readblock

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The readblock function reads a block of data (segment or record) from the input file and places it into the argument of a string variable. The readblock and writeblock functions are used in conjunction with each other to pass a block of data from the input file to the output file without compliance checking or testing for proper EDI syntax. Together, these functions provide a more efficient alternative of using wildcard segments, which are typically implemented in build and break maps.

Readblock, writeblock, and unreadblock are supported only for positional and EDI files, and are not supported for XML files.

Note: The readblock function returns a zero (0) if it does not read any data. However, if readblock returns a zero value, you should not assume the translator has reached the end of the file. If the data file has a number of new lines embedded in it, the readblock function returns a zero for each new line. If you want to know for certain when the end of the file is reached, use the eof function.

Syntax

Use this syntax:


readblock(string_variable);

Example

An example of this function follows:


while readblock(temp_buffer) do
begin
   if left(tem_buffer,3) = "IEA" then
       begin
            unreadblock();
             break;
        end
   writeblock(temp_buffer);
end
//Read record from input file and place in temp_buffer. Look for 
//"IEA" record tag. If found, reset file pointer to where it was
//before the "IEA" record was read. Write contents of temp_buffer to
//output file.

The readblock and writeblock functions are also used in conjunction with the Document Extraction service, to specify the beginning and end of each document in a batch of documents, so that each document can be extracted individually.

For more information about using the corollary Update standard rule to complete the document extraction, see Set an Update Standard Rule as Part of Document Extraction.

Example

An example of this function follows:


string[250] buffer;
string[3] match;
integer match_len;
integer eofInput;
 
// set these next two variables
match = "SUM";  // the tag of the last record in the document
match_len = 3;  // the length of the tag
 
// read the block we're on and write it
readblock(buffer);
writeblock(buffer);
 
eofInput = eof(0); // check if we are at the end of the input document
 
// keep reading and writing records until the end of the document
while !eofInput do
begin
  if readblock(buffer) then
  begin
    writeblock(buffer);
    if left(buffer, match_len) = match then 
//write the document, not new lines and continues to process documents
       begin
         break;
       end
  end
  eofInput = eof(0); 
//set the value of eofInput to 0 because the end of file has been reached
end