Jerasure
1.2
A Library in C/C++ Facilitating Erasure Coding for Storage Applications
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00001 /* Galois.h 00002 * James S. Plank 00003 00004 Jerasure - A C/C++ Library for a Variety of Reed-Solomon and RAID-6 Erasure Coding Techniques 00005 00006 Revision 1.2A 00007 May 24, 2011 00008 00009 James S. Plank 00010 Department of Electrical Engineering and Computer Science 00011 University of Tennessee 00012 Knoxville, TN 37996 00013 plank@cs.utk.edu 00014 00015 Copyright (c) 2011, James S. Plank 00016 All rights reserved. 00017 00018 Redistribution and use in source and binary forms, with or without 00019 modification, are permitted provided that the following conditions 00020 are met: 00021 00022 - Redistributions of source code must retain the above copyright 00023 notice, this list of conditions and the following disclaimer. 00024 00025 - Redistributions in binary form must reproduce the above copyright 00026 notice, this list of conditions and the following disclaimer in 00027 the documentation and/or other materials provided with the 00028 distribution. 00029 00030 - Neither the name of the University of Tennessee nor the names of its 00031 contributors may be used to endorse or promote products derived 00032 from this software without specific prior written permission. 00033 00034 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 00035 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00036 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 00037 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 00038 HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 00039 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 00040 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 00041 OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 00042 AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 00043 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY 00044 WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 00045 POSSIBILITY OF SUCH DAMAGE. 00046 00047 */ 00048 00049 #ifndef _GALOIS_H 00050 #define _GALOIS_H 00051 00052 #include <stdio.h> 00053 #include <stdlib.h> 00054 00055 extern int galois_single_multiply(int a, int b, int w); 00056 extern int galois_single_divide(int a, int b, int w); 00057 extern int galois_log(int value, int w); 00058 extern int galois_ilog(int value, int w); 00059 00060 extern int galois_create_log_tables(int w); /* Returns 0 on success, -1 on failure */ 00061 extern int galois_logtable_multiply(int x, int y, int w); 00062 extern int galois_logtable_divide(int x, int y, int w); 00063 00064 extern int galois_create_mult_tables(int w); /* Returns 0 on success, -1 on failure */ 00065 extern int galois_multtable_multiply(int x, int y, int w); 00066 extern int galois_multtable_divide(int x, int y, int w); 00067 00068 extern int galois_shift_multiply(int x, int y, int w); 00069 extern int galois_shift_divide(int x, int y, int w); 00070 00071 extern int galois_create_split_w8_tables(); 00072 extern int galois_split_w8_multiply(int x, int y); 00073 00074 extern int galois_inverse(int x, int w); 00075 extern int galois_shift_inverse(int y, int w); 00076 00077 extern int *galois_get_mult_table(int w); 00078 extern int *galois_get_div_table(int w); 00079 extern int *galois_get_log_table(int w); 00080 extern int *galois_get_ilog_table(int w); 00081 00082 void galois_region_xor( char *r1, /* Region 1 */ 00083 char *r2, /* Region 2 */ 00084 char *r3, /* Sum region (r3 = r1 ^ r2) -- can be r1 or r2 */ 00085 int nbytes); /* Number of bytes in region */ 00086 00087 /* These multiply regions in w=8, w=16 and w=32. They are much faster 00088 than calling galois_single_multiply. The regions must be long word aligned. */ 00089 00090 void galois_w08_region_multiply(char *region, /* Region to multiply */ 00091 int multby, /* Number to multiply by */ 00092 int nbytes, /* Number of bytes in region */ 00093 char *r2, /* If r2 != NULL, products go here. 00094 Otherwise region is overwritten */ 00095 int add); /* If (r2 != NULL && add) the produce is XOR'd with r2 */ 00096 00097 void galois_w16_region_multiply(char *region, /* Region to multiply */ 00098 int multby, /* Number to multiply by */ 00099 int nbytes, /* Number of bytes in region */ 00100 char *r2, /* If r2 != NULL, products go here. 00101 Otherwise region is overwritten */ 00102 int add); /* If (r2 != NULL && add) the produce is XOR'd with r2 */ 00103 00104 void galois_w32_region_multiply(char *region, /* Region to multiply */ 00105 int multby, /* Number to multiply by */ 00106 int nbytes, /* Number of bytes in region */ 00107 char *r2, /* If r2 != NULL, products go here. 00108 Otherwise region is overwritten */ 00109 int add); /* If (r2 != NULL && add) the produce is XOR'd with r2 */ 00110 00111 #endif