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ICU-2235 in-place charset swapping needs to permutate through a temporary array

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X-SVN-Rev: 13201
This commit is contained in:
Markus Scherer 2003-09-25 15:40:02 +00:00
parent 0e10d4f927
commit dd9fe662f0
1 changed files with 44 additions and 4 deletions
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48
icu4c/source/common/propname.cpp
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@ -399,10 +399,50 @@ NameToEnum::swap(const UDataSwapper *ds,
}
/* copy/swap/permutate _enumArray[] and _nameArray[] */
for(i=0; i<tempMap->count; ++i) {
oldIndex=sortArray[i].index;
ds->swapArray32(ds, inEnumArray+oldIndex, 4, outEnumArray+i, pErrorCode);
ds->swapArray16(ds, inNameArray+oldIndex, 2, outNameArray+i, pErrorCode);
if(inEnumArray!=outEnumArray) {
for(i=0; i<tempMap->count; ++i) {
oldIndex=sortArray[i].index;
ds->swapArray32(ds, inEnumArray+oldIndex, 4, outEnumArray+i, pErrorCode);
ds->swapArray16(ds, inNameArray+oldIndex, 2, outNameArray+i, pErrorCode);
}
} else {
/*
* in-place swapping: need to permutate into a temporary array
* and then copy back to not destroy the data
*/
EnumValue *tempEnumArray;
Offset *oldIndexes;
/* write name offsets directly from sortArray */
for(i=0; i<tempMap->count; ++i) {
ds->writeUInt16((uint16_t *)outNameArray+i, (uint16_t)sortArray[i].name);
}
/*
* compress the oldIndexes into a separate array to make space for tempEnumArray
* the tempMap _nameArray becomes oldIndexes[], getting the index
* values from the 2D sortArray[],
* while sortArray=tempMap _enumArray[] becomes tempEnumArray[]
* this saves us allocating more memory
*
* it works because sizeof(NameAndIndex)<=sizeof(EnumValue)
* and because the nameArray[] can be used for oldIndexes[]
*/
tempEnumArray=(EnumValue *)sortArray;
oldIndexes=(Offset *)(sortArray+tempMap->count);
/* copy sortArray[].index values into oldIndexes[] */
for(i=0; i<tempMap->count; ++i) {
oldIndexes[i]=sortArray[i].index;
}
/* permutate inEnumArray[] into tempEnumArray[] */
for(i=0; i<tempMap->count; ++i) {
ds->swapArray32(ds, inEnumArray+oldIndexes[i], 4, tempEnumArray+i, pErrorCode);
}
/* copy tempEnumArray[] to outEnumArray[] */
uprv_memcpy(outEnumArray, tempEnumArray, tempMap->count*4);
}
}