From 57afb98d2c982607ca7aae4741aae38be20d5e74 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Bylica?= <chfast@gmail.com>
Date: Fri, 24 Jun 2016 11:40:06 +0200
Subject: [PATCH] Example usage of EVM-C

---
 examples/CMakeLists.txt |  2 ++
 examples/capi.c         | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)
 create mode 100644 examples/CMakeLists.txt
 create mode 100644 examples/capi.c

diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
new file mode 100644
index 0000000..1ceaeea
--- /dev/null
+++ b/examples/CMakeLists.txt
@@ -0,0 +1,2 @@
+add_library(example-capi STATIC EXCLUDE_FROM_ALL capi.c)
+target_include_directories(example-capi PRIVATE ../include)
\ No newline at end of file
diff --git a/examples/capi.c b/examples/capi.c
new file mode 100644
index 0000000..6419ade
--- /dev/null
+++ b/examples/capi.c
@@ -0,0 +1,37 @@
+#include "evm.h"
+
+struct evm_uint256 balance(struct evm_env*, struct evm_hash160 address);
+
+union evm_variant query(struct evm_env* env,
+                        enum evm_query_key key,
+                        union evm_variant arg) {
+    union evm_variant result;
+    switch (key) {
+    case EVM_GAS_LIMIT: result.int64 = 314; break;
+
+    case EVM_BALANCE:
+        result.uint256 = balance(env, arg.address);
+        break;
+
+    default: result.int64 = 0; break;
+    }
+    return result;
+}
+
+/// Example how the API is supposed to be used.
+void example() {
+    struct evm_instance* jit = evm_create(query, 0, 0, 0);
+
+    char const code[] = "exec()";
+    struct evm_bytes_view code_view = {code, sizeof(code)};
+    struct evm_hash256 code_hash = {{1, 2, 3}};
+    struct evm_bytes_view input = {"Hello World!", 12};
+    struct evm_uint256 value = {{1, 0, 0, 0}};
+
+    int64_t gas = 200000;
+    struct evm_result result =
+        evm_execute(jit, NULL, code_hash, code_view, gas, input, value);
+
+    evm_destroy_result(result);
+    evm_destroy(jit);
+}