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| Title: |
| PackBoolTags -- builds a "flag" word from a tag list. (V36) |
| Synopsis: |
| flags = PackBoolTags(initialFlags,tagList,boolMap); D0 D0 A0 A1 ULONG PackBoolTags(ULONG,struct TagItem *,struct TagItem *); |
| Function: |
| Picks out the boolean tag items in a tag list and converts them into bit-flag representations according to a correspondence defined by the tag list 'boolMap'. A boolean tag item is one where only the logical value of the ti_Data is relevant. If this field is 0, the value is FALSE, otherwise TRUE. |
| Parameters: |
| initialFlags - a starting set of bit-flags which will be changed by the processing of TRUE and FALSE boolean tags in tagList. tagList - a TagItem list which may contain several tag items defined to be boolean by their presence in boolMap. The logical value of ti_Data determines whether a tag item causes the bit-flag value related by boolMap to be set or cleared in the returned flag longword. boolMap - a tag list defining the boolean tags to be recognized, and the bit (or bits) in the returned longword that are to be set or cleared when a boolean Tag is found to be TRUE or FALSE in tagList. |
| Results: |
| flags - the accumulated longword of bit-flags, starting with initialFlags and modified by each boolean tag item encountered. |
| Examples: |
| /* define some nice user tag values ... */ enum mytags { tag1 = TAG_USER+1, tag2, tag3, tag4, tag5 }; /* this TagItem list defines the correspondence between boolean tags * and bit-flag values. */ struct TagItem boolMap[] = { {tag1, 0x0001}, {tag2, 0x0002}, {tag3, 0x0004}, {tag4, 0x0008}, {TAG_DONE, } }; /* You are probably passed these by some client, and you want * to "collapse" the boolean content into a single longword. */ struct TagItem boolExample[] = { {tag1, TRUE}, {tag2, FALSE}, {tag5, Irrelevant}, {tag3, TRUE}, {TAG_DONE, } }; /* Perhaps 'boolFlags' already has a current value of 0x800002. */ boolFlags = PackBoolTags(boolFlags,boolExample,boolMap); /* The resulting new value of 'boolFlags' will be 0x80005. /* |
| *** WARNING ***: |
| In a case where there is duplication of a tag in tagList, the last of the identical tags will hold sway. |
| Related topics: |
| <utility/tagitem.h>, GetTagData(), FindTagItem(), NextTagItem() |