[13] | 1 | /* |
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| 2 | * $Id: list.c,v 1.11 2009/04/11 02:02:54 fabio Exp $ |
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| 3 | * |
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| 4 | */ |
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| 5 | /* |
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| 6 | * List Management Package |
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| 7 | * |
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| 8 | * David Harrison |
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| 9 | * University of California, Berkeley, 1985 |
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| 10 | * |
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| 11 | * This package implements a simple generic linked list data type. It |
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| 12 | * uses a doubly linked list structure and provides some standard operations |
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| 13 | * for storing and retrieving data from the list. |
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| 14 | */ |
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| 15 | |
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| 16 | #include "util.h" |
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| 17 | #include "list.h" /* Self declaration */ |
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| 18 | |
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| 19 | |
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| 20 | /* |
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| 21 | * The list identifier is in reality a pointer to the following list |
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| 22 | * descriptor structure. Lists are doubly linked with both top and |
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| 23 | * bottom pointers stored in the list descriptor. The length |
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| 24 | * of the list is also stored in the descriptor. |
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| 25 | */ |
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| 26 | |
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| 27 | typedef struct list_elem { /* One list element */ |
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| 28 | struct list_desc *mainList; /* List descriptor */ |
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| 29 | struct list_elem *prevPtr; /* Previous element */ |
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| 30 | struct list_elem *nextPtr; /* Next list element */ |
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| 31 | lsGeneric userData; /* User pointer */ |
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| 32 | } lsElem; |
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| 33 | |
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| 34 | typedef struct list_desc { /* List descriptor record */ |
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| 35 | lsElem *topPtr, *botPtr; /* Pointer to top and bottom of list */ |
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| 36 | int length; /* Length of list */ |
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| 37 | } lsDesc; |
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| 38 | |
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| 39 | |
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| 40 | /* |
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| 41 | * Generators are in reality pointers to the generation descriptor |
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| 42 | * defined below. A generator has a current spot which is *between* |
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| 43 | * two items. Thus, a generator consists of two pointers: record |
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| 44 | * before spot and record after spot. A pointer to the main list |
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| 45 | * is included so the top and bottom pointers of the list can be |
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| 46 | * modified if needed. |
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| 47 | */ |
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| 48 | |
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| 49 | typedef struct gen_desc { /* Generator Descriptor */ |
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| 50 | lsDesc *mainList; /* Pointer to list descriptor */ |
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| 51 | lsElem *beforeSpot; /* Item before the current spot */ |
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| 52 | lsElem *afterSpot; /* Item after the current spot */ |
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| 53 | } lsGenInternal; |
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| 54 | |
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| 55 | /* |
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| 56 | * Handles are in reality pointers to lsElem records. They are |
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| 57 | * cheap to generate and need not be disposed. |
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| 58 | */ |
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| 59 | |
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| 60 | |
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| 61 | |
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| 62 | /* |
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| 63 | * List Creation and Deletion |
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| 64 | */ |
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| 65 | |
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| 66 | lsList lsCreate(void) |
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| 67 | /* |
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| 68 | * Creates a new linked list and returns its handle. The handle is used |
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| 69 | * by all other list manipulation routines and should not be discarded. |
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| 70 | */ |
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| 71 | { |
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| 72 | lsDesc *newList; |
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| 73 | |
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| 74 | newList = ALLOC(lsDesc, 1); |
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| 75 | newList->topPtr = newList->botPtr = NIL(lsElem); |
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| 76 | newList->length = 0; |
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| 77 | return( (lsList) newList ); |
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| 78 | } |
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| 79 | |
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| 80 | lsStatus lsDestroy( |
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| 81 | lsList list /* List to destroy */, |
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| 82 | void (*delFunc)(lsGeneric) /* Routine to release user data */) |
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| 83 | /* |
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| 84 | * Frees all resources associated with the specified list. It frees memory |
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| 85 | * associated with all elements of the list and then deletes the list. |
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| 86 | * User data is released by calling 'delFunc' with the pointer as the |
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| 87 | * argument. Accessing a list after its destruction is a no-no. |
