From: Sergey Poznyakoff Date: Mon, 1 Dec 2003 21:18:30 +0000 (+0000) Subject: Initial implementation of GNU/pax sparse file format. X-Git-Url: https://git.dogcows.com/gitweb?a=commitdiff_plain;h=374ce58aa070510949652e6cbfb0a584b78b9fbc;p=chaz%2Ftar Initial implementation of GNU/pax sparse file format. --- diff --git a/src/sparse.c b/src/sparse.c index 39be72d..670cf4f 100644 --- a/src/sparse.c +++ b/src/sparse.c @@ -216,6 +216,7 @@ sparse_scan_file (struct tar_sparse_file *file) static struct tar_sparse_optab oldgnu_optab; static struct tar_sparse_optab star_optab; +static struct tar_sparse_optab pax_optab; static bool sparse_select_optab (struct tar_sparse_file *file) @@ -232,8 +233,8 @@ sparse_select_optab (struct tar_sparse_file *file) break; case POSIX_FORMAT: - /* FIXME: Add method */ - return false; + file->optab = &pax_optab; + break; case STAR_FORMAT: file->optab = &star_optab; @@ -713,3 +714,59 @@ static struct tar_sparse_optab star_optab = { NULL, /* No dump region function */ sparse_extract_region, }; + + +/* GNU PAX sparse file format. The sparse file map is stored in + x header: + + GNU.sparse.size Real size of the stored file + GNU.sparse.numblocks Number of blocks in the sparse map + repeat numblocks time + GNU.sparse.offset Offset of the next data block + GNU.sparse.numbytes Size of the next data block + end repeat +*/ + +static bool +pax_dump_header (struct tar_sparse_file *file) +{ + off_t block_ordinal = current_block_ordinal (); + union block *blk; + size_t i; + + /* Store the real file size */ + xheader_store ("GNU.sparse.size", file->stat_info, NULL); + xheader_store ("GNU.sparse.numblocks", file->stat_info, NULL); + for (i = 0; i < file->stat_info->sparse_map_avail; i++) + { + xheader_store ("GNU.sparse.offset", file->stat_info, &i); + xheader_store ("GNU.sparse.numbytes", file->stat_info, &i); + } + + blk = start_header (file->stat_info); + /* Store the effective (shrunken) file size */ + OFF_TO_CHARS (file->stat_info->archive_file_size, blk->header.size); + finish_header (file->stat_info, blk, block_ordinal); + return true; +} + +static bool +pax_decode_header (struct tar_sparse_file *file) +{ + /* Restore actual size */ + size_t s = file->stat_info->archive_file_size; + file->stat_info->archive_file_size = file->stat_info->stat.st_size; + file->stat_info->stat.st_size = s; + return true; +} + +static struct tar_sparse_optab pax_optab = { + NULL, /* No init function */ + NULL, /* No done function */ + pax_dump_header, + pax_decode_header, + NULL, /* No scan_block function */ + sparse_dump_region, + sparse_extract_region, +}; +