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Fork of STM32_USBDevice by
USBSerial/CircBuffer.h@77:a98f786d05d4, 2018-07-24 (annotated)
- Committer:
- Troels Nilsson
- Date:
- Tue Jul 24 13:08:29 2018 +0200
- Branch:
- feature_WebUSB
- Revision:
- 77:a98f786d05d4
- Parent:
- 56:151ba33713ff
Changed USBWebUSBSerial to use non-blocking writes
USBWebUSBSerial now uses an internal buffer to do non-blocking, async writes
Expanded CircBuffer to be able to queue/dequeue a block of data (to avoid looping a lot)
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
samux | 1:80ab0d068708 | 1 | /* Copyright (c) 2010-2011 mbed.org, MIT License |
samux | 1:80ab0d068708 | 2 | * |
samux | 1:80ab0d068708 | 3 | * Permission is hereby granted, free of charge, to any person obtaining a copy of this software |
samux | 1:80ab0d068708 | 4 | * and associated documentation files (the "Software"), to deal in the Software without |
samux | 1:80ab0d068708 | 5 | * restriction, including without limitation the rights to use, copy, modify, merge, publish, |
samux | 1:80ab0d068708 | 6 | * distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the |
samux | 1:80ab0d068708 | 7 | * Software is furnished to do so, subject to the following conditions: |
samux | 1:80ab0d068708 | 8 | * |
samux | 1:80ab0d068708 | 9 | * The above copyright notice and this permission notice shall be included in all copies or |
samux | 1:80ab0d068708 | 10 | * substantial portions of the Software. |
samux | 1:80ab0d068708 | 11 | * |
samux | 1:80ab0d068708 | 12 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING |
samux | 1:80ab0d068708 | 13 | * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
samux | 1:80ab0d068708 | 14 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, |
samux | 1:80ab0d068708 | 15 | * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
samux | 1:80ab0d068708 | 16 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
samux | 1:80ab0d068708 | 17 | */ |
samux | 1:80ab0d068708 | 18 | |
samux | 1:80ab0d068708 | 19 | #ifndef CIRCBUFFER_H |
samux | 1:80ab0d068708 | 20 | #define CIRCBUFFER_H |
samux | 1:80ab0d068708 | 21 | |
mbed_official | 51:deafa44182d9 | 22 | template <class T, int Size> |
samux | 1:80ab0d068708 | 23 | class CircBuffer { |
samux | 1:80ab0d068708 | 24 | public: |
mbed_official | 51:deafa44182d9 | 25 | CircBuffer():write(0), read(0){} |
samux | 1:80ab0d068708 | 26 | bool isFull() { |
samux | 1:80ab0d068708 | 27 | return ((write + 1) % size == read); |
samux | 1:80ab0d068708 | 28 | }; |
samux | 1:80ab0d068708 | 29 | |
samux | 1:80ab0d068708 | 30 | bool isEmpty() { |
samux | 1:80ab0d068708 | 31 | return (read == write); |
samux | 1:80ab0d068708 | 32 | }; |
samux | 1:80ab0d068708 | 33 | |
samux | 1:80ab0d068708 | 34 | void queue(T k) { |
samux | 1:80ab0d068708 | 35 | if (isFull()) { |
samux | 1:80ab0d068708 | 36 | read++; |
samux | 1:80ab0d068708 | 37 | read %= size; |
samux | 1:80ab0d068708 | 38 | } |
samux | 1:80ab0d068708 | 39 | buf[write++] = k; |
samux | 1:80ab0d068708 | 40 | write %= size; |
samux | 1:80ab0d068708 | 41 | } |
samux | 1:80ab0d068708 | 42 | |
samux | 1:80ab0d068708 | 43 | uint16_t available() { |
samux | 1:80ab0d068708 | 44 | return (write >= read) ? write - read : size - read + write; |
samux | 1:80ab0d068708 | 45 | }; |
samux | 1:80ab0d068708 | 46 | |
samux | 1:80ab0d068708 | 47 | bool dequeue(T * c) { |
samux | 1:80ab0d068708 | 48 | bool empty = isEmpty(); |
samux | 1:80ab0d068708 | 49 | if (!empty) { |
samux | 1:80ab0d068708 | 50 | *c = buf[read++]; |
samux | 1:80ab0d068708 | 51 | read %= size; |
samux | 1:80ab0d068708 | 52 | } |
samux | 1:80ab0d068708 | 53 | return(!empty); |
samux | 1:80ab0d068708 | 54 | }; |
samux | 1:80ab0d068708 | 55 | |
Troels Nilsson |
77:a98f786d05d4 | 56 | void flush() |
Troels Nilsson |
77:a98f786d05d4 | 57 | { |
Troels Nilsson |
77:a98f786d05d4 | 58 | write = 0; |
Troels Nilsson |
77:a98f786d05d4 | 59 | read = 0; |
Troels Nilsson |
77:a98f786d05d4 | 60 | } |
Troels Nilsson |
77:a98f786d05d4 | 61 | |
Troels Nilsson |
77:a98f786d05d4 | 62 | // Queue a block of data of blockSize items |
Troels Nilsson |
77:a98f786d05d4 | 63 | void queue(const T *block, uint16_t blockSize) |
Troels Nilsson |
77:a98f786d05d4 | 64 | { |
Troels Nilsson |
77:a98f786d05d4 | 65 | if (blockSize >= size) |
Troels Nilsson |
77:a98f786d05d4 | 66 | { |
Troels Nilsson |
77:a98f786d05d4 | 67 | // Block is too big to fit in buffer, take the last size-1 items |
Troels Nilsson |
77:a98f786d05d4 | 68 | block = &block[blockSize - (size-1)]; |
Troels Nilsson |
77:a98f786d05d4 | 69 | blockSize = size-1; |
Troels Nilsson |
77:a98f786d05d4 | 70 | } |
Troels Nilsson |
77:a98f786d05d4 | 71 | |
Troels Nilsson |
77:a98f786d05d4 | 72 | if (write + blockSize > size) |
Troels Nilsson |
77:a98f786d05d4 | 73 | { |
Troels Nilsson |
77:a98f786d05d4 | 74 | // Need to wrap around |
Troels Nilsson |
77:a98f786d05d4 | 75 | std::memcpy(&buf[write], block, sizeof(T)*(size-write)); |
Troels Nilsson |
77:a98f786d05d4 | 76 | std::memcpy(buf, &block[size-write], sizeof(T)*(blockSize - (size-write))); |
Troels Nilsson |
77:a98f786d05d4 | 77 | } |
Troels Nilsson |
77:a98f786d05d4 | 78 | else |
Troels Nilsson |
77:a98f786d05d4 | 79 | { |
Troels Nilsson |
77:a98f786d05d4 | 80 | std::memcpy(&buf[write], block, sizeof(T)*blockSize); |
Troels Nilsson |
77:a98f786d05d4 | 81 | } |
Troels Nilsson |
77:a98f786d05d4 | 82 | |
Troels Nilsson |
77:a98f786d05d4 | 83 | // Update write position |
Troels Nilsson |
77:a98f786d05d4 | 84 | uint16_t wasFree = available() - size - 1; |
Troels Nilsson |
77:a98f786d05d4 | 85 | write = write + blockSize; |
Troels Nilsson |
77:a98f786d05d4 | 86 | write %= size; |
Troels Nilsson |
77:a98f786d05d4 | 87 | if (wasFree < blockSize) |
Troels Nilsson |
77:a98f786d05d4 | 88 | { |