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| 88 | */ |
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| 89 | { |
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| 90 | lsDesc *realList; |
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| 91 | lsElem *index, *temp; |
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| 92 | |
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| 93 | realList = (lsDesc *) list; |
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| 94 | /* Get rid of elements */ |
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| 95 | index = realList->topPtr; |
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| 96 | while (index != NIL(lsElem)) { |
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| 97 | temp = index; index = index->nextPtr; |
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| 98 | if (delFunc) |
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| 99 | (*delFunc)(temp->userData); |
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| 100 | FREE(temp); |
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| 101 | } |
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| 102 | /* Get rid of descriptor */ |
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| 103 | FREE(realList); |
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| 104 | return(LS_OK); |
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| 105 | } |
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| 106 | |
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| 107 | |
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| 108 | /* |
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| 109 | * Copying lists |
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| 110 | */ |
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| 111 | |
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| 112 | static lsGeneric lsIdentity(lsGeneric data) |
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| 113 | /* Identity copy function */ |
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| 114 | { |
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| 115 | return data; |
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| 116 | } |
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| 117 | |
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| 118 | lsList lsCopy( |
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| 119 | lsList list /* List to be copied */, |
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| 120 | lsGeneric (*copyFunc)(lsGeneric) /* Routine to copy user data */) |
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| 121 | /* |
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| 122 | * Returns a copy of list `list'. If `copyFunc' is non-zero, |
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| 123 | * it will be called for each item in `list' and the pointer it |
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| 124 | * returns will be used in place of the original user data for the |
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| 125 | * item in the newly created list. The form of `copyFunc' should be: |
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| 126 | * lsGeneric copyFunc(data) |
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| 127 | * lsGeneric data; |
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| 128 | * This is normally used to make copies of the user data in the new list. |
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| 129 | * If no `copyFunc' is provided, an identity function is used. |
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| 130 | */ |
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| 131 | { |
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| 132 | lsList newList; |
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| 133 | lsGen gen; |
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| 134 | lsGeneric data; |
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| 135 | |
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| 136 | if (!copyFunc) copyFunc = lsIdentity; |
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| 137 | newList = lsCreate(); |
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| 138 | gen = lsStart(list); |
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| 139 | while (lsNext(gen, &data, LS_NH) == LS_OK) { |
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| 140 | (void) lsNewEnd(newList, (*copyFunc)(data), LS_NH); |
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| 141 | } |
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| 142 | lsFinish(gen); |
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| 143 | return newList; |
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| 144 | } |
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| 145 | |
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| 146 | |
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| 147 | /* |
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| 148 | * Adding New Elements to the Beginning and End of a List |
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| 149 | */ |
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| 150 | |
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| 151 | lsStatus lsNewBegin( |
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| 152 | lsList list /* List to add element to */, |
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| 153 | lsGeneric data /* Arbitrary pointer to data */, |
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| 154 | lsHandle *itemHandle /* Handle to data (returned) */) |
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| 155 | /* |
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| 156 | * Adds a new item to the start of a previously created linked list. |
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| 157 | * If 'itemHandle' is non-zero, it will be filled with a handle |
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| 158 | * which can be used to generate a generator positioned at the |
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| 159 | * item without generating through the list. |
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| 160 | */ |
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| 161 | { |
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| 162 | lsDesc *realList = (lsDesc *) list; |
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| 163 | lsElem *newElem; |
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| 164 | |
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| 165 | newElem = ALLOC(lsElem, 1); |
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| 166 | newElem->userData = data; |
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| 167 | newElem->nextPtr = realList->topPtr; |
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| 168 | newElem->prevPtr = NIL(lsElem); |
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| 169 | newElem->mainList = realList; |
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| 170 | if (realList->topPtr == NIL(lsElem)) { |
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| 171 | /* The new item is both the top and bottom element */ |
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| 172 | realList->botPtr = newElem; |
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| 173 | } else { |
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| 174 | /* There was a top element - make its prev correct */ |
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| 175 | realList->topPtr->prevPtr = newElem; |
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| 176 | } |
