start coding for multi-sensor variant: gather data of all sensors and process image[N] only by request

F3:F303/MLX90640multi/ringbuffer.c

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+/*
+ * Copyright 2023 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+
+#include "ringbuffer.h"
+
+static int datalen(ringbuffer *b){
+    if(b->tail >= b->head) return (b->tail - b->head);
+    else return (b->length - b->head + b->tail);
+}
+
+// stored data length
+int RB_datalen(ringbuffer *b){
+    if(b->busy) return -1;
+    b->busy = 1;
+    int l = datalen(b);
+    b->busy = 0;
+    return l;
+}
+
+static int hasbyte(ringbuffer *b, uint8_t byte){
+    if(b->head == b->tail) return -1; // no data in buffer
+    int startidx = b->head;
+    if(b->head > b->tail){ //
+        for(int found = b->head; found < b->length; ++found)
+            if(b->data[found] == byte) return found;
+        startidx = 0;
+    }
+    for(int found = startidx; found < b->tail; ++found)
+        if(b->data[found] == byte) return found;
+    return -1;
+}
+
+/**
+ * @brief RB_hasbyte - check if buffer has given byte stored
+ * @param b - buffer
+ * @param byte - byte to find
+ * @return index if found, -1 if none or busy
+ */
+int RB_hasbyte(ringbuffer *b, uint8_t byte){
+    if(b->busy) return -1;
+    b->busy = 1;
+    int ret = hasbyte(b, byte);
+    b->busy = 0;
+    return ret;
+}
+
+// increment head or tail
+TRUE_INLINE void incr(ringbuffer *b, volatile int *what, int n){
+    *what += n;
+    if(*what >= b->length) *what -= b->length;
+}
+
+static int read(ringbuffer *b, uint8_t *s, int len){
+    int l = datalen(b);
+    if(!l) return 0;
+    if(l > len) l = len;
+    int _1st = b->length - b->head;
+    if(_1st > l) _1st = l;
+    if(_1st > len) _1st = len;
+    memcpy(s, b->data + b->head, _1st);
+    if(_1st < len && l > _1st){
+        memcpy(s+_1st, b->data, l - _1st);
+        incr(b, &b->head, l);
+        return l;
+    }
+    incr(b, &b->head, _1st);
+    return _1st;
+}
+
+/**
+ * @brief RB_read - read data from ringbuffer
+ * @param b - buffer
+ * @param s - array to write data
+ * @param len - max len of `s`
+ * @return bytes read or -1 if busy
+ */
+int RB_read(ringbuffer *b, uint8_t *s, int len){
+    if(b->busy) return -1;
+    b->busy = 1;
+    int r = read(b, s, len);
+    b->busy = 0;
+    return r;
+}
+
+static int readto(ringbuffer *b, uint8_t byte, uint8_t *s, int len){
+    int idx = hasbyte(b, byte);
+    if(idx < 0) return 0;
+    int partlen = idx + 1 - b->head;
+    // now calculate length of new data portion
+    if(idx < b->head) partlen += b->length;
+    if(partlen > len) return -read(b, s, len);
+    return read(b, s, partlen);
+}
+
+/**
+ * @brief RB_readto fill array `s` with data until byte `byte` (with it)
+ * @param b - ringbuffer
+ * @param byte - check byte
+ * @param s - buffer to write data
+ * @param len - length of `s`
+ * @return amount of bytes written (negative, if len<data in buffer or buffer is busy)
+ */
+int RB_readto(ringbuffer *b, uint8_t byte, uint8_t *s, int len){
+    if(b->busy) return -1;
+    b->busy = 1;
+    int n = readto(b, byte, s, len);
+    b->busy = 0;
+    return n;
+}
+
+static int write(ringbuffer *b, const uint8_t *str, int l){
+    int r = b->length - 1 - datalen(b); // rest length
+    if(l > r || !l) return 0;
+    int _1st = b->length - b->tail;
+    if(_1st > l) _1st = l;
+    memcpy(b->data + b->tail, str, _1st);
+    if(_1st < l){ // add another piece from start
+        memcpy(b->data, str+_1st, l-_1st);
+    }
+    incr(b, &b->tail, l);
+    return l;
+}
+
+/**
+ * @brief RB_write - write some data to ringbuffer
+ * @param b - buffer
+ * @param str - data
+ * @param l - length
+ * @return amount of bytes written or -1 if busy
+ */
+int RB_write(ringbuffer *b, const uint8_t *str, int l){
+    if(b->busy) return -1;
+    b->busy = 1;
+    int w = write(b, str, l);
+    b->busy = 0;
+    return w;
+}
+
+// just delete all information in buffer `b`
+int RB_clearbuf(ringbuffer *b){
+    if(b->busy) return -1;
+    b->busy = 1;
+    b->head = 0;
+    b->tail = 0;
+    b->busy = 0;
+    return 1;
+}