diff options
Diffstat (limited to 'src/util')
| -rw-r--r-- | src/util/bit_reverse.c | 31 | ||||
| -rw-r--r-- | src/util/bit_reverse.h | 35 | ||||
| -rw-r--r-- | src/util/byte_reverse.c | 123 | ||||
| -rw-r--r-- | src/util/byte_reverse.h | 55 | ||||
| -rw-r--r-- | src/util/list.h | 608 | ||||
| -rw-r--r-- | src/util/list_sort.c | 162 | ||||
| -rw-r--r-- | src/util/list_sort.h | 33 |
7 files changed, 1047 insertions, 0 deletions
diff --git a/src/util/bit_reverse.c b/src/util/bit_reverse.c new file mode 100644 index 000000000..ba8a23ef1 --- /dev/null +++ b/src/util/bit_reverse.c @@ -0,0 +1,31 @@ +/* + * Copyright (C) 2003-2012 The Music Player Daemon Project + * http://www.musicpd.org + * + * 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 program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "bit_reverse.h" + +/** + * @see http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable + */ +const uint8_t bit_reverse_table[256] = +{ +#define R2(n) n, n + 2*64, n + 1*64, n + 3*64 +#define R4(n) R2(n), R2(n + 2*16), R2(n + 1*16), R2(n + 3*16) +#define R6(n) R4(n), R4(n + 2*4 ), R4(n + 1*4 ), R4(n + 3*4 ) + R6(0), R6(2), R6(1), R6(3) +}; diff --git a/src/util/bit_reverse.h b/src/util/bit_reverse.h new file mode 100644 index 000000000..e44693b1d --- /dev/null +++ b/src/util/bit_reverse.h @@ -0,0 +1,35 @@ +/* + * Copyright (C) 2003-2012 The Music Player Daemon Project + * http://www.musicpd.org + * + * 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 program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#ifndef MPD_BIT_REVERSE_H +#define MPD_BIT_REVERSE_H + +#include <glib.h> +#include <stdint.h> + +extern const uint8_t bit_reverse_table[256]; + +G_GNUC_CONST +static inline uint8_t +bit_reverse(uint8_t x) +{ + return bit_reverse_table[x]; +} + +#endif diff --git a/src/util/byte_reverse.c b/src/util/byte_reverse.c new file mode 100644 index 000000000..e96af14b9 --- /dev/null +++ b/src/util/byte_reverse.c @@ -0,0 +1,123 @@ +/* + * Copyright (C) 2003-2012 The Music Player Daemon Project + * http://www.musicpd.org + * + * 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 program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "byte_reverse.h" + +#include <glib.h> +#include <assert.h> + +void +reverse_bytes_16(uint16_t *dest, const uint16_t *src, const uint16_t *src_end) +{ + assert(dest != NULL); + assert(src != NULL); + assert(src_end >= src); + + while (src < src_end) { + const uint16_t x = *src++; + *dest++ = GUINT16_SWAP_LE_BE(x); + } +} + +void +reverse_bytes_32(uint32_t *dest, const uint32_t *src, const uint32_t *src_end) +{ + assert(dest != NULL); + assert(src != NULL); + assert(src_end >= src); + + while (src < src_end) { + const uint32_t x = *src++; + *dest++ = GUINT32_SWAP_LE_BE(x); + } +} + +void +reverse_bytes_64(uint64_t *dest, const uint64_t *src, const uint64_t *src_end) +{ + assert(dest != NULL); + assert(src != NULL); + assert(src_end >= src); + + while (src < src_end) { + const uint64_t x = *src++; + *dest++ = GUINT64_SWAP_LE_BE(x); + } +} + +static void +reverse_bytes_linear(uint8_t *dest, const uint8_t *src, size_t n) +{ + src += n; + + while (n-- > 0) + *dest++ = *--src; +} + +static void +reverse_bytes_generic(uint8_t *dest, + const uint8_t *src, const uint8_t *src_end, + size_t frame_size) +{ + assert(dest != NULL); + assert(src != NULL); + assert(src_end >= src); + assert(frame_size > 0); + assert((src_end - src) % frame_size == 0); + + while (src < src_end) { + reverse_bytes_linear(dest, src, frame_size); + dest += frame_size; + src += frame_size; + } +} + +void +reverse_bytes(uint8_t *dest, const uint8_t *src, const uint8_t *src_end, + size_t frame_size) +{ + assert(dest != NULL); + assert(src != NULL); + assert(src_end >= src); + assert(frame_size > 0); + assert((src_end - src) % frame_size == 0); + + switch (frame_size) { + case 2: + reverse_bytes_16((uint16_t *)dest, + (const uint16_t *)src, + (const uint16_t *)src_end); + break; + + case 4: + reverse_bytes_32((uint32_t *)dest, + (const uint32_t *)src, + (const uint32_t *)src_end); + break; + + case 8: + reverse_bytes_64((uint64_t *)dest, + (const uint64_t *)src, + (const uint64_t *)src_end); + break; + + default: + reverse_bytes_generic(dest, src, src_end, frame_size); + } +} diff --git a/src/util/byte_reverse.h b/src/util/byte_reverse.h new file mode 100644 index 000000000..63213d6c2 --- /dev/null +++ b/src/util/byte_reverse.h @@ -0,0 +1,55 @@ +/* + * Copyright (C) 2003-2012 The Music Player Daemon Project + * http://www.musicpd.org + * + * 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 program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#ifndef