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| 177 | realList->topPtr = newElem; |
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| 178 | realList->length += 1; |
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| 179 | if (itemHandle) *itemHandle = (lsHandle) newElem; |
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| 180 | return(LS_OK); |
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| 181 | } |
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| 182 | |
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| 183 | lsStatus lsNewEnd( |
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| 184 | lsList list /* List to append element to */, |
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| 185 | lsGeneric data /* Arbitrary pointer to data */, |
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| 186 | lsHandle *itemHandle /* Handle to data (returned) */) |
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| 187 | /* |
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| 188 | * Adds a new item to the end of a previously created linked list. |
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| 189 | * This routine appends the item in constant time and |
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| 190 | * can be used freely without guilt. |
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| 191 | */ |
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| 192 | { |
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| 193 | lsDesc *realList = (lsDesc *) list; |
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| 194 | lsElem *newElem; |
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| 195 | |
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| 196 | newElem = ALLOC(lsElem, 1); |
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| 197 | newElem->userData = data; |
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| 198 | newElem->prevPtr = realList->botPtr; |
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| 199 | newElem->nextPtr = NIL(lsElem); |
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| 200 | newElem->mainList = realList; |
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| 201 | if (realList->topPtr == NIL(lsElem)) |
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| 202 | realList->topPtr = newElem; |
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| 203 | if (realList->botPtr != NIL(lsElem)) |
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| 204 | realList->botPtr->nextPtr = newElem; |
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| 205 | realList->botPtr = newElem; |
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| 206 | realList->length += 1; |
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| 207 | if (itemHandle) *itemHandle = (lsHandle) newElem; |
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| 208 | return(LS_OK); |
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| 209 | } |
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| 210 | |
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| 211 | /* |
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| 212 | * Retrieving the first and last items of a list |
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| 213 | */ |
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| 214 | |
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| 215 | lsStatus lsFirstItem( |
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| 216 | lsList list /* List to get item from */, |
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| 217 | lsGeneric data /* User data (returned) */, |
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| 218 | lsHandle *itemHandle /* Handle to data (returned) */) |
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| 219 | /* |
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| 220 | * Returns the first item in the list. If the list is empty, |
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| 221 | * it returns LS_NOMORE. Otherwise, it returns LS_OK. |
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| 222 | * If 'itemHandle' is non-zero, it will be filled with a |
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| 223 | * handle which may be used to generate a generator. |
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| 224 | */ |
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| 225 | { |
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| 226 | lsDesc *realList = (lsDesc *) list; |
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| 227 | |
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| 228 | if (realList->topPtr != NIL(lsElem)) { |
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| 229 | *(void **)data = realList->topPtr->userData; |
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| 230 | if (itemHandle) *itemHandle = (lsHandle) (realList->topPtr); |
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| 231 | return(LS_OK); |
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| 232 | } else { |
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| 233 | *(void **)data = (lsGeneric) 0; |
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| 234 | if (itemHandle) *itemHandle = (lsHandle) 0; |
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| 235 | return(LS_NOMORE); |
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| 236 | } |
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| 237 | } |
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| 238 | |
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| 239 | lsStatus lsLastItem( |
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| 240 | lsList list /* List to get item from */, |
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| 241 | lsGeneric data /* User data (returned) */, |
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| 242 | lsHandle *itemHandle /* Handle to data (returned) */) |
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| 243 | /* |
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| 244 | * Returns the last item of a list. If the list is empty, |
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| 245 | * the routine returns LS_NOMORE. Otherwise, 'data' will |
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| 246 | * be set to the last item and the routine will return LS_OK. |
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| 247 | * If 'itemHandle' is non-zero, it will be filled with a |
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| 248 | * handle which can be used to generate a generator postioned |
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| 249 | * at this item. |
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| 250 | */ |
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| 251 | { |
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| 252 | lsDesc *realList = (lsDesc *) list; |
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| 253 | |
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| 254 | if (realList->botPtr != NIL(lsElem)) { |
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| 255 | *(void **)data = realList->botPtr->userData; |
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| 256 | if (itemHandle) *itemHandle = (lsHandle) (realList->botPtr); |
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| 257 | return(LS_OK); |
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| 258 | } else { |
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| 259 | *(void **)data = (lsGeneric) 0; |
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| 260 | if (itemHandle) *itemHandle = (lsHandle) 0; |
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| 261 | return(LS_NOMORE); |
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| 262 | } |
