/**************************************************************************** * * Copyright (C) 1991 Kendall Bennett. * All rights reserved. * * Filename: $RCSfile$ * Version: $Revision$ * * Language: ANSI C * Environment: any * * Description: Module to implement doubly linked lists. Includes a routine * to peform a mergesort on the doubly linked list. * * $Id$ * * Revision History: * ----------------- * * $Log$ * Revision 1.1 1999/07/19 18:58:44 andrey * Moving dlist stuff into core. * * Revision 1.2 1999/05/11 00:01:42 zeev * * Get Apache to work. POST doesn't work yet. * * There are now -I directives for the absolute path of php4, php4/libzend and the builddir for * the Apache module, so we can #include any php/Zend header. * * Rename config.h to php_config.h * * Revision 1.1 1999/04/21 23:11:20 ssb * moved apache, com and hyperwave into ext/ * * Revision 1.1.1.1 1999/04/07 21:03:31 zeev * PHP 4.0 * * Revision 1.1.1.1 1999/03/17 04:29:11 andi * PHP4 * * Revision 1.1.1.1 1998/12/21 07:56:22 andi * Trying to start the zend CVS tree * * Revision 1.1 1998/08/12 09:29:16 steinm * First version of Hyperwave module. * * Revision 1.5 91/12/31 19:39:49 kjb * Modified include file directories. * * Revision 1.4 91/10/28 03:16:39 kjb * Ported to the Iris. * * Revision 1.3 91/09/27 03:09:18 kjb * Cosmetic change. * * Revision 1.2 91/09/03 18:27:42 ROOT_DOS * Ported to UNIX. * * Revision 1.1 91/09/01 18:35:23 ROOT_DOS * Initial revision * ****************************************************************************/ #ifndef MSVC5 #include "php_config.h" #endif #include #include #include #include "dlist.h" #define PUBLIC #define PRIVATE static PUBLIC void *dlst_newnode(int size) /**************************************************************************** * * Function: dlst_newnode * Parameters: size - Amount of memory to allocate for node * Returns: Pointer to the allocated node's user space. * * Description: Allocates the memory required for a node, adding a small * header at the start of the node. We return a reference to * the user space of the node, as if it had been allocated via * malloc(). * ****************************************************************************/ { PHP_DLST_BUCKET *node; if ( !(node = (PHP_DLST_BUCKET*)malloc(size + sizeof(PHP_DLST_BUCKET))) ) { fprintf(stderr,"Not enough memory to allocate list node.\n"); /* raise(SIGABRT);*/ return NULL; } return PHP_DLST_USERSPACE(node); /* Return pointer to user space */ } PUBLIC void dlst_freenode(void *node) /**************************************************************************** * * Function: dlst_freenode * Parameters: node - Node to free. * * Description: Frees a node previously allocated with lst_newnode(). * ****************************************************************************/ { free(PHP_DLST_HEADER(node)); } PUBLIC DLIST *dlst_init(void) /**************************************************************************** * * Function: dlst_init * Returns: Pointer to a newly created list. * * Description: Initialises a list and returns a pointer to it. * ****************************************************************************/ { DLIST *l; if ((l = (DLIST*)malloc(sizeof(DLIST))) != NULL) { l->count = 0; l->head = &(l->hz[0]); l->z = &(l->hz[1]); l->head->next = l->z->next = l->z; l->z->prev = l->head->prev = l->head; } else { fprintf(stderr,"Insufficient memory to allocate list\n"); /*raise(SIGABRT);*/ return NULL; } return l; } PUBLIC void dlst_kill(DLIST *l,void (*freeNode)(void *node)) /**************************************************************************** * * Function: dlst_kill * Parameters: l - List to kill * freeNode - Pointer to user routine to free a node * * Description: Kills the list l, by deleting all of the elements contained * within the list one by one and then deleting the list * itself. Note that we call the user supplied routine * (*freeNode)() to free each list node. This allows the user * program to perform any extra processing needed to kill each * node (if each node contains pointers to other items on the * heap for example). If no extra processing is required, just * pass the address of dlst_freenode(), ie: * * dlst_kill(myList,dlst_freenode); * ****************************************************************************/ { PHP_DLST_BUCKET *n,*p; n = l->head->next; while (n != l->z) { /* Free all nodes in list */ p = n; n = n->next; (*freeNode)(PHP_DLST_USERSPACE(p)); } free(l); /* Free the list itself */ } PUBLIC void dlst_insertafter(DLIST *l,void *node,void *after) /**************************************************************************** * * Function: lst_insertafter * Parameters: l - List to insert node into * node - Pointer to user space of node to insert * after - Pointer to user space of node to insert node after * * Description: Inserts a new node into the list after the node 'after'. To * insert a new node at the beginning of the list, user the * macro PHP_DLST_HEAD in place of 'after'. ie: * * dlst_insertafter(mylist,node,PHP_DLST_HEAD(mylist)); * ****************************************************************************/ { PHP_DLST_BUCKET *n = PHP_DLST_HEADER(node),*a = PHP_DLST_HEADER(after); n->next = a->next; a->next = n; n->prev = a; n->next->prev = n; l->count++; } PUBLIC void *dlst_deletenext(DLIST *l,void *node) /**************************************************************************** * * Function: lst_deletenext * Parameters: l - List to delete node from. * node - Node to delete the next node from * Returns: Pointer to the deleted node's userspace. * * Description: Removes the node AFTER 'node' from the list l. * ****************************************************************************/ { PHP_DLST_BUCKET *n = PHP_DLST_HEADER(node); node = PHP_DLST_USERSPACE(n->next); n->next->next->prev = n; n->next = n->next->next; l->count--; return node; } PUBLIC void *dlst_first(DLIST *l) /**************************************************************************** * * Function: dlst_first * Parameters: l - List to obtain first node from * Returns: Pointer to first node in list, NULL if list is empty. * * Description: Returns a pointer to the user space of the first node in * the list. If the list is empty, we return NULL. * ****************************************************************************/ { PHP_DLST_BUCKET *n; n = l->head->next; return (n == l->z ? NULL : PHP_DLST_USERSPACE(n)); } PUBLIC void *dlst_last(DLIST *l) /**************************************************************************** * * Function: dlst_last * Parameters: l - List to obtain last node from * Returns: Pointer to last node in list, NULL if list is empty. * * Description: Returns a pointer to the user space of the last node in * the list. If the list is empty, we return NULL. * ****************************************************************************/ { PHP_DLST_BUCKET *n; n = l->z->prev; return (n == l->head ? NULL : PHP_DLST_USERSPACE(n)); } PUBLIC void *dlst_next(void *prev) /**************************************************************************** * * Function: dlst_next * Parameters: prev - Previous node in list to obtain next node from * Returns: Pointer to the next node in the list, NULL at end of list. * * Description: Returns a pointer to the user space of the next node in the * list given a pointer to the user space of the previous node. * If we have reached the end of the list, we return NULL. The * end of the list is detected when the next pointer of a node * points back to itself, as does the dummy last node's next * pointer. This enables us to detect the end of the list * without needed access to the list data structure itself. * * NOTE: We do no checking to ensure that 'prev' is NOT a * NULL pointer. * ****************************************************************************/ { PHP_DLST_BUCKET *n = PHP_DLST_HEADER(prev); n = n->next; return (n == n->next ? NULL : PHP_DLST_USERSPACE(n)); } PUBLIC void *dlst_prev(void *next) /**************************************************************************** * * Function: dlst_prev * Parameters: next - Next node in list to obtain previous node from * Returns: Pointer to the previous node in the list, NULL at start list. * * Description: Returns a pointer to the user space of the prev node in the * list given a pointer to the user space of the next node. * If we have reached the start of the list, we return NULL. The * start of the list is detected when the prev pointer of a node * points back to itself, as does the dummy head node's prev * pointer. This enables us to detect the start of the list * without needed access to the list data structure itself. * * NOTE: We do no checking to ensure that 'next' is NOT a * NULL pointer. * ****************************************************************************/ { PHP_DLST_BUCKET *n = PHP_DLST_HEADER(next); n = n->prev; return (n == n->prev ? NULL : PHP_DLST_USERSPACE(n)); } /* Static globals required by merge() */ static PHP_DLST_BUCKET *z; static int (*cmp)(void*,void*); PRIVATE PHP_DLST_BUCKET *merge(PHP_DLST_BUCKET *a,PHP_DLST_BUCKET *b,PHP_DLST_BUCKET **end) /**************************************************************************** * * Function: merge * Parameters: a,b - Sublist's to merge * Returns: Pointer to the merged sublists. * * Description: Merges two sorted lists of nodes together into a single * sorted list. * ****************************************************************************/ { PHP_DLST_BUCKET *c; /* Go through the lists, merging them together in sorted order */ c = z; while (a != z && b != z) { if ((*cmp)(PHP_DLST_USERSPACE(a),PHP_DLST_USERSPACE(b)) <= 0) { c->next = a; c = a; a = a->next; } else { c->next = b; c = b; b = b->next; } }; /* If one of the lists is not exhausted, then re-attach it to the end * of the newly merged list */ if (a != z) c->next = a; if (b != z) c->next = b; /* Set *end to point to the end of the newly merged list */ while (c->next != z) c = c->next; *end = c; /* Determine the start of the merged lists, and reset z to point to * itself */ c = z->next; z->next = z; return c; } PUBLIC void dlst_mergesort(DLIST *l,int (*cmp_func)(void*,void*)) /**************************************************************************** * * Function: dlst_mergesort * Parameters: l - List to merge sort * cmp_func - Function to compare two user spaces * * Description: Mergesort's all the nodes in the list. 'cmp' must point to * a comparison function that can compare the user spaces of * two different nodes. 'cmp' should work the same as * strcmp(), in terms of the values it returns. Rather than * waste processing time keeping the previous pointers up to * date while performing the mergesort, we simply run through * the list at the end of the sort to fix the previous pointers. * ****************************************************************************/ { int i,N; PHP_DLST_BUCKET *a,*b; /* Pointers to sublists to merge */ PHP_DLST_BUCKET *c; /* Pointer to end of sorted sublists */ PHP_DLST_BUCKET *head; /* Pointer to dummy head node for list */ PHP_DLST_BUCKET *todo; /* Pointer to sublists yet to be sorted */ PHP_DLST_BUCKET *t; /* Temporary */ /* Set up globals required by merge() and pointer to head */ z = l->z; cmp = cmp_func; head = l->head; for (N = 1,a = z; a != head->next; N = N + N) { todo = head->next; c = head; while (todo != z) { /* Build first sublist to be merged, and splice from main list */ a = t = todo; for (i = 1; i < N; i++) t = t->next; b = t->next; t->next = z; t = b; /* Build second sublist to be merged and splice from main list */ for (i = 1; i < N; i++) t = t->next; todo = t->next; t->next = z; /* Merge the two sublists created, and set 'c' to point to the * end of the newly merged sublists. */ c->next = merge(a,b,&t); c = t; } } /* Fix the previous pointers for the list */ a = b = l->head; b = b->next; while (1) { b->prev = a; if (b == z) break; a = a->next; b = b->next; } }