feat(lazy): structural patching for decode+modify+encode

include/qjson.h

@@ -80,6 +80,8 @@ int qjson_cursor_get_bool (const qjson_cursor*, const char* path, size_t path_le
 int qjson_cursor_typeof   (const qjson_cursor*, const char* path, size_t path_len, int*     out);
 int qjson_cursor_len      (const qjson_cursor*, const char* path, size_t path_len, size_t*  out);
 int qjson_cursor_bytes    (const qjson_cursor*, size_t* byte_start, size_t* byte_end);
+int qjson_cursor_field_bytes(const qjson_cursor*, const char* key, size_t key_len,
+                            size_t* value_start, size_t* value_end);
 int qjson_cursor_object_entry_at(const qjson_cursor*, size_t i,
                                 const uint8_t** key_ptr, size_t* key_len,
                                 qjson_cursor* value_out);

lua/qjson.lua

@@ -1,5 +1,4 @@
 local ffi = require("ffi")
-
 local C = require("qjson.lib")
 
 local err_box  = ffi.new("int[1]")

lua/qjson/lib.lua

@@ -38,6 +38,8 @@ int qjson_cursor_get_bool(const qjson_cursor*, const char*, size_t, int*);
 int qjson_cursor_typeof  (const qjson_cursor*, const char*, size_t, int*);
 int qjson_cursor_len     (const qjson_cursor*, const char*, size_t, size_t*);
 int qjson_cursor_bytes(const qjson_cursor*, size_t* byte_start, size_t* byte_end);
+int qjson_cursor_field_bytes(const qjson_cursor*, const char* key, size_t key_len,
+                            size_t* value_start, size_t* value_end);
 int qjson_cursor_object_entry_at(const qjson_cursor*, size_t i,
                                 const uint8_t** key_ptr, size_t* key_len,
                                 qjson_cursor* value_out);
@@ -69,6 +71,7 @@ local required_symbols = {
     "qjson_cursor_typeof",
     "qjson_cursor_len",
     "qjson_cursor_bytes",
+    "qjson_cursor_field_bytes",
     "qjson_cursor_object_entry_at",
 }