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 // copy first chunk 88 unsigned int bytes_until_end = ring_buffer->size - ring_buffer->last_written_index; 89 unsigned int bytes_to_copy = btstack_min(bytes_until_end, data_length); 90 memcpy(&ring_buffer->storage[ring_buffer->last_written_index], data, bytes_to_copy); 91 data_length -= bytes_to_copy; 92 data += bytes_to_copy; 93 94 // update last written index 95 ring_buffer->last_written_index += bytes_to_copy; 96 if (ring_buffer->last_written_index == ring_buffer->size){ 97 ring_buffer->last_written_index = 0; 98 } 99 100 // copy second chunk 101 if (data_length) { 102 memcpy(&ring_buffer->storage[0], data, data_length); 103 ring_buffer->last_written_index += data_length; 104 } 105 106 // mark buffer as full 107 if (ring_buffer->last_written_index == ring_buffer->last_read_index){ 108 ring_buffer->full = 1; 109 } 110 return 0; 111 } 112 113 // fetch data_length bytes from ring buffer 114 void btstack_ring_buffer_read(btstack_ring_buffer_t * ring_buffer, uint8_t * data, uint32_t data_length, uint32_t * number_of_bytes_read){ 115 // limit data to get and report 116 data_length = btstack_min(data_length, btstack_ring_buffer_bytes_available(ring_buffer)); 117 *number_of_bytes_read = data_length; 118 119 // copy first chunk 120 unsigned int bytes_until_end = ring_buffer->size - ring_buffer->last_read_index; 121 unsigned int bytes_to_copy = btstack_min(bytes_until_end, data_length); 122 memcpy(data, &ring_buffer->storage[ring_buffer->last_read_index], bytes_to_copy); 123 data_length -= bytes_to_copy; 124 data += bytes_to_copy; 125 126 // update last read index 127 ring_buffer->last_read_index += bytes_to_copy; 128 if (ring_buffer->last_read_index == ring_buffer->size){ 129 ring_buffer->last_read_index = 0; 130 } 131 132 // copy second chunk 133 if (data_length) { 134 memcpy(data, &ring_buffer->storage[0], data_length); 135 ring_buffer->last_read_index += data_length; 136 } 137 138 // clear full flag 139 ring_buffer->full = 0; 140 } 141 142