const void *data2, unsigned short length2, const void *context);Copyright ©1995 by NeXT Computer, Inc. All Rights Reserved.
| IXCompareBytes(), IXCompareUnsignedBytes(), IXCompareShorts(), IXCompareUnsignedShorts(), IXCompareLongs(), IXCompareUnsignedLongs(), IXCompareFloats(), IXCompareDoubles() |
| SUMMARY Compare two data items as arrays of numbers and return their ordering.
DECLARED IN btree/protocols.h SYNOPSIS int IXCompareBytes(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) |
| int IXCompareUnsignedBytes(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) int IXCompareShorts(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) int IXCompareUnsignedShorts(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) int IXCompareLongs(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) int IXCompareUnsignedLongs(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) int IXCompareFloats(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) int IXCompareDoubles(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) |
| DESCRIPTION Each of these functions compares two arrays of arbitrary data, data1 and data2 (of length1 and length2 bytes respectively), and returns an integer indicating their ordering. The arrays are compared as though they contained elements of the type indicated by the function name; for example, IXCompareUnsignedLongs() compares data1 and data2 as arrays of items of type unsigned long int. All of these functions return an integer less than, equal to, or greater than 0, according to whether data1 is less than, equal to, or greater than data2. |
| The data in the arrays is compared serially until one element isn't equal to the other, or until either length1 or length2 bytes have been exhausted in the corresponding array. If two arrays are otherwise equal, the shorter is considered the lesser in value.
All of these functions match the IXComparator function type, which has the form: |
| typedef int IXComparator(const void *data1, unsigned short length1,const void *data2, unsigned short length2, const void *context); |
| Where data1 is an array of length1 bytes, data2 is an array of length2 bytes; context is a pointer to arbitrary data for use by the function. Only IXFormatComparator() (see below) makes use of a context argument (for that function it's called format). You are free to write functions matching this type definition that use context in any way you choose. |
| RETURN These functions return an integer less than 0 if data1 is considered less than data2, 0 if they are considered equal, or an integer greater than 0 if data1 is considered greater than data2.
SEE ALSO IXCompareShort(), IXBTree class, IXComparatorSetting protocol |
IXCompareDouble()  See IXCompareShort()
IXCompareDoubles() IXCompareFloat() IXCompareFloats() IXCompareLong() IXCompareLongs() IXCompareMonocaseStrings() |
| IXCompareShort(), IXCompareUnsignedShort(), IXCompareLong(), IXCompareUnsignedLong(), IXCompareFloat(), IXCompareDouble() |
| SUMMARY Compare two data items as numbers and return their ordering.
DECLARED IN btree/protocols.h SYNOPSIS int IXCompareShort(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) |
| int IXCompareUnsignedShort(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) int IXCompareLong(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) int IXCompareUnsignedLong(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) int IXCompareFloat(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) int IXCompareDouble(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) |
| DESCRIPTION Each of these functions compares two data items, pointed to by data1 and data2, as elements of the type indicated by the function name, and returns an integer indicating their ordering (length1, length2 and context are ignored). The items are compared by pointer dereference; for example, IXCompareFloat() compares the values pointed to by data1 and data2 as type float. All of these functions return an integer less than, equal to, or greater than 0, depending on whether data1 is less than, equal to, or greater than data2. |
| For more information on comparator functions, see the IXCompareBytes() function description. |
| RETURN These functions return an integer less than 0 if data1 is considered less than data2, 0 if they are considered equal, or an integer greater than 0 if data1 is considered greater than data2.
SEE ALSO IXCompareBytes(), IXBTree class, IXComparatorSetting protocol |
| IXCompareShorts() See IXCompareBytes() |
| IXCompareStringAndUnsigneds(), IXCompareUnsignedAndStrings() |
| SUMMARY Compare two data items as a combinations of strings and numbers and return their ordering.
DECLARED IN btree/protocols.h SYNOPSIS int IXCompareStringAndUnsigneds(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) |
| int IXCompareUnsignedAndStrings(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) |
| DESCRIPTION These functions combine the comparisons of IXCompareStrings() and IXCompareUnsignedLongs(). |
| IXCompareStringAndUnsigned() compares data1 and data2 as strings until the first null character is encountered. If the strings are equal up to and including the null character, the remainders are compared in the manner of IXCompareUnsignedLongs(). Each length argument must be the length in bytes of the string, plus 1 for the terminating null character, plus the length in bytes of the array of unsigned integers following the string.
IXCompareUnsignedAndStrings() compares the first part of data1 and data2 as a single unsigned long integer. If those are equal, the remainders are compared in the manner of IXCompareStrings(). Each length argument must be the length in bytes of an unsigned long integer, plus the length in bytes of the string, plus 1 for the terminating null character. For more information on comparator functions, see the IXCompareBytes() function description. |
| RETURN These functions return an integer less than 0 if data1 is considered less than data2, 0 if they are considered equal, or an integer greater than 0 if data1 is considered greater than data2.
SEE ALSO IXCompareBytes(), IXBTree class, IXComparatorSetting protocol |
| IXCompareStrings(), IXCompareMonocaseStrings() |
| SUMMARY Compare two sets of data as strings and return their ordering.
