// Copyright (c) 2009 - Mozy, Inc.

#include "hash.h"

#include <boost/bind.hpp>

#include "buffer.h"
#include "mordor/assert.h"
#include "mordor/endian.h"

namespace Mordor {

size_t
HashStream::read(Buffer &buffer, size_t length)
{
    Buffer temp;
    size_t result = parent()->read(temp, length);
    temp.visit(boost::bind(&HashStream::updateHash, this, _1, _2), result);
    buffer.copyIn(temp);
    return result;
}

size_t
HashStream::read(void *buffer, size_t length)
{
    size_t result = parent()->read(buffer, length);
    updateHash(buffer, result);
    return result;
}

size_t
HashStream::write(const Buffer &buffer, size_t length)
{
    size_t result = parent()->write(buffer, length);
    buffer.visit(boost::bind(&HashStream::updateHash, this, _1, _2), result);
    return result;
}

size_t
HashStream::write(const void *buffer, size_t length)
{
    size_t result = parent()->write(buffer, length);
    updateHash(buffer, result);
    return result;
}

long long
HashStream::seek(long long offset, Anchor anchor)
{
    MORDOR_NOTREACHED();
}

std::string
HashStream::hash() const
{
    std::string result;
    result.resize(hashSize());
    hash(&result[0], result.size());
    return result;
}

