Developer Reference

  • 2020
  • 07/15/2020
  • Public Content
Contents

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.
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 2017-2020 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 <ippdc.h> /* Data compression functions */ #include <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 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; }

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804