From maintainers-request at octave dot org Mon Jan 10 09:47:26 2005 Subject: Matlab compressed file format From: David Bateman To: maintainers at octave dot org Date: Mon, 10 Jan 2005 16:47:42 +0100 Over the weekend I took a quick look at the Matlab V7 file format and in particular the miCompressed data-type. It seems to be a pretty easy format in that each data-element is compressed seperately, with an 8-byte header with the miCompressed flag and a 4-byte length of the compressed block. So the easiest way to treat this is to use zlib's uncompress function on an mmaped version of the file, creating a decompressed version of the data-element, and then using the exist code to parse that. However, one thing I don't like about this is that there is a second copy of the data in memory as the uncompressed data.. Do someone with a bit more experience with zlib know if there is a way to attach an open istream to a gzFile descriptor and then use the functions gzread and gzwrite directly, so that I don't need a second copy in memory of the data? Regards David -- David Bateman David dot Bateman at motorola dot com Motorola CRM +33 1 69 35 48 04 (Ph) Parc Les Algorithmes, Commune de St Aubin +33 1 69 35 77 01 (Fax) 91193 Gif-Sur-Yvette FRANCE The information contained in this communication has been classified as: [x] General Business Information [ ] Motorola Internal Use Only [ ] Motorola Confidential Proprietary