#include "mbedtls/error.h"
#include <string.h>
#include <stdio.h>

// test_code checks that the provided code results in the provided error string for any size
// buffer. It calls mbedtls_strerror() to fill a buffer that is from 1 to 100 bytes in length
// and then checks that the buffer contents is OK and that a few guard bytes before and after
// the buffer were not overwritten.
int test_code(int code, char *str) {
 char buf[100];
 int ok = 1;
 int res;

 // test zero-length buffer
 memset(buf, -3, 100);
 mbedtls_strerror(code, buf + 4, 0);
 for (int i = 0; i < 10; i++) {
 if (buf[i] != -3) {
 printf("Error: guard overwritten buflen=0 i=%d buf[i]=%d\n", i, buf[i]);
 ok = 0;
 }
 }

 // test
 for (size_t buflen = 1; buflen < 90; buflen++) {
 memset(buf, -3, 100);
 mbedtls_strerror(code, buf + 4, buflen);
 for (int i = 0; i < 4; i++) {
 if (buf[i] != -3) {
 printf("Error: pre-guard overwritten buflen=%d i=%d buf[i]=%d\n", buflen, i, buf[i]);
 ok = 0;
 }
 }
 for (int i = 4 + buflen; i < 100; i++) {
 if (buf[i] != -3) {
 printf("Error: post-guard overwritten buflen=%d i=%d buf[i]=%d\n", buflen, i, buf[i]);
 ok = 0;
 }
 }
 char exp[100];
 strncpy(exp, str, buflen);
 exp[buflen - 1] = 0;
 if (strcmp(buf + 4, exp) != 0) {
 printf("Error: expected %s, got %s\n", exp, buf);
 ok = 0;
 }
 }

 printf("Test %x -> %s is %s\n", code, str, ok?"OK":"*** BAD ***");
}

int main() {
 test_code(0x7200, "MBEDTLS_ERR_SSL_INVALID_RECORD");
 test_code(0x7780, "MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE");
 test_code(0x0074, "MBEDTLS_ERR_SHA256_BAD_INPUT_DATA");
 test_code(0x6600 | 0x0074, "MBEDTLS_ERR_SSL_INVALID_VERIFY_HASH+MBEDTLS_ERR_SHA256_BAD_INPUT_DATA");
 test_code(103, "MBEDTLS_ERR_UNKNOWN (0x0067)");
}