gamebook: load expanded books from PSRAM

idf_zacus/components/gamebook/gamebook.c

@@ -9,6 +9,7 @@
 
 #include "cJSON.h"
 #include "esp_log.h"
+#include "esp_heap_caps.h"
 
 #include "display_ui.h"
 #include "media_manager.h"
@@ -17,7 +18,7 @@ static const char *TAG = "gamebook";
 
 #define GAMEBOOK_DIR   "/sdcard/gamebook"
 #define LIBRARY_JSON   GAMEBOOK_DIR "/library.json"
-#define JSON_MAX       (64 * 1024)   /* per-file JSON sanity cap */
+#define JSON_MAX       (256 * 1024)  /* expanded books are ~80 KB of JSON */
 #define LIB_MAX        6             /* matches the display tile grid */
 
 typedef enum { GB_OFF, GB_LIBRARY, GB_STORY } gb_mode_t;
@@ -39,6 +40,10 @@ static volatile gb_mode_t s_mode = GB_OFF;
 
 bool gamebook_active(void) { return s_mode != GB_OFF; }
 
+/* PSRAM allocators for cJSON — book trees are large (see gamebook_init). */
+static void *gb_malloc(size_t sz) { return heap_caps_malloc(sz, MALLOC_CAP_SPIRAM); }
+static void  gb_free(void *p)      { heap_caps_free(p); }
+
 /* Read a whole JSON file from the SD into a cJSON tree (caller frees). */
 static cJSON *load_json(const char *path)
 {
@@ -48,13 +53,13 @@ static cJSON *load_json(const char *path)
     long sz = ftell(f);
     rewind(f);
     if (sz <= 0 || sz > JSON_MAX) { fclose(f); ESP_LOGW(TAG, "%s size %ld", path, sz); return NULL; }
-    char *buf = malloc((size_t)sz + 1);
+    char *buf = heap_caps_malloc((size_t)sz + 1, MALLOC_CAP_SPIRAM);
     if (!buf) { fclose(f); return NULL; }
     size_t rd = fread(buf, 1, (size_t)sz, f);
     fclose(f);
     buf[rd] = '\0';
     cJSON *root = cJSON_Parse(buf);
-    free(buf);
+    heap_caps_free(buf);
     if (!root) ESP_LOGW(TAG, "malformed JSON: %s", path);
     return root;
 }
@@ -285,6 +290,14 @@ void gamebook_stop(void)
 
 void gamebook_init(void)
 {
+    /* Keep the large book trees in PSRAM — an expanded book is ~80 KB of JSON,
+     * whose parsed node tree would exhaust the internal heap on this firmware. */
+    static cJSON_Hooks hooks = {
+        .malloc_fn = gb_malloc,
+        .free_fn   = gb_free,
+    };
+    cJSON_InitHooks(&hooks);
+
     /* Only register the pad hook here — the SD and media_manager aren't up yet
      * at this point in boot. main.c calls gamebook_start() once they are, to
      * boot into the library. */