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SCUMM: Document ScummEngine_v90he::sortArray

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svn-id: r53671
This commit is contained in:
Max Horn 2010-10-21 09:31:42 +00:00
parent cca5504b6c
commit 66fabfa049
2 changed files with 22 additions and 5 deletions
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2
engines/scumm/he/script_v72he.cpp
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@ -173,7 +173,7 @@ int ScummEngine_v72he::readArray(int array, int idx2, int idx1) {
}
const int offset = (FROM_LE_32(ah->dim1end) - FROM_LE_32(ah->dim1start) + 1) *
(idx2 - FROM_LE_32(ah->dim2start)) - FROM_LE_32(ah->dim1start) + idx1;
(idx2 - FROM_LE_32(ah->dim2start)) + (idx1 - FROM_LE_32(ah->dim1start));
switch (FROM_LE_32(ah->type)) {
case kByteArray:

25
engines/scumm/he/script_v90he.cpp
View File

@ -1986,6 +1986,13 @@ static int compareDwordArrayReverse(const void *a, const void *b) {
return vb - va;
}
/**
* Sort a row range in a two-dimensional array by the value in a given column.
*
* We sort the data in the row range [dim2start..dim2end], according to the value
* in column dim1start == dim1end.
*/
void ScummEngine_v90he::sortArray(int array, int dim2start, int dim2end, int dim1start, int dim1end, int sortOrder) {
debug(9, "sortArray(%d, [%d,%d,%d,%d], %d)", array, dim2start, dim2end, dim1start, dim1end, sortOrder);
@ -1994,11 +2001,21 @@ void ScummEngine_v90he::sortArray(int array, int dim2start, int dim2end, int dim
ArrayHeader *ah = (ArrayHeader *)getResourceAddress(rtString, readVar(array));
assert(ah);
const int num = dim2end - dim2start + 1;
const int pitch = FROM_LE_32(ah->dim1end) - FROM_LE_32(ah->dim1start) + 1;
const int offset = pitch * (dim2start - FROM_LE_32(ah->dim2start));
sortArrayOffset = dim1start - FROM_LE_32(ah->dim1start);
const int num = dim2end - dim2start + 1; // number of rows to sort
const int pitch = FROM_LE_32(ah->dim1end) - FROM_LE_32(ah->dim1start) + 1; // length of a row = number of columns in it
const int offset = pitch * (dim2start - FROM_LE_32(ah->dim2start)); // memory offset to the first row to be sorted
sortArrayOffset = dim1start - FROM_LE_32(ah->dim1start); // offset to the column by which we sort
// Now we just have to invoke qsort on the appropriate row range. We
// need to pass sortArrayOffset as an implicit parameter to the
// comparison functions, which makes it necessary to use a global
// (albeit local to this file) variable.
// This could be avoided by using qsort_r or a self-written portable
// analog (this function passes an additional, user determined
// parameter to the comparison function).
// Another idea would be to use Common::sort, but that only is
// suitable if you sort objects of fixed size, which must be known
// during compilation time; clearly this not the case here.
switch (FROM_LE_32(ah->type)) {
case kByteArray:
case kStringArray: