1 /* 2 * uncompress.c 3 * 4 * (C) Copyright 1999 Linus Torvalds 5 * 6 * cramfs interfaces to the uncompression library. There's really just 7 * three entrypoints: 8 * 9 * - cramfs_uncompress_init() - called to initialize the thing. 10 * - cramfs_uncompress_exit() - tell me when you're done 11 * - cramfs_uncompress_block() - uncompress a block. 12 * 13 * NOTE NOTE NOTE! The uncompression is entirely single-threaded. We 14 * only have one stream, and we'll initialize it only once even if it 15 * then is used by multiple filesystems. 16 */ 17 18 #include <linux/kernel.h> 19 #include <linux/errno.h> 20 #include <linux/vmalloc.h> 21 #include <linux/zlib.h> 22 #include <linux/cramfs_fs.h> 23 24 static z_stream stream; 25 static int initialized; 26 27 /* Returns length of decompressed data. */ 28 int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen) 29 { 30 int err; 31 32 stream.next_in = src; 33 stream.avail_in = srclen; 34 35 stream.next_out = dst; 36 stream.avail_out = dstlen; 37 38 err = zlib_inflateReset(&stream); 39 if (err != Z_OK) { 40 printk("zlib_inflateReset error %d\n", err); 41 zlib_inflateEnd(&stream); 42 zlib_inflateInit(&stream); 43 } 44 45 err = zlib_inflate(&stream, Z_FINISH); 46 if (err != Z_STREAM_END) 47 goto err; 48 return stream.total_out; 49 50 err: 51 printk("Error %d while decompressing!\n", err); 52 printk("%p(%d)->%p(%d)\n", src, srclen, dst, dstlen); 53 return -EIO; 54 } 55 56 int cramfs_uncompress_init(void) 57 { 58 if (!initialized++) { 59 stream.workspace = vmalloc(zlib_inflate_workspacesize()); 60 if ( !stream.workspace ) { 61 initialized = 0; 62 return -ENOMEM; 63 } 64 stream.next_in = NULL; 65 stream.avail_in = 0; 66 zlib_inflateInit(&stream); 67 } 68 return 0; 69 } 70 71 void cramfs_uncompress_exit(void) 72 { 73 if (!--initialized) { 74 zlib_inflateEnd(&stream); 75 vfree(stream.workspace); 76 } 77 } 78