// Code adapted from http://www.ietf.org/rfc/rfc3309.txt

static unsigned int ieeeTable[] =
{
    0x00000000u, 0x77073096u, 0xee0e612cu, 0x990951bau, 0x076dc419u,
    0x706af48fu, 0xe963a535u, 0x9e6495a3u, 0x0edb8832u, 0x79dcb8a4u,
    0xe0d5e91eu, 0x97d2d988u, 0x09b64c2bu, 0x7eb17cbdu, 0xe7b82d07u,
    0x90bf1d91u, 0x1db71064u, 0x6ab020f2u, 0xf3b97148u, 0x84be41deu,
    0x1adad47du, 0x6ddde4ebu, 0xf4d4b551u, 0x83d385c7u, 0x136c9856u,
    0x646ba8c0u, 0xfd62f97au, 0x8a65c9ecu, 0x14015c4fu, 0x63066cd9u,
    0xfa0f3d63u, 0x8d080df5u, 0x3b6e20c8u, 0x4c69105eu, 0xd56041e4u,
    0xa2677172u, 0x3c03e4d1u, 0x4b04d447u, 0xd20d85fdu, 0xa50ab56bu,
    0x35b5a8fau, 0x42b2986cu, 0xdbbbc9d6u, 0xacbcf940u, 0x32d86ce3u,
    0x45df5c75u, 0xdcd60dcfu, 0xabd13d59u, 0x26d930acu, 0x51de003au,
    0xc8d75180u, 0xbfd06116u, 0x21b4f4b5u, 0x56b3c423u, 0xcfba9599u,
    0xb8bda50fu, 0x2802b89eu, 0x5f058808u, 0xc60cd9b2u, 0xb10be924u,
    0x2f6f7c87u, 0x58684c11u, 0xc1611dabu, 0xb6662d3du, 0x76dc4190u,
    0x01db7106u, 0x98d220bcu, 0xefd5102au, 0x71b18589u, 0x06b6b51fu,
    0x9fbfe4a5u, 0xe8b8d433u, 0x7807c9a2u, 0x0f00f934u, 0x9609a88eu,
    0xe10e9818u, 0x7f6a0dbbu, 0x086d3d2du, 0x91646c97u, 0xe6635c01u,
    0x6b6b51f4u, 0x1c6c6162u, 0x856530d8u, 0xf262004eu, 0x6c0695edu,
    0x1b01a57bu, 0x8208f4c1u, 0xf50fc457u, 0x65b0d9c6u, 0x12b7e950u,
    0x8bbeb8eau, 0xfcb9887cu, 0x62dd1ddfu, 0x15da2d49u, 0x8cd37cf3u,
    0xfbd44c65u, 0x4db26158u, 0x3ab551ceu, 0xa3bc0074u, 0xd4bb30e2u,
    0x4adfa541u, 0x3dd895d7u, 0xa4d1c46du, 0xd3d6f4fbu, 0x4369e96au,
    0x346ed9fcu, 0xad678846u, 0xda60b8d0u, 0x44042d73u, 0x33031de5u,
    0xaa0a4c5fu, 0xdd0d7cc9u, 0x5005713cu, 0x270241aau, 0xbe0b1010u,
    0xc90c2086u, 0x5768b525u, 0x206f85b3u, 0xb966d409u, 0xce61e49fu,
    0x5edef90eu, 0x29d9c998u, 0xb0d09822u, 0xc7d7a8b4u, 0x59b33d17u,
