Intel® Integrated Performance Primitives (Intel® IPP) Developer Guide and Reference

ID 790148
Date 10/31/2024
Public
Document Table of Contents

EncodeLZ4HashTableInit, EncodeLZ4DictHashTableInit

Initializes the LZ4 hash table.

Syntax

IppStatus ippsEncodeLZ4HashTableInit_8u(Ipp8u* pHashTable, int srcLen);

IppStatus ippsEncodeLZ4DictHashTableInit_8u(Ipp8u* pHashTable, int srcLen);

Include Files

ippdc.h

Domain Dependencies

Headers: ippcore.h, ippvm.h, ipps.h

Libraries: ippcore.lib, ippvm.lib, ipps.lib

Parameters

pHashTable

Pointer to the LZ4 hash table.

srcLen

Length of the source data for compression.

Description

This function initializes the LZ4 hash table. Before using this function, compute the size of the LZ4 hash table using the EncodeLZ4HashTableGetSize function.

Return Values

ippStsNoErr

Indicates no error.

ippStsNullPtrErr

Indicates an error if the pHashTable pointer is NULL.

ippStsSizeErr

Indicates an error if the srcLen value is less than, or equal to zero.

Example

/*******************************************************************************
* Copyright 2015 Intel Corporation.
*
*
* This software and the related documents are Intel copyrighted materials, and your use of them is governed by
* the express license under which they were provided to you ('License'). Unless the License provides otherwise,
* you may not use, modify, copy, publish, distribute, disclose or transmit this software or the related
* documents without Intel's prior written permission.
* This software and the related documents are provided as is, with no express or implied warranties, other than
* those that are expressly stated in the License.
*******************************************************************************/

/*
 The example below shows how to use the functions:
     ippsEncodeLZ4HashTableGetSize_8u
     ippsEncodeLZ4HashTableInit_8u
     ippsEncodeLZ4_8u
     ippsDecodeLZ4_8u
*/

#include <stdio.h>
#include <string.h>

#include <ipp/ippdc.h>
#include <ipp/ipps.h>

/* Next two defines are created to simplify code reading and understanding */
#define EXIT_MAIN       exitLine:                              /* Label for Exit */
#define check_sts(st)   if((st) != ippStsNoErr) goto exitLine; /* Go to Exit if Intel(R) Integrated Performance Primitives (Intel(R) IPP) function returned status different from ippStsNoErr */

#define TEST_SIZE (1024)

int main(void)
{
    Ipp8u       *srcBuf = NULL, *comprBuf = NULL, *decomprBuf = NULL, *hashTable = NULL;
    IppStatus   st = ippStsNoErr;
    int         hashSize = 0, 
                comprLen = TEST_SIZE + TEST_SIZE / 255 + 16,    /* Extra bytes for
                                                                    uncompressible data */
                decomprLen = TEST_SIZE + 33;
    int         i;

    srcBuf      = ippsMalloc_8u(TEST_SIZE);
    decomprBuf  = ippsMalloc_8u(decomprLen);                    /* Spare bytes for "wild"
                                                            (non-safe) decompression */
    comprBuf    = ippsMalloc_8u(comprLen);
    /* Initialize source buffer */
    check_sts(      st = ippsVectorJaehne_8u(srcBuf, TEST_SIZE, IPP_MAX_8U) )
    for(i = 0; i < TEST_SIZE; i++)
        srcBuf[i] >>= 6;                  /* Decrease source data entropy */
    /* Init and allocate hash table */
    check_sts(  st = ippsEncodeLZ4HashTableGetSize_8u(&hashSize)    )
    hashTable   = ippsMalloc_8u(hashSize);
    check_sts(  st = ippsEncodeLZ4HashTableInit_8u(hashTable, TEST_SIZE)    )
    /* Compress source data */
    check_sts(  st = ippsEncodeLZ4_8u((const Ipp8u*)srcBuf, TEST_SIZE, comprBuf,
                                      &comprLen, hashTable) )
    /* Print compression result */
    printf("Compression: %d bytes compressed into %d bytes\n", TEST_SIZE, comprLen);
    /* Decompression */
    decomprLen  = TEST_SIZE + 33;
    check_sts(  st = ippsDecodeLZ4_8u((const Ipp8u*)comprBuf, comprLen, decomprBuf,
                                      &decomprLen)  )
    /* Check */
    if(decomprLen == TEST_SIZE)/* Decompressed size must be equal to source data size */
    {
        if(memcmp(srcBuf, decomprBuf, TEST_SIZE) != 0)
        {
            printf("Wrong decompression!\n");
            st = ippStsErr;
        }
        else
            printf("Decompressed by ippsDecodeLZ4_8u OK\n");
    }
    else
        printf("Invalid decompressed length %d\n", decomprLen);

EXIT_MAIN
    ippsFree(srcBuf);
    ippsFree(comprBuf);
    ippsFree(decomprBuf);
    ippsFree(hashTable);
    return (int)st;
}