FreeBSD/Linux Kernel Cross Reference
sys/fs/cramfs/uncompress.c

     /*
      * 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>
    
    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 0;
    }
    
    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;
    }
    
    int cramfs_uncompress_exit(void)
    {
            if (!--initialized) {
                    zlib_inflateEnd(&stream);
                    vfree(stream.workspace);
            }
            return 0;
    }

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