    0x2eb40d81u, 0xb7bd5c3bu, 0xc0ba6cadu, 0xedb88320u, 0x9abfb3b6u,
    0x03b6e20cu, 0x74b1d29au, 0xead54739u, 0x9dd277afu, 0x04db2615u,
    0x73dc1683u, 0xe3630b12u, 0x94643b84u, 0x0d6d6a3eu, 0x7a6a5aa8u,
    0xe40ecf0bu, 0x9309ff9du, 0x0a00ae27u, 0x7d079eb1u, 0xf00f9344u,
    0x8708a3d2u, 0x1e01f268u, 0x6906c2feu, 0xf762575du, 0x806567cbu,
    0x196c3671u, 0x6e6b06e7u, 0xfed41b76u, 0x89d32be0u, 0x10da7a5au,
    0x67dd4accu, 0xf9b9df6fu, 0x8ebeeff9u, 0x17b7be43u, 0x60b08ed5u,
    0xd6d6a3e8u, 0xa1d1937eu, 0x38d8c2c4u, 0x4fdff252u, 0xd1bb67f1u,
    0xa6bc5767u, 0x3fb506ddu, 0x48b2364bu, 0xd80d2bdau, 0xaf0a1b4cu,
    0x36034af6u, 0x41047a60u, 0xdf60efc3u, 0xa867df55u, 0x316e8eefu,
    0x4669be79u, 0xcb61b38cu, 0xbc66831au, 0x256fd2a0u, 0x5268e236u,
    0xcc0c7795u, 0xbb0b4703u, 0x220216b9u, 0x5505262fu, 0xc5ba3bbeu,
    0xb2bd0b28u, 0x2bb45a92u, 0x5cb36a04u, 0xc2d7ffa7u, 0xb5d0cf31u,
    0x2cd99e8bu, 0x5bdeae1du, 0x9b64c2b0u, 0xec63f226u, 0x756aa39cu,
    0x026d930au, 0x9c0906a9u, 0xeb0e363fu, 0x72076785u, 0x05005713u,
    0x95bf4a82u, 0xe2b87a14u, 0x7bb12baeu, 0x0cb61b38u, 0x92d28e9bu,
    0xe5d5be0du, 0x7cdcefb7u, 0x0bdbdf21u, 0x86d3d2d4u, 0xf1d4e242u,
    0x68ddb3f8u, 0x1fda836eu, 0x81be16cdu, 0xf6b9265bu, 0x6fb077e1u,
    0x18b74777u, 0x88085ae6u, 0xff0f6a70u, 0x66063bcau, 0x11010b5cu,
    0x8f659effu, 0xf862ae69u, 0x616bffd3u, 0x166ccf45u, 0xa00ae278u,
    0xd70dd2eeu, 0x4e048354u, 0x3903b3c2u, 0xa7672661u, 0xd06016f7u,
    0x4969474du, 0x3e6e77dbu, 0xaed16a4au, 0xd9d65adcu, 0x40df0b66u,
    0x37d83bf0u, 0xa9bcae53u, 0xdebb9ec5u, 0x47b2cf7fu, 0x30b5ffe9u,
    0xbdbdf21cu, 0xcabac28au, 0x53b39330u, 0x24b4a3a6u, 0xbad03605u,
    0xcdd70693u, 0x54de5729u, 0x23d967bfu, 0xb3667a2eu, 0xc4614ab8u,
    0x5d681b02u, 0x2a6f2b94u, 0xb40bbe37u, 0xc30c8ea1u, 0x5a05df1bu,
    0x2d02ef8du
};

