Module:Check isxn

--[[

This code is derived from the ISXN validation code at Module:Citation/CS1. It allows validating ISBN, ISMN, and ISSN without invoking a citation template.

]]

local p = {}

--[[--< E R R _ M S G _ S U P L _ T >--

error message supplements for check_isbn; adapted from a similarly named table at Module:Citation/CS1/Configuration

]]

local err_msg_supl_t = { ['char'] = 'invalid character', ['check'] = 'checksum', ['form'] = 'invalid form', ['group'] = 'invalid group id', ['length'] = 'length', ['prefix'] = 'invalid prefix', }

--[[--< IS _ V A L I D _ I S X N >-

ISBN-10 and ISSN validator code calculates checksum across all isbn/issn digits including the check digit. ISBN-13 is checked in check_isbn. If the number is valid the result will be 0. Before calling this function, issbn/issn must be checked for length and stripped of dashes, spaces and other non-isxn characters.

]]

local function is_valid_isxn (isxn_str, len) local temp = 0; isxn_str = { isxn_str:byte(1, len) };	-- make a table of byte values '0' → 0x30 .. '9' → 0x39, 'X' → 0x58 len = len+1;							-- adjust to be a loop counter for i, v in ipairs( isxn_str ) do		-- loop through all of the bytes and calculate the checksum if v == string.byte( "X" ) then		-- if checkdigit is X (compares the byte value of 'X' which is 0x58) temp = temp + 10*( len - i );	-- it represents 10 decimal else temp = temp + tonumber( string.char(v) )*(len-i); end end return temp % 11 == 0;					-- returns true if calculation result is zero end

--[[--< IS _ V A L I D _ I S X N _ 1 3 >--

ISBN-13 and ISMN validator code calculates checksum across all 13 isbn/ismn digits including the check digit. If the number is valid, the result will be 0. Before calling this function, isbn-13/ismn must be checked for length and stripped of dashes, spaces and other non-isxn-13 characters.

]]

local function is_valid_isxn_13 (isxn_str) local temp=0; isxn_str = { isxn_str:byte(1, 13) };										-- make a table of byte values '0' → 0x30 .. '9' → 0x39 for i, v in ipairs( isxn_str ) do		temp = temp + (3 - 2*(i % 2)) * tonumber( string.char(v) );				-- multiply odd index digits by 1, even index digits by 3 and sum; includes check digit end return temp % 10 == 0;														-- sum modulo 10 is zero when isbn-13/ismn is correct end

--[[--< C H E C K _ I S B N >

Determines whether an ISBN string is valid. Implements an ISBN validity check for ISBN, , , and .

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local function check_isbn (isbn_str, frame) local function return_result (check, err_type)								-- local function to render the various error returns if not check then														-- false when there is an error local template = ((frame.args.template_name and '' ~= frame.args.template_name) and frame.args.template_name) or nil;	-- get template name if not template then return ' calling template requires template_name parameter '; end

local out_t = {' '};		-- open the error message span table.insert (out_t, ' Parameter error in : ');								-- close wikilink; close 'template' markup table.insert (out_t, err_type);										-- type of isbn error table.insert (out_t, ' ')										-- close the error message span if 0 == mw.title.getCurrentTitle.namespace then					-- categorize only when this template is used in mainspace local category = table.concat ({''}); table.insert (out_t, category); end return table.concat (out_t);										-- make a big string and done end return '';																	-- no error, return an empty string end

if nil ~= isbn_str:match ('[^%s-0-9X]') then return return_result (false, err_msg_supl_t.char);						-- fail if isbn_str contains anything but digits, hyphens, or the uppercase X	end

local id = isbn_str:gsub ('[%s-]', '');										-- remove hyphens and whitespace

local len = id:len; if len ~= 10 and len ~= 13 then return return_result (false, err_msg_supl_t.length);					-- fail if incorrect length end

if len == 10 then if id:match ('^%d*X?$') == nil then										-- fail if isbn_str has 'X' anywhere but last position return return_result (false, err_msg_supl_t.form); end if id:find ('^63[01]') then												-- 630xxxxxxx and 631xxxxxxx are (apparently) not valid isbn group ids but are used by amazon as numeric identifiers (asin) return return_result (false, err_msg_supl_t.group);					-- fail if isbn-10 begins with 630/1 end return return_result (is_valid_isxn (id, 10), err_msg_supl_t.check);	-- pass if isbn-10 is numerically valid (checksum) else if id:match ('^%d+$') == nil then return return_result (false, err_msg_supl_t.char);					-- fail if ISBN-13 is not all digits end if id:match ('^97[89]%d*$') == nil then return return_result (false, err_msg_supl_t.prefix);				-- fail when ISBN-13 does not begin with 978 or 979 end if id:match ('^9790') then return return_result (false, err_msg_supl_t.group);					-- group identifier '0' is reserved to ISMN end return return_result (is_valid_isxn_13 (id), err_msg_supl_t.check);		-- pass if isbn-10 is numerically valid (checksum) end end

--[[--< C H E C K _ I S M N >

Determines whether an ISMN string is valid. Similar to isbn-13, ismn is 13 digits begining 979-0-... and uses the same check digit calculations. See http://www.ismn-international.org/download/Web_ISMN_Users_Manual_2008-6.pdf section 2, pages 9–12.

]]

local function check_ismn (id, error_string) local text; local valid_ismn = true;

id=id:gsub( "[%s-–]", "" );													-- strip spaces, hyphens, and endashes from the ismn

if 13 ~= id:len or id:match( "^9790%d*$" ) == nil then					-- ismn must be 13 digits and begin 9790 valid_ismn = false; else valid_ismn=is_valid_isxn_13 (id);										-- validate ismn end

return valid_ismn and '' or error_string end

--[[--< I S S N >--

Validate and format an issn. This code fixes the case where an editor has included an ISSN in the citation but has separated the two groups of four digits with a space. When that condition occurred, the resulting link looked like this:

|issn=0819 4327 gives: 4327 0819 4327 -- can't have spaces in an external link This code now prevents that by inserting a hyphen at the issn midpoint. It also validates the issn for length and makes sure that the checkdigit agrees with the calculated value. Incorrect length (8 digits), characters other than 0-9 and X, or checkdigit / calculated value mismatch will all cause a check issn error message.

]]

local function check_issn(id, error_string) local issn_copy = id;		-- save a copy of unadulterated issn; use this version for display if issn does not validate local text; local valid_issn = true;

if not id:match ('^%d%d%d%d%-%d%d%d[%dX]$') then return error_string; end id=id:gsub( "[%s-–]", "" );									-- strip spaces, hyphens, and endashes from the issn

if 8 ~= id:len or nil == id:match( "^%d*X?$" ) then		-- validate the issn: 8 digits long, containing only 0-9 or X in the last position valid_issn=false;										-- wrong length or improper character else valid_issn=is_valid_isxn(id, 8);						-- validate issn end

return valid_issn and '' or error_string end

--< E N T R Y  P O I N T S >--====

function p.check_isbn(frame) return check_isbn(frame.args[1] or frame:getParent.args[1], frame) end

function p.check_ismn(frame) return check_ismn(frame.args[1] or frame:getParent.args[1], frame.args['error'] or frame:getParent.args['error'] or 'error') end

function p.check_issn(frame) return check_issn(frame.args[1] or frame:getParent.args[1], frame.args['error'] or frame:getParent.args['error'] or 'error') end

return p