]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/hfs/rangelist.c
xnu-3248.60.10.tar.gz
[apple/xnu.git] / bsd / hfs / rangelist.c
index a69f16f0db1dacbe534fb4348f4f323d135ef2db..81b384c480c26c60373147093d660ab17015965a 100644 (file)
@@ -1,14 +1,19 @@
 /*
- * Copyright (c) 2001 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2001-2014 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ * 
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
  * 
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * Please see the License for the specific language governing rights and
  * limitations under the License.
  * 
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 
+#if HFS
+
 #include <sys/param.h>
 #include <mach/boolean.h>
 #include <sys/time.h>
 #include <sys/malloc.h>
 
+#if !RANGELIST_TEST
+#include <kern/debug.h>
+#endif
+
 #include "rangelist.h"
 
 static enum rl_overlaptype rl_scan_from(struct rl_head *rangelist, off_t start, off_t end, struct rl_entry **overlap, struct rl_entry *range);
@@ -38,17 +49,13 @@ static void rl_collapse_neighbors(struct rl_head *rangelist, struct rl_entry *ra
 static void
 rl_verify(struct rl_head *rangelist) {
        struct rl_entry *entry;
+       struct rl_entry *next;
        off_t limit = 0;
        
-       if (CIRCLEQ_EMPTY(rangelist)) return;
-       entry = CIRCLEQ_FIRST(rangelist);
-       while (1) {
-               if (CIRCLEQ_NEXT(entry, rl_link) == entry) panic("rl_verify: circular rangelist?!");
-               if ((limit > 0) && (entry->rl_start <= limit)) panic("rl_verify: bad entry start?!");
-               if (entry->rl_end < entry->rl_start) panic("rl_verify: bad entry end?!");
+       TAILQ_FOREACH_SAFE(rangelist, entry, rl_link, next) {
+               if ((limit > 0) && (entry->rl_start <= limit)) panic("hfs: rl_verify: bad entry start?!");
+               if (entry->rl_end < entry->rl_start) panic("hfs: rl_verify: bad entry end?!");
                limit = entry->rl_end;
-               if (entry == CIRCLEQ_LAST(rangelist)) return;
-               entry = CIRCLEQ_NEXT(entry, rl_link);
        };
 }
 #endif
@@ -61,11 +68,9 @@ rl_verify(struct rl_head *rangelist) {
 void
 rl_init(struct rl_head *rangelist)
 {
-    CIRCLEQ_INIT(rangelist);
+    TAILQ_INIT(rangelist);
 }
 
-
-
 /*
  * Add a range to the list
  */
@@ -77,7 +82,7 @@ rl_add(off_t start, off_t end, struct rl_head *rangelist)
        enum rl_overlaptype ovcase;
 
 #ifdef RL_DIAGNOSTIC
-       if (end < start) panic("rl_add: end < start?!");
+       if (end < start) panic("hfs: rl_add: end < start?!");
 #endif
 
        ovcase = rl_scan(rangelist, start, end, &overlap);
@@ -94,20 +99,18 @@ rl_add(off_t start, off_t end, struct rl_head *rangelist)
        switch (ovcase) {
                case RL_NOOVERLAP: /* 0: no overlap */
                        /*
-                               * If the list was empty 'prev' is undisturbed and 'overlap' == NULL;
-                               * if the search hit a non-overlapping entry PAST the start of the
-                               * new range, 'prev' points to ITS predecessor, and 'overlap' points
-                               * to that entry:
-                               */
+                        * overlap points to the entry we should insert before, or
+                        * if NULL, we should insert at the end.
+                        */
                        MALLOC(range, struct rl_entry *, sizeof(*range), M_TEMP, M_WAITOK);
                        range->rl_start = start;
                        range->rl_end = end;
                        