static unsigned int castagnoliTable[] =
{
    0x00000000u, 0xf26b8303u, 0xe13b70f7u, 0x1350f3f4u, 0xc79a971fu,
    0x35f1141cu, 0x26a1e7e8u, 0xd4ca64ebu, 0x8ad958cfu, 0x78b2dbccu,
    0x6be22838u, 0x9989ab3bu, 0x4d43cfd0u, 0xbf284cd3u, 0xac78bf27u,
    0x5e133c24u, 0x105ec76fu, 0xe235446cu, 0xf165b798u, 0x030e349bu,
    0xd7c45070u, 0x25afd373u, 0x36ff2087u, 0xc494a384u, 0x9a879fa0u,
    0x68ec1ca3u, 0x7bbcef57u, 0x89d76c54u, 0x5d1d08bfu, 0xaf768bbcu,
    0xbc267848u, 0x4e4dfb4bu, 0x20bd8edeu, 0xd2d60dddu, 0xc186fe29u,
    0x33ed7d2au, 0xe72719c1u, 0x154c9ac2u, 0x061c6936u, 0xf477ea35u,
    0xaa64d611u, 0x580f5512u, 0x4b5fa6e6u, 0xb93425e5u, 0x6dfe410eu,
    0x9f95c20du, 0x8cc531f9u, 0x7eaeb2fau, 0x30e349b1u, 0xc288cab2u,
    0xd1d83946u, 0x23b3ba45u, 0xf779deaeu, 0x05125dadu, 0x1642ae59u,
    0xe4292d5au, 0xba3a117eu, 0x4851927du, 0x5b016189u, 0xa96ae28au,
    0x7da08661u, 0x8fcb0562u, 0x9c9bf696u, 0x6ef07595u, 0x417b1dbcu,
    0xb3109ebfu, 0xa0406d4bu, 0x522bee48u, 0x86e18aa3u, 0x748a09a0u,
    0x67dafa54u, 0x95b17957u, 0xcba24573u, 0x39c9c670u, 0x2a993584u,
    0xd8f2b687u, 0x0c38d26cu, 0xfe53516fu, 0xed03a29bu, 0x1f682198u,
    0x5125dad3u, 0xa34e59d0u, 0xb01eaa24u, 0x42752927u, 0x96bf4dccu,
    0x64d4cecfu, 0x77843d3bu, 0x85efbe38u, 0xdbfc821cu, 0x2997011fu,
    0x3ac7f2ebu, 0xc8ac71e8u, 0x1c661503u, 0xee0d9600u, 0xfd5d65f4u,
    0x0f36e6f7u, 0x61c69362u, 0x93ad1061u, 0x80fde395u, 0x72966096u,
    0xa65c047du, 0x5437877eu, 0x4767748au, 0xb50cf789u, 0xeb1fcbadu,
    0x197448aeu, 0x0a24bb5au, 0xf84f3859u, 0x2c855cb2u, 0xdeeedfb1u,
    0xcdbe2c45u, 0x3fd5af46u, 0x7198540du, 0x83f3d70eu, 0x90a324fau,
    0x62c8a7f9u, 0xb602c312u, 0x44694011u, 0x5739b3e5u, 0xa55230e6u,
    0xfb410cc2u, 0x092a8fc1u, 0x1a7a7c35u, 0xe811ff36u, 0x3cdb9bddu,
    0xceb018deu, 0xdde0eb2au, 0x2f8b6829u, 0x82f63b78u, 0x709db87bu,
    0x63cd4b8fu, 0x91a6c88cu, 0x456cac67u, 0xb7072f64u, 0xa457dc90u,
    0x563c5f93u, 0x082f63b7u, 0xfa44e0b4u, 0xe9141340u, 0x1b7f9043u,
    0xcfb5f4a8u, 0x3dde77abu, 0x2e8e845fu, 0xdce5075cu, 0x92a8fc17u,
    0x60c37f14u, 0x73938ce0u, 0x81f80fe3u, 0x55326b08u, 0xa759e80bu,
    0xb4091bffu, 0x466298fcu, 0x1871a4d8u, 0xea1a27dbu, 0xf94ad42fu,
    0x0b21572cu, 0xdfeb33c7u, 0x2d80b0c4u, 0x3ed04330u, 0xccbbc033u,
    0xa24bb5a6u, 0x502036a5u, 0x4370c551u, 0xb11b4652u, 0x65d122b9u,
    0x97baa1bau, 0x84ea524eu, 0x7681d14du, 0x2892ed69u, 0xdaf96e6au,
    0xc9a99d9eu, 0x3bc21e9du, 0xef087a76u, 0x1d63f975u, 0x0e330a81u,
    0xfc588982u, 0xb21572c9u, 0x407ef1cau, 0x532e023eu, 0xa145813du,
    0x758fe5d6u, 0x87e466d5u, 0x94b49521u, 0x66df1622u, 0x38cc2a06u,
    0xcaa7a905u, 0xd9f75af1u, 0x2b9cd9f2u, 0xff56bd19u, 0x0d3d3e1au,
    0x1e6dcdeeu, 0xec064eedu, 0xc38d26c4u, 0x31e6a5c7u, 0x22b65633u,
    0xd0ddd530u, 0x0417b1dbu, 0xf67c32d8u, 0xe52cc12cu, 0x1747422fu,
    0x49547e0bu, 0xbb3ffd08u, 0xa86f0efcu, 0x5a048dffu, 0x8ecee914u,
    0x7ca56a17u, 0x6ff599e3u, 0x9d9e1ae0u, 0xd3d3e1abu, 0x21b862a8u,
    0x32e8915cu, 0xc083125fu, 0x144976b4u, 0xe622f5b7u, 0xf5720643u,
    0x07198540u, 0x590ab964u, 0xab613a67u, 0xb831c993u, 0x4a5a4a90u,
    0x9e902e7bu, 0x6cfbad78u, 0x7fab5e8cu, 0x8dc0dd8fu, 0xe330a81au,
    0x115b2b19u, 0x020bd8edu, 0xf0605beeu, 0x24aa3f05u, 0xd6c1bc06u,
    0xc5914ff2u, 0x37faccf1u, 0x69e9f0d5u, 0x9b8273d6u, 0x88d28022u,
    0x7ab90321u, 0xae7367cau, 0x5c18e4c9u, 0x4f48173du, 0xbd23943eu,
    0xf36e6f75u, 0x0105ec76u, 0x12551f82u, 0xe03e9c81u, 0x34f4f86au,
    0xc69f7b69u, 0xd5cf889du, 0x27a40b9eu, 0x79b737bau, 0x8bdcb4b9u,
    0x988c474du, 0x6ae7c44eu, 0xbe2da0a5u, 0x4c4623a6u, 0x5f16d052u,
    0xad7d5351u
};

