Chapter 6 Function Descriptions

AZSetHSzClr/DSSetHSzClr

MgErr AZSetHSzClr(h, size);

MgErr DSSetHSzClr(h, size);

Purpose

Changes the size of the block of memory referenced by the specified handle and sets any new memory to zero. Do not use this function on a locked handle.

Parameters

Name	Type	Description
h	UHandle	Handle you want to resize.
size	int32	New size, in bytes, of the handle.

Return Value

mgErr, which can contain the following errors:

NoErr	No error.
MFullErr	Not enough memory to perform the operation.
mZoneErr	Handle or pointer not in specified zone.

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Chapter 6 Function Descriptions

BinSearch

int32 BinSearch(arrayp, n, elmtSize, key, compareProcP);

Purpose

Searches an array of an arbitrary data type using the binary search algorithm. In addition to passing the array you want to search to this routine, you also pass a comparison procedure that this sort routine then uses to compare elements in the array.

The comparison routine should return a number less than zero if a is less than b, zero if a is equal to b, and a number greater than zero if a is greater than b.

You should declare the comparison routine to have the following parameters and return type.

int32 compareProcP(UPtr a, UPtr b);

Parameters

Name	Type	Description
arrayp	Uptr	Pointer to an array of data.
n	int32	Number of elements in the array you want to
		search.
elmtSize	int32	Size in bytes of an array element.
key	Uptr	Pointer to the data for which you want to
		search.
compareProcP	ProcPtr	Comparison routine you want BinSearch to
		use to compare array elements. BinSearch
		passes this routine the addresses of two
		elements that it needs to compare.

Return Value

The position in the array where the data is found, with 0 being the first element of the array, if it is found. If the data is not found, BinSearch returns –i–1, where i is the position where x should be placed.

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Chapter 6 Function Descriptions

BlockCmp

int32 BlockCmp(p1, p2, numBytes);

Purpose

Compares two blocks of memory to determine whether one is less than, equal to, or greater than the other.

Parameters

Name	Type	Description
p1	UPtr	Pointer to a block of memory.
p2	UPtr	Pointer to a block of memory.
numBytes	int32	Number of bytes you want to compare.

Return Value

A negative number, zero, or a positive number if p1 is less than, equal to, or greater than p2, respectively.

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Chapter 6 Function Descriptions

Cat4Chrs

Macro

int32 Cat4Chrs(a,b,c,d);

Purpose

Constructs an int32 parameter from four uInt8 parameters, with the first parameter as the high byte and the last parameter as the low byte.

Parameters

Name	Type	Description
a	uInt8	High order byte of the high word of the
		resulting int32.
b	uInt8	Low order byte of the high word of the
		resulting int32.
c	uInt8	High order byte of the low word of the
		resulting int32.
d	uInt8	Low order byte of the low word of the
		resulting int32.

Return Value

The resulting int32.

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