MPD_BYTE_REVERSE_H +#define MPD_BYTE_REVERSE_H + +#include <stdint.h> +#include <stddef.h> + +/** + * Reverse the bytes in each 16 bit "frame". This function can be + * used for in-place operation. + */ +void +reverse_bytes_16(uint16_t *dest, const uint16_t *src, const uint16_t *src_end); + +/** + * Reverse the bytes in each 32 bit "frame". This function can be + * used for in-place operation. + */ +void +reverse_bytes_32(uint32_t *dest, const uint32_t *src, const uint32_t *src_end); + +/** + * Reverse the bytes in each 64 bit "frame". This function can be + * used for in-place operation. + */ +void +reverse_bytes_64(uint64_t *dest, const uint64_t *src, const uint64_t *src_end); + +/** + * Reverse the bytes in each "frame". This function cannot be used + * for in-place operation. + */ +void +reverse_bytes(uint8_t *dest, const uint8_t *src, const uint8_t *src_end, + size_t frame_size); + +#endif diff --git a/src/util/list.h b/src/util/list.h new file mode 100644 index 000000000..fdab47675 --- /dev/null +++ b/src/util/list.h @@ -0,0 +1,608 @@ +/* + * Copyright (C) 2003-2012 The Music Player Daemon Project + * http://www.musicpd.org + * + * 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 program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +/* + * This code was imported from the Linux kernel. + * + */ + +#ifndef _LINUX_LIST_H +#define _LINUX_LIST_H + +#include <glib.h> + +#ifdef __clang__ +/* allow typeof() */ +#pragma GCC diagnostic ignored "-Wlanguage-extension-token" +#endif + +/** + * container_of - cast a member of a structure out to the containing structure + * @ptr: the pointer to the member. + * @type: the type of the container struct this is embedded in. + * @member: the name of the member within the struct. + * + */ +#define container_of(ptr, type, member) \ + (&G_STRUCT_MEMBER(type, ptr, -G_STRUCT_OFFSET(type, member))) + +/* + * These are non-NULL pointers that will result in page faults + * under normal circumstances, used to verify that nobody uses + * non-initialized list entries. + */ +#define LIST_POISON1 ((void *) 0x00100100) +#define LIST_POISON2 ((void *) 0x00200200) + +/* + * Simple doubly linked list implementation. + * + * Some of the internal functions ("__xxx") are useful when + * manipulating whole lists rather than single entries, as + * sometimes we already know the next/prev entries and we can + * generate better code by using them directly rather than + * using the generic single-entry routines. + */ + +struct list_head { + struct list_head *next, *prev; +}; + +#define LIST_HEAD_INIT(name) { &(name), &(name) } + +#define LIST_HEAD(name) \ + struct list_head name = LIST_HEAD_INIT(name) + +static inline void INIT_LIST_HEAD(struct list_head *list) +{ + list->next = list; + list->prev = list; +} + +/* + * Insert a new entry between two known consecutive entries. + * + * This is only for internal list manipulation where we know + * the prev/next entries already! + */ +#ifndef CONFIG_DEBUG_LIST +static inline void __list_add(struct list_head *new, + struct list_head *prev, + struct list_head *next) +{ + next->prev = new; + new->next = next; + new->prev = prev; + prev->next = new; +} +#else +extern void __list_add(struct list_head *new, + struct list_head *prev, + struct list_head *next); +#endif + +/** + * list_add - add a new entry + * @new: new entry to be added + * @head: list head to add it after + * + * Insert a new entry after the specified head. + * This is good for implementing stacks. + */ +static inline void list_add(struct list_head *new, struct list_head *head) +{ + __list_add(new, head, head->next); +} + + +/** + * list_add_tail - add a new entry + * @new: new entry to be added + * @head: list head to add it before + * + * Insert a new entry before the specified head. + * This is useful for implementing queues. + */ +static inline void list_add_tail(struct list_head *new, struct list_head *head) +{ + __list_add(new, head->prev, head); +} + +/* + * Delete a list entry by making the prev/next entries + * point to each other. + * + * This is only for internal list manipulation where we know + * the prev/next entries already! + */ +static inline void __list_del(struct list_head * prev, struct list_head * next) +{ + next->prev = prev; + prev->next = next; +} + +/** + * list_del - deletes entry from list. + * @entry: the element to delete from the list. + * Note: list_empty() on entry does not return true after this, the entry is + * in an undefined state. + */ +#ifndef CONFIG_DEBUG_LIST +static inline void __list_del_entry(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); +} + +static