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| 263 | } |
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| 264 | |
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| 265 | |
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| 266 | /* Length of a list */ |
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| 267 | |
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| 268 | int lsLength( |
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| 269 | lsList list /* List to get the length of */) |
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| 270 | /* |
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| 271 | * Returns the length of the list. The list must have been |
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| 272 | * already created using lsCreate. |
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| 273 | */ |
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| 274 | { |
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| 275 | lsDesc *realList = (lsDesc *) list; |
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| 276 | |
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| 277 | return(realList->length); |
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| 278 | } |
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| 279 | |
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| 280 | |
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| 281 | /* |
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| 282 | * Deleting first and last items of a list |
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| 283 | */ |
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| 284 | |
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| 285 | lsStatus lsDelBegin( |
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| 286 | lsList list /* List to delete item from */, |
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| 287 | lsGeneric data /* First item (returned) */) |
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| 288 | /* |
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| 289 | * This routine deletes the first item of a list. The user |
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| 290 | * data associated with the item is returned so the caller |
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| 291 | * may dispose of it. Returns LS_NOMORE if there is no |
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| 292 | * item to delete. |
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| 293 | */ |
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| 294 | { |
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| 295 | lsDesc *realList = (lsDesc *) list; |
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| 296 | lsElem *temp; |
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| 297 | |
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| 298 | if (realList->topPtr == NIL(lsElem)) { |
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| 299 | /* Nothing to delete */ |
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| 300 | *(void **)data = (lsGeneric) 0; |
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| 301 | return LS_NOMORE; |
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| 302 | } else { |
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| 303 | *(void **)data = realList->topPtr->userData; |
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| 304 | temp = realList->topPtr; |
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| 305 | realList->topPtr = realList->topPtr->nextPtr; |
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| 306 | if (temp->nextPtr != NIL(lsElem)) { |
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| 307 | /* There is something after the first item */ |
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| 308 | temp->nextPtr->prevPtr = NIL(lsElem); |
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| 309 | } else { |
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| 310 | /* Nothing after it - bottom becomes null as well */ |
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| 311 | realList->botPtr = NIL(lsElem); |
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| 312 | } |
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| 313 | FREE(temp); |
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| 314 | realList->length -= 1; |
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| 315 | } |
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| 316 | return LS_OK; |
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| 317 | } |
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| 318 | |
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| 319 | |
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| 320 | lsStatus lsDelEnd( |
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| 321 | lsList list /* List to delete item from */, |
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| 322 | lsGeneric data /* Last item (returned) */) |
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| 323 | /* |
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| 324 | * This routine deletes the last item of a list. The user |
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| 325 | * data associated with the item is returned so the caller |
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| 326 | * may dispose of it. Returns LS_NOMORE if there is nothing |
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| 327 | * to delete. |
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| 328 | */ |
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| 329 | { |
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| 330 | lsDesc *realList = (lsDesc *) list; |
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| 331 | lsElem *temp; |
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| 332 | |
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| 333 | if (realList->botPtr == NIL(lsElem)) { |
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| 334 | /* Nothing to delete */ |
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| 335 | *(void **)data = (lsGeneric) 0; |
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| 336 | return LS_NOMORE; |
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| 337 | } else { |
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| 338 | *(void **)data = realList->botPtr->userData; |
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| 339 | temp = realList->botPtr; |
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| 340 | realList->botPtr = realList->botPtr->prevPtr; |
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| 341 | if (temp->prevPtr != NIL(lsElem)) { |
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| 342 | /* There is something before the last item */ |
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| 343 | temp->prevPtr->nextPtr = NIL(lsElem); |
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| 344 | } else { |
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| 345 | /* Nothing before it - top becomes null as well */ |
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| 346 | realList->topPtr = NIL(lsElem); |
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| 347 | } |
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| 348 | FREE(temp); |
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| 349 | realList->length -= 1; |
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| 350 | } |
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| 351 | return LS_OK; |
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| 352 | } |
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| 353 | |
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| 354 | |
