/* * JFFS2 -- Journalling Flash File System, Version 2. * * Copyright © 2001-2007 Red Hat, Inc. * Copyright © 2004-2010 David Woodhouse * * Created by Arjan van de Ven * * For licensing information, see the file 'LICENCE' in this directory. * * * * Very simple lz77-ish encoder. * * Theory of operation: Both encoder and decoder have a list of "last * occurrences" for every possible source-value; after sending the * first source-byte, the second byte indicated the "run" length of * matches * * The algorithm is intended to only send "whole bytes", no bit-messing. * */ #include #include #include #include #include #include "compr.h" /* _compress returns the compressed size, -1 if bigger */ static int jffs2_rtime_compress(unsigned char *data_in, unsigned char *cpage_out, uint32_t *sourcelen, uint32_t *dstlen) { unsigned short positions[256]; int outpos = 0; int pos=0; memset(positions,0,sizeof(positions)); while (pos < (*sourcelen) && outpos <= (*dstlen)-2) { int backpos, runlen=0; unsigned char value; value = data_in[pos]; cpage_out[outpos++] = data_in[pos++]; backpos = positions[value]; positions[value]=pos; while ((backpos < pos) && (pos < (*sourcelen)) && (data_in[pos]==data_in[backpos++]) && (runlen<255)) { pos++; runlen++; } cpage_out[outpos++] = runlen; } if (outpos >= pos) { /* We failed */ return -1; } /* Tell the caller how much we managed to compress, and how much space it took */ *sourcelen = pos; *dstlen = outpos; return 0; } static int jffs2_rtime_decompress(unsigned char *data_in, unsigned char *cpage_out, uint32_t srclen, uint32_t destlen) { unsigned short positions[256]; int outpos = 0; int pos=0; memset(positions,0,sizeof(positions)); while (outpos= outpos) { while(repeat) { cpage_out[outpos++] = cpage_out[backoffs++]; repeat--; } } else { memcpy(&cpage_out[outpos],&cpage_out[backoffs],repeat); outpos+=repeat; } } } return 0; } static struct jffs2_compressor jffs2_rtime_comp = { .priority = JFFS2_RTIME_PRIORITY, .name = "rtime", .compr = JFFS2_COMPR_RTIME, .compress = &jffs2_rtime_compress, .decompress = &jffs2_rtime_decompress, #ifdef JFFS2_RTIME_DISABLED .disabled = 1, #else .disabled = 0, #endif }; int jffs2_rtime_init(void) { return jffs2_register_compressor(&jffs2_rtime_comp); } void jffs2_rtime_exit(void) { jffs2_unregister_compressor(&jffs2_rtime_comp); } s='path'>path: root/tools/lib/subcmd/subcmd-config.c

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