                        /* Link in the new range: */
                        if (overlap) {
-                               CIRCLEQ_INSERT_AFTER(rangelist, overlap, range, rl_link);
+                               TAILQ_INSERT_BEFORE(overlap, range, rl_link);
                        } else {
-                               CIRCLEQ_INSERT_HEAD(rangelist, range, rl_link);
+                               TAILQ_INSERT_TAIL(rangelist, range, rl_link);
                        }
                        
                        /* Check to see if any ranges can be combined (possibly including the immediately
@@ -167,22 +170,22 @@ void
 rl_remove(off_t start, off_t end, struct rl_head *rangelist)
 {
        struct rl_entry *range, *next_range, *overlap, *splitrange;
-       int ovcase, moretotest;
+       int ovcase;
 
 #ifdef RL_DIAGNOSTIC
-       if (end < start) panic("rl_remove: end < start?!");
+       if (end < start) panic("hfs: rl_remove: end < start?!");
 #endif
 
-       if (CIRCLEQ_EMPTY(rangelist)) {
+       if (TAILQ_EMPTY(rangelist)) {
                return;
        };
-        
-       range = CIRCLEQ_FIRST(rangelist);
+
+       range = TAILQ_FIRST(rangelist);
        while ((ovcase = rl_scan_from(rangelist, start, end, &overlap, range))) {
                switch (ovcase) {
 
                case RL_MATCHINGOVERLAP: /* 1: overlap == range */
-                       CIRCLEQ_REMOVE(rangelist, overlap, rl_link);
+                       TAILQ_REMOVE(rangelist, overlap, rl_link);
                        FREE(overlap, M_TEMP);
                        break;
 
@@ -208,33 +211,26 @@ rl_remove(off_t start, off_t end, struct rl_head *rangelist)
                        /*
                        * Now link the new entry into the range list after the range from which it was split:
                        */
-                       CIRCLEQ_INSERT_AFTER(rangelist, overlap, splitrange, rl_link);
+                       TAILQ_INSERT_AFTER(rangelist, overlap, splitrange, rl_link);
                        break;
 
                case RL_OVERLAPISCONTAINED: /* 3: range contains overlap */
-                       moretotest = (overlap != CIRCLEQ_LAST(rangelist));
-#ifdef RL_DIAGNOSTIC
-                       if (CIRCLEQ_NEXT(overlap, rl_link) == overlap) panic("rl_remove: circular range list?!");
-#endif
-                       next_range = CIRCLEQ_NEXT(overlap, rl_link);    /* Check before discarding overlap entry */
-                       CIRCLEQ_REMOVE(rangelist, overlap, rl_link);
+                       /* Check before discarding overlap entry */
+                       next_range = TAILQ_NEXT(overlap, rl_link);
+                       TAILQ_REMOVE(rangelist, overlap, rl_link);
                        FREE(overlap, M_TEMP);
-                       if (moretotest) {
+                       if (next_range) {
                                range = next_range;
                                continue;
                        };
                        break;
 
                case RL_OVERLAPSTARTSBEFORE: /* 4: overlap starts before range */
-                       moretotest = (overlap != CIRCLEQ_LAST(rangelist));
                        overlap->rl_end = start - 1;
-                       if (moretotest) {
-#ifdef RL_DIAGNOSTIC
-                               if (CIRCLEQ_NEXT(overlap, rl_link) == overlap) panic("rl_remove: circular range list?!");
-#endif
-                               range = CIRCLEQ_NEXT(overlap, rl_link);
+                       range = TAILQ_NEXT(overlap, rl_link);
+                       if (range) {
                                continue;
-                       };
+                       }
                        break;
 
                case RL_OVERLAPENDSAFTER: /* 5: overlap ends after range */
@@ -263,16 +259,53 @@ rl_scan(struct rl_head *rangelist,
                off_t start,
                off_t end,
                struct rl_entry **overlap) {
-               
-       if (CIRCLEQ_EMPTY(rangelist)) {
-               *overlap = NULL;
-               return RL_NOOVERLAP;
-       };
-        
-       return rl_scan_from(rangelist, start, end, overlap, CIRCLEQ_FIRST(rangelist));  
+
+       return rl_scan_from(rangelist, start, end, overlap, TAILQ_FIRST(rangelist));    
 }
 