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| 355 | /* |
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| 356 | * List Generation Routines |
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| 357 | * |
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| 358 | * nowPtr is the element just before the next one to be generated |
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| 359 | */ |
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| 360 | |
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| 361 | lsGen lsStart( |
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| 362 | lsList list /* List to generate items from */) |
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| 363 | /* |
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| 364 | * This routine defines a generator which is used to step through |
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| 365 | * each item of the list. It returns a generator handle which should |
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| 366 | * be used when calling lsNext, lsPrev, lsInBefore, lsInAfter, lsDelete, |
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| 367 | * or lsFinish. |
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| 368 | */ |
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| 369 | { |
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| 370 | lsDesc *realList = (lsDesc *) list; |
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| 371 | lsGenInternal *newGen; |
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| 372 | |
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| 373 | newGen = ALLOC(lsGenInternal, 1); |
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| 374 | newGen->mainList = realList; |
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| 375 | newGen->beforeSpot = NIL(lsElem); |
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| 376 | newGen->afterSpot = realList->topPtr; |
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| 377 | return ( (lsGen) newGen ); |
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| 378 | } |
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| 379 | |
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| 380 | lsGen lsEnd( |
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| 381 | lsList list /* List to generate items from */) |
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| 382 | /* |
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| 383 | * This routine defines a generator which is used to step through |
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| 384 | * each item of a list. The generator is initialized to the end |
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| 385 | * of the list. |
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| 386 | */ |
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| 387 | { |
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| 388 | lsDesc *realList = (lsDesc *) list; |
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| 389 | lsGenInternal *newGen; |
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| 390 | |
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| 391 | newGen = ALLOC(lsGenInternal, 1); |
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| 392 | newGen->mainList = realList; |
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| 393 | newGen->beforeSpot = realList->botPtr; |
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| 394 | newGen->afterSpot = NIL(lsElem); |
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| 395 | return (lsGen) newGen; |
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| 396 | } |
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| 397 | |
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| 398 | lsGen lsGenHandle( |
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| 399 | lsHandle itemHandle /* Handle of an item */, |
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| 400 | lsGeneric data /* Data associated with item */, |
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| 401 | int option /* LS_BEFORE or LS_AFTER */) |
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| 402 | /* |
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| 403 | * This routine produces a generator given a handle. Handles |
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| 404 | * are produced whenever an item is added to a list. The generator |
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| 405 | * produced by this routine may be used when calling any of |
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| 406 | * the standard generation routines. NOTE: the generator |
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| 407 | * should be freed using lsFinish. The 'option' parameter |
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| 408 | * determines whether the generator spot is before or after |
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| 409 | * the handle item. |
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| 410 | */ |
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| 411 | { |
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| 412 | lsElem *realItem = (lsElem *) itemHandle; |
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| 413 | lsGenInternal *newGen; |
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| 414 | |
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| 415 | newGen = ALLOC(lsGenInternal, 1); |
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| 416 | newGen->mainList = realItem->mainList; |
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| 417 | *(void **)data = realItem->userData; |
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| 418 | if (option & LS_BEFORE) { |
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| 419 | newGen->beforeSpot = realItem->prevPtr; |
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| 420 | newGen->afterSpot = realItem; |
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| 421 | } else if (option & LS_AFTER) { |
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| 422 | newGen->beforeSpot = realItem; |
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| 423 | newGen->afterSpot = realItem->nextPtr; |
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| 424 | } else { |
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| 425 | FREE(newGen); |
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| 426 | newGen = (lsGenInternal *) 0; |
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| 427 | } |
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| 428 | return ( (lsGen) newGen ); |
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| 429 | } |
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| 430 | |
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| 431 | |
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| 432 | lsStatus lsNext( |
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| 433 | lsGen generator /* Generator handle */, |
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| 434 | lsGeneric data /* User data (return) */, |
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| 435 | lsHandle *itemHandle /* Handle to item (return) */) |
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| 436 | /* |
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| 437 | * Generates the item after the item previously generated by lsNext |
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| 438 | * or lsPrev. It returns a pointer to the user data structure in 'data'. |
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| 439 | * 'itemHandle' may be used to get a generation handle without |
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| 440 | * generating through the list to find the item. If there are no more |
