/* * JFFS2 LZO Compression Interface. * * Copyright (C) 2007 Nokia Corporation. All rights reserved. * * Author: Richard Purdie <rpurdie@openedhand.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * version 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA * */ #include <stdint.h> #include <stdio.h> #include <string.h> #include <asm/types.h> #include <linux/jffs2.h> #include <lzo/lzo1x.h> #include "compr.h" extern int page_size; static void *lzo_mem; static void *lzo_compress_buf; /* * Note about LZO compression. * * We want to use the _999_ compression routine which gives better compression * rates at the expense of time. Decompression time is unaffected. We might as * well use the standard lzo library routines for this but they will overflow * the destination buffer since they don't check the destination size. * * We therefore compress to a temporary buffer and copy if it will fit. * */ static int jffs2_lzo_cmpr(unsigned char *data_in, unsigned char *cpage_out, uint32_t *sourcelen, uint32_t *dstlen) { lzo_uint compress_size; int ret; ret = lzo1x_999_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem); if (ret != LZO_E_OK) return -1; if (compress_size > *dstlen) return -1; memcpy(cpage_out, lzo_compress_buf, compress_size); *dstlen = compress_size; return 0; } static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out, uint32_t srclen, uint32_t destlen) { int ret; lzo_uint dl; dl = destlen; ret = lzo1x_decompress_safe(data_in,srclen,cpage_out,&dl,NULL); if (ret != LZO_E_OK || dl != destlen) return -1; return 0; } static struct jffs2_compressor jffs2_lzo_comp = { .priority = JFFS2_LZO_PRIORITY, .name = "lzo", .compr = JFFS2_COMPR_LZO, .compress = &jffs2_lzo_cmpr, .decompress = &jffs2_lzo_decompress, .disabled = 1, }; int jffs2_lzo_init(void) { int ret; lzo_mem = malloc(LZO1X_999_MEM_COMPRESS); if (!lzo_mem) return -1; /* Worse case LZO compression size from their FAQ */ lzo_compress_buf = malloc(page_size + (page_size / 16) + 64 + 3); if (!lzo_compress_buf) { free(lzo_mem); return -1; } ret = jffs2_register_compressor(&jffs2_lzo_comp); if (ret < 0) { free(lzo_compress_buf); free(lzo_mem); } return ret; } void jffs2_lzo_exit(void) { jffs2_unregister_compressor(&jffs2_lzo_comp); free(lzo_compress_buf); free(lzo_mem); }