+enum rl_overlaptype
+rl_overlap(const struct rl_entry *range, off_t start, off_t end)
+{
+       /*
+        * OK, check for overlap
+        *
+        * Six cases:
+        *      0) no overlap (RL_NOOVERLAP)
+        *      1) overlap == range (RL_MATCHINGOVERLAP)
+        *      2) overlap contains range (RL_OVERLAPCONTAINSRANGE)
+        *      3) range contains overlap (RL_OVERLAPISCONTAINED)
+        *      4) overlap starts before range (RL_OVERLAPSTARTSBEFORE)
+        *      5) overlap ends after range (RL_OVERLAPENDSAFTER)
+        */
+       if (start > range->rl_end || range->rl_start > end) {
+               /* Case 0 (RL_NOOVERLAP) */
+               return RL_NOOVERLAP;
+       }
+
+       if (range->rl_start == start && range->rl_end == end) {
+               /* Case 1 (RL_MATCHINGOVERLAP) */
+               return RL_MATCHINGOVERLAP;
+       }
+
+       if (range->rl_start <= start && range->rl_end >= end) {
+               /* Case 2 (RL_OVERLAPCONTAINSRANGE) */
+               return RL_OVERLAPCONTAINSRANGE;
+       }
 
+       if (start <= range->rl_start && end >= range->rl_end) {
+               /* Case 3 (RL_OVERLAPISCONTAINED) */
+               return RL_OVERLAPISCONTAINED;
+       }
+
+       if (range->rl_start < start && range->rl_end < end) {
+               /* Case 4 (RL_OVERLAPSTARTSBEFORE) */
+               return RL_OVERLAPSTARTSBEFORE;
+       }
+
+       /* Case 5 (RL_OVERLAPENDSAFTER) */
+       // range->rl_start > start && range->rl_end > end
+       return RL_OVERLAPENDSAFTER;
+}
 
 /*
  * Walk the list of ranges for an entry to
@@ -282,119 +315,50 @@ rl_scan(struct rl_head *rangelist,
  *          There may be more than one.
  */
 static enum rl_overlaptype
-rl_scan_from(struct rl_head *rangelist,
+rl_scan_from(struct rl_head *rangelist __unused,
                         off_t start,
                         off_t end,
                         struct rl_entry **overlap,
-                       struct rl_entry *range)
+                        struct rl_entry *range)
 {
-       if (CIRCLEQ_EMPTY(rangelist)) {
-               *overlap = NULL;
-               return RL_NOOVERLAP;
-       };
-        
 #ifdef RL_DIAGNOSTIC
-               rl_verify(rangelist);
+       rl_verify(rangelist);
 #endif
 
