| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | #include "../libnetdata.h" |
| 4 | #include "ringbuffer_internal.h" |
| 5 | |
| 6 | rbuf_t rbuf_create(size_t size) |
| 7 | { |
| 8 | rbuf_t buffer = mallocz(sizeof(struct rbuf) + size); |
| 9 | memset(buffer, 0, sizeof(struct rbuf)); |
| 10 | |
| 11 | buffer->data = ((char*)buffer) + sizeof(struct rbuf); |
| 12 | |
| 13 | buffer->head = buffer->data; |
| 14 | buffer->tail = buffer->data; |
| 15 | buffer->size = size; |
| 16 | buffer->end = buffer->data + size; |
| 17 | |
| 18 | return buffer; |
| 19 | } |
| 20 | |
| 21 | void rbuf_free(rbuf_t buffer) |
| 22 | { |
| 23 | freez(buffer); |
| 24 | } |
| 25 | |
| 26 | void rbuf_flush(rbuf_t buffer) |
| 27 | { |
| 28 | buffer->head = buffer->data; |
| 29 | buffer->tail = buffer->data; |
| 30 | buffer->size_data = 0; |
| 31 | } |
| 32 | |
| 33 | char *rbuf_get_linear_insert_range(rbuf_t buffer, size_t *bytes) |
| 34 | { |
| 35 | *bytes = 0; |
| 36 | if (buffer->head == buffer->tail && buffer->size_data) |
| 37 | return NULL; |
| 38 | |
| 39 | *bytes = ((buffer->head >= buffer->tail) ? buffer->end : buffer->tail) - buffer->head; |
| 40 | return buffer->head; |
| 41 | } |
| 42 | |
| 43 | char *rbuf_get_linear_read_range(rbuf_t buffer, size_t *bytes) |
| 44 | { |
| 45 | *bytes = 0; |
| 46 | if(buffer->head == buffer->tail && !buffer->size_data) |
| 47 | return NULL; |
| 48 | |
| 49 | *bytes = ((buffer->tail >= buffer->head) ? buffer->end : buffer->head) - buffer->tail; |
| 50 | |
| 51 | return buffer->tail; |
| 52 | } |
| 53 | |
| 54 | int rbuf_bump_head(rbuf_t buffer, size_t bytes) |
| 55 | { |
| 56 | size_t free_bytes = rbuf_bytes_free(buffer); |
| 57 | if (bytes > free_bytes) |
| 58 | return 0; |
| 59 | int i = buffer->head - buffer->data; |
| 60 | buffer->head = &buffer->data[(i + bytes) % buffer->size]; |
| 61 | buffer->size_data += bytes; |
| 62 | return 1; |
| 63 | } |
| 64 | |
| 65 | int rbuf_bump_tail_noopt(rbuf_t buffer, size_t bytes) |
| 66 | { |
| 67 | if (bytes > buffer->size_data) |
| 68 | return 0; |
| 69 | int i = buffer->tail - buffer->data; |
| 70 | buffer->tail = &buffer->data[(i + bytes) % buffer->size]; |
| 71 | buffer->size_data -= bytes; |
| 72 | |
| 73 | return 1; |
| 74 | } |
| 75 | |
| 76 | int rbuf_bump_tail(rbuf_t buffer, size_t bytes) |
| 77 | { |
| 78 | if(!rbuf_bump_tail_noopt(buffer, bytes)) |
| 79 | return 0; |
| 80 | |
| 81 | // if tail catched up with head |
| 82 | // start writing buffer from beggining |
| 83 | // this is not necessary (rbuf must work well without it) |
| 84 | // but helps to optimize big writes as rbuf_get_linear_insert_range |
| 85 | // will return bigger continuous region |
| 86 | if(buffer->tail == buffer->head) { |
| 87 | assert(buffer->size_data == 0); |
| 88 | rbuf_flush(buffer); |
| 89 | } |
| 90 | |
| 91 | return 1; |
| 92 | } |
| 93 | |
| 94 | size_t rbuf_get_capacity(rbuf_t buffer) |
| 95 | { |
| 96 | return buffer->size; |
| 97 | } |
| 98 | |
| 99 | size_t rbuf_bytes_available(rbuf_t buffer) |
| 100 | { |