Troels Nilsson |
77:a98f786d05d4 | 89 | // Update read position as well |
Troels Nilsson |
77:a98f786d05d4 | 90 | read = write + 1; |
Troels Nilsson |
77:a98f786d05d4 | 91 | read %= size; |
Troels Nilsson |
77:a98f786d05d4 | 92 | } |
Troels Nilsson |
77:a98f786d05d4 | 93 | } |
Troels Nilsson |
77:a98f786d05d4 | 94 | |
Troels Nilsson |
77:a98f786d05d4 | 95 | // Dequeue a block of data of at most blockSize items, writing them into block |
Troels Nilsson |
77:a98f786d05d4 | 96 | // Returns the number of items dequeued |
Troels Nilsson |
77:a98f786d05d4 | 97 | uint16_t dequeue(T *block, uint16_t blockSize) |
Troels Nilsson |
77:a98f786d05d4 | 98 | { |
Troels Nilsson |
77:a98f786d05d4 | 99 | if (isEmpty()) |
Troels Nilsson |
77:a98f786d05d4 | 100 | { |
Troels Nilsson |
77:a98f786d05d4 | 101 | return 0; |
Troels Nilsson |
77:a98f786d05d4 | 102 | } |
Troels Nilsson |
77:a98f786d05d4 | 103 | |
Troels Nilsson |
77:a98f786d05d4 | 104 | uint16_t isAvailable = available(); |
Troels Nilsson |
77:a98f786d05d4 | 105 | if (isAvailable < blockSize) |
Troels Nilsson |
77:a98f786d05d4 | 106 | { |
Troels Nilsson |
77:a98f786d05d4 | 107 | // Only return what we have |
Troels Nilsson |
77:a98f786d05d4 | 108 | blockSize = isAvailable; |
Troels Nilsson |
77:a98f786d05d4 | 109 | } |
Troels Nilsson |
77:a98f786d05d4 | 110 | |
Troels Nilsson |
77:a98f786d05d4 | 111 | if (read + blockSize > size) |
Troels Nilsson |
77:a98f786d05d4 | 112 | { |
Troels Nilsson |
77:a98f786d05d4 | 113 | // Need to wrap around |
Troels Nilsson |
77:a98f786d05d4 | 114 | std::memcpy(block, &buf[read], sizeof(T)*(size-read)); |
Troels Nilsson |
77:a98f786d05d4 | 115 | std::memcpy(&block[size-read], buf, sizeof(T)*(blockSize - (size-read))); |
Troels Nilsson |
77:a98f786d05d4 | 116 | } |
Troels Nilsson |
77:a98f786d05d4 | 117 | else |
Troels Nilsson |
77:a98f786d05d4 | 118 | { |
Troels Nilsson |
77:a98f786d05d4 | 119 | std::memcpy(block, &buf[read], sizeof(T)*blockSize); |
Troels Nilsson |
77:a98f786d05d4 | 120 | } |
Troels Nilsson |
77:a98f786d05d4 | 121 | |
Troels Nilsson |
77:a98f786d05d4 | 122 | // Update read position |
Troels Nilsson |
77:a98f786d05d4 | 123 | read = read + blockSize; |
Troels Nilsson |
77:a98f786d05d4 | 124 | read %= size; |
Troels Nilsson |
77:a98f786d05d4 | 125 | |
Troels Nilsson |
77:a98f786d05d4 | 126 | return blockSize; |
Troels Nilsson |
77:a98f786d05d4 | 127 | } |
Troels Nilsson |
77:a98f786d05d4 | 128 | |
samux | 1:80ab0d068708 | 129 | private: |
samux | 1:80ab0d068708 | 130 | volatile uint16_t write; |
samux | 1:80ab0d068708 | 131 | volatile uint16_t read; |
mbed_official | 51:deafa44182d9 | 132 | static const int size = Size+1; //a modern optimizer should be able to remove this so it uses no ram. |
mbed_official | 56:151ba33713ff | 133 | T buf[Size+1]; |
samux | 1:80ab0d068708 | 134 | }; |
samux | 1:80ab0d068708 | 135 | |
samux | 1:80ab0d068708 | 136 | #endif |