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| 441 | * elements to generate, the routine returns LS_NOMORE (normally it |
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| 442 | * returns LS_OK). lsNext DOES NOT automatically clean up after all |
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| 443 | * elements have been generated. lsFinish must be called explicitly to do this. |
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| 444 | */ |
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| 445 | { |
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| 446 | register lsGenInternal *realGen = (lsGenInternal *) generator; |
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| 447 | |
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| 448 | if (realGen->afterSpot == NIL(lsElem)) { |
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| 449 | /* No more stuff to generate */ |
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| 450 | *(void **) data = (lsGeneric) 0; |
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| 451 | if (itemHandle) *itemHandle = (lsHandle) 0; |
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| 452 | return LS_NOMORE; |
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| 453 | } else { |
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| 454 | *(void **) data = realGen->afterSpot->userData; |
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| 455 | if (itemHandle) *itemHandle = (lsHandle) (realGen->afterSpot); |
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| 456 | /* Move the pointers down one */ |
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| 457 | realGen->beforeSpot = realGen->afterSpot; |
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| 458 | realGen->afterSpot = realGen->afterSpot->nextPtr; |
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| 459 | return LS_OK; |
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| 460 | } |
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| 461 | } |
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| 462 | |
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| 463 | |
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| 464 | lsStatus lsPrev( |
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| 465 | lsGen generator /* Generator handle */, |
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| 466 | lsGeneric data /* User data (return) */, |
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| 467 | lsHandle *itemHandle /* Handle to item (return) */) |
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| 468 | /* |
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| 469 | * Generates the item before the item previously generated by lsNext |
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| 470 | * or lsPrev. It returns a pointer to the user data structure in 'data'. |
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| 471 | * 'itemHandle' may be used to get a generation handle without |
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| 472 | * generating through the list to find the item. If there are no more |
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| 473 | * elements to generate, the routine returns LS_NOMORE (normally it |
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| 474 | * returns LS_OK). lsPrev DOES NOT automatically clean up after all |
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| 475 | * elements have been generated. lsFinish must be called explicitly to do this. |
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| 476 | */ |
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| 477 | { |
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| 478 | register lsGenInternal *realGen = (lsGenInternal *) generator; |
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| 479 | |
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| 480 | if (realGen->beforeSpot == NIL(lsElem)) { |
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| 481 | /* No more stuff to generate */ |
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| 482 | *(void **) data = (lsGeneric) 0; |
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| 483 | if (itemHandle) *itemHandle = (lsHandle) 0; |
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| 484 | return LS_NOMORE; |
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| 485 | } else { |
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| 486 | *(void **) data = realGen->beforeSpot->userData; |
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| 487 | if (itemHandle) *itemHandle = (lsHandle) (realGen->beforeSpot); |
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| 488 | /* Move the pointers down one */ |
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| 489 | realGen->afterSpot = realGen->beforeSpot; |
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| 490 | realGen->beforeSpot = realGen->beforeSpot->prevPtr; |
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| 491 | return LS_OK; |
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| 492 | } |
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| 493 | |
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| 494 | } |
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| 495 | |
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| 496 | lsStatus lsInBefore( |
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| 497 | lsGen generator /* Generator handle */, |
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| 498 | lsGeneric data /* Arbitrary pointer to data */, |
---|
| 499 | lsHandle *itemHandle /* Handle to item (return) */) |
---|
| 500 | /* |
---|
| 501 | * Inserts an element BEFORE the current spot. The item generated |
---|
| 502 | * by lsNext will be unchanged; the inserted item will be generated |
---|
| 503 | * by lsPrev. This modifies the list. 'itemHandle' may be used at |
---|
| 504 | * a later time to produce a generation handle without generating |
---|
| 505 | * through the list. |
---|
| 506 | */ |
---|
| 507 | { |
---|
| 508 | lsGenInternal *realGen = (lsGenInternal *) generator; |
---|
| 509 | lsElem *newElem; |
---|
| 510 | |
---|
| 511 | if (realGen->beforeSpot == NIL(lsElem)) { |
---|
| 512 | /* Item added to the beginning of the list */ |
---|
| 513 | (void) lsNewBegin((lsList) realGen->mainList, data, itemHandle); |
---|
| 514 | realGen->beforeSpot = realGen->mainList->topPtr; |
---|
| 515 | return LS_OK; |
---|
| 516 | } else if (realGen->afterSpot == NIL(lsElem)) { |
---|
| 517 | /* Item added to the end of the list */ |
---|
| 518 | (void) lsNewEnd((lsList) realGen->mainList, data, itemHandle); |
---|
| 519 | realGen->afterSpot = realGen->mainList->botPtr; |
---|
| 520 | return LS_OK; |
---|
| 521 | } else { |
---|
| 522 | /* Item added in the middle of the list */ |
---|
| 523 | newElem = ALLOC(lsElem, 1); |
---|
| 524 | newElem->mainList = realGen->mainList; |
---|
| 525 | newElem->prevPtr = realGen->beforeSpot; |
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| 526 | newElem->nextPtr = realGen->afterSpot; |
---|
| 527 | newElem->userData = data; |
---|
| 528 | realGen->beforeSpot->nextPtr = newElem; |
---|
| 529 | realGen->afterSpot->prevPtr = newElem; |
---|
| 530 | realGen->beforeSpot = newElem; |
---|
| 531 | realGen->mainList->length += 1; |
---|
| 532 | if (itemHandle) *itemHandle = (lsHandle) newElem; |
---|
| 533 | return LS_OK; |
---|
| 534 | } |
---|
| 535 | } |
---|
| 536 | |
---|
| 537 | lsStatus lsInAfter( |
---|
| 538 | lsGen generator /* Generator handle */, |
---|
| 539 | lsGeneric data /* Arbitrary pointer to data */, |
---|
| 540 | lsHandle *itemHandle /* Handle to item (return) */) |
---|
| 541 | /* |
---|
