Hi all, Who could help me and post this information about Compress() function in Online Dictionary: http://docs.runrev.com/Function/compress
You corrections and additions are welcome! :-) Thanks in advance! Alejandro ------------------------------------------------------------------------------------------------ The compress function returns a gzip compressed string of binary data structured in the following format: 1) A 10-byte header, containing: A magic number, composed by two bytes: 1F 8B (Hexadecimal) or 31 139 (ASCII Numbers of both characters) A version number (always 08), that specify compression compression method used in the file. In this case Rev write the byte 08. This single character correspond to DEFLATE compression. Additional information like timestamp, optional extra headers, (as the original file name) are not included and in their place Rev writes six null bytes: 00 00 00 00 00 00 Last char of 10 byte header correspond to the type of file system on which compression took place. Rev writes the single byte 03, that correspond to Unix. For example: First Ten characters of a gzipped binary string (Hexadecimal) 1F 8B 08 00 00 00 00 00 00 03 (ASCII Characters numbers) 31 139 08 00 00 00 00 00 00 03 2- a body, containing DEFLATE-compressed data 3- Last 8 characters contains a CRC-32 checksum and length of the original uncompressed data: For example: Last 8 characters of gzipped binary string (Hexadecimal) 8C 72 E5 F5 1A 34 02 00 Last four bytes: 1A 34 02 00 = 0002341A = 144,410 represent the file length (142 k) Bytes 8C 72 E5 F5 correspond to CRC-32 of this file: F5E5728C If you need to use only the binary string of DEFLATE-compressed data, without the gzip header and footer, use a script like this: put compress(myData) into myGzippedData put char 11 to -9 of myGzippedData into myDeflateData or the short version: put char 11 to -9 of compress(myData) into myDeflateData This binary string of DEFLATE-compressed data is useful if you need to write a Flate Encoded stream in a PDF file like this: put "xÚ" & char 11 to -9 of myGzippedData into myFlateEncodedStream _______________________________________________ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution