https://github.com/WebBluetoothCG/demos/pull/42
Dependencies: BLE_API mbed-dev-bin nRF51822
Fork of microbit-dal by
source/types/RefCounted.cpp@74:04376b21995b, 2016-07-21 (annotated)
- Committer:
- fbeaufort
- Date:
- Thu Jul 21 07:19:19 2016 +0000
- Revision:
- 74:04376b21995b
- Parent:
- 1:8aa5cdb4ab67
First commit
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
Jonathan Austin |
1:8aa5cdb4ab67 | 1 | /* |
Jonathan Austin |
1:8aa5cdb4ab67 | 2 | The MIT License (MIT) |
Jonathan Austin |
1:8aa5cdb4ab67 | 3 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 4 | Copyright (c) 2016 British Broadcasting Corporation. |
Jonathan Austin |
1:8aa5cdb4ab67 | 5 | This software is provided by Lancaster University by arrangement with the BBC. |
Jonathan Austin |
1:8aa5cdb4ab67 | 6 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 7 | Permission is hereby granted, free of charge, to any person obtaining a |
Jonathan Austin |
1:8aa5cdb4ab67 | 8 | copy of this software and associated documentation files (the "Software"), |
Jonathan Austin |
1:8aa5cdb4ab67 | 9 | to deal in the Software without restriction, including without limitation |
Jonathan Austin |
1:8aa5cdb4ab67 | 10 | the rights to use, copy, modify, merge, publish, distribute, sublicense, |
Jonathan Austin |
1:8aa5cdb4ab67 | 11 | and/or sell copies of the Software, and to permit persons to whom the |
Jonathan Austin |
1:8aa5cdb4ab67 | 12 | Software is furnished to do so, subject to the following conditions: |
Jonathan Austin |
1:8aa5cdb4ab67 | 13 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 14 | The above copyright notice and this permission notice shall be included in |
Jonathan Austin |
1:8aa5cdb4ab67 | 15 | all copies or substantial portions of the Software. |
Jonathan Austin |
1:8aa5cdb4ab67 | 16 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 17 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
Jonathan Austin |
1:8aa5cdb4ab67 | 18 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
Jonathan Austin |
1:8aa5cdb4ab67 | 19 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
Jonathan Austin |
1:8aa5cdb4ab67 | 20 | THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
Jonathan Austin |
1:8aa5cdb4ab67 | 21 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
Jonathan Austin |
1:8aa5cdb4ab67 | 22 | FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
Jonathan Austin |
1:8aa5cdb4ab67 | 23 | DEALINGS IN THE SOFTWARE. |
Jonathan Austin |
1:8aa5cdb4ab67 | 24 | */ |
Jonathan Austin |
1:8aa5cdb4ab67 | 25 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 26 | /** |
Jonathan Austin |
1:8aa5cdb4ab67 | 27 | * Base class for payload for ref-counted objects. Used by ManagedString and MicroBitImage. |
Jonathan Austin |
1:8aa5cdb4ab67 | 28 | * There is no constructor, as this struct is typically malloc()ed. |
Jonathan Austin |
1:8aa5cdb4ab67 | 29 | */ |
Jonathan Austin |
1:8aa5cdb4ab67 | 30 | #include "mbed.h" |
Jonathan Austin |
1:8aa5cdb4ab67 | 31 | #include "MicroBitConfig.h" |
Jonathan Austin |
1:8aa5cdb4ab67 | 32 | #include "RefCounted.h" |
Jonathan Austin |
1:8aa5cdb4ab67 | 33 | #include "MicroBitDisplay.h" |
Jonathan Austin |
1:8aa5cdb4ab67 | 34 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 35 | /** |
Jonathan Austin |
1:8aa5cdb4ab67 | 36 | * Initializes for one outstanding reference. |
Jonathan Austin |
1:8aa5cdb4ab67 | 37 | */ |
Jonathan Austin |
1:8aa5cdb4ab67 | 38 | void RefCounted::init() |
Jonathan Austin |
1:8aa5cdb4ab67 | 39 | { |
Jonathan Austin |
1:8aa5cdb4ab67 | 40 | // Initialize to one reference (lowest bit set to 1) |
