reverse-ramdisk.c: improve, separate debug log

c-programming/reverse-ramdisk.c

@@ -3,7 +3,13 @@ C programming idea: Handling temporary files like memory allocations (allocating
 
 50% AI, 50% human (the code is tested and reviewed)
 
-GCC/Clang/TCC: Compile with -DTEST to set macro TEST as defined
+Warning: The current result is quick and dirty. Not for educational or
+production purposes.
+
+GCC/Clang/TCC: Compile with -DTEST to set macro TEST as defined, with -DDEBUG
+to enable debug mode
+
+To-Do: error handling on line 167, function fread()
 */
 
 #include <errno.h>
@@ -21,14 +27,34 @@ typedef struct {
 TempFile* temp_files = NULL;
 size_t num_temp_files = 0;
 
-#define line_fail(x) do { \
+#ifdef DEBUG
+# define line_fail(x) do { \
 	printf("failed on line %d\n", __LINE__ + x); \
 } while (0)
+#else
+# define line_fail(x) do {} while (0)
+#endif
 
 int tf_alloc(size_t n, size_t type_size) {
 	// Create an empty file
-	char file_path[20];
-	sprintf(file_path, "tf_%zu.tmp", num_temp_files);
+	size_t len_digit;
+	if (num_temp_files == 0)
+		len_digit = 1;
+	else
+		len_digit = (size_t) log((double) num_temp_files + 1.) / log(10.);
+	size_t file_path_len = len_digit + strlen("tf_.tmp");
+	char* file_path = malloc((file_path_len + 1) * sizeof(char));
+	if (file_path == NULL) {
+		fail_line(-2);
+		return -1;
+	}
+	int res = snprintf(file_path, file_path_len, "tf_%zu.tmp", num_temp_files);
+	if ((size_t) res != file_path_len) {
+		fail_line(-2);
+		return -1;
+	}
+
+	// Open the file
 	FILE* file = fopen(file_path, "w+b");
 	if (file == NULL) {
 		line_fail(-2);
@@ -36,7 +62,7 @@ int tf_alloc(size_t n, size_t type_size) {
 	}
 
 	// Allocate memory for the TempFile struct
-	TempFile* temp_file = (TempFile*)malloc(sizeof(TempFile));
+	TempFile* temp_file = malloc(sizeof(TempFile));
 	if (temp_file == NULL) {
 		line_fail(-2);
 		return -1;
@@ -51,7 +77,7 @@ int tf_alloc(size_t n, size_t type_size) {
 	num_temp_files++;
 
 	// Reallocate memory for the temp_files array
-	temp_files = (TempFile*)realloc(temp_files, num_temp_files * sizeof(TempFile));
+	temp_files = realloc(temp_files, num_temp_files * sizeof(TempFile));
 	if (temp_files == NULL) {
 		line_fail(-2);
 		return -1;
@@ -64,13 +90,7 @@ int tf_alloc(size_t n, size_t type_size) {
 }
 
 int tf_free(int ID) {
-	// Find the temp file with the given ID
-	int index = -1;
-	for (int i = 0; i < num_temp_files; i++)
-		if (temp_files[i].ID == ID) {
-			index = i;
-			break;
-		}
+	size_t index = (size_t) ID;
 
 	if (index == -1)
 		return -1;
@@ -79,6 +99,7 @@ int tf_free(int ID) {
 
 	// Delete the file
 	if (remove(temp_files[index].file_path) != 0) {
+		line_fail(-1);
 		return -1;
 	}
 
@@ -86,15 +107,15 @@ int tf_free(int ID) {
 
 	// Shift the remaining temp files in the array
 	for (int i = index; i < num_temp_files - 1; i++) {
-		temp_files[i] = temp_files[i + 1];
+		temp_files[(size_t) i] = temp_files[(size_t) i + 1];
 	}
 
-	// Decrease the number of temp files
 	num_temp_files--;
 
 	// Reallocate memory for the temp_files array
-	temp_files = (TempFile*)realloc(temp_files, num_temp_files * sizeof(TempFile));
+	temp_files = realloc(temp_files, num_temp_files * sizeof(TempFile));
 	if (temp_files == NULL && num_temp_files > 0) {
+		line_fail(-2);
 		return -1;
 	}
 
@@ -102,24 +123,17 @@ int tf_free(int ID) {
 }
 
 int tf_write(int ID, size_t offset, void* data, size_t data_size) {
-	// Find the temp file with the given ID
-	int index = -1;
-	for (int i = 0; i < num_temp_files; i++) {
-		if (temp_files[i].ID == ID) {
-			index = i;
-			break;
-		}
-	}
+	size_t index = (size_t) ID;
 
 	if (index == -1)
 		return -1;
 
-	// Open the file in append mode
+	// Check file handler for NULL
 	FILE* file = temp_files[index].file;
 	if (file == NULL)
 		return -1;
 
-	// Seek
+	// Set the position
 	fseek(file, offset, SEEK_SET);
 
 	// Write the data to the file
@@ -132,18 +146,7 @@ int tf_write(int ID, size_t offset, void* data, size_t data_size) {
 }
 
 int tf_read(int ID, size_t offset, void* dest, size_t data_size) {
-	// Find the temp file with the given ID
-	int index = -1;
-	for (int i = 0; i < num_temp_files; i++) {
-		if (temp_files[i].ID == ID) {
-			index = i;
-			break;
-		}
-	}
-
-	if (index == -1) {
-		return -1;
-	}
+	size_t index = (size_t) ID;
 
 	// Open the file in read mode
 	FILE* file = temp_files[index].file;
@@ -154,16 +157,14 @@ int tf_read(int ID, size_t offset, void* dest, size_t data_size) {
 	void* data = malloc(data_size);
 	if (data == NULL) {
 		fclose(file);
+		fail_line(-3);
 		return -1;
 	}
 
 	// Initialize the memory in the data buffer
-	memset(data, 0, data_size);
-
-	fseek(file, offset, SEEK_SET);
-	size_t bytes_read = fread(data, 1, data_size, file);
-
-	// Copy the data to the destination pointer
+	memset(data, 0, data_size); // clear destination
+	fseek(file, offset, SEEK_SET); // set position
+	size_t bytes_read = fread(data, 1, data_size, file); // read bytes
 	memcpy(dest, data, data_size);
 
 	free(data); // Free the allocated memory
@@ -173,11 +174,13 @@ int tf_read(int ID, size_t offset, void* dest, size_t data_size) {
 		return -1;
 	}
 
+#ifdef DEBUG
 	printf("Read: ID = %d, data = %016" PRIXPTR ", size = %zu -> '",
 		ID, (uintptr_t)dest, data_size);
 	for (size_t i = 0; i < data_size; i++)
 		printf("0x%02" PRIX8 " ", *((uint8_t*)(dest + i)));
 	printf("'\n");
+#endif
 	return 0;
 }