-       *overlap = range;
-        
-       while (1) {
-               /*
-                * OK, check for overlap
-                *
-                * Six cases:
-                *      0) no overlap (RL_NOOVERLAP)
-                *      1) overlap == range (RL_MATCHINGOVERLAP)
-                *      2) overlap contains range (RL_OVERLAPCONTAINSRANGE)
-                *      3) range contains overlap (RL_OVERLAPISCONTAINED)
-                *      4) overlap starts before range (RL_OVERLAPSTARTSBEFORE)
-                *      5) overlap ends after range (RL_OVERLAPENDSAFTER)
-                */
-               if (((range->rl_end != RL_INFINITY) && (start > range->rl_end)) ||
-                       ((end != RL_INFINITY) && (range->rl_start > end))) {
-                       /* Case 0 (RL_NOOVERLAP), at least with the current entry: */
-                       if ((end != RL_INFINITY) && (range->rl_start > end)) {
-                               return RL_NOOVERLAP;
-                       };
-                       
-                       /* Check the other entries in the list: */
-                       if (range == CIRCLEQ_LAST(rangelist)) {
-                               return RL_NOOVERLAP;
-                       };
-#ifdef RL_DIAGNOSTIC
-                       if (CIRCLEQ_NEXT(range, rl_link) == range) panic("rl_scan_from: circular range list?!");
-#endif
-                       *overlap = range = CIRCLEQ_NEXT(range, rl_link);
-                       continue;
-               }
-               
-               if ((range->rl_start == start) && (range->rl_end == end)) {
-                       /* Case 1 (RL_MATCHINGOVERLAP) */
-                       return RL_MATCHINGOVERLAP;
-               }
-               
-               if ((range->rl_start <= start) &&
-                       (end != RL_INFINITY) &&
-                       ((range->rl_end >= end) || (range->rl_end == RL_INFINITY))) {
-                               /* Case 2 (RL_OVERLAPCONTAINSRANGE) */
-                       return RL_OVERLAPCONTAINSRANGE;
-               }
-               
-               if ((start <= range->rl_start) &&
-                       ((end == RL_INFINITY) ||
-                        ((range->rl_end != RL_INFINITY) && (end >= range->rl_end)))) {
-                       /* Case 3 (RL_OVERLAPISCONTAINED) */
-                       return RL_OVERLAPISCONTAINED;
-               }
-               
-               if ((range->rl_start < start) &&
-                       ((range->rl_end >= start) || (range->rl_end == RL_INFINITY))) {
-                       /* Case 4 (RL_OVERLAPSTARTSBEFORE) */
-                       return RL_OVERLAPSTARTSBEFORE;
-               }
-               
-               if ((range->rl_start > start) &&
-                       (end != RL_INFINITY) &&
-                       ((range->rl_end > end) || (range->rl_end == RL_INFINITY))) {
-                       /* Case 5 (RL_OVERLAPENDSAFTER) */
-                       return RL_OVERLAPENDSAFTER;
+       while (range) {
+               enum rl_overlaptype ot = rl_overlap(range, start, end);
+
+               if (ot != RL_NOOVERLAP || range->rl_start > end) {
+                       *overlap = range;
+                       return ot;
                }
 
-               /* Control should never reach here... */
-#ifdef RL_DIAGNOSTIC
-               panic("rl_scan_from: unhandled overlap condition?!");
-#endif
+               range = TAILQ_NEXT(range, rl_link);
        }
-        
+
+       *overlap = NULL;
        return RL_NOOVERLAP;
 }
 
 
 static void
 rl_collapse_forwards(struct rl_head *rangelist, struct rl_entry *range) {
-    struct rl_entry *next_range;
-    
-    while (1) {
-               if (range == CIRCLEQ_LAST(rangelist)) return;
-    
-#ifdef RL_DIAGNOSTIC
-               if (CIRCLEQ_NEXT(range, rl_link) == range) panic("rl_collapse_forwards: circular range list?!");
-#endif
-               next_range = CIRCLEQ_NEXT(range, rl_link);
-        if ((range->rl_end != RL_INFINITY) && (range->rl_end < next_range->rl_start - 1)) return;
+       struct rl_entry *next_range;
+       
+       while ((next_range = TAILQ_NEXT(range, rl_link))) { 
+               if ((range->rl_end != RL_INFINITY) && (range->rl_end < next_range->rl_start - 1)) return;
 
-        /* Expand this range to include the next range: */
-        range->rl_end = next_range->rl_end;
-        
-        /* Remove the now covered range from the list: */
-        CIRCLEQ_REMOVE(rangelist, next_range, rl_link);
-        FREE(next_range, M_TEMP);
+               /* Expand this range to include the next range: */
+               range->rl_end = next_range->rl_end;
+
+               /* Remove the now covered range from the list: */
+               TAILQ_REMOVE(rangelist, next_range, rl_link);
+               FREE(next_range, M_TEMP);
 
 #ifdef RL_DIAGNOSTIC
                rl_verify(rangelist);
 #endif
-    };
+       };
 }
 