| 542 | * Inserts an element AFTER the current spot. The next item generated |
---|
| 543 | * by lsNext will be the new element. The next item generated by |
---|
| 544 | * lsPrev is unchanged. This modifies the list. 'itemHandle' may |
---|
| 545 | * be used at a later time to generate a generation handle without |
---|
| 546 | * searching through the list to find the item. |
---|
| 547 | */ |
---|
| 548 | { |
---|
| 549 | lsGenInternal *realGen = (lsGenInternal *) generator; |
---|
| 550 | lsElem *newElem; |
---|
| 551 | |
---|
| 552 | if (realGen->beforeSpot == NIL(lsElem)) { |
---|
| 553 | /* Item added to the beginning of the list */ |
---|
| 554 | (void) lsNewBegin((lsList) realGen->mainList, data, itemHandle); |
---|
| 555 | realGen->beforeSpot = realGen->mainList->topPtr; |
---|
| 556 | return LS_OK; |
---|
| 557 | } else if (realGen->afterSpot == NIL(lsElem)) { |
---|
| 558 | /* Item added to the end of the list */ |
---|
| 559 | (void) lsNewEnd((lsList) realGen->mainList, data, itemHandle); |
---|
| 560 | realGen->afterSpot = realGen->mainList->botPtr; |
---|
| 561 | return LS_OK; |
---|
| 562 | } else { |
---|
| 563 | /* Item added in the middle of the list */ |
---|
| 564 | newElem = ALLOC(lsElem, 1); |
---|
| 565 | newElem->mainList = realGen->mainList; |
---|
| 566 | newElem->prevPtr = realGen->beforeSpot; |
---|
| 567 | newElem->nextPtr = realGen->afterSpot; |
---|
| 568 | newElem->userData = data; |
---|
| 569 | realGen->beforeSpot->nextPtr = newElem; |
---|
| 570 | realGen->afterSpot->prevPtr = newElem; |
---|
| 571 | realGen->afterSpot = newElem; |
---|
| 572 | realGen->mainList->length += 1; |
---|
| 573 | if (itemHandle) *itemHandle = (lsHandle) newElem; |
---|
| 574 | return LS_OK; |
---|
| 575 | } |
---|
| 576 | } |
---|
| 577 | |
---|
| 578 | |
---|
| 579 | lsStatus lsDelBefore( |
---|
| 580 | lsGen generator /* Generator handle */, |
---|
| 581 | lsGeneric data /* Deleted item (returned) */) |
---|
| 582 | /* |
---|
| 583 | * Removes the item before the current spot. The next call to lsPrev |
---|
| 584 | * will return the item before the deleted item. The next call to lsNext |
---|
| 585 | * will be uneffected. This modifies the list. The routine returns |
---|
| 586 | * LS_BADSTATE if the user tries to call the routine and there is |
---|
| 587 | * no item before the current spot. This routine returns the userData |
---|
| 588 | * of the deleted item so it may be freed (if necessary). |
---|
| 589 | */ |
---|
| 590 | { |
---|
| 591 | lsGenInternal *realGen = (lsGenInternal *) generator; |
---|
| 592 | lsElem *doomedItem; |
---|
| 593 | |
---|
| 594 | if (realGen->beforeSpot == NIL(lsElem)) { |
---|
| 595 | /* No item to delete */ |
---|
| 596 | *(void **)data = (lsGeneric) 0; |
---|
| 597 | return LS_BADSTATE; |
---|
| 598 | } else if (realGen->beforeSpot == realGen->mainList->topPtr) { |
---|
| 599 | /* Delete the first item of the list */ |
---|
| 600 | realGen->beforeSpot = realGen->beforeSpot->prevPtr; |
---|
| 601 | return lsDelBegin((lsList) realGen->mainList, data); |
---|
| 602 | } else if (realGen->beforeSpot == realGen->mainList->botPtr) { |
---|
| 603 | /* Delete the last item of the list */ |
---|
| 604 | realGen->beforeSpot = realGen->beforeSpot->prevPtr; |
---|
| 605 | return lsDelEnd((lsList) realGen->mainList, data); |
---|
| 606 | } else { |
---|
| 607 | /* Normal mid list deletion */ |
---|
| 608 | doomedItem = realGen->beforeSpot; |
---|
| 609 | doomedItem->prevPtr->nextPtr = doomedItem->nextPtr; |
---|
| 610 | doomedItem->nextPtr->prevPtr = doomedItem->prevPtr; |
---|
| 611 | realGen->beforeSpot = doomedItem->prevPtr; |
---|
| 612 | realGen->mainList->length -= 1; |
---|
| 613 | *(void **)data = doomedItem->userData; |
---|
| 614 | FREE(doomedItem); |
---|
| 615 | return LS_OK; |
---|
| 616 | } |
---|
| 617 | } |
---|
| 618 | |
---|
| 619 | |
---|
| 620 | lsStatus lsDelAfter( |
---|
| 621 | lsGen generator /* Generator handle */, |
---|
| 622 | lsGeneric data /* Deleted item (returned) */) |
---|
| 623 | /* |
---|
| 624 | * Removes the item after the current spot. The next call to lsNext |
---|
| 625 | * will return the item after the deleted item. The next call to lsPrev |
---|
| 626 | * will be uneffected. This modifies the list. The routine returns |
---|
| 627 | * LS_BADSTATE if the user tries to call the routine and there is |
---|
| 628 | * no item after the current spot. This routine returns the userData |
---|
| 629 | * of the deleted item so it may be freed (if necessary). |
---|
| 630 | */ |
---|
| 631 | { |
---|
| 632 | lsGenInternal *realGen = (lsGenInternal *) generator; |
---|
| 633 | lsElem *doomedItem; |
---|
| 634 | |
---|
| 635 | if (realGen->afterSpot == NIL(lsElem)) { |
---|
| 636 | /* No item to delete */ |
---|
| 637 | *(void **)data = (lsGeneric) 0; |
---|
| 638 | return LS_BADSTATE; |
---|
| 639 | } else if (realGen->afterSpot == realGen->mainList->topPtr) { |
---|
| 640 | /* Delete the first item of the list */ |
---|
| 641 | realGen->afterSpot = realGen->afterSpot->nextPtr; |
---|
| 642 | return lsDelBegin((lsList) realGen->mainList, data); |
---|
| 643 | } else if (realGen->afterSpot == realGen->mainList->botPtr) { |
---|
| 644 | /* Delete the last item of the list */ |
---|
| 645 | realGen->afterSpot = realGen->afterSpot->nextPtr; |
---|
| 646 | return lsDelEnd((lsList) realGen->mainList, data); |
---|
| 647 | } else { |
---|
| 648 | /* Normal mid list deletion */ |
---|
| 649 | doomedItem = realGen->afterSpot; |
---|
| 650 | doomedItem->prevPtr->nextPtr = doomedItem->nextPtr; |
---|
| 651 | doomedItem->nextPtr->prevPtr = doomedItem->prevPtr; |
---|
| 652 | realGen->afterSpot = doomedItem->nextPtr; |
---|
| 653 | realGen->mainList->length -= 1; |
---|
| 654 | *(void **)data = doomedItem->userData; |
---|
| 655 | FREE(doomedItem); |
---|
| 656 | return LS_OK; |
---|
| 657 | } |
---|
| 658 | } |
---|
| 659 | |
---|
| 660 | |
---|
| 661 | lsStatus lsFinish( |
---|
| 662 | lsGen generator /* Generator handle */) |
---|
| 663 | /* |
---|
| 664 | * Marks the completion of a generation of list items. This routine should |
---|
| 665 | * be called after calls to lsNext to free resources used by the |
---|
| 666 | * generator. This rule applies even if all items of a list are |
---|
| 667 | * generated by lsNext. |
---|
| 668 | */ |
---|
| 669 | { |
---|
| 670 | lsGenInternal *realGen = (lsGenInternal *) generator; |
---|
| 671 | |
---|
| 672 | FREE(realGen); |
---|
| 673 | return(LS_OK); |
---|
| 674 | } |
---|
| 675 | |
---|
| 676 | |
---|
| 677 | |
---|
| 678 | /* |
---|
| 679 | * Functional list generation |
---|
| 680 | * |
---|
| 681 | * An alternate form of generating through items of a list is provided. |
---|
| 682 | * The routines below generatae through all items of a list in a given |
---|
| 683 | * direction and call a user provided function for each one. |
---|
| 684 | */ |
---|
| 685 | |
---|
| 686 | static lsStatus lsGenForm(lsStatus (*userFunc)(lsGeneric, lsGeneric), |
---|
| 687 | lsGeneric arg, lsGen gen, |
---|
| 688 | lsStatus (*gen_func)(lsGen, lsGeneric, lsHandle *), |
---|
| 689 | lsStatus (*del_func)(lsGen, lsGeneric)); |
---|
| 690 | |
---|
| 691 | lsStatus lsForeach( |
---|
| 692 | lsList list /* List to generate through */, |
---|
| 693 | lsStatus (*userFunc)(lsGeneric, lsGeneric) /* User provided function */, |
---|
| 694 | lsGeneric arg /* User provided data */) |
---|
| 695 | /* |
---|
| 696 | * This routine generates all items in `list' from the first item |
---|
| 697 | * to the last calling `userFunc' for each item. The function |
---|
| 698 | * should have the following form: |
---|
| 699 | * lsStatus userFunc(data, arg) |
---|
| 700 | * lsGeneric data; |
---|
| 701 | * lsGeneric arg; |
---|
| 702 | * `data' will be the user data associated with the item generated. |
---|
