Add 'examples/hello/' from commit 'e88e5a6ff3b0f55671cb64c0a506e552360010e9'

git-subtree-dir: examples/hello
git-subtree-mainline: f44e3bc6d0
git-subtree-split: e88e5a6ff3

examples/hello/logic/state.c

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+/* logic/state.c — 计数业务态（taps/secs）+ 可选推送监听器（biz→UI）。
+ *
+ * 纯 C（无 meow_ui.h 依赖）：状态 + getter/setter + 监听器。UI 经 logic_taps_bump()/
+ * logic_secs_add() 改状态；业务改后触发监听器（若已注册）通知 UI 刷新——契约 ①②（§B.1）。
+ */
+#include "logic.h"
+#include <stddef.h>
+
+static int g_taps = 0;
+static int g_secs = 0;
+static int g_prog = 0;   /* demo 进度语义值 0..100（批③ 自 ui/demo/demo.c 上收） */
+static logic_listener_fn g_listener = NULL;
+static void *g_listener_ctx = NULL;
+
+int logic_taps_get(void)
+{
+    return g_taps;
+}
+void logic_taps_bump(void)
+{
+    g_taps++;
+    if (g_listener) g_listener(LOGIC_EV_TAPS, g_listener_ctx);
+}
+
+int logic_secs_get(void)
+{
+    return g_secs;
+}
+void logic_secs_add(int n)
+{
+    g_secs += n;
+    if (g_listener) g_listener(LOGIC_EV_SECS, g_listener_ctx);
+}
+
+int logic_prog_get(void)
+{
+    return g_prog;
+}
+void logic_prog_set(int p)
+{
+    if (p < 0) p = 0;
+    if (p > 100) p = 100;
+    g_prog = p;
+    if (g_listener) g_listener(LOGIC_EV_PROG, g_listener_ctx);
+}
+
+void logic_set_listener(logic_listener_fn cb, void *ctx)
+{
+    g_listener = cb;
+    g_listener_ctx = ctx;
+}