Developer Reference

  • 2021
  • 01/15/2021
  • Public Content
Contents

DecodeLZOSafe

Decompresses input data with constantly checking integrity of output.

Syntax

IppStatus ippsDecodeLZOSafe_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
This function is a version of the function
ippsDecodeLZO
. It decompresses the source (compressed) data according to the compressed data format. The function can decompress both single-thread and multi-threaded data. The maximum performance can be obtained only in multi-threaded decompression of data compressed in the multi-threaded mode. Additionally this function checks the integrity of the destination data buffer, that is checks the buffer boundary limits. This function works slower, it can be used in doubtful cases when the compressed data integrity is not guaranteed, for example, decoding data received via non-reliable communication lines.
Destination data buffer must have enough free space to hold uncompressed data. Prior to the function call the destination buffer size variable pointed to by
pDstLen
must be initialized with actual number of free bytes in the destination buffer.
Return Values
ippStsNoErr
Indicates no error.
ippStsNullPtrErr
Indicates an error if one of the specified pointers is
NULL
.
ippStsLzoBrokenStreamErr
Indicates an error if compressed data is not valid - not an LZO compressed data.
ippStsDstSizeLessExpected
Destination buffer is too small to store decompressed data.

Example

/******************************************************************************* * Copyright 2017-2021 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

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.