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