 
@@ -403,14 +367,8 @@ static void
 rl_collapse_backwards(struct rl_head *rangelist, struct rl_entry *range) {
     struct rl_entry *prev_range;
     
-    while (1) {
-        if (range == CIRCLEQ_FIRST(rangelist)) return;
-        
-#ifdef RL_DIAGNOSTIC
-               if (CIRCLEQ_PREV(range, rl_link) == range) panic("rl_collapse_backwards: circular range list?!");
-#endif
-        prev_range = CIRCLEQ_PREV(range, rl_link);
-        if (prev_range->rl_end < range->rl_start - 1) {
+               while ((prev_range = TAILQ_PREV(range, rl_head, rl_link))) {
+                       if (prev_range->rl_end < range->rl_start -1) {
 #ifdef RL_DIAGNOSTIC
                        rl_verify(rangelist);
 #endif
@@ -421,7 +379,7 @@ rl_collapse_backwards(struct rl_head *rangelist, struct rl_entry *range) {
         range->rl_start = prev_range->rl_start;
     
         /* Remove the now covered range from the list: */
-        CIRCLEQ_REMOVE(rangelist, prev_range, rl_link);
+        TAILQ_REMOVE(rangelist, prev_range, rl_link);
         FREE(prev_range, M_TEMP);
     };
 }
@@ -434,3 +392,79 @@ rl_collapse_neighbors(struct rl_head *rangelist, struct rl_entry *range)
     rl_collapse_forwards(rangelist, range);
     rl_collapse_backwards(rangelist, range);
 }
+
+void rl_remove_all(struct rl_head *rangelist)
+{
+       struct rl_entry *r, *nextr;
+       TAILQ_FOREACH_SAFE(r, rangelist, rl_link, nextr)
+               FREE(r, M_TEMP);
+       TAILQ_INIT(rangelist);
+}
+
+/*
+ * In the case where b is contained by a, we return the the largest part
+ * remaining.  The result is stored in a.
+ */
+void rl_subtract(struct rl_entry *a, const struct rl_entry *b)
+{
+       switch (rl_overlap(b, a->rl_start, a->rl_end)) {
+               case RL_MATCHINGOVERLAP:
+               case RL_OVERLAPCONTAINSRANGE:
+                       a->rl_end = a->rl_start - 1;
+                       break;
+               case RL_OVERLAPISCONTAINED:
+                       // Keep the bigger part
+                       if (b->rl_start - a->rl_start >= a->rl_end - b->rl_end) {
+                               // Keep left
+                               a->rl_end = b->rl_start - 1;
+                       } else {
+                               // Keep right
+                               a->rl_start = b->rl_end + 1;
+                       }
+                       break;
+               case RL_OVERLAPSTARTSBEFORE:
+                       a->rl_start = b->rl_end + 1;
+                       break;
+               case RL_OVERLAPENDSAFTER:
+                       a->rl_end = b->rl_start - 1;
+                       break;
+               case RL_NOOVERLAP:
+                       break;
+       }
+}
+
+#else /* not HFS - temp workaround until 4277828 is fixed */
+/* stubs for exported routines that aren't present when we build kernel without HFS */
+
+#include <sys/types.h>
+
+void rl_add(off_t start, off_t end, void *rangelist);
+void rl_init(void *rangelist);
+void rl_remove(off_t start, off_t end, void *rangelist);
+int rl_scan(void *rangelist, off_t start, off_t end, void **overlap);
+
+void rl_add(__unused off_t start, __unused off_t end, __unused void *rangelist)
+{
+       return;
+}
+
+void rl_init(__unused void *rangelist)
+{
+       return;
+}
+
+void rl_remove(__unused off_t start, __unused off_t end, __unused void *rangelist)
+{
+       return;
+}
+
+int rl_scan(__unused void *rangelist, __unused off_t start, __unused off_t end, __unused void **overlap)
+{
+       return(0);
+}
+
+void rl_remove_all(struct rl_head *rangelist)
+{
+}
+
+#endif /* HFS */