inline void list_del(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); + entry->next = LIST_POISON1; + entry->prev = LIST_POISON2; +} +#else +extern void __list_del_entry(struct list_head *entry); +extern void list_del(struct list_head *entry); +#endif + +/** + * list_replace - replace old entry by new one + * @old : the element to be replaced + * @new : the new element to insert + * + * If @old was empty, it will be overwritten. + */ +static inline void list_replace(struct list_head *old, + struct list_head *new) +{ + new->next = old->next; + new->next->prev = new; + new->prev = old->prev; + new->prev->next = new; +} + +static inline void list_replace_init(struct list_head *old, + struct list_head *new) +{ + list_replace(old, new); + INIT_LIST_HEAD(old); +} + +/** + * list_del_init - deletes entry from list and reinitialize it. + * @entry: the element to delete from the list. + */ +static inline void list_del_init(struct list_head *entry) +{ + __list_del_entry(entry); + INIT_LIST_HEAD(entry); +} + +/** + * list_move - delete from one list and add as another's head + * @list: the entry to move + * @head: the head that will precede our entry + */ +static inline void list_move(struct list_head *list, struct list_head *head) +{ + __list_del_entry(list); + list_add(list, head); +} + +/** + * list_move_tail - delete from one list and add as another's tail + * @list: the entry to move + * @head: the head that will follow our entry + */ +static inline void list_move_tail(struct list_head *list, + struct list_head *head) +{ + __list_del_entry(list); + list_add_tail(list, head); +} + +/** + * list_is_last - tests whether @list is the last entry in list @head + * @list: the entry to test + * @head: the head of the list + */ +static inline int list_is_last(const struct list_head *list, + const struct list_head *head) +{ + return list->next == head; +} + +/** + * list_empty - tests whether a list is empty + * @head: the list to test. + */ +static inline int list_empty(const struct list_head *head) +{ + return head->next == head; +} + +/** + * list_empty_careful - tests whether a list is empty and not being modified + * @head: the list to test + * + * Description: + * tests whether a list is empty _and_ checks that no other CPU might be + * in the process of modifying either member (next or prev) + * + * NOTE: using list_empty_careful() without synchronization + * can only be safe if the only activity that can happen + * to the list entry is list_del_init(). Eg. it cannot be used + * if another CPU could re-list_add() it. + */ +static inline int list_empty_careful(const struct list_head *head) +{ + struct list_head *next = head->next; + return (next == head) && (next == head->prev); +} + +/** + * list_rotate_left - rotate the list to the left + * @head: the head of the list + */ +static inline void list_rotate_left(struct list_head *head) +{ + struct list_head *first; + + if (!list_empty(head)) { + first = head->next; + list_move_tail(first, head); + } +} + +/** + * list_is_singular - tests whether a list has just one entry. + * @head: the list to test. + */ +static inline int list_is_singular(const struct list_head *head) +{ + return !list_empty(head) && (head->next == head->prev); +} + +static inline void __list_cut_position(struct list_head *list, + struct list_head *head, struct list_head *entry) +{ + struct list_head *new_first = entry->next; + list->next = head->next; + list->next->prev = list; + list->prev = entry; + entry->next = list; + head->next = new_first; + new_first->prev = head; +} + +/** + * list_cut_position - cut a list into two + * @list: a new list to add all removed entries + * @head: a list with entries + * @entry: an entry within head, could be the head itself + * and if so we won't cut the list + * + * This helper moves the initial part of @head, up to and + * including @entry, from @head to @list. You should + * pass on @entry an element you know is on @head. @list + * should be an empty list or a list you do not care about + * losing its data. + * + */ +static inline void list_cut_position(struct list_head *list, + struct list_head *head, struct list_head *entry) +{ + if (list_empty(head)) + return; + if (list_is_singular(head) && + (head->next != entry && head != entry)) + return; + if (entry == head) + INIT_LIST_HEAD(list); + else + __list_cut_position(list, head, entry); +} + +static inline void __list_splice(const struct list_head *list, + struct list_head *prev, + struct list_head *next) +{ + struct list_head *first = list->next; + struct list_head *last = list->prev; + + first->prev = prev; + prev->next = first; + + last->next = next; + next->prev = last; +} + +/** + * list_splice - join two lists, this is designed for stacks + * @list: the new list to add. + * @head: the place to add it in the first list. + */ +static inline void list_splice(const struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) + __list_splice(list, head, head->next); +} + +/** + * list_splice_tail - join two lists, each list being a queue + * @list: the new list to add. + * @head: the place to add it in the first list. + */ +static inline void list_splice_tail(struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) + __list_splice(list, head->prev, head); +} + +/** + * list_splice_init - join two lists and reinitialise the emptied list. + * @list: the new list to add. + * @head: the place to add it in the first list. + * + * The list at @list is reinitialised + */ +static inline void list_splice_init(struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) { + __list_splice(list, head, head->next); + INIT_LIST_HEAD(list); + } +} + +/** + * list_splice_tail_init - join two lists and reinitialise the emptied list + * @list: the new list to add. + * @head: the place to add it in the first list. + * + * Each of the lists is a queue. + * The list at @list is reinitialised + */ +static inline void list_splice_tail_init(struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) { + __list_splice(list, head->prev, head); + INIT_LIST_HEAD(list); + } +} + +/** + * list_entry - get the struct for this entry + * @ptr: the &struct list_head pointer. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_struct within the struct. + */ +#define list_entry(ptr, type, member) \ + container_of(ptr, type, member) + +/** + * list_first_entry - get the first element from a list + * @ptr: the list head to take the element from. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_struct within the struct. + * + * Note, that list is expected to be not empty. + */ +#define list_first_entry(ptr, type, member) \ + list_entry((ptr)->next, type, member) + +/** + * list_for_each - iterate over a list + * @pos: the &struct list_head to use as a loop cursor. + * @head: the head for your list. + */ +#define list_for_each(pos, head) \ + for (pos = (head)->next; pos != (head); pos = pos->next) + +/** + * __list_for_each - iterate over a list + * @pos: the &struct list_head to use as a loop cursor. + * @head: the head for your list. + * + * This variant doesn't differ from list_for_each() any more. + * We don't do prefetching in either case. + */ +#define __list_for_each(pos, head) \ + for (pos = (head)->next; pos != (head); pos = pos->next) + +/** + * list_for_each_prev - iterate over a list backwards + * @pos: the &struct list_head to use as a loop cursor. + * @head: the head for your list. + */ +#define list_for_each_prev(pos, head) \ + for (pos = (head)->prev; pos != (head); pos = pos->prev) + +/** + * list_for_each_safe - iterate over a list safe against removal of list entry + * @pos: the &struct list_head to use as a loop cursor. + * @n: another &struct list_head to use as temporary storage + * @head: the head for your list. + */ +#define list_for_each_safe(pos, n, head) \ + for (pos = (head)->next, n = pos->next; pos != (head); \ + pos = n, n = pos->next) + +/** + * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry + * @pos: the &struct list_head to use as a loop cursor. + * @n: another &struct list_head to use as temporary storage + * @head: the head for your list. + */ +#define list_for_each_prev_safe(pos, n, head) \ + for (pos = (head)->prev, n = pos->prev; \ + pos != (head); \ + pos = n, n = pos->prev) + +/** + * list_for_each_entry - iterate over list of given type + * @pos: the type * to use as a loop cursor. + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + */ +#define list_for_each_entry(pos, head, member) \ + for (pos = list_entry((head)->next, typeof(*pos), member); \ + &pos->member != (head); \ + pos = list_entry(pos->member.next, typeof(*pos), member)) + +/** + * list_for_each_entry_reverse - iterate backwards over list of given type. + * @pos: the type * to use as a loop cursor. + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + */ +#define list_for_each_entry_reverse(pos, head, member) \ + for (pos = list_entry((head)->prev, typeof(*pos), member); \ + &pos->member != (head); \ + pos = list_entry(pos->member.prev, typeof(*pos), member)) + +/** + * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue() + * @pos: the type * to use as a start point + * @head: the head of the list + * @member: the name of the list_struct within