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 <stdlib.h> 46 #include <stdio.h> 47 #include <string.h> 48 49 #include "btstack_ring_buffer.h" 50 #include "btstack_util.h" 51 52 #define ERROR_CODE_MEMORY_CAPACITY_EXCEEDED 0x07 53 54 55 // init ring buffer 56 void btstack_ring_buffer_init(btstack_ring_buffer_t * ring_buffer, uint8_t * storage, uint32_t storage_size){ 57 ring_buffer->storage = storage; 58 ring_buffer->size = storage_size; 59 ring_buffer->last_read_index = 0; 60 ring_buffer->last_written_index = 0; 61 ring_buffer->full = 0; 62 } 63 64 uint32_t btstack_ring_buffer_bytes_available(btstack_ring_buffer_t * ring_buffer){ 65 if (ring_buffer->full) return ring_buffer->size; 66 int diff = ring_buffer->last_written_index - ring_buffer->last_read_index; 67 if (diff >= 0) return diff; 68 return diff + ring_buffer->size; 69 } 70 71 // test if ring buffer is empty 72 int btstack_ring_buffer_empty(btstack_ring_buffer_t * ring_buffer){ 73 return btstack_ring_buffer_bytes_available(ring_buffer) == 0; 74 } 75 76 // 77 uint32_t btstack_ring_buffer_bytes_free(btstack_ring_buffer_t * ring_buffer){ 78 return ring_buffer->size - btstack_ring_buffer_bytes_available(ring_buffer); 79 } 80 81 // add byte block to ring buffer, 82 int btstack_ring_buffer_write(btstack_ring_buffer_t * ring_buffer, uint8_t * data, uint32_t data_length){ 83 if (btstack_ring_buffer_bytes_free(ring_buffer) < data_length){ 84 return ERROR_CODE_MEMORY_CAPACITY_EXCEEDED; 85 } 86 87 // simplify logic below by asserting data_length > 0 88 if (data_length == 0) return 0; 89 90 // copy first chunk 91 unsigned int bytes_until_end = ring_buffer->size - ring_buffer->last_written_index; 92 unsigned int bytes_to_copy = btstack_min(bytes_until_end, data_length); 93 (void)memcpy(&ring_buffer->storage[ring_buffer->last_written_index], 94 data, bytes_to_copy); 95 data_length -= bytes_to_copy; 96 data += bytes_to_copy; 97 98 // update last written index 99 ring_buffer->last_written_index += bytes_to_copy; 100 if (ring_buffer->last_written_index == ring_buffer->size){ 101 ring_buffer->last_written_index = 0; 102 } 103 104 // copy second chunk 105 if (data_length) { 106 (void)memcpy(&ring_buffer->storage[0], data, data_length); 107 ring_buffer->last_written_index += data_length; 108 } 109 110 // mark buffer as full 111 if (ring_buffer->last_written_index == ring_buffer->last_read_index){ 112 ring_buffer->full = 1; 113 } 114 return 0; 115 } 116 117 // fetch data_length bytes from ring buffer 118 void btstack_ring_buffer_read(btstack_ring_buffer_t * ring_buffer, uint8_t * data, uint32_t data_length, uint32_t * number_of_bytes_read){ 119 // limit data to get and report 120 data_length = btstack_min(data_length, btstack_ring_buffer_bytes_available(ring_buffer)); 121 *number_of_bytes_read = data_length; 122 123 // simplify logic below by asserting data_length > 0 124 if (data_length == 0) return; 125 126 // copy first chunk 127 unsigned int bytes_until_end = ring_buffer->size - ring_buffer->last_read_index; 128 unsigned int bytes_to_copy = btstack_min(bytes_until_end, data_length); 129 (void)memcpy(data, &ring_buffer->storage[ring_buffer->last_read_index], 130 bytes_to_copy); 131 data_length -= bytes_to_copy; 132 data += bytes_to_copy; 133 134 // update last read index 135 ring_buffer->last_read_index += bytes_to_copy; 136 if (ring_buffer->last_read_index == ring_buffer->size){ 137 ring_buffer->last_read_index = 0; 138 } 139 140 // copy second chunk 141 if (data_length) { 142 (void)memcpy(data, &ring_buffer->storage[0], data_length); 143 ring_buffer->last_read_index += data_length; 144 } 145 146 // clear full flag 147 ring_buffer->full = 0; 148 } 149 150