| 101 | return buffer->size_data; |
| 102 | } |
| 103 | |
| 104 | size_t rbuf_bytes_free(rbuf_t buffer) |
| 105 | { |
| 106 | return buffer->size - buffer->size_data; |
| 107 | } |
| 108 | |
| 109 | size_t rbuf_push(rbuf_t buffer, const char *data, size_t len) |
| 110 | { |
| 111 | size_t to_cpy; |
| 112 | char *w_ptr = rbuf_get_linear_insert_range(buffer, &to_cpy); |
| 113 | if(!to_cpy) |
| 114 | return to_cpy; |
| 115 | |
| 116 | to_cpy = MIN(to_cpy, len); |
| 117 | memcpy(w_ptr, data, to_cpy); |
| 118 | rbuf_bump_head(buffer, to_cpy); |
| 119 | if(to_cpy < len) |
| 120 | to_cpy += rbuf_push(buffer, &data[to_cpy], len - to_cpy); |
| 121 | return to_cpy; |
| 122 | } |
| 123 | |
| 124 | size_t rbuf_pop(rbuf_t buffer, char *data, size_t len) |
| 125 | { |
| 126 | size_t to_cpy; |
| 127 | const char *r_ptr = rbuf_get_linear_read_range(buffer, &to_cpy); |
| 128 | if(!to_cpy) |
| 129 | return to_cpy; |
| 130 | |
| 131 | to_cpy = MIN(to_cpy, len); |
| 132 | memcpy(data, r_ptr, to_cpy); |
| 133 | rbuf_bump_tail(buffer, to_cpy); |
| 134 | if(to_cpy < len) |
| 135 | to_cpy += rbuf_pop(buffer, &data[to_cpy], len - to_cpy); |
| 136 | return to_cpy; |
| 137 | } |
| 138 | |
| 139 | static inline void rbuf_ptr_inc(rbuf_t buffer, const char **ptr) |
| 140 | { |
| 141 | (*ptr)++; |
| 142 | if(*ptr >= buffer->end) |
| 143 | *ptr = buffer->data; |
| 144 | } |
| 145 | |
| 146 | int rbuf_memcmp(rbuf_t buffer, const char *haystack, const char *needle, size_t needle_bytes) |
| 147 | { |
| 148 | const char *end = needle + needle_bytes; |
| 149 | |
| 150 | // as head==tail can mean 2 things here |
| 151 | if (haystack == buffer->head && buffer->size_data) { |
| 152 | if (*haystack != *needle) |
| 153 | return (*haystack - *needle); |
| 154 | rbuf_ptr_inc(buffer, &haystack); |
| 155 | needle++; |
| 156 | } |
| 157 | |
| 158 | while (haystack != buffer->head && needle != end) { |
| 159 | if (*haystack != *needle) |
| 160 | return (*haystack - *needle); |
| 161 | rbuf_ptr_inc(buffer, &haystack); |
| 162 | needle++; |
| 163 | } |
| 164 | return 0; |
| 165 | } |
| 166 | |
| 167 | int rbuf_memcmp_n(rbuf_t buffer, const char *to_cmp, size_t to_cmp_bytes) |
| 168 | { |
| 169 | return rbuf_memcmp(buffer, buffer->tail, to_cmp, to_cmp_bytes); |
| 170 | } |
| 171 | |
| 172 | char *rbuf_find_bytes(rbuf_t buffer, const char *needle, size_t needle_bytes, int *found_idx) |
| 173 | { |
| 174 | const char *ptr = buffer->tail; |
| 175 | *found_idx = 0; |
| 176 | |
| 177 | if (!rbuf_bytes_available(buffer)) |
| 178 | return NULL; |
| 179 | |
| 180 | if (buffer->head == buffer->tail && buffer->size_data) { |
| 181 | if(!rbuf_memcmp(buffer, ptr, needle, needle_bytes)) |
| 182 | return (char *)ptr; |
| 183 | rbuf_ptr_inc(buffer, &ptr); |
| 184 | (*found_idx)++; |
| 185 | } |
| 186 | |
| 187 | while (ptr != buffer->head) |
| 188 | { |
| 189 | if(!rbuf_memcmp(buffer, ptr, needle, needle_bytes)) |
| 190 | return (char *)ptr; |
| 191 | rbuf_ptr_inc(buffer, &ptr); |
| 192 | (*found_idx)++; |
| 193 | } |
| 194 | return NULL; |
| 195 | } |