158 lines
7.5 KiB
C++
158 lines
7.5 KiB
C++
// This may look like C code, but it is really -*- C++ -*-
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// ------------------------------------------------------------------
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// The Goldware Library
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// Copyright (C) 1990-1999 Odinn Sorensen
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// ------------------------------------------------------------------
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Library General Public
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// License as published by the Free Software Foundation; either
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// version 2 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Library General Public License for more details.
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//
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// You should have received a copy of the GNU Library General Public
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// License along with this program; if not, write to the Free
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// Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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// MA 02111-1307, USA
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// ------------------------------------------------------------------
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// $Id$
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// ------------------------------------------------------------------
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// CRC-16, CRC-32 and Hashing
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// ------------------------------------------------------------------
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#include <gcrcall.h>
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// ------------------------------------------------------------------
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// Quickie table for CRC-32 calculations
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//
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// Copyright (C) 1986 Gary S. Brown. You may use this table as
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// desired without restriction.
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//
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// First, the polynomial itself and its table of feedback terms. The
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// polynomial is
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//
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// X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0
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//
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// Note that we take it "backwards" and put the highest-order term in
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// the lowest-order bit. The X^32 term is "implied"; the LSB is the
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// X^31 term, etc. The X^0 term (usually shown as "+1") results in
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// the MSB being 1.
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//
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// Note that the usual hardware shift register implementation, which
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// is what we're using (we're merely optimizing it by doing eight-bit
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// chunks at a time) shifts bits into the lowest-order term. In our
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// implementation, that means shifting towards the right. Why do we
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// do it this way? Because the calculated CRC must be transmitted in
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// order from highest-order term to lowest-order term. UARTs transmit
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// characters in order from LSB to MSB. By storing the CRC this way,
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// we hand it to the UART in the order low-byte to high-byte; the
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// UART sends each low-bit to hight-bit; and the result is trans-
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// mission bit by bit from highest- to lowest-order term without re-
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// quiring any bit shuffling on our part. Reception works similarly.
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//
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// The feedback terms table consists of 256, 32-bit entries. Notes:
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//
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// 1. The table can be generated at runtime if desired; code to do
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// so is shown later [ED: Nope]. It might not be obvious, but the
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// feedback terms simply represent the results of eight shift/xor
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// operations for all combinations of data and CRC register
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// values.
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//
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// 2. The CRC accumulation logic is the same for all CRC polyno-
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// mials, be they sixteen or thirty-two bits wide. You simply
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// choose the appropriate table. Alternatively, because the table
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// can be generated at runtime, you can start by generating the
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// table for the polynomial in question and use exactly the same
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// "updcrc", if your application needn't simultaneously handle
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// two CRC polynomials. (Note, however, that XMODEM is strange.)
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//
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// 3. For 16-bit CRCs, the table entries need be only 16 bits wide;
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// of course, 32-bit entries work OK if the high 16 bits are
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// zero.
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//
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// 4. The values must be right-shifted by eight bits by the "updcrc"
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// logic; the shift must be unsigned (bring in zeroes). On some
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// hardware you could probably optimize the shift in assembler by
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// using byte-swap instructions. [ED: But we let the compiler
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// worry about the details in this implementation...]
