ZipZSTD.cxx

Go to the documentation of this file.

// Original Author: Brian Bockelman
 
/*************************************************************************
 * Copyright (C) 1995-2019, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
#include "ZipZSTD.h"
 
#include "ROOT/RConfig.hxx"
 
#include "zdict.h"
#include <zstd.h>
#include <memory>
 
#include <iostream>
 
static const int kHeaderSize = 9;
 
static const size_t errorCodeSmallBuffer = (size_t)-70;
 
void R__zipZSTD(int cxlevel, int *srcsize, const char *src, int *tgtsize, char *tgt, int *irep)
{
    using Ctx_ptr = std::unique_ptr<ZSTD_CCtx, decltype(&ZSTD_freeCCtx)>;
    Ctx_ptr fCtx{ZSTD_createCCtx(), &ZSTD_freeCCtx};
 
    *irep = 0;
 
    size_t retval = ZSTD_compressCCtx(fCtx.get(),
                                        &tgt[kHeaderSize], static_cast<size_t>(*tgtsize - kHeaderSize),
                                        src, static_cast<size_t>(*srcsize),
                                        2*cxlevel);
 
    if (R__unlikely(ZSTD_isError(retval))) {
        if (R__unlikely(retval != errorCodeSmallBuffer)) {
            std::cerr << "Error in zip ZSTD. Type = " << ZSTD_getErrorName(retval) <<
            " . Code = " << retval << std::endl;
            return;
        }
    }
    else {
        *irep = static_cast<size_t>(retval + kHeaderSize);
    }
 
    size_t deflate_size = retval;
    size_t inflate_size = static_cast<size_t>(*srcsize);
    tgt[0] = 'Z';
    tgt[1] = 'S';
    tgt[2] = '\1';
    tgt[3] = deflate_size & 0xff;
    tgt[4] = (deflate_size >> 8) & 0xff;
    tgt[5] = (deflate_size >> 16) & 0xff;
    tgt[6] = inflate_size & 0xff;
    tgt[7] = (inflate_size >> 8) & 0xff;
    tgt[8] = (inflate_size >> 16) & 0xff;
}
 
void R__unzipZSTD(int *srcsize, const unsigned char *src, int *tgtsize, unsigned char *tgt, int *irep)
{
    using Ctx_ptr = std::unique_ptr<ZSTD_DCtx, decltype(&ZSTD_freeDCtx)>;
    Ctx_ptr fCtx{ZSTD_createDCtx(), &ZSTD_freeDCtx};
    *irep = 0;
 
    if (R__unlikely(src[0] != 'Z' || src[1] != 'S')) {
      std::cerr << "R__unzipZSTD: algorithm run against buffer with incorrect header (got " <<
      src[0] << src[1] << "; expected ZS)." << std::endl;
      return;
    }
 
    int ZSTD_version =  ZSTD_versionNumber() / (100 * 100);
    if (R__unlikely(src[2] != ZSTD_version)) {
      std::cerr << "R__unzipZSTD: This version of ZSTD is incompatible with the on-disk version "
      "got "<< src[2] << "; expected "<< ZSTD_version << ")" << std::endl;
      return;
    }
 
    size_t retval = ZSTD_decompressDCtx(fCtx.get(),
                                        (char *)tgt, static_cast<size_t>(*tgtsize),
                                        (char *)&src[kHeaderSize], static_cast<size_t>(*srcsize - kHeaderSize));
 
    /* The error code 18446744073709551546 arises when the tgt buffer is too small
     * However this error is already handled outside of the compression algorithm
     */
    if (R__unlikely(ZSTD_isError(retval))) {
        if (R__unlikely(retval != errorCodeSmallBuffer)) {
            std::cerr << "Error in unzip ZSTD. Type = " << ZSTD_getErrorName(retval) <<
            " . Code = " << retval << std::endl;
            return;
        }
    }
    else {
        *irep = retval;
    }
}