1 /* 2 * Copyright (C) 2016 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define BTSTACK_FILE__ "btstack_ring_buffer.c" 39 40 /* 41 * btstack_ring_buffer.c 42 * 43 */ 44 45 #include <string.h> 46 47 #include "btstack_ring_buffer.h" 48 #include "btstack_util.h" 49 50 #define ERROR_CODE_MEMORY_CAPACITY_EXCEEDED 0x07 51 52 53 // init ring buffer 54 void btstack_ring_buffer_init(btstack_ring_buffer_t * ring_buffer, uint8_t * storage, uint32_t storage_size){ 55 ring_buffer->storage = storage; 56 ring_buffer->size = storage_size; 57 btstack_ring_buffer_reset(ring_buffer); 58 } 59 60 void btstack_ring_buffer_reset(btstack_ring_buffer_t * ring_buffer){ 61 ring_buffer->last_read_index = 0; 62 ring_buffer->last_written_index = 0; 63 ring_buffer->full = 0; 64 } 65 66 uint32_t btstack_ring_buffer_bytes_available(btstack_ring_buffer_t * ring_buffer){ 67 if (ring_buffer->full) return ring_buffer->size; 68 int diff = ring_buffer->last_written_index - ring_buffer->last_read_index; 69 if (diff >= 0) return diff; 70 return diff + ring_buffer->size; 71 } 72 73 // test if ring buffer is empty 74 int btstack_ring_buffer_empty(btstack_ring_buffer_t * ring_buffer){ 75 return btstack_ring_buffer_bytes_available(ring_buffer) == 0u; 76 } 77 78 // 79 uint32_t btstack_ring_buffer_bytes_free(btstack_ring_buffer_t * ring_buffer){ 80 return ring_buffer->size - btstack_ring_buffer_bytes_available(ring_buffer); 81 } 82 83 // add byte block to ring buffer, 84 int btstack_ring_buffer_write(btstack_ring_buffer_t * ring_buffer, uint8_t * data, uint32_t data_length){ 85 if (btstack_ring_buffer_bytes_free(ring_buffer) < data_length){ 86 return ERROR_CODE_MEMORY_CAPACITY_EXCEEDED; 87 } 88 89 // simplify logic below by asserting data_length > 0 90 if (data_length == 0u) return 0u; 91 92 // copy first chunk 93 unsigned int bytes_until_end = ring_buffer->size - ring_buffer->last_written_index; 94 unsigned int bytes_to_copy = btstack_min(bytes_until_end, data_length); 95 (void)memcpy(&ring_buffer->storage[ring_buffer->last_written_index], 96 data, bytes_to_copy); 97 data_length -= bytes_to_copy; 98 data += bytes_to_copy; 99 100 // update last written index 101 ring_buffer->last_written_index += bytes_to_copy; 102 if (ring_buffer->last_written_index == ring_buffer->size){ 103 ring_buffer->last_written_index = 0; 104 } 105 106 // copy second chunk 107 if (data_length) { 108 (void)memcpy(&ring_buffer->storage[0], data, data_length); 109 ring_buffer->last_written_index += data_length; 110 } 111 112 // mark buffer as full 113 if (ring_buffer->last_written_index == ring_buffer->last_read_index){ 114 ring_buffer->full = 1; 115 } 116 return 0; 117 } 118 119 // fetch data_length bytes from ring buffer 120 void btstack_ring_buffer_read(btstack_ring_buffer_t * ring_buffer, uint8_t * data, uint32_t data_length, uint32_t * number_of_bytes_read){ 121 // limit data to get and report 122 data_length = btstack_min(data_length, btstack_ring_buffer_bytes_available(ring_buffer)); 123 *number_of_bytes_read = data_length; 124 125 // simplify logic below by asserting data_length > 0 126 if (data_length == 0u) return; 127 128 // copy first chunk 129 unsigned int bytes_until_end = ring_buffer->size - ring_buffer->last_read_index; 130 unsigned int bytes_to_copy = btstack_min(bytes_until_end, data_length); 131 (void)memcpy(data, &ring_buffer->storage[ring_buffer->last_read_index], 132 bytes_to_copy); 133 data_length -= bytes_to_copy; 134 data += bytes_to_copy; 135 136 // update last read index 137 ring_buffer->last_read_index += bytes_to_copy; 138 if (ring_buffer->last_read_index == ring_buffer->size){ 139 ring_buffer->last_read_index = 0; 140 } 141 142 // copy second chunk 143 if (data_length) { 144 (void)memcpy(data, &ring_buffer->storage[0], data_length); 145 ring_buffer->last_read_index += data_length; 146 } 147 148 // clear full flag 149 ring_buffer->full = 0; 150 } 151 152