smaz.cpp

#include <string>
#include <sstream>
#include <string.h>
#include <fc/exception/exception.hpp>
namespace fc {

typedef const char*  const_char_ptr;
/* Our compression codebook, used for compression */
static const_char_ptr Smaz_cb[241] = {
"\002s,\266", "\003had\232\002leW", "\003on \216", "", "\001yS",
"\002ma\255\002li\227", "\003or \260", "", "\002ll\230\003s t\277",
"\004fromg\002mel", "", "\003its\332", "\001z\333", "\003ingF", "\001>\336",
"\001 \000\003   (\002nc\344", "\002nd=\003 on\312",
"\002ne\213\003hat\276\003re q", "", "\002ngT\003herz\004have\306\003s o\225",
"", "\003ionk\003s a\254\002ly\352", "\003hisL\003 inN\003 be\252", "",
"\003 fo\325\003 of \003 ha\311", "", "\002of\005",
"\003 co\241\002no\267\003 ma\370", "", "", "\003 cl\356\003enta\003 an7",
"\002ns\300\001\"e", "\003n t\217\002ntP\003s, \205",
"\002pe\320\003 we\351\002om\223", "\002on\037", "", "\002y G", "\003 wa\271",
"\003 re\321\002or*", "", "\002=\"\251\002ot\337", "\003forD\002ou[",
"\003 toR", "\003 th\r", "\003 it\366",
"\003but\261\002ra\202\003 wi\363\002</\361", "\003 wh\237", "\002  4",
"\003nd ?", "\002re!", "", "\003ng c", "",
"\003ly \307\003ass\323\001a\004\002rir", "", "", "", "\002se_", "\003of \"",
"\003div\364\002ros\003ere\240", "", "\002ta\310\001bZ\002si\324", "",
"\003and\a\002rs\335", "\002rt\362", "\002teE", "\003ati\316", "\002so\263",
"\002th\021", "\002tiJ\001c\034\003allp", "\003ate\345", "\002ss\246",
"\002stM", "", "\002><\346", "\002to\024", "\003arew", "\001d\030",
"\002tr\303", "", "\001\n1\003 a \222", "\003f tv\002veo", "\002un\340", "",
"\003e o\242", "\002a \243\002wa\326\001e\002", "\002ur\226\003e a\274",
"\002us\244\003\n\r\n\247", "\002ut\304\003e c\373", "\002we\221", "", "",
"\002wh\302", "\001f,", "", "", "", "\003d t\206", "", "", "\003th \343",
"\001g;", "", "", "\001\r9\003e s\265", "\003e t\234", "", "\003to Y",
"\003e\r\n\236", "\002d \036\001h\022", "", "\001,Q", "\002 a\031", "\002 b^",
"\002\r\n\025\002 cI", "\002 d\245", "\002 e\253", "\002 fh\001i\b\002e \v",
"", "\002 hU\001-\314", "\002 i8", "", "", "\002 l\315", "\002 m{",
"\002f :\002 n\354", "\002 o\035", "\002 p}\001.n\003\r\n\r\250", "",
"\002 r\275", "\002 s>", "\002 t\016", "", "\002g \235\005which+\003whi\367",
"\002 w5", "\001/\305", "\003as \214", "\003at \207", "", "\003who\331", "",
"\001l\026\002h \212", "", "\002, $", "", "\004withV", "", "", "", "\001m-", "",
"", "\002ac\357", "\002ad\350", "\003TheH", "", "", "\004this\233\001n\t",
"", "\002. y", "", "\002alX\003e, \365", "\003tio\215\002be\\",
"\002an\032\003ver\347", "", "\004that0\003tha\313\001o\006", "\003was2",
"\002arO", "\002as.", "\002at'\003the\001\004they\200\005there\322\005theird",
"\002ce\210", "\004were]", "", "\002ch\231\002l \264\001p<", "", "",
"\003one\256", "", "\003he \023\002dej", "\003ter\270", "\002cou", "",
"\002by\177\002di\201\002eax", "", "\002ec\327", "\002edB", "\002ee\353", "",
"", "\001r\f\002n )", "", "", "", "\002el\262", "", "\003in i\002en3", "",
"\002o `\001s\n", "", "\002er\033", "\003is t\002es6", "", "\002ge\371",
"\004.com\375", "\002fo\334\003our\330", "\003ch \301\001t\003", "\002hab", "",
"\003men\374", "", "\002he\020", "", "", "\001u&", "\002hif", "",
"\003not\204\002ic\203", "\003ed @\002id\355", "", "", "\002ho\273",
"\002r K\001vm", "", "", "", "\003t t\257\002il\360", "\002im\342",
"\003en \317\002in\017", "\002io\220", "\002s \027\001wA", "", "\003er |",
"\003es ~\002is%", "\002it/", "", "\002iv\272", "",
"\002t #\ahttp://C\001x\372", "\002la\211", "\001<\341", "\003, a\224"
};


/* Reverse compression codebook, used for decompression */
static const_char_ptr Smaz_rcb[254] = {
" ", "the", "e", "t", "a", "of", "o", "and", "i", "n", "s", "e ", "r", " th",
" t", "in", "he", "th", "h", "he ", "to", "\r\n", "l", "s ", "d", " a", "an",
"er", "c", " o", "d ", "on", " of", "re", "of ", "t ", ", ", "is", "u", "at",
"   ", "n ", "or", "which", "f", "m", "as", "it", "that", "\n", "was", "en",
"  ", " w", "es", " an", " i", "\r", "f ", "g", "p", "nd", " s", "nd ", "ed ",
"w", "ed", "http://", "for", "te", "ing", "y ", "The", " c", "ti", "r ", "his",
"st", " in", "ar", "nt", ",", " to", "y", "ng", " h", "with", "le", "al", "to ",
"b", "ou", "be", "were", " b", "se", "o ", "ent", "ha", "ng ", "their", "\"",
"hi", "from", " f", "in ", "de", "ion", "me", "v", ".", "ve", "all", "re ",
"ri", "ro", "is ", "co", "f t", "are", "ea", ". ", "her", " m", "er ", " p",
"es ", "by", "they", "di", "ra", "ic", "not", "s, ", "d t", "at ", "ce", "la",
"h ", "ne", "as ", "tio", "on ", "n t", "io", "we", " a ", "om", ", a", "s o",
"ur", "li", "ll", "ch", "had", "this", "e t", "g ", "e\r\n", " wh", "ere",
" co", "e o", "a ", "us", " d", "ss", "\n\r\n", "\r\n\r", "=\"", " be", " e",
"s a", "ma", "one", "t t", "or ", "but", "el", "so", "l ", "e s", "s,", "no",
"ter", " wa", "iv", "ho", "e a", " r", "hat", "s t", "ns", "ch ", "wh", "tr",
"ut", "/", "have", "ly ", "ta", " ha", " on", "tha", "-", " l", "ati", "en ",
"pe", " re", "there", "ass", "si", " fo", "wa", "ec", "our", "who", "its", "z",
"fo", "rs", ">", "ot", "un", "<", "im", "th ", "nc", "ate", "><", "ver", "ad",
" we", "ly", "ee", " n", "id", " cl", "ac", "il", "</", "rt", " wi", "div",
"e, ", " it", "whi", " ma", "ge", "x", "e c", "men", ".com"
};

uint32_t smaz_compress(const char *in, int inlen, char *out, int outlen) {
    unsigned int h1,h2,h3=0;
    int verblen = 0, _outlen = outlen;
    char verb[256], *_out = out;

    while(inlen) {
        int j = 7, needed;
        char *flush = NULL;
        const char *slot;

        h1 = h2 = in[0]<<3;
        if (inlen > 1) h2 += in[1];
        if (inlen > 2) h3 = h2^in[2];
        if (j > inlen) j = inlen;

        /* Try to lookup substrings into the hash table, starting from the
         * longer to the shorter substrings */
        for (; j > 0; j--) {
            switch(j) {
            case 1: slot = Smaz_cb[h1%241]; break;
            case 2: slot = Smaz_cb[h2%241]; break;
            default: slot = Smaz_cb[h3%241]; break;
            }
            while(slot[0]) {
                if (slot[0] == j && memcmp(slot+1,in,j) == 0) {
                    /* Match found in the hash table,
                     * prepare a verbatim bytes flush if needed */
                    if (verblen) {
                        needed = (verblen == 1) ? 2 : 2+verblen;
                        flush = out;
                        out += needed;
                        outlen -= needed;
                    }
                    /* Emit the byte */
                    if (outlen <= 0) return _outlen+1;
                    out[0] = slot[slot[0]+1];
                    out++;
                    outlen--;
                    inlen -= j;
                    in += j;
                    goto out;
                } else {
                    slot += slot[0]+2;
                }
            }
        }
        /* Match not found - add the byte to the verbatim buffer */
        verb[verblen] = in[0];
        verblen++;
        inlen--;
        in++;
out:
        /* Prepare a flush if we reached the flush length limit, and there
         * is not already a pending flush operation. */
        if (!flush && (verblen == 256 || (verblen > 0 && inlen == 0))) {
            needed = (verblen == 1) ? 2 : 2+verblen;
            flush = out;
            out += needed;
            outlen -= needed;
            if (outlen < 0) return _outlen+1;
        }
        /* Perform a verbatim flush if needed */
        if (flush) {
            if (verblen == 1) {
                flush[0] = (signed char)254;
                flush[1] = verb[0];
            } else {
                flush[0] = (signed char)255;
                flush[1] = (signed char)(verblen-1);
                memcpy(flush+2,verb,verblen);
            }
            flush = NULL;
            verblen = 0;
        }
    }
    return out-_out;
}

void smaz_decompress(const char *in, uint32_t inlen, std::stringstream& ss ) {
    const unsigned char *c = (const unsigned char*) in;
//    char *_out = out;
//    int _outlen = outlen;

    while(inlen) {
        if (*c == 254) {
            /* Verbatim byte */
            //if (outlen < 1) return _outlen+1;
            //*out = *(c+1);
            ss.put( *(c+1) );
            //out++;
            //outlen--;
            c += 2;
            inlen -= 2;
        } else if (*c == 255) {
            /* Verbatim string */
            int len = (*(c+1))+1;
            //if (outlen < len) return _outlen+1;
            ss.write( (const char*)(c+2),len );

            //memcpy(out,c+2,len);
            //out += len;
            //outlen -= len;
            c += 2+len;
            inlen -= 2+len;
        } else {
            /* Codebook entry */
            const char *s = Smaz_rcb[*c];
            int len = strlen(s);

            //if (outlen < len) return _outlen+1;
            //memcpy(out,s,len);
            ss.write( s, len );
            //out += len;
            //outlen -= len;
            c++;
            inlen--;
        }
    }
}



  std::string smaz_compress( const std::string& in )
  {
    std::string out;
    out.resize(in.size());
    auto out_len = smaz_compress( in.c_str(), in.size(), &out[0], out.size() );
    FC_ASSERT( out_len <= out.size() );
    out.resize(out_len);
    return out;
  }
  std::string smaz_decompress( const std::string& compressed )
  {
    std::stringstream ss;
    smaz_decompress( compressed.c_str(), compressed.length(), ss );
    return ss.str();
  }

} // namespace fc