DecodeLZO

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

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ID 790148

Date 4/28/2026

Version

Public

DecodeLZO

Decompresses input data, returns the length of the decompressed data.

Syntax

IppStatus ippsDecodeLZO_8u (const Ipp8u* pSrc, Ipp32u srcLen, Ipp8u* pDst, Ipp32u* pDstLen);

Include Files

ippdc.h

Domain Dependencies

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

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

Parameters

`pSrc`	Pointer to the source data buffer.
`srcLen`	Number of elements in the source data buffer.
`pDst`	Pointer to the destination data buffer.
`pDstLen`	Pointer to the variable with the number of elements in the destination data buffer.

Description

The function decompresses the source (compressed) data according to the compressed data format. This function can decompress both single-thread and multi-threaded data. Note that the maximum performance can be obtained only in multi-threaded decompression of data compressed in the multi-threaded mode.

NOTE:

Destination data buffer must have enough free space to hold uncompressed data. No output buffer check is performed and no error code is returned. In the case of doubts use safe version of this function DecodeLZOSafe .

Code example shows how the Intel IPP functions for the LZO compression can be used.

Return Values

`ippStsNoErr`	Indicates no error.
`ippStsNullPtrErr`	Indicates an error if one of the specified pointers is `NULL`.

Example

/*******************************************************************************
 * Copyright 2017 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:
        ippsEncodeLZOGetSize
        ippsEncodeLZO_8u
        ippsEncodeLZOInit_8u
        ippsDecodeLZO_8u
        ippsDecodeLZOSafe_8u
*/

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

#include <ipp/ippdc.h> /* Data compression functions       */
#include <ipp/ipps.h>  /* Malloc/vector initialization function   */

/* 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 * 4)
#define DECOMPR_MAX (TEST_SIZE + 64)

int main(void)
{
    Ipp8u *srcBuf = NULL, *comprBuf = NULL, *decomprBuf = NULL;
    IppStatus st;
    int i;
    Ipp32u stateSize;
    IppLZOState_8u *lzoState = NULL;
    Ipp32u comprLen, decomprLen;

    /* Allocate buffers */
    srcBuf = ippsMalloc_8u(TEST_SIZE);
    decomprBuf = ippsMalloc_8u(DECOMPR_MAX); /* Extra 64 bytes may be required
                                                   for non-safe decompression       */
    comprBuf = ippsMalloc_8u(TEST_SIZE + TEST_SIZE / 10);
    /* 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 */
    /* Allocate and initialize LZO structure */
    check_sts(st = ippsEncodeLZOGetSize(IppLZO1XST, TEST_SIZE, &stateSize));
    lzoState = (IppLZOState_8u *)ippsMalloc_8u(stateSize);
    check_sts(st = ippsEncodeLZOInit_8u(IppLZO1XST, TEST_SIZE, lzoState));
    /* LZO compress, decompress and compare */
    comprLen = (TEST_SIZE + TEST_SIZE / 10);
    check_sts(st = ippsEncodeLZO_8u(srcBuf, TEST_SIZE, comprBuf, &comprLen, lzoState));
    printf("LZO compress: %d bytes compressed into %d bytes\n", TEST_SIZE, (int)comprLen);
    decomprLen = DECOMPR_MAX;
    check_sts(st = ippsDecodeLZO_8u(comprBuf, comprLen, decomprBuf, &decomprLen));
    if (decomprLen != TEST_SIZE || memcmp(decomprBuf, srcBuf, TEST_SIZE) != 0) {
        printf("Non-safe decompress failed!\n");
        st = ippStsErr;
        goto exitLine;
    } else
        printf("Non-safe decompress verified.\n");
    /* Decompress using safe function */
    ippsZero_8u(decomprBuf, DECOMPR_MAX);
    decomprLen = TEST_SIZE; /* Can specify exact size */
    check_sts(st = ippsDecodeLZOSafe_8u(comprBuf, comprLen, decomprBuf, &decomprLen));
    if (decomprLen != TEST_SIZE || memcmp(decomprBuf, srcBuf, TEST_SIZE) != 0) {
        printf("Safe decompress failed!\n");
        st = ippStsErr;
        goto exitLine;
    } else
        printf("Safe decompress verified.\n");

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

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

DecodeLZO

Syntax

Include Files

Domain Dependencies

Parameters

Description

Return Values

Example