if ( url_exists( f, urltag, xxx_url ) )
str_empty( xxx_url );
}
void
doi_to_url( fields *f, int n, char *urltag, str *url )
{
xxx_to_url( f, n, "https://doi.org", urltag, url, '/' );
}
void
jstor_to_url( fields *f, int n, char *urltag, str *url )
{
xxx_to_url( f, n, "http://www.jstor.org/stable", urltag, url, '/' );
}
void
pmid_to_url( fields *f, int n, char *urltag, str *url )
{
xxx_to_url( f, n, "http://www.ncbi.nlm.nih.gov/pubmed", urltag, url, '/' );
}
void
pmc_to_url( fields *f, int n, char *urltag, str *url )
{
xxx_to_url( f, n, "http://www.ncbi.nlm.nih.gov/pmc/articles", urltag, url, '/' );
}
void
arxiv_to_url( fields *f, int n, char *urltag, str *url )
{
xxx_to_url( f, n, "http://arxiv.org/abs", urltag, url, '/' );
}
void
mrnumber_to_url( fields *f, int n, char *urltag, str *url )
{
xxx_to_url( f, n, "http://www.ams.org/mathscinet-getitem?mr=", urltag, url, '\0' );
}
/* Rules for the pattern:
* '#' = number
* isalpha() = match precisely (matchcase==1) or match regardless of case
* (matchcase==0)
* all others must match precisely
*/
static int
string_pattern( char *s, char *pattern, int matchcase )
{
int patlen, match, i;
patlen = strlen( pattern );
if ( strlen( s ) < patlen ) return 0; /* too short */
for ( i=0; i<patlen; ++i ) {
match = 0;
if ( pattern[i]=='#' ) {
if ( isdigit( (unsigned char)s[i] ) ) match = 1;
} else if ( !matchcase && isalpha( (unsigned char)pattern[i] ) ) {
if ( tolower((unsigned char)pattern[i])==tolower((unsigned char)s[i])) match = 1;
} else {
if ( pattern[i] == s[i] ) match = 1;
}
if ( !match ) return 0;
}
return 1;
}
/* science direct is now doing "M3 - doi: DOI: 10.xxxx/xxxxx" */
int
is_doi( char *s )
{
if ( string_pattern( s, "##.####/", 0 ) ) return 0;
if ( string_pattern( s, "doi:##.####/", 0 ) ) return 4;
if ( string_pattern( s, "doi: ##.####/", 0 ) ) return 5;
if ( string_pattern( s, "doi: DOI: ##.####/", 0 ) ) return 10;
return -1;
}
/* determine if string has the header of a Universal Resource Identifier
*
* returns -1, if not true
* returns offset that skips over the URI scheme, if true
*/
int
is_uri_remote_scheme( char *p )
{
char *scheme[] = { "http:", "https:", "ftp:", "git:", "gopher:" };
int schemelen[] = { 5, 6, 4, 4, 7 };
int i, nschemes = sizeof( scheme ) / sizeof( scheme[0] );
for ( i=0; i<nschemes; ++i ) {
if ( !strncasecmp( p, scheme[i], schemelen[i] ) ) return schemelen[i];
}
return -1;
}
int
is_reference_database( char *p )
{
char *scheme[] = { "arXiv:", "pubmed:", "medline:", "isi:" };
int schemelen[] = { 6, 7, 8, 4 };
int i, nschemes = sizeof( scheme ) / sizeof( scheme[0] );
for ( i=0; i<nschemes; ++i ) {
if ( !strncasecmp( p, scheme[i], schemelen[i] ) ) return schemelen[i];
}
return -1;
}
/* many fields have been abused to embed URLs, DOIs, etc. */
int
is_embedded_link( char *s )
{
if ( is_uri_remote_scheme( s ) != -1 ) return 1;
if ( is_reference_database( s ) != -1 ) return 1;
if ( is_doi( s ) !=-1 ) return 1;
return 0;
}
typedef struct url_t {
char *tag;
char *prefix;
int offset;
} url_t;
static url_t prefixes[] = {
/* 00000000001111111112222222222333333333344444444445 */
/* 12345678901234567890123456789012345678901234567890 */
{ "ARXIV", "http://arxiv.org/abs/", 21 },
{ "DOI", "https://doi.org/", 16 },
{ "JSTOR", "http://www.jstor.org/stable/", 28 },