Jonathan Austin |
1:8aa5cdb4ab67 | 41 | refCount = 3; |
Jonathan Austin |
1:8aa5cdb4ab67 | 42 | } |
Jonathan Austin |
1:8aa5cdb4ab67 | 43 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 44 | /** |
Jonathan Austin |
1:8aa5cdb4ab67 | 45 | * Checks if the object resides in flash memory. |
Jonathan Austin |
1:8aa5cdb4ab67 | 46 | * |
Jonathan Austin |
1:8aa5cdb4ab67 | 47 | * @param t the object to check. |
Jonathan Austin |
1:8aa5cdb4ab67 | 48 | * |
Jonathan Austin |
1:8aa5cdb4ab67 | 49 | * @return true if the object resides in flash memory, false otherwise. |
Jonathan Austin |
1:8aa5cdb4ab67 | 50 | */ |
Jonathan Austin |
1:8aa5cdb4ab67 | 51 | static inline bool isReadOnlyInline(RefCounted *t) |
Jonathan Austin |
1:8aa5cdb4ab67 | 52 | { |
Jonathan Austin |
1:8aa5cdb4ab67 | 53 | uint32_t refCount = t->refCount; |
Jonathan Austin |
1:8aa5cdb4ab67 | 54 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 55 | if (refCount == 0xffff) |
Jonathan Austin |
1:8aa5cdb4ab67 | 56 | return true; // object in flash |
Jonathan Austin |
1:8aa5cdb4ab67 | 57 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 58 | // Do some sanity checking while we're here |
Jonathan Austin |
1:8aa5cdb4ab67 | 59 | if (refCount == 1 || // object should have been deleted |
Jonathan Austin |
1:8aa5cdb4ab67 | 60 | (refCount & 1) == 0) // refCount doesn't look right |
Jonathan Austin |
1:8aa5cdb4ab67 | 61 | microbit_panic(MICROBIT_HEAP_ERROR); |
Jonathan Austin |
1:8aa5cdb4ab67 | 62 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 63 | // Not read only |
Jonathan Austin |
1:8aa5cdb4ab67 | 64 | return false; |
Jonathan Austin |
1:8aa5cdb4ab67 | 65 | } |
Jonathan Austin |
1:8aa5cdb4ab67 | 66 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 67 | /** |
Jonathan Austin |
1:8aa5cdb4ab67 | 68 | * Checks if the object resides in flash memory. |
Jonathan Austin |
1:8aa5cdb4ab67 | 69 | * |
Jonathan Austin |
1:8aa5cdb4ab67 | 70 | * @return true if the object resides in flash memory, false otherwise. |
Jonathan Austin |
1:8aa5cdb4ab67 | 71 | */ |
Jonathan Austin |
1:8aa5cdb4ab67 | 72 | bool RefCounted::isReadOnly() |
Jonathan Austin |
1:8aa5cdb4ab67 | 73 | { |
Jonathan Austin |
1:8aa5cdb4ab67 | 74 | return isReadOnlyInline(this); |
Jonathan Austin |
1:8aa5cdb4ab67 | 75 | } |
Jonathan Austin |
1:8aa5cdb4ab67 | 76 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 77 | /** |
Jonathan Austin |
1:8aa5cdb4ab67 | 78 | * Increment reference count. |
Jonathan Austin |
1:8aa5cdb4ab67 | 79 | */ |
Jonathan Austin |
1:8aa5cdb4ab67 | 80 | void RefCounted::incr() |
Jonathan Austin |
1:8aa5cdb4ab67 | 81 | { |
Jonathan Austin |
1:8aa5cdb4ab67 | 82 | if (!isReadOnlyInline(this)) |
Jonathan Austin |
1:8aa5cdb4ab67 | 83 | refCount += 2; |
Jonathan Austin |
1:8aa5cdb4ab67 | 84 | } |
Jonathan Austin |
1:8aa5cdb4ab67 | 85 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 86 | /** |
Jonathan Austin |
1:8aa5cdb4ab67 | 87 | * Decrement reference count. |
Jonathan Austin |
1:8aa5cdb4ab67 | 88 | */ |
Jonathan Austin |
1:8aa5cdb4ab67 | 89 | void RefCounted::decr() |
Jonathan Austin |
1:8aa5cdb4ab67 | 90 | { |
Jonathan Austin |
1:8aa5cdb4ab67 | 91 | if (isReadOnlyInline(this)) |
Jonathan Austin |
1:8aa5cdb4ab67 | 92 | return; |
Jonathan Austin |
1:8aa5cdb4ab67 | 93 | |
Jonathan Austin |
1:8aa5cdb4ab67 | 94 | refCount -= 2; |
Jonathan Austin |
1:8aa5cdb4ab67 | 95 | if (refCount == 1) { |
Jonathan Austin |
1:8aa5cdb4ab67 | 96 | free(this); |
Jonathan Austin |
1:8aa5cdb4ab67 | 97 | } |
Jonathan Austin |
1:8aa5cdb4ab67 | 98 | } |