feat(dmr): add receive frontend and AMBE adapter

native/dmr/ewsdr_dmr.h

@@ -0,0 +1,53 @@
+#ifndef EWSDR_DMR_H
+#define EWSDR_DMR_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#if defined(_WIN32)
+#  if defined(EWSDR_DMR_BUILD)
+#    define EWSDR_DMR_API __declspec(dllexport)
+#  else
+#    define EWSDR_DMR_API __declspec(dllimport)
+#  endif
+#else
+#  define EWSDR_DMR_API __attribute__((visibility("default")))
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define EWSDR_DMR_ABI_VERSION 1u
+#define EWSDR_DMR_AMBE_BITS   96u
+#define EWSDR_DMR_PCM_SAMPLES 160u
+
+typedef struct ewsdr_dmr_mbe ewsdr_dmr_mbe;
+
+typedef struct ewsdr_dmr_mbe_result {
+  int errors_c0;
+  int errors_total;
+} ewsdr_dmr_mbe_result;
+
+EWSDR_DMR_API uint32_t ewsdr_dmr_abi_version(void);
+EWSDR_DMR_API ewsdr_dmr_mbe *ewsdr_dmr_mbe_create(int uv_quality);
+EWSDR_DMR_API void ewsdr_dmr_mbe_destroy(ewsdr_dmr_mbe *decoder);
+EWSDR_DMR_API void ewsdr_dmr_mbe_reset(ewsdr_dmr_mbe *decoder);
+
+/*
+ * Decode one already deinterleaved DMR AMBE+2 frame. ambe_bits is a row-major
+ * char[4][24] matrix containing only 0/1 values. pcm_out receives 160 float
+ * samples at 8 kHz. Frame extraction/deinterleaving remains in the DMR burst
+ * layer, keeping mbelib and its state behind this stable ABI.
+ */
+EWSDR_DMR_API int ewsdr_dmr_mbe_decode(
+    ewsdr_dmr_mbe *decoder,
+    const uint8_t ambe_bits[EWSDR_DMR_AMBE_BITS],
+    float pcm_out[EWSDR_DMR_PCM_SAMPLES],
+    ewsdr_dmr_mbe_result *result);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif