From 00236595527e0a695a2e547d2fcb8c5310367735 Mon Sep 17 00:00:00 2001
From: Sander Speetjens <sander.speetjens@gmail.com>
Date: Wed, 6 Dec 2023 14:58:41 +0100
Subject: [PATCH] tftp

- Remove the suggestion of null terimination of the custom_fread custom_fwrite functions
- Update the tests
---
 project/Core/Src/tftp.c | 17 +++++++++++------
 tests/tfpt_tests.cpp    | 15 +++++++++++----
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/project/Core/Src/tftp.c b/project/Core/Src/tftp.c
index 6173a1d..c674a42 100644
--- a/project/Core/Src/tftp.c
+++ b/project/Core/Src/tftp.c
@@ -73,17 +73,17 @@ void tftp_custom_fseek(tftp_custom_file_t* handle, size_t offset, int whence) {
  *        auto rolling over the offset
  *        if the bytes to read is bigger than the remaining bytes
  *        it will read the remaining bytes and set the bytes to 0
+ *        this function does not handle null termination
  * @param[out] buf The buffer to write the data to
  * @param[in] bytes The number of bytes to read
  * @param[in,out] handle Custom file handles
  */
 size_t tftp_custom_fread(void* buf, size_t bytes, tftp_custom_file_t* handle) {
-    if (handle->offset + bytes >= handle->len) {
-        bytes = handle->len - handle->offset - 1;
+    if (handle->offset + bytes > handle->len) {
+        bytes = handle->len - handle->offset;
     }
     memcpy(buf, handle->data + handle->offset, bytes);
     handle->offset += bytes;
-    ((char*)buf)[bytes] = '\0';
     if (handle->offset > handle->len) {
         bytes = 0;
     }
@@ -92,7 +92,12 @@ size_t tftp_custom_fread(void* buf, size_t bytes, tftp_custom_file_t* handle) {
 
 /**
  * @brief tftp custom file functions to write the data
- *        auto rolling over the offset
+ *     auto rolling over the offset
+ *     if the bytes to write is bigger than the remaining bytes
+ *     it will write the remaining bytes and set the bytes to 0
+ *     this function does not handle null termination
+ *     if you want to write a null termination you have to add it to the data
+ *     and set the len to the new length before calling this function
  *
  * @param buf The buffer to write the data to
  * @param bytes The number of bytes to write
@@ -100,8 +105,8 @@ size_t tftp_custom_fread(void* buf, size_t bytes, tftp_custom_file_t* handle) {
  * @return The number of bytes written
  */
 size_t tftp_custom_fwrite(const void* buf, size_t bytes, tftp_custom_file_t* handle) {
-    if (handle->offset + bytes >= handle->len) {
-        bytes = handle->len - handle->offset - 1;
+    if (handle->offset + bytes > handle->len) {
+        bytes = handle->len - handle->offset;
     }
     memcpy(handle->data + handle->offset, buf, bytes);
     handle->offset += bytes;
diff --git a/tests/tfpt_tests.cpp b/tests/tfpt_tests.cpp
index aba9a79..f58a197 100644
--- a/tests/tfpt_tests.cpp
+++ b/tests/tfpt_tests.cpp
@@ -77,20 +77,27 @@ TEST(TFTP, custom_fwrite) {
 }
 
 TEST(TFTP, custom_fread_fwrite_suggested_by_Lorenz) {
+    char buf[21];
     write_file.data = (char*)malloc(21 * sizeof(char));
     write_file.len = 21;
     write_file.offset = 0;
     tftp_custom_fwrite("1234567890123456789", 19, &write_file);
 
-    tftp_custom_fwrite("0987654321", 10, &write_file);
-    EXPECT_EQ(write_file.offset, 20);
+    tftp_custom_fwrite("0987654321", 11, &write_file);
+    // the above function does not write the null terminator
+    EXPECT_EQ(write_file.offset, 21);
     EXPECT_EQ(write_file.len, 21);
-    EXPECT_EQ(memcmp(write_file.data, "12345678901234567890", 21), 0);
+    EXPECT_EQ(memcmp(write_file.data, "12345678901234567890", 20), 0);
+
+    tftp_custom_fseek(&write_file, 0, SEEK_SET);
+    tftp_custom_fread(buf, 20, &write_file);
+    // the above function does not write the null terminator
+    buf[20] = '\0';
+    EXPECT_EQ(memcmp(buf, "12345678901234567890", 21), 0);
     free(write_file.data);
     write_file.data = NULL;
     write_file.len = 0;
 
-    char buf[21];
     file.offset = 9;
     tftp_custom_fread(buf, 20, &file);
     EXPECT_EQ(memcmp(buf, "0", 2), 0);