| 703 | * `arg' will be the same pointer provided to lsForeach. The |
---|
| 704 | * routine should return LS_OK to continue the generation, LS_STOP |
---|
| 705 | * to stop generating items, and LS_DELETE to delete the item |
---|
| 706 | * from the list. If the generation was stopped prematurely, |
---|
| 707 | * the routine will return LS_STOP. If the user provided function |
---|
| 708 | * does not return an appropriate value, the routine will return |
---|
| 709 | * LS_BADPARAM. |
---|
| 710 | */ |
---|
| 711 | { |
---|
| 712 | return lsGenForm(userFunc, arg, lsStart(list), lsNext, lsDelBefore); |
---|
| 713 | } |
---|
| 714 | |
---|
| 715 | |
---|
| 716 | lsStatus lsBackeach( |
---|
| 717 | lsList list /* List to generate through */, |
---|
| 718 | lsStatus (*userFunc)(lsGeneric, lsGeneric) /* User provided function */, |
---|
| 719 | lsGeneric arg /* User provided data */) |
---|
| 720 | /* |
---|
| 721 | * This routine is just like lsForeach except it generates |
---|
| 722 | * all items in `list' from the last item to the first. |
---|
| 723 | */ |
---|
| 724 | { |
---|
| 725 | return lsGenForm(userFunc, arg, lsEnd(list), lsPrev, lsDelAfter); |
---|
| 726 | } |
---|
| 727 | |
---|
| 728 | |
---|
| 729 | static lsStatus lsGenForm( |
---|
| 730 | lsStatus (*userFunc)(lsGeneric, lsGeneric) /* User provided function */, |
---|
| 731 | lsGeneric arg /* Data to pass to function */, |
---|
| 732 | lsGen gen /* Generator to use */, |
---|
| 733 | lsStatus (*gen_func)(lsGen, lsGeneric, lsHandle *) |
---|
| 734 | /* Generator function to use */, |
---|
| 735 | lsStatus (*del_func)(lsGen, lsGeneric) /* Deletion function to use */) |
---|
| 736 | /* |
---|
| 737 | * This is the function used to implement the two functional |
---|
| 738 | * generation interfaces to lists. |
---|
| 739 | */ |
---|
| 740 | { |
---|
| 741 | lsGeneric data; |
---|
| 742 | |
---|
| 743 | while ((*gen_func)(gen, &data, LS_NH) == LS_OK) { |
---|
| 744 | switch ((*userFunc)(data, arg)) { |
---|
| 745 | case LS_OK: |
---|
| 746 | /* Nothing */ |
---|
| 747 | break; |
---|
| 748 | case LS_STOP: |
---|
| 749 | (void) lsFinish(gen); |
---|
| 750 | return LS_STOP; |
---|
| 751 | case LS_DELETE: |
---|
| 752 | (*del_func)(gen, &data); |
---|
| 753 | break; |
---|
| 754 | default: |
---|
| 755 | return LS_BADPARAM; |
---|
| 756 | } |
---|
| 757 | } |
---|
| 758 | (void) lsFinish(gen); |
---|
| 759 | return LS_OK; |
---|
| 760 | } |
---|
| 761 | |
---|
| 762 | |
---|
| 763 | lsList lsQueryHandle( |
---|
| 764 | lsHandle itemHandle /* Handle of an item */) |
---|
| 765 | /* |
---|
| 766 | * This routine returns the associated list of the specified |
---|
| 767 | * handle. Returns 0 if there were problems. |
---|
| 768 | */ |
---|
| 769 | { |
---|
| 770 | lsElem *realHandle = (lsElem *) itemHandle; |
---|
| 771 | |
---|
| 772 | if (realHandle) { |
---|
| 773 | return (lsList) realHandle->mainList; |
---|
| 774 | } else { |
---|
| 775 | return (lsList) 0; |
---|
| 776 | } |
---|
| 777 | } |
---|
| 778 | |
---|
| 779 | lsGeneric lsFetchHandle(lsHandle itemHandle) |
---|
| 780 | /* |
---|
| 781 | * This routine returns the user data of the item associated with |
---|
| 782 | * `itemHandle'. |
---|
| 783 | */ |
---|
| 784 | { |
---|
| 785 | return ((lsElem *) itemHandle)->userData; |
---|
| 786 | } |
---|
| 787 | |
---|
| 788 | lsStatus lsRemoveItem( |
---|
| 789 | lsHandle itemHandle /* Handle of an item */, |
---|
| 790 | lsGeneric userData /* Returned data */) |
---|
| 791 | /* |
---|
| 792 | * This routine removes the item associated with `handle' from |
---|
| 793 | * its list and returns the user data associated with the item |
---|
| 794 | * for reclaimation purposes. Note this modifies the list |
---|
| 795 | * that originally contained `item'. |
---|
| 796 | */ |
---|
| 797 | { |
---|
| 798 | lsElem *realItem = (lsElem *) itemHandle; |
---|
| 799 | lsGenInternal gen; |
---|
| 800 | |
---|
| 801 | gen.mainList = realItem->mainList; |
---|
| 802 | gen.beforeSpot = realItem->prevPtr; |
---|
| 803 | gen.afterSpot = realItem; |
---|
| 804 | return lsDelAfter((lsGen) &gen, userData); |
---|
| 805 | } |
---|
| 806 | |
---|
| 807 | |
---|
| 808 | /* List sorting support */ |
---|
| 809 | #define TYPE lsElem |
---|
| 810 | #define SORT lsSortItems |
---|
| 811 | #define NEXT nextPtr |
---|
| 812 | #define FIELD userData |
---|
| 813 | #include "lsort.h" /* Merge sort by R. Rudell */ |
---|
| 814 | |
---|
| 815 | lsStatus lsSort( |
---|
| 816 | lsList list /* List to sort */, |
---|
| 817 | int (*compare)(lsGeneric, lsGeneric) /* Comparison function */) |
---|
| 818 | /* |
---|
| 819 | * This routine sorts `list' using `compare' as the comparison |
---|
| 820 | * function between items in the list. `compare' has the following form: |
---|
| 821 | * int compare(item1, item2) |
---|
| 822 | * lsGeneric item1, item2; |
---|
| 823 | * The routine should return -1 if item1 is less than item2, 0 if |
---|
| 824 | * they are equal, and 1 if item1 is greater than item2. |
---|
| 825 | * The routine uses a generic merge sort written by Rick Rudell. |
---|
| 826 | */ |
---|
| 827 | { |
---|
| 828 | lsDesc *realList = (lsDesc *) list; |
---|
| 829 | lsElem *idx, *lastElem; |
---|
| 830 | |
---|
| 831 | realList->topPtr = lsSortItems(realList->topPtr, compare, |
---|
| 832 | realList->length); |
---|
| 833 | |
---|
| 834 | /* Forward pointers are correct - fix backward pointers */ |
---|
| 835 | lastElem = (lsElem *) 0; |
---|
| 836 | for (idx = realList->topPtr; idx != (lsElem *) 0; idx = idx->nextPtr) { |
---|
| 837 | idx->prevPtr = lastElem; |
---|
| 838 | lastElem = idx; |
---|
| 839 | } |
---|
| 840 | /* lastElem is last item in list */ |
---|
| 841 | realList->botPtr = lastElem; |
---|
| 842 | return LS_OK; |
---|
| 843 | } |
---|
| 844 | |
---|
| 845 | |
---|
| 846 | lsStatus lsUniq( |
---|
| 847 | lsList list /* List to remove duplicates from */, |
---|
| 848 | int (*compare)(lsGeneric, lsGeneric) /* Item comparison function */, |
---|
| 849 | void (*delFunc)(lsGeneric) /* Function to release user data */) |
---|
| 850 | /* |
---|
| 851 | * This routine takes a sorted list and removes all duplicates |
---|
| 852 | * from it. `compare' has the following form: |
---|
| 853 | * int compare(item1, item2) |
---|
| 854 | * lsGeneric item1, item2; |
---|
| 855 | * The routine should return -1 if item1 is less than item2, 0 if |
---|
| 856 | * they are equal, and 1 if item1 is greater than item2. `delFunc' |
---|
| 857 | * will be called with a pointer to a user data item for each |
---|
| 858 | * duplicate destroyed. `delFunc' can be zero if no clean up |
---|
| 859 | * is required. |
---|
| 860 | */ |
---|
| 861 | { |
---|
| 862 | lsGeneric this_item, last_item; |
---|
| 863 | lsGenInternal realGen; |
---|
| 864 | lsDesc *realList = (lsDesc *) list; |
---|
| 865 | |
---|
| 866 | if (realList->length > 1) { |
---|
| 867 | last_item = realList->topPtr->userData; |
---|
| 868 | |
---|
| 869 | /* Inline creation of generator */ |
---|
| 870 | realGen.mainList = realList; |
---|
| 871 | realGen.beforeSpot = realList->topPtr; |
---|
| 872 | realGen.afterSpot = realList->topPtr->nextPtr; |
---|
| 873 | |
---|
| 874 | while (realGen.afterSpot) { |
---|
| 875 | this_item = realGen.afterSpot->userData; |
---|
| 876 | if ((*compare)(this_item, last_item) == 0) { |
---|
| 877 | /* Duplicate -- eliminate */ |
---|
| 878 | (void) lsDelAfter((lsGen) &realGen, &this_item); |
---|
| 879 | if (delFunc) (*delFunc)(this_item); |
---|
| 880 | } else { |
---|
| 881 | /* Move generator forward */ |
---|
| 882 | realGen.beforeSpot = realGen.afterSpot; |
---|
| 883 | realGen.afterSpot = realGen.afterSpot->nextPtr; |
---|
| 884 | last_item = this_item; |
---|
| 885 | } |
---|
| 886 | } |
---|
| 887 | } |
---|
| 888 | return LS_OK; |
---|
| 889 | } |
---|