Add mbedtls dependency

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "subprojects/munit"]
 	path = subprojects/munit
 	url = https://github.com/nemequ/munit.git
+[submodule "subprojects/mbedtls"]
+	path = subprojects/mbedtls
+	url = https://github.com/ARMmbed/mbedtls.git

meson.build

@@ -5,12 +5,18 @@ m_dep = cc.find_library('m', required : false)
 
 incdir = include_directories('src')
 
+cmake = import('cmake')
+mbedtls_proj = cmake.subproject('mbedtls')
+mbedtls_dep = mbedtls_proj.dependency('mbedtls')
+
 executable('ex01', ['src/ex01/main.c', 'src/utils.c'], dependencies: m_dep, include_directories: incdir)
 executable('ex02', ['src/ex02/main.c', 'src/utils.c'], dependencies: m_dep, include_directories: incdir)
 executable('ex03', ['src/ex03/main.c', 'src/utils.c'], dependencies: m_dep, include_directories: incdir)
 executable('ex04', ['src/ex04/main.c', 'src/utils.c'], dependencies: m_dep, include_directories: incdir)
 executable('ex05', ['src/ex05/main.c', 'src/utils.c'], dependencies: m_dep, include_directories: incdir)
 executable('ex06', ['src/ex06/main.c', 'src/utils.c'], dependencies: m_dep, include_directories: incdir)
+executable('ex07', ['src/ex07/main.c', 'src/utils.c'],
+	   dependencies: [m_dep, mbedtls_dep], include_directories: incdir)
 
 munit_dep = dependency('munit', fallback: ['munit', 'munit_dep'])
 

src/ex07/main.c

@@ -0,0 +1,47 @@
+#include "utils.h"
+#include <ctype.h>
+#include <math.h>
+#include <stdio.h>
+#include <string.h>
+#include "mbedtls/aes.h"
+
+#define BUF_SIZE 4096
+
+int main(int argc, char *argv[]) {
+  if (argc < 3) {
+    printf("Usage: %s <key> <filename>\n", argv[0]);
+    return EXIT_FAILURE;
+  }
+
+  const char *key = argv[1];
+  const char *filename = argv[2];
+
+  FILE *fp = fopen(filename, "r");
+  if (fp == NULL) {
+    printf("Error opening file %s\n", filename);
+    return EXIT_FAILURE;
+  }
+
+  char input[BUF_SIZE] = {'\0'};
+  size_t nread = fread(input, 1, BUF_SIZE, fp);
+  if (nread == 0) {
+    printf("Cannot read any character from file %s\n", filename);
+    return EXIT_FAILURE;
+  }
+
+  unsigned char buf[BUF_SIZE] = {0};
+  size_t len = base64_to_bytes(buf, input);
+  if (len == 0) {
+    printf("Could not decode base64\n");
+    return EXIT_FAILURE;
+  }
+
+  mbedtls_aes_context aes;
+
+  if (fclose(fp)) {
+    printf("Error closing file %s\n", filename);
+    return EXIT_FAILURE;
+  }
+
+  return EXIT_SUCCESS;
+}

subprojects/mbedtls

@@ -0,0 +1 @@
+Subproject commit 2a1d9332d55d1270084232e42df08fdb08129f1b