root / branches / autonomous_recharging / code / projects / colonet / utilities / robot_wireless_relay / ring_buffer.h @ 1390
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1 | 13 | emarinel | /** @file Include macros to create a ring buffer. Originally written for 15-410.
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2 | * Modified for use in ATMega128 serial driver
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3 | *
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4 | * @author Cornell Wright (cgwright)
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5 | * @author Jason P. Winters (jpwinter)
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6 | *
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7 | * @bugs None known.
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8 | */
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9 | |||
10 | |||
11 | #ifndef _RING_BUFFER_H
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12 | #define _RING_BUFFER_H
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13 | |||
14 | /** @brief Creates the struct for a new ring buffer. This just expands to a
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15 | * structure definition and thus should be invoked in the global context.
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16 | *
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17 | * @param struct_name Name of the ring buffer struct.
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18 | *
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19 | * @param size The size of the buffer to create.
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20 | *
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21 | * @param type The type of object that the queue is to hold.
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22 | *
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23 | * @param ... Name or names of the instance or instances of the ring buffer(s)
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24 | * to be created.
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25 | */
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26 | #define RING_BUFFER_NEW(struct_name, size, type, ...) \
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27 | struct struct_name { \
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28 | type queue[size]; \ |
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29 | uint8_t start; \ |
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30 | uint8_t end; \ |
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31 | } __VA_ARGS__ |
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32 | |||
33 | #define RING_BUFFER_BIT_NEW(struct_name, size, ...) \
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34 | struct struct_name { \
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35 | int8_t queue[(size / 8) + 1]; \ |
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36 | uint16_t start; \ |
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37 | uint16_t end; \ |
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38 | } __VA_ARGS__ |
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39 | |||
40 | /** @brief Sets the specified ring buffer to be empty.
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41 | *
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42 | * @param buf The ring buffer to make empty.
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43 | */
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44 | #define RING_BUFFER_CLEAR(buf) \
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45 | do { \
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46 | (buf).start = 0; \
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47 | (buf).end = 0; \
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48 | } while (0) |
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49 | |||
50 | #define RING_BUFFER_BIT_CLEAR(buf) RING_BUFFER_CLEAR(buf)
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51 | /** @brief Returns true if the ring buffer specified is empty.
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52 | *
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53 | * @param buf The buffer to check emptiness of.
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54 | */
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55 | #define RING_BUFFER_EMPTY(buf) ((buf).start == (buf).end)
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56 | |||
57 | |||
58 | |||
59 | #define RING_BUFFER_BIT_EMPTY(buf) RING_BUFFER_EMPTY(buf)
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60 | |||
61 | |||
62 | /** @brief Returns true if the ring buffer specified is full.
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63 | *
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64 | * @param buf The buffer to check fullness of.
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65 | */
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66 | #define RING_BUFFER_FULL(buf) \
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67 | (((buf).end + 1) % sizeof((buf).queue) == (buf).start) |
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68 | |||
69 | #define RING_BUFFER_BIT_FULL(buf) RING_BUFFER_FULL(buf)
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70 | |||
71 | /** @brief Adds val to ring buffer buf. Note that val must be of the type
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72 | * used in creating the ring buffer to prevent the compiler from spewing
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73 | * confusing errors. Also, this assumes that the ring buffer is not full.
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74 | *
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75 | * @param buf The ring buffer to add to.
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76 | * @param val The value to add.
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77 | */
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78 | #define RING_BUFFER_ADD(buf, val) \
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79 | do { \
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80 | (buf).queue[(buf).end] = val; \ |
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81 | (buf).end = ((buf).end + 1) % sizeof((buf).queue); \ |
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82 | } while (0) |
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83 | |||
84 | #define RING_BUFFER_BIT_ADD(buf, val) \
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85 | do { \
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86 | if (val) { \
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87 | (buf).queue[((buf).end >> 3) & 0xff] |= _BV((buf).end & 0x7); \ |
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88 | } \ |
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89 | else { \
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90 | (buf).queue[((buf).end >> 3) & 0xff] &= ~_BV((buf).end & 0x7); \ |
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91 | } \ |
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92 | (buf).end = ((buf).end + 1) % (sizeof((buf).queue) << 3); \ |
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93 | } while (0) |
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94 | |||
95 | |||
96 | /** @brief Removes the value at the head of the ring buffer and puts it in
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97 | * val_ret. Note that val_ret must be the same type used in creating the ring
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98 | * buffer to prevent the compiler from spewing confusing errors. Also, this
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99 | * assumes that the ring buffer is not empty.
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100 | *
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101 | * @param buf The ring buffer to remove from.
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102 | * @param val_ret Where to put the value removed from the head of the ring
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103 | * buffer.
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104 | */
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105 | #define RING_BUFFER_REMOVE(buf, val_ret) \
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106 | do { \
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107 | (val_ret) = (buf).queue[(buf).start]; \ |
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108 | (buf).start = ((buf).start + 1) % sizeof((buf).queue); \ |
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109 | } while (0) |
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110 | |||
111 | #define RING_BUFFER_BIT_REMOVE(buf, val_ret) \
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112 | do { \
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113 | (val_ret) = ((buf).queue[((buf).start >> 3) & 0xff] & _BV((buf).start & 0x7)) ? 1 : 0; \ |
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114 | (buf).start = ((buf).start + 1) % (sizeof((buf).queue) << 3); \ |
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115 | } while (0) |
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116 | |||
117 | #endif /* _RING_BUFFER_H */ |