static unsigned int koopmanTable[] =
{
    0x00000000u, 0x9695c4cau, 0xfb4839c9u, 0x6dddfd03u, 0x20f3c3cfu,
    0xb6660705u, 0xdbbbfa06u, 0x4d2e3eccu, 0x41e7879eu, 0xd7724354u,
    0xbaafbe57u, 0x2c3a7a9du, 0x61144451u, 0xf781809bu, 0x9a5c7d98u,
    0x0cc9b952u, 0x83cf0f3cu, 0x155acbf6u, 0x788736f5u, 0xee12f23fu,
    0xa33cccf3u, 0x35a90839u, 0x5874f53au, 0xcee131f0u, 0xc22888a2u,
    0x54bd4c68u, 0x3960b16bu, 0xaff575a1u, 0xe2db4b6du, 0x744e8fa7u,
    0x199372a4u, 0x8f06b66eu, 0xd1fdae25u, 0x47686aefu, 0x2ab597ecu,
    0xbc205326u, 0xf10e6deau, 0x679ba920u, 0x0a465423u, 0x9cd390e9u,
    0x901a29bbu, 0x068fed71u, 0x6b521072u, 0xfdc7d4b8u, 0xb0e9ea74u,
    0x267c2ebeu, 0x4ba1d3bdu, 0xdd341777u, 0x5232a119u, 0xc4a765d3u,
    0xa97a98d0u, 0x3fef5c1au, 0x72c162d6u, 0xe454a61cu, 0x89895b1fu,
    0x1f1c9fd5u, 0x13d52687u, 0x8540e24du, 0xe89d1f4eu, 0x7e08db84u,
    0x3326e548u, 0xa5b32182u, 0xc86edc81u, 0x5efb184bu, 0x7598ec17u,
    0xe30d28ddu, 0x8ed0d5deu, 0x18451114u, 0x556b2fd8u, 0xc3feeb12u,
    0xae231611u, 0x38b6d2dbu, 0x347f6b89u, 0xa2eaaf43u, 0xcf375240u,
    0x59a2968au, 0x148ca846u, 0x82196c8cu, 0xefc4918fu, 0x79515545u,
    0xf657e32bu, 0x60c227e1u, 0x0d1fdae2u, 0x9b8a1e28u, 0xd6a420e4u,
    0x4031e42eu, 0x2dec192du, 0xbb79dde7u, 0xb7b064b5u, 0x2125a07fu,
    0x4cf85d7cu, 0xda6d99b6u, 0x9743a77au, 0x01d663b0u, 0x6c0b9eb3u,
    0xfa9e5a79u, 0xa4654232u, 0x32f086f8u, 0x5f2d7bfbu, 0xc9b8bf31u,
    0x849681fdu, 0x12034537u, 0x7fdeb834u, 0xe94b7cfeu, 0xe582c5acu,
    0x73170166u, 0x1ecafc65u, 0x885f38afu, 0xc5710663u, 0x53e4c2a9u,
    0x3e393faau, 0xa8acfb60u, 0x27aa4d0eu, 0xb13f89c4u, 0xdce274c7u,
    0x4a77b00du, 0x07598ec1u, 0x91cc4a0bu, 0xfc11b708u, 0x6a8473c2u,
    0x664dca90u, 0xf0d80e5au, 0x9d05f359u, 0x0b903793u, 0x46be095fu,
    0xd02bcd95u, 0xbdf63096u, 0x2b63f45cu, 0xeb31d82eu, 0x7da41ce4u,
    0x1079e1e7u, 0x86ec252du, 0xcbc21be1u, 0x5d57df2bu, 0x308a2228u,
    0xa61fe6e2u, 0xaad65fb0u, 0x3c439b7au, 0x519e6679u, 0xc70ba2b3u,
    0x8a259c7fu, 0x1cb058b5u, 0x716da5b6u, 0xe7f8617cu, 0x68fed712u,
    0xfe6b13d8u, 0x93b6eedbu, 0x05232a11u, 0x480d14ddu, 0xde98d017u,
    0xb3452d14u, 0x25d0e9deu, 0x2919508cu, 0xbf8c9446u, 0xd2516945u,
    0x44c4ad8fu, 0x09ea9343u, 0x9f7f5789u, 0xf2a2aa8au, 0x64376e40u,
    0x3acc760bu, 0xac59b2c1u, 0xc1844fc2u, 0x57118b08u, 0x1a3fb5c4u,
    0x8caa710eu, 0xe1778c0du, 0x77e248c7u, 0x7b2bf195u, 0xedbe355fu,
    0x8063c85cu, 0x16f60c96u, 0x5bd8325au, 0xcd4df690u, 0xa0900b93u,
    0x3605cf59u, 0xb9037937u, 0x2f96bdfdu, 0x424b40feu, 0xd4de8434u,
    0x99f0baf8u, 0x0f657e32u, 0x62b88331u, 0xf42d47fbu, 0xf8e4fea9u,
    0x6e713a63u, 0x03acc760u, 0x953903aau, 0xd8173d66u, 0x4e82f9acu,
    0x235f04afu, 0xb5cac065u, 0x9ea93439u, 0x083cf0f3u, 0x65e10df0u,
    0xf374c93au, 0xbe5af7f6u, 0x28cf333cu, 0x4512ce3fu, 0xd3870af5u,
    0xdf4eb3a7u, 0x49db776du, 0x24068a6eu, 0xb2934ea4u, 0xffbd7068u,
    0x6928b4a2u, 0x04f549a1u, 0x92608d6bu, 0x1d663b05u, 0x8bf3ffcfu,
    0xe62e02ccu, 0x70bbc606u, 0x3d95f8cau, 0xab003c00u, 0xc6ddc103u,
    0x504805c9u, 0x5c81bc9bu, 0xca147851u, 0xa7c98552u, 0x315c4198u,
    0x7c727f54u, 0xeae7bb9eu, 0x873a469du, 0x11af8257u, 0x4f549a1cu,
    0xd9c15ed6u, 0xb41ca3d5u, 0x2289671fu, 0x6fa759d3u, 0xf9329d19u,
    0x94ef601au, 0x027aa4d0u, 0x0eb31d82u, 0x9826d948u, 0xf5fb244bu,
    0x636ee081u, 0x2e40de4du, 0xb8d51a87u, 0xd508e784u, 0x439d234eu,
    0xcc9b9520u, 0x5a0e51eau, 0x37d3ace9u, 0xa1466823u, 0xec6856efu,
    0x7afd9225u, 0x17206f26u, 0x81b5abecu, 0x8d7c12beu, 0x1be9d674u,
    0x76342b77u, 0xe0a1efbdu, 0xad8fd171u, 0x3b1a15bbu, 0x56c7e8b8u,
    0xc0522c72u
};

