1#include <stdio.h>
2#include <stdlib.h>
3#include <string.h>
4#include <inttypes.h>
5
6#include "wasm.h"
7
8#define own
9
10// A function to be called from Wasm code.
11own wasm_trap_t* hello_callback(
12  const wasm_val_t args[], wasm_val_t results[]
13) {
14  printf("Calling back...\n");
15  printf("> Hello World!\n");
16  return NULL;
17}
18
19
20int main(int argc, const char* argv[]) {
21  // Initialize.
22  printf("Initializing...\n");
23  wasm_engine_t* engine = wasm_engine_new();
24  wasm_store_t* store = wasm_store_new(engine);
25
26  // Load binary.
27  printf("Loading binary...\n");
28  FILE* file = fopen("hello.wasm", "r");
29  if (!file) {
30    printf("> Error loading module!\n");
31    return 1;
32  }
33  fseek(file, 0L, SEEK_END);
34  size_t file_size = ftell(file);
35  fseek(file, 0L, SEEK_SET);
36  wasm_byte_vec_t binary;
37  wasm_byte_vec_new_uninitialized(&binary, file_size);
38  if (fread(binary.data, file_size, 1, file) != 1) {
39    printf("> Error loading module!\n");
40    return 1;
41  }
42  fclose(file);
43
44  // Compile.
45  printf("Compiling module...\n");
46  own wasm_module_t* module = wasm_module_new(store, &binary);
47  if (!module) {
48    printf("> Error compiling module!\n");
49    return 1;
50  }
51
52  wasm_byte_vec_delete(&binary);
53
54  // Create external print functions.
55  printf("Creating callback...\n");
56  own wasm_functype_t* hello_type = wasm_functype_new_0_0();
57  own wasm_func_t* hello_func =
58    wasm_func_new(store, hello_type, hello_callback);
59
60  wasm_functype_delete(hello_type);
61
62  // Instantiate.
63  printf("Instantiating module...\n");
64  const wasm_extern_t* imports[] = { wasm_func_as_extern(hello_func) };
65  own wasm_instance_t* instance =
66    wasm_instance_new(store, module, imports, NULL);
67  if (!instance) {
68    printf("> Error instantiating module!\n");
69    return 1;
70  }
71
72  wasm_func_delete(hello_func);
73
74  // Extract export.
75  printf("Extracting export...\n");
76  own wasm_extern_vec_t exports;
77  wasm_instance_exports(instance, &exports);
78  if (exports.size == 0) {
79    printf("> Error accessing exports!\n");
80    return 1;
81  }
82  const wasm_func_t* run_func = wasm_extern_as_func(exports.data[0]);
83  if (run_func == NULL) {
84    printf("> Error accessing export!\n");
85    return 1;
86  }
87
88  wasm_module_delete(module);
89  wasm_instance_delete(instance);
90
91  // Call.
92  printf("Calling export...\n");
93  if (wasm_func_call(run_func, NULL, NULL)) {
94    printf("> Error calling function!\n");
95    return 1;
96  }
97
98  wasm_extern_vec_delete(&exports);
99
100  // Shut down.
101  printf("Shutting down...\n");
102  wasm_store_delete(store);
103  wasm_engine_delete(engine);
104
105  // All done.
106  printf("Done.\n");
107  return 0;
108}
109