diff --git a/firmware/SOURCES b/firmware/SOURCES index a9f9ce5780..a68c4921ba 100644 --- a/firmware/SOURCES +++ b/firmware/SOURCES @@ -172,6 +172,7 @@ common/dircache.c #endif /* HAVE_DIRCACHE */ common/filefuncs.c common/format.c +common/linked_list.c #ifdef APPLICATION common/rbpaths.c #endif diff --git a/firmware/common/linked_list.c b/firmware/common/linked_list.c new file mode 100644 index 0000000000..006caacc91 --- /dev/null +++ b/firmware/common/linked_list.c @@ -0,0 +1,312 @@ +/*************************************************************************** + * __________ __ ___. + * Open \______ \ ____ ____ | | _\_ |__ _______ ___ + * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / + * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < + * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ + * \/ \/ \/ \/ \/ + * $Id$ + * + * Copyright (C) 2014 by Michael Sevakis + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + ****************************************************************************/ +#include +#include "linked_list.h" + + +/** (L)inked (L)ist **/ + +/** + * Helper to find the node previous to 'find' + * + * returns: NULL if 'find' is the first node + * last node if the 'find' isn't found in the list + */ +static struct ll_node * ll_search_prev(struct ll_head *list, + struct ll_node *find) +{ + struct ll_node *prev = NULL; + struct ll_node *node = list->head; + + while (node != NULL && node != find) + { + prev = node; + node = node->next; + } + + return prev; +} + +/** + * Initializes the singly-linked list + */ +void ll_init(struct ll_head *list) +{ + list->head = NULL; + list->tail = NULL; +} + +/** + * Adds a node to s singly-linked list using "insert next" + */ +void ll_insert_next(struct ll_head *list, struct ll_node *node, + struct ll_node *newnode) +{ + if (node == NULL) + { + node = list->head; + + newnode->next = node; + list->head = newnode; + + if (node == NULL) + list->tail = node; + } + else + { + struct ll_node *next = node->next; + + newnode->next = next; + node->next = newnode; + + if (next == NULL) + list->tail = newnode; + } +} + +/** + * Adds a node to a singly-linked list using "insert first" + */ +void ll_insert_first(struct ll_head *list, struct ll_node *node) +{ + struct ll_node *head = list->head; + + node->next = head; + list->head = node; + + if (head == NULL) + list->tail = node; +} + +/** + * Adds a node to a singly-linked list using "insert last" + */ +void ll_insert_last(struct ll_head *list, struct ll_node *node) +{ + struct ll_node *tail = list->tail; + + node->next = NULL; + list->tail = node; + + if (tail == NULL) + list->head = node; + else + tail->next = node; +} + +/** + * Removes the node after "node"; if there is none, nothing is changed + */ +void ll_remove_next(struct ll_head *list, struct ll_node *node) +{ + if (node == NULL) + { + node = list->head->next; + + list->head = node; + + if (node == NULL) + list->tail = NULL; + } + else + { + struct ll_node *next = node->next; + + if (next != NULL) + { + next = next->next; + node->next = next; + + if (!next) + list->tail = node; + } + } +} + +/** + * Removes the first node in the list + */ +void ll_remove_first(struct ll_head *list) +{ + struct ll_node *node = list->head->next; + + list->head = node; + + if (node == NULL) + list->tail = NULL; +} + +/** + * Removes the node from the list + */ +void ll_remove(struct ll_head *list, struct ll_node *node) +{ + ll_remove_next(list, ll_search_prev(list, node)); +} + + +/** (L)inked (L)ist (D)ouble **/ + +/** + * Initializes the doubly-linked list + */ +void lld_init(struct lld_head *list) +{ + list->head = NULL; + list->tail = NULL; + + /* tail could be stored in first item's prev pointer but this simplifies + the routines and maintains the non-circularity */ +} + +/** + * Adds a node to a doubly-linked list using "insert first" + */ +void lld_insert_first(struct lld_head *list, struct lld_node *node) +{ + struct lld_node *head = list->head; + + list->head = node; + + if (head == NULL) + list->tail = node; + else + head->prev = node; + + node->next = head; + node->prev = NULL; +} + +/** + * Adds a node to a doubly-linked list using "insert last" + */ +void lld_insert_last(struct lld_head *list, struct lld_node *node) +{ + struct lld_node *tail = list->tail; + + list->tail = node; + + if (tail == NULL) + list->head = node; + else + tail->next = node; + + node->next = NULL; + node->prev = tail; +} + +/** + * Removes a node from a doubly-linked list + */ +void lld_remove(struct lld_head *list, struct lld_node *node) +{ + struct lld_node *next = node->next; + struct lld_node *prev = node->prev; + + if (node == list->head) + list->head = next; + + if (node == list->tail) + list->tail = prev; + + if (prev != NULL) + prev->next = next; + + if (next != NULL) + next->prev = prev; +} + + +/** (L)inked (L)ist (D)ouble (C)ircular **/ + +/** + * Helper that inserts a node into a doubly-link circular list; does not + * affect list->head, just returns its state + */ +static inline struct lldc_node * lldc_insert(struct lldc_head *list, + struct lldc_node *node) +{ + struct lldc_node *head = list->head; + + if (head == NULL) + { + node->prev = node; + node->next = node; + } + else + { + node->prev = head->prev; + node->next = head; + head->prev->next = node; + head->prev = node; + } + + return head; +} + +/** + * Initializes the doubly-linked circular list + */ +void lldc_init(struct lldc_head *list) +{ + list->head = NULL; +} + +/** + * Adds a node to a doubly-linked circular list using "insert first" + */ +void lldc_insert_first(struct lldc_head *list, struct lldc_node *node) +{ + lldc_insert(list, node); + list->head = node; +} + +/** + * Adds a node to a doubly-linked circular list using "insert last" + */ +void lldc_insert_last(struct lldc_head *list, struct lldc_node *node) +{ + if (lldc_insert(list, node) == NULL) + list->head = node; +} + +/** + * Removes a node from a doubly-linked circular list + */ +void lldc_remove(struct lldc_head *list, struct lldc_node *node) +{ + struct lldc_node *next = node->next; + + if (node == list->head) + { + if (node == next) + { + list->head = NULL; + return; + } + + list->head = next; + } + + struct lldc_node *prev = node->prev; + next->prev = prev; + prev->next = next; +} diff --git a/firmware/include/linked_list.h b/firmware/include/linked_list.h new file mode 100644 index 0000000000..c678cfa7eb --- /dev/null +++ b/firmware/include/linked_list.h @@ -0,0 +1,114 @@ +/*************************************************************************** + * __________ __ ___. + * Open \______ \ ____ ____ | | _\_ |__ _______ ___ + * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / + * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < + * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ + * \/ \/ \/ \/ \/ + * $Id$ + * + * Copyright (C) 2014 by Michael Sevakis + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + ****************************************************************************/ +#ifndef LINKED_LIST_H +#define LINKED_LIST_H + +/*** + ** NOTES: + ** Node field order chosen so that one type can alias the other for forward + ** list traveral by the same code. + ** + ** Structures are separate, even if logically equivalent, to perform compile- + ** time type checking. + ** + */ + + +/* (L)inked (L)ist + * + * Format: + * + * XX->YY->ZZ->0 + * head--^ ^ + * tail----------+ + */ +struct ll_head +{ + struct ll_node *head; /* First list item */ + struct ll_node *tail; /* Last list item (to make insert_last O(1)) */ +}; + +struct ll_node +{ + struct ll_node *next; /* Next list item */ +}; + +void ll_init(struct ll_head *list); +void ll_insert_next(struct ll_head *list, struct ll_node *node, + struct ll_node *newnode); +void ll_insert_last(struct ll_head *list, struct ll_node *node); +void ll_remove_next(struct ll_head *list, struct ll_node *node); +void ll_remove(struct ll_head *list, struct ll_node *node); +void ll_insert_first(struct ll_head *list, struct ll_node *node); +void ll_remove_first(struct ll_head *list); + + +/* (L)inked (L)ist (D)double + * + * Format: + * + * 0<-XX<->YY<->ZZ->0 + * head----^ ^ + * tail--------------+ + */ +struct lld_head +{ + struct lld_node *head; /* First list item */ + struct lld_node *tail; /* Last list item (to make insert_last O(1)) */ +}; + +struct lld_node +{ + struct lld_node *next; /* Next list item */ + struct lld_node *prev; /* Previous list item */ +}; + +void lld_init(struct lld_head *list); +void lld_insert_first(struct lld_head *list, struct lld_node *node); +void lld_insert_last(struct lld_head *list, struct lld_node *node); +void lld_remove(struct lld_head *list, struct lld_node *node); + + +/* (L)inked (L)ist (D)ouble (C)ircular + * + * Format: + * +----------------+ + * | | + * +->XX<->YY<->ZZ<-+ + * head------^ + */ +struct lldc_head +{ + struct lldc_node *head; /* First list item */ +}; + +struct lldc_node +{ + struct lldc_node *next; /* Next list item */ + struct lldc_node *prev; /* Previous list item */ +}; + +void lldc_init(struct lldc_head *list); +void lldc_insert_first(struct lldc_head *list, struct lldc_node *node); +void lldc_insert_last(struct lldc_head *list, struct lldc_node *node); +void lldc_remove(struct lldc_head *list, struct lldc_node *node); + +#endif /* LINKED_LIST_H */