static const unsigned int *selectPrecomputedTable(unsigned int polynomial,
    const std::vector<unsigned int> &myTable)
{
    switch (polynomial) {
        case CRC32Stream::IEEE:
            return ieeeTable;
        case CRC32Stream::CASTAGNOLI:
            return castagnoliTable;
        case CRC32Stream::KOOPMAN:
            return koopmanTable;
        default:
            return &myTable[0];
    }
}

static std::vector<unsigned int> precomputeTableSkip(unsigned int polynomial)
{
    std::vector<unsigned int> result;
    switch (polynomial) {
        case CRC32Stream::IEEE:
        case CRC32Stream::CASTAGNOLI:
        case CRC32Stream::KOOPMAN:
            return result;
        default:
            return CRC32Stream::precomputeTable(polynomial);
    }
}

CRC32Stream::CRC32Stream(Stream::ptr parent, unsigned int polynomial, bool own)
: HashStream(parent, own),
  m_crc(~0u),
  m_tableStorage(precomputeTableSkip(polynomial)),
  m_table(selectPrecomputedTable(polynomial, m_tableStorage))
{}

CRC32Stream::CRC32Stream(Stream::ptr parent,
    const unsigned int *precomputedTable, bool own)
: HashStream(parent, own),
  m_crc(~0u),
  m_table(precomputedTable)
{}

static unsigned int reflect(unsigned int b)
{
    unsigned int rw = 0;
    for (int i = 0; i < 32; ++i) {
        if (b & 1)
            rw |= 1 << (31 - i);
        b >>= 1;
    }
    return rw;
}

std::vector<unsigned int>
CRC32Stream::precomputeTable(unsigned int polynomial)
{
    std::vector<unsigned int> result;
    result.resize(256);
    for (unsigned int i = 0; i < 256; ++i) {
        unsigned int rb = reflect(i);
        for (int j = 0; j < 8; ++j) {
            if (rb & 0x80000000)
                rb = (rb << 1) ^ polynomial;
            else
                rb <<= 1;
        }
        result[i] = reflect(rb);
    }
    return result;
}

size_t
CRC32Stream::hashSize() const
{
    return 4;
}

void
CRC32Stream::hash(void *result, size_t length) const
{
    MORDOR_ASSERT(length == 4);
    *(unsigned int *)result = byteswapOnLittleEndian(~m_crc);
}

void
CRC32Stream::reset()
{
    m_crc = ~0u;
}

void
CRC32Stream::updateHash(const void *buffer, size_t length)
{
    const unsigned char *bytes = (const unsigned char *)buffer;
    const unsigned char *end = bytes + length;
    while (bytes < end)
        m_crc = (m_crc >> 8) ^ m_table[(m_crc ^ *bytes++) & 0xff];
}

}