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//
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// 5. The CRC-32 polynomial value is: 0xEDB88320.
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//
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// ------------------------------------------------------------------
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dword __crc32_table[256] = {
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0x00000000L, 0x77073096L, 0xEE0E612CL, 0x990951BAL,
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0x076DC419L, 0x706AF48FL, 0xE963A535L, 0x9E6495A3L,
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0x0EDB8832L, 0x79DCB8A4L, 0xE0D5E91EL, 0x97D2D988L,
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0x09B64C2BL, 0x7EB17CBDL, 0xE7B82D07L, 0x90BF1D91L,
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0x1DB71064L, 0x6AB020F2L, 0xF3B97148L, 0x84BE41DEL,
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0x1ADAD47DL, 0x6DDDE4EBL, 0xF4D4B551L, 0x83D385C7L,
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0x136C9856L, 0x646BA8C0L, 0xFD62F97AL, 0x8A65C9ECL,
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0x14015C4FL, 0x63066CD9L, 0xFA0F3D63L, 0x8D080DF5L,
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0x3B6E20C8L, 0x4C69105EL, 0xD56041E4L, 0xA2677172L,
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0x3C03E4D1L, 0x4B04D447L, 0xD20D85FDL, 0xA50AB56BL,
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0x35B5A8FAL, 0x42B2986CL, 0xDBBBC9D6L, 0xACBCF940L,
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0x32D86CE3L, 0x45DF5C75L, 0xDCD60DCFL, 0xABD13D59L,
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0x26D930ACL, 0x51DE003AL, 0xC8D75180L, 0xBFD06116L,
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0x21B4F4B5L, 0x56B3C423L, 0xCFBA9599L, 0xB8BDA50FL,
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0x2802B89EL, 0x5F058808L, 0xC60CD9B2L, 0xB10BE924L,
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0x2F6F7C87L, 0x58684C11L, 0xC1611DABL, 0xB6662D3DL,
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0x76DC4190L, 0x01DB7106L, 0x98D220BCL, 0xEFD5102AL,
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0x71B18589L, 0x06B6B51FL, 0x9FBFE4A5L, 0xE8B8D433L,
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0x7807C9A2L, 0x0F00F934L, 0x9609A88EL, 0xE10E9818L,
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0x7F6A0DBBL, 0x086D3D2DL, 0x91646C97L, 0xE6635C01L,
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0x6B6B51F4L, 0x1C6C6162L, 0x856530D8L, 0xF262004EL,
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0x6C0695EDL, 0x1B01A57BL, 0x8208F4C1L, 0xF50FC457L,
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0x65B0D9C6L, 0x12B7E950L, 0x8BBEB8EAL, 0xFCB9887CL,
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0x62DD1DDFL, 0x15DA2D49L, 0x8CD37CF3L, 0xFBD44C65L,
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0x4DB26158L, 0x3AB551CEL, 0xA3BC0074L, 0xD4BB30E2L,
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0x4ADFA541L, 0x3DD895D7L, 0xA4D1C46DL, 0xD3D6F4FBL,
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0x4369E96AL, 0x346ED9FCL, 0xAD678846L, 0xDA60B8D0L,
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0x44042D73L, 0x33031DE5L, 0xAA0A4C5FL, 0xDD0D7CC9L,
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0x5005713CL, 0x270241AAL, 0xBE0B1010L, 0xC90C2086L,
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0x5768B525L, 0x206F85B3L, 0xB966D409L, 0xCE61E49FL,
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0x5EDEF90EL, 0x29D9C998L, 0xB0D09822L, 0xC7D7A8B4L,
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0x59B33D17L, 0x2EB40D81L, 0xB7BD5C3BL, 0xC0BA6CADL,
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0xEDB88320L, 0x9ABFB3B6L, 0x03B6E20CL, 0x74B1D29AL,
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0xEAD54739L, 0x9DD277AFL, 0x04DB2615L, 0x73DC1683L,
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0xE3630B12L, 0x94643B84L, 0x0D6D6A3EL, 0x7A6A5AA8L,
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0xE40ECF0BL, 0x9309FF9DL, 0x0A00AE27L, 0x7D079EB1L,
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0xF00F9344L, 0x8708A3D2L, 0x1E01F268L, 0x6906C2FEL,
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0xF762575DL, 0x806567CBL, 0x196C3671L, 0x6E6B06E7L,
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0xFED41B76L, 0x89D32BE0L, 0x10DA7A5AL, 0x67DD4ACCL,
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0xF9B9DF6FL, 0x8EBEEFF9L, 0x17B7BE43L, 0x60B08ED5L,
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0xD6D6A3E8L, 0xA1D1937EL, 0x38D8C2C4L, 0x4FDFF252L,
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0xD1BB67F1L, 0xA6BC5767L, 0x3FB506DDL, 0x48B2364BL,
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0xD80D2BDAL, 0xAF0A1B4CL, 0x36034AF6L, 0x41047A60L,
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0xDF60EFC3L, 0xA867DF55L, 0x316E8EEFL, 0x4669BE79L,
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0xCB61B38CL, 0xBC66831AL, 0x256FD2A0L, 0x5268E236L,
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0xCC0C7795L, 0xBB0B4703L, 0x220216B9L, 0x5505262FL,
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0xC5BA3BBEL, 0xB2BD0B28L, 0x2BB45A92L, 0x5CB36A04L,
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0xC2D7FFA7L, 0xB5D0CF31L, 0x2CD99E8BL, 0x5BDEAE1DL,
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0x9B64C2B0L, 0xEC63F226L, 0x756AA39CL, 0x026D930AL,
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0x9C0906A9L, 0xEB0E363FL, 0x72076785L, 0x05005713L,
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0x95BF4A82L, 0xE2B87A14L, 0x7BB12BAEL, 0x0CB61B38L,
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0x92D28E9BL, 0xE5D5BE0DL, 0x7CDCEFB7L, 0x0BDBDF21L,
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0x86D3D2D4L, 0xF1D4E242L, 0x68DDB3F8L, 0x1FDA836EL,
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0x81BE16CDL, 0xF6B9265BL, 0x6FB077E1L, 0x18B74777L,
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0x88085AE6L, 0xFF0F6A70L, 0x66063BCAL, 0x11010B5CL,
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0x8F659EFFL, 0xF862AE69L, 0x616BFFD3L, 0x166CCF45L,
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0xA00AE278L, 0xD70DD2EEL, 0x4E048354L, 0x3903B3C2L,
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0xA7672661L, 0xD06016F7L, 0x4969474DL, 0x3E6E77DBL,
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0xAED16A4AL, 0xD9D65ADCL, 0x40DF0B66L, 0x37D83BF0L,
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0xA9BCAE53L, 0xDEBB9EC5L, 0x47B2CF7FL, 0x30B5FFE9L,
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0xBDBDF21CL, 0xCABAC28AL, 0x53B39330L, 0x24B4A3A6L,
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0xBAD03605L, 0xCDD70693L, 0x54DE5729L, 0x23D967BFL,
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0xB3667A2EL, 0xC4614AB8L, 0x5D681B02L, 0x2A6F2B94L,
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0xB40BBE37L, 0xC30C8EA1L, 0x5A05DF1BL, 0x2D02EF8DL
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};
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// ------------------------------------------------------------------
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