feat: add decoder module, host unit tests, and GitHub Actions CI pipeline

2026-06-12 14:04:58 +01:00
parent f5ec189dc4
commit 98d35a82e1
7 changed files with 587 additions and 174 deletions
@@ -0,0 +1,115 @@
+#include "decoder.h"
+
+static enqueue_frame_cb_t s_enqueue_cb = NULL;
+static print_frame_cb_t s_print_cb = NULL;
+
+void decoder_init(enqueue_frame_cb_t enqueue_cb, print_frame_cb_t print_cb) {
+    s_enqueue_cb = enqueue_cb;
+    s_print_cb = print_cb;
+}
+
+uint8_t classify_pulse(uint32_t us) {
+    if (us < MIN_VALID_US)       return PC_GLITCH;
+    if (us > MAX_VALID_US)       return PC_IDLE_GAP;
+    if (us > MERGE_THRESHOLD_US) return PC_MERGED;
+    if (us < THRESHOLD_US)       return PC_LOGIC_0;
+    return PC_LOGIC_1;
+}
+
+void reset_decoder(struct DecoderContext *ctx_ptr) {
+    ctx_ptr->state           = DS_HUNT_SYNC;
+    ctx_ptr->sync_count      = 0;
+    ctx_ptr->bit_count       = 0;
+    ctx_ptr->byte_count      = 0;
+    ctx_ptr->separator_count = 0;
+    ctx_ptr->frame_errors    = 0;
+    ctx_ptr->bytes_this_frame = 0;
+}
+
+static void feed_bit(struct DecoderContext *ctx_ptr, uint8_t pc) {
+    switch (ctx_ptr->state) {
+        case DS_HUNT_SYNC:
+            if (pc == PC_LOGIC_1) {
+                ctx_ptr->sync_count++;
+                if (ctx_ptr->sync_count >= SYNC_ONES_NEEDED) {
+                    ctx_ptr->sync_count       = 0;
+                    ctx_ptr->byte_count       = 0;
+                    ctx_ptr->bit_count        = 0;
+                    ctx_ptr->separator_count  = 0;
+                    ctx_ptr->frame_errors     = 0;
+                    ctx_ptr->bytes_this_frame = 0;
+                    ctx_ptr->state            = DS_AWAIT_START;
+                }
+            } else {
+                ctx_ptr->sync_count = 0;
+            }
+            break;
+
+        case DS_AWAIT_START:
+            if (pc == PC_LOGIC_0) {
+                ctx_ptr->current_byte    = 0;
+                ctx_ptr->bit_count       = 0;
+                ctx_ptr->separator_count = 0; 
+                ctx_ptr->state           = DS_READ_BITS;
+            } else {
+                ctx_ptr->separator_count++;
+                if (ctx_ptr->separator_count > MAX_SEPARATORS) {
+                    reset_decoder(ctx_ptr);
+                }
+            }
+            break;
+
+        case DS_READ_BITS: {
+            uint8_t bit_val  = (pc == PC_LOGIC_1) ? 1u : 0u;
+            ctx_ptr->current_byte = (uint8_t)((ctx_ptr->current_byte << 1) | bit_val);
+            ctx_ptr->bit_count++;
+
+            if (ctx_ptr->bit_count == 8) {
+                ctx_ptr->frame[ctx_ptr->byte_count] = ctx_ptr->current_byte;
+                ctx_ptr->bytes_this_frame++;
+                ctx_ptr->bit_count = 0;
+                ctx_ptr->byte_count++;
+                
+                if (ctx_ptr->byte_count >= PAYLOAD_BYTES) {
+                    ctx_ptr->frames_decoded++;
+                    
+                    if (s_print_cb) {
+                        s_print_cb(ctx_ptr->frames_decoded, ctx_ptr->frame);
+                    }
+                    if (s_enqueue_cb) {
+                        s_enqueue_cb(ctx_ptr->frame, PAYLOAD_BYTES);
+                    }
+                    
+                    reset_decoder(ctx_ptr);
+                } else {
+                    ctx_ptr->separator_count = 0;
+                    ctx_ptr->state = DS_AWAIT_START;
+                }
+            }
+            break;
+        }
+        default:
+            reset_decoder(ctx_ptr);
+            break;
+    }
+}
+
+void process_pulse(struct DecoderContext *ctx_ptr, uint32_t pulse_us) {
+    uint8_t pc = classify_pulse(pulse_us);
+    if (pc == PC_GLITCH) return;
+
+    if (pc == PC_IDLE_GAP) {
+        reset_decoder(ctx_ptr);
+        return;
+    }
+
+    if (pc == PC_MERGED) {
+        uint32_t hidden_est  = pulse_us - LOGIC1_PULSE_US;
+        uint8_t  hidden_bit  = (hidden_est >= THRESHOLD_US) ? PC_LOGIC_1 : PC_LOGIC_0;
+        feed_bit(ctx_ptr, hidden_bit);
+        feed_bit(ctx_ptr, PC_LOGIC_1); 
+        return;
+    }
+
+    feed_bit(ctx_ptr, pc);
+}