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 /* 39 * btstack_ring_buffer.c 40 * 41 */ 42 43 #include <stdlib.h> 44 #include <stdio.h> 45 46 #include "btstack_ring_buffer.h" 47 48 #define ERROR_CODE_MEMORY_CAPACITY_EXCEEDED 0x07 49 50 51 // init ring buffer 52 void btstack_ring_buffer_init(btstack_ring_buffer_t * ring_buffer, uint8_t * storage, uint32_t storage_size){ 53 ring_buffer->storage = storage; 54 ring_buffer->size = storage_size; 55 ring_buffer->last_read_index = 0; 56 ring_buffer->last_written_index = 0; 57 ring_buffer->full = 0; 58 } 59 60 int btstack_ring_buffer_bytes_available(btstack_ring_buffer_t * ring_buffer){ 61 if (ring_buffer->full) return ring_buffer->size; 62 int diff = ring_buffer->last_written_index - ring_buffer->last_read_index; 63 if (diff >= 0) return diff; 64 return diff + ring_buffer->size; 65 } 66 67 // test if ring buffer is empty 68 int btstack_ring_buffer_empty(btstack_ring_buffer_t * ring_buffer){ 69 return btstack_ring_buffer_bytes_available(ring_buffer) == 0; 70 } 71 72 // 73 int btstack_ring_buffer_bytes_free(btstack_ring_buffer_t * ring_buffer){ 74 return ring_buffer->size - btstack_ring_buffer_bytes_available(ring_buffer); 75 } 76 77 // add byte block to ring buffer, 78 int btstack_ring_buffer_write(btstack_ring_buffer_t * ring_buffer, uint8_t * data, uint32_t data_length){ 79 if (btstack_ring_buffer_bytes_free(ring_buffer) < data_length){ 80 return ERROR_CODE_MEMORY_CAPACITY_EXCEEDED; 81 } 82 int count = 0; 83 while (count < data_length){ 84 if (ring_buffer->last_written_index < ring_buffer->size - 1){ 85 ring_buffer->last_written_index++; 86 } else { 87 ring_buffer->last_written_index = 0; 88 } 89 ring_buffer->storage[ring_buffer->last_written_index] = data[count++]; 90 } 91 if (ring_buffer->last_written_index == ring_buffer->last_read_index){ 92 ring_buffer->full = 1; 93 } 94 return 0; 95 } 96 97 // fetch data_length bytes from ring buffer 98 void btstack_ring_buffer_read(btstack_ring_buffer_t * ring_buffer, uint8_t * data, uint32_t data_length, uint32_t * number_of_bytes_read){ 99 uint32_t count = 0; 100 while (count < data_length && btstack_ring_buffer_bytes_available(ring_buffer)){ 101 if (ring_buffer->last_read_index < ring_buffer->last_written_index ) { 102 ring_buffer->last_read_index++; 103 } else { 104 if (ring_buffer->last_read_index < ring_buffer->size - 1){ 105 ring_buffer->last_read_index++; 106 } else { 107 ring_buffer->last_read_index = 0; 108 } 109 } 110 ring_buffer->full = 0; 111 data[count++] = ring_buffer->storage[ring_buffer->last_read_index]; 112 } 113 *number_of_bytes_read = count; 114 } 115 116