Visible to Intel only — GUID: GUID-9A5C7110-BC7A-4CDF-A872-E7C37EB83972
Visible to Intel only — GUID: GUID-9A5C7110-BC7A-4CDF-A872-E7C37EB83972
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 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;
}