/* * uncompress.c * * (C) Copyright 1999 Linus Torvalds * * cramfs interfaces to the uncompression library. There's really just * three entrypoints: * * - cramfs_uncompress_init() - called to initialize the thing. * - cramfs_uncompress_exit() - tell me when you're done * - cramfs_uncompress_block() - uncompress a block. * * NOTE NOTE NOTE! The uncompression is entirely single-threaded. We * only have one stream, and we'll initialize it only once even if it * then is used by multiple filesystems. */ #include <linux/kernel.h> #include <linux/errno.h> #include <linux/vmalloc.h> #include <linux/zlib.h> #include "internal.h" static z_stream stream; static int initialized; /* Returns length of decompressed data. */ int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen) { int err; stream.next_in = src; stream.avail_in = srclen; stream.next_out = dst; stream.avail_out = dstlen; err = zlib_inflateReset(&stream); if (err != Z_OK) { printk("zlib_inflateReset error %d\n", err); zlib_inflateEnd(&stream); zlib_inflateInit(&stream); } err = zlib_inflate(&stream, Z_FINISH); if (err != Z_STREAM_END) goto err; return stream.total_out; err: printk("Error %d while decompressing!\n", err); printk("%p(%d)->%p(%d)\n", src, srclen, dst, dstlen); return -EIO; } int cramfs_uncompress_init(void) { if (!initialized++) { stream.workspace = vmalloc(zlib_inflate_workspacesize()); if ( !stream.workspace ) { initialized = 0; return -ENOMEM; } stream.next_in = NULL; stream.avail_in = 0; zlib_inflateInit(&stream); } return 0; } void cramfs_uncompress_exit(void) { if (!--initialized) { zlib_inflateEnd(&stream); vfree(stream.workspace); } }