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 23 static z_stream stream; 24 static int initialized; 25 26 /* Returns length of decompressed data. */ 27 int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen) 28 { 29 int err; 30 31 stream.next_in = src; 32 stream.avail_in = srclen; 33 34 stream.next_out = dst; 35 stream.avail_out = dstlen; 36 37 err = zlib_inflateReset(&stream); 38 if (err != Z_OK) { 39 printk("zlib_inflateReset error %d\n", err); 40 zlib_inflateEnd(&stream); 41 zlib_inflateInit(&stream); 42 } 43 44 err = zlib_inflate(&stream, Z_FINISH); 45 if (err != Z_STREAM_END) 46 goto err; 47 return stream.total_out; 48 49 err: 50 printk("Error %d while decompressing!\n", err); 51 printk("%p(%d)->%p(%d)\n", src, srclen, dst, dstlen); 52 return 0; 53 } 54 55 int cramfs_uncompress_init(void) 56 { 57 if (!initialized++) { 58 stream.workspace = vmalloc(zlib_inflate_workspacesize()); 59 if ( !stream.workspace ) { 60 initialized = 0; 61 return -ENOMEM; 62 } 63 stream.next_in = NULL; 64 stream.avail_in = 0; 65 zlib_inflateInit(&stream); 66 } 67 return 0; 68 } 69 70 int cramfs_uncompress_exit(void) 71 { 72 if (!--initialized) { 73 zlib_inflateEnd(&stream); 74 vfree(stream.workspace); 75 } 76 return 0; 77 } 78