{ "MRNUMBER", "http://www.ams.org/mathscinet-getitem?mr=", 41 },
{ "PMID", "http://www.ncbi.nlm.nih.gov/pubmed/", 35 },
{ "PMC", "http://www.ncbi.nlm.nih.gov/pmc/articles/", 41 },
{ "ISIREFNUM", "isi:", 4 },
};
static int nprefixes = sizeof( prefixes ) / sizeof( prefixes[0] );
/* do not add, but recognize */
static url_t extraprefixes[] = {
/* 00000000001111111112222222222333333333344444444445 */
/* 12345678901234567890123456789012345678901234567890 */
{ "ARXIV", "arXiv:", 6 },
{ "DOI", "http://dx.doi.org/", 18 },
{ "JSTOR", "jstor:", 6 },
{ "PMID", "pmid:", 5 },
{ "PMID", "pubmed:", 7 },
{ "PMC", "pmc:", 4 },
{ "URL", "\\urllink", 8 },
{ "URL", "\\url", 4 },
};
static int nextraprefixes = sizeof( extraprefixes ) / sizeof( extraprefixes[0] );
static int
find_prefix( char *s, url_t *p, int np )
{
int i;
for ( i=0; i<np; ++i )
if ( !strncmp( p[i].prefix, s, p[i].offset ) ) return i;
return -1;
}
int
urls_split_and_add( char *value_in, fields *out, int lvl_out )
{
int n, fstatus, status = BIBL_OK;
char *tag = "URL";
int offset = 0;
n = find_prefix( value_in, prefixes, nprefixes );
if ( n!=-1 ) {
tag = prefixes[n].tag;
offset = prefixes[n].offset;
} else {
n = find_prefix( value_in, extraprefixes, nextraprefixes );
if ( n!=-1 ) {
tag = extraprefixes[n].tag;
offset = extraprefixes[n].offset;
}
}
fstatus = fields_add( out, tag, &(value_in[offset]), lvl_out );
if ( fstatus!=FIELDS_OK ) status = BIBL_ERR_MEMERR;
return status;
}
/* urls_add_type()
*
* Append urls of a specific type with a specific prefix (which can be empty).
* We don't allow duplications here.
*
*/
static int
urls_merge_and_add_type( fields *out, char *tag_out, int lvl_out, char *prefix, vplist *values )
{
int fstatus, status = BIBL_OK;
vplist_index i;
str url;
str_init( &url );
for ( i=0; i<values->n; ++i ) {
str_strcpyc( &url, prefix );
str_strcatc( &url, ( char * ) vplist_get( values, i ) );
fstatus = fields_add( out, tag_out, str_cstr( &url ), lvl_out );
if ( fstatus!=FIELDS_OK ) {
status = BIBL_ERR_MEMERR;
goto out;
}
}
out:
str_free( &url );
return status;
}
/*
* urls_merge_and_add()
*
* Append urls of types controlled by the list type and automatically append appropriate
* prefixes. If no prefix is found for the entry, don't add one (e.g. "URL" entries).
*
* Control of the types to be added by list type is necessary as some reference formats
* like bibtex ought to do special things with DOI, ARXIV, MRNUMBER, and the like.
*/
int
urls_merge_and_add( fields *in, int lvl_in, fields *out, char *tag_out, int lvl_out, slist *types )
{
int i, j, status = BIBL_OK;
char *tag, *prefix, *empty="";
vplist a;
vplist_init( &a );
for ( i=0; i<types->n; ++i ) {
tag = slist_cstr( types, i );
/* ...look for data of requested type; if not found skip */
vplist_empty( &a );
fields_findv_each( in, lvl_in, FIELDS_CHRP, &a, tag );
if ( a.n==0 ) continue;
/* ...find the prefix (if present) */
prefix = empty;
for ( j=0; j<nprefixes; ++j ) {
if ( !strcmp( prefixes[j].tag, tag ) ) {
prefix = prefixes[j].prefix;
break; /* take the first prefix in the list */
}
}
/* ...append all data of this type */
status = urls_merge_and_add_type( out, tag_out, lvl_out, prefix, &a );
if ( status!=BIBL_OK ) goto out;
}
out:
vplist_free( &a );
return status;
}