DECLARED IN btree/protocols.h SYNOPSIS int IXCompareStrings(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) |
| int IXCompareMonocaseStrings(const void *data1, unsigned short length1, const void *data2, unsigned short length2, const void *context) |
| DESCRIPTION These functions compare serial arrays of strings in the NEXTSTEP character encoding. They accept either single null-terminated strings along with their lengths, or arrays of characters forming consecutive null-terminated strings (for example, "This is a string\0And this is another\0") along with the total length. Only the length argument is used to determine the length of a string; a null character is treated as any other character for comparison purposes. Both of these functions return an integer less than, equal to, or greater than 0, depending on whether data1 is less than, equal to, or greater than data2. |
| The data in the arrays is compared serially until one element isn't equal to the other, or until either length1 or length2 bytes have been exhausted in the corresponding array. If two arrays are otherwise equal, the shorter is considered the lesser in value.
IXCompareStrings() distinguishes between uppercase and lowercase when comparing strings. IXCompareMonocaseStrings() disregards case distinctions in its comparison. For more information on comparator functions, see the IXCompareBytes() function description. |
| RETURN These functions return an integer less than 0 if data1 is considered less than data2, 0 if they are considered equal, or an integer greater than 0 if data1 is considered greater than data2.
SEE ALSO IXCompareBytes(), IXBTree class, IXComparatorSetting protocol |
| IXCompareUnsignedBytes() See IXCompareBytes()
IXCompareUnsignedAndStrings() IXCompareUnsignedLong() IXCompareUnsignedLongs() IXCompareUnsignedShort() IXCompareUnsignedShorts() |
| IXFormatComparator() |
| SUMMARY Compare two arrays of data based on a type encoding and return their ordering.
DECLARED IN btree/protocols.h SYNOPSIS int IXFormatComparator(const void *data1, unsigned short length1, const void *data2, unsigned short length2, void *format) DESCRIPTION IXFormatComparator() compares two arrays of data, determining the data type from an Objective C type encoding supplied in format. For example, supplying "l" as the format indicates that data1 and data2 are arrays of long integers. IXFormatComparator() uses the other standard comparison functions as needed on the data arrays until their ordering is decided. |
| IXFormatComparator() currently uses only the first type declared in the format string, except for the compound formats corresponding to IXCompareStringAndUnsigneds() and IXCompareUnsignedAndStrings(), which it recognizes. Any array lengths in the format string are ignored; the actual lengths are determined from the length1 and length2 arguments passed to the function. If a comparison function can't be determined from the format string, IXCompareStrings() is used. NeXT reserves the right to interpret more than the first type declaration in future releases, as well as structure declarations, bit fields and unions.
For more information on comparator functions, see the IXCompareBytes() function description. For more information on comparison formats, see the IXComparisonSetting protocol specification. |
| RETURN IXFormatComparator() returns an integer less than 0 if data1 is considered less than data2, 0 if they are considered equal, or an integer greater than 0 if data1 is considered greater than data2.
SEE ALSO IXCompareBytes(), IXBTree class, IXComparisonSetting protocol |
| IXLockBTreeMutex(), IXUnlockBTreeMutex() |
| SUMMARY Lock and unlock an IXBTree for thread-safe access
DECLARED IN btree/IXBTree.h SYNOPSIS void IXLockBTreeMutex(IXBTree *aBTree) |
| void IXUnlockBTreeMutex(IXBTree *aBTree) |
| DESCRIPTION These macros expand to calls to mutex_lock() or mutex_unlock() on the mutex lock instance variable of their IXBTree. They should be used to guarantee that the IXBTree isn't accessed simultaneously by two Mach threads.
SEE ALSO mutex_lock() (NEXTSTEP Operating System Software), mutex_unlock() (NEXTSTEP Operating System Software), IXBTree class |
| IXReadObjectFromStore() See IXWriteRootObjectToStore()
IXUnlockBTreeMutex() |
| IXWriteRootObjectToStore(), IXReadObjectFromStore() |
| SUMMARY Archive or unarchive an object to or from an IXStore
DECLARED IN store/IXStoreBlock.h SYNOPSIS unsigned int IXWriteRootObjectToStore(IXStore *aStore, unsigned int aHandle, id anObject) |
| id IXReadObjectFromStore(IXStore *aStore, unsigned int aHandle, NXZone *aZone) |
| DESCRIPTION IXWriteRootObjectToStore() archives anObject into the IXStore block identified by aStore and aHandle. This involves creating a memory stream, archiving the object into that stream, resizing the block to accommodate the resulting stream length, and then copying the contents of the stream into the block. Any object that implements the write: method using the standard archiving functions (including NXWriteObjectReference()) can be archived in this way. IXReadObjectFromStore() unarchives an object from the IXStore block identified by aStore and aHandle, allocating the unarchived object from aZone. For further information on object archiving, see the description for the NXReadObject() function in the Application Kit documentation.
RETURN IXWriteRootObjectToStore() returns aHandle. IXReadObjectFromStore() returns the id of the unarchived object. SEE ALSO NXWriteRootObject() (Application Kit Function), NXReadObject() (Application Kit Function), IXStoreBlock class. |