the struct. + * + * Prepares a pos entry for use as a start point in list_for_each_entry_continue(). + */ +#define list_prepare_entry(pos, head, member) \ + ((pos) ? : list_entry(head, typeof(*pos), member)) + +/** + * list_for_each_entry_continue - continue iteration over list of given type + * @pos: the type * to use as a loop cursor. + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + * + * Continue to iterate over list of given type, continuing after + * the current position. + */ +#define list_for_each_entry_continue(pos, head, member) \ + for (pos = list_entry(pos->member.next, typeof(*pos), member); \ + &pos->member != (head); \ + pos = list_entry(pos->member.next, typeof(*pos), member)) + +/** + * list_for_each_entry_continue_reverse - iterate backwards from the given point + * @pos: the type * to use as a loop cursor. + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + * + * Start to iterate over list of given type backwards, continuing after + * the current position. + */ +#define list_for_each_entry_continue_reverse(pos, head, member) \ + for (pos = list_entry(pos->member.prev, typeof(*pos), member); \ + &pos->member != (head); \ + pos = list_entry(pos->member.prev, typeof(*pos), member)) + +/** + * list_for_each_entry_from - iterate over list of given type from the current point + * @pos: the type * to use as a loop cursor. + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + * + * Iterate over list of given type, continuing from current position. + */ +#define list_for_each_entry_from(pos, head, member) \ + for (; &pos->member != (head); \ + pos = list_entry(pos->member.next, typeof(*pos), member)) + +/** + * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry + * @pos: the type * to use as a loop cursor. + * @n: another type * to use as temporary storage + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + */ +#define list_for_each_entry_safe(pos, n, head, member) \ + for (pos = list_entry((head)->next, typeof(*pos), member), \ + n = list_entry(pos->member.next, typeof(*pos), member); \ + &pos->member != (head); \ + pos = n, n = list_entry(n->member.next, typeof(*n), member)) + +/** + * list_for_each_entry_safe_continue - continue list iteration safe against removal + * @pos: the type * to use as a loop cursor. + * @n: another type * to use as temporary storage + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + * + * Iterate over list of given type, continuing after current point, + * safe against removal of list entry. + */ +#define list_for_each_entry_safe_continue(pos, n, head, member) \ + for (pos = list_entry(pos->member.next, typeof(*pos), member), \ + n = list_entry(pos->member.next, typeof(*pos), member); \ + &pos->member != (head); \ + pos = n, n = list_entry(n->member.next, typeof(*n), member)) + +/** + * list_for_each_entry_safe_from - iterate over list from current point safe against removal + * @pos: the type * to use as a loop cursor. + * @n: another type * to use as temporary storage + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + * + * Iterate over list of given type from current point, safe against + * removal of list entry. + */ +#define list_for_each_entry_safe_from(pos, n, head, member) \ + for (n = list_entry(pos->member.next, typeof(*pos), member); \ + &pos->member != (head); \ + pos = n, n = list_entry(n->member.next, typeof(*n), member)) + +/** + * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal + * @pos: the type * to use as a loop cursor. + * @n: another type * to use as temporary storage + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + * + * Iterate backwards over list of given type, safe against removal + * of list entry. + */ +#define list_for_each_entry_safe_reverse(pos, n, head, member) \ + for (pos = list_entry((head)->prev, typeof(*pos), member), \ + n = list_entry(pos->member.prev, typeof(*pos), member); \ + &pos->member != (head); \ + pos = n, n = list_entry(n->member.prev, typeof(*n), member)) + +/** + * list_safe_reset_next - reset a stale list_for_each_entry_safe loop + * @pos: the loop cursor used in the list_for_each_entry_safe loop + * @n: temporary storage used in list_for_each_entry_safe + * @member: the name of the list_struct within the struct. + * + * list_safe_reset_next is not safe to use in general if the list may be + * modified concurrently (eg. the lock is dropped in the loop body). An + * exception to this is if the cursor element (pos) is pinned in the list, + * and list_safe_reset_next is called after re-taking the lock and before + * completing the current iteration of the loop body. + */ +#define list_safe_reset_next(pos, n, member) \ + n = list_entry(pos->member.next, typeof(*pos), member) + +#endif diff --git a/src/util/list_sort.c b/src/util/list_sort.c new file mode 100644 index 000000000..ddf3208e9 --- /dev/null +++ b/src/util/list_sort.c @@ -0,0 +1,162 @@ +/* + * Copyright (C) 2003-2012 The Music Player Daemon Project + * http://www.musicpd.org + * + * 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 program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +/* + * This code was imported from the Linux kernel. + * + */ + +#include "list_sort.h" +#include "list.h" + +#include <glib.h> +#include <string.h> + +#define unlikely G_UNLIKELY +#define ARRAY_SIZE G_N_ELEMENTS + +#define MAX_LIST_LENGTH_BITS 20 + +/* + * Returns a list organized in an intermediate format suited + * to chaining of merge() calls: null-terminated, no reserved or + * sentinel head node, "prev" links not maintained. + */ +static struct list_head *merge(void *priv, + int (*cmp)(void *priv, struct list_head *a, + struct list_head *b), + struct list_head *a, struct list_head *b) +{ + struct list_head head, *tail = &head; + + while (a && b) { + /* if equal, take 'a' -- important for sort stability */ + if ((*cmp)(priv, a, b) <= 0) { + tail->next = a; + a = a->next; + } else { + tail->next = b; + b = b->next; + } + tail = tail->next; + } + tail->next = a?a:b; + return head.next; +} + +/* + * Combine final list merge with restoration of standard doubly-linked + * list structure. This approach duplicates code from merge(), but + * runs faster than the tidier alternatives of either a separate final + * prev-link restoration pass, or maintaining the prev links + * throughout. + */ +static void merge_and_restore_back_links(void *priv, + int (*cmp)(void *priv, struct list_head *a, + struct list_head *b), + struct list_head *head, + struct list_head *a, struct list_head *b) +{ + struct list_head *tail = head; + + while (a && b) { + /* if equal, take 'a' -- important for sort stability */ + if ((*cmp)(priv, a, b) <= 0) { + tail->next = a; + a->prev = tail; + a = a->next; + } else { + tail->next = b; + b->prev = tail; + b = b->next; + } + tail = tail->next; + } + tail->next = a ? a : b; + + do { + /* + * In worst cases this loop may run many iterations. + * Continue callbacks to the client even though no + * element comparison is needed, so the client's cmp() + * routine can invoke cond_resched() periodically. + */ + (*cmp)(priv, tail->next, tail->next); + + tail->next->prev = tail; + tail = tail->next; + } while (tail->next); + + tail->next = head; + head->prev = tail; +} + +/** + * list_sort - sort a list + * @priv: private data, opaque to list_sort(), passed to @cmp + * @head: the list to sort + * @cmp: the elements comparison function + * + * This function implements "merge sort", which has O(nlog(n)) + * complexity. + * + * The comparison function @cmp must return a negative value if @a + * should sort before @b, and a positive value if @a should sort after + * @b. If @a and @b are equivalent, and their original relative + * ordering is to be preserved, @cmp must return 0. + */ +void list_sort(void *priv, struct list_head *head, + int (*cmp)(void *priv, struct list_head *a, + struct list_head *b)) +{ + struct list_head *part[MAX_LIST_LENGTH_BITS+1]; /* sorted partial lists + -- last slot is a sentinel */ + int lev; /* index into part[] */ + int max_lev = 0; + struct list_head *list; + + if (list_empty(head)) + return; + + memset(part, 0, sizeof(part)); + + head->prev->next = NULL; + list = head->next; + + while (list) { + struct list_head *cur = list; + list = list->next; + cur->next = NULL; + + for (lev = 0; part[lev]; lev++) { + cur = merge(priv, cmp, part[lev], cur); + part[lev] = NULL; + } + if (lev > max_lev) { + max_lev = lev; + } + part[lev] = cur; + } + + for (lev = 0; lev < max_lev; lev++) + if (part[lev]) + list = merge(priv, cmp, part[lev], list); + + merge_and_restore_back_links(priv, cmp, head, part[max_lev], list); +} diff --git a/src/util/list_sort.h b/src/util/list_sort.h new file mode 100644 index 000000000..7a65020b9 --- /dev/null +++ b/src/util/list_sort.h @@ -0,0 +1,33 @@ +/* + * Copyright (C) 2003-2012 The Music Player Daemon Project + * http://www.musicpd.org + * + * 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 program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +/* + * This code was imported from the Linux kernel. + * + */ + +#ifndef _LINUX_LIST_SORT_H +#define _LINUX_LIST_SORT_H + +struct list_head; + +void list_sort(void *priv, struct list_head *head, + int (*cmp)(void *priv, struct list_head *a, + struct list_head *b)); +#endif |