feat: finished io_backend

src/io_backend/io_backend.c

@@ -1,34 +1,102 @@
 #include "io_backend.h"
 
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+// === Static variables
 
 static struct iob_context context;
-static FILE *input;
+static FILE *input = NULL;
+static char *stream_buf = NULL;
+static size_t stream_buf_size = 0;
+static enum iob_state state = IOB_STATE_NOT_INITIALIZED;
+
+// === Functions
 
 int iob_init(struct iob_context *ctx)
 {
+    if (state != IOB_STATE_NOT_INITIALIZED)
+        return IOB_ERROR_MODULE_NOT_INITIALIZED;
+
     context = *ctx;
 
     switch (context.mode)
     {
-    IOB_MODE_STDIN:
+    case IOB_MODE_STDIN:
         input = stdin;
+        state = IOB_STATE_READY;
         return 0;
 
-    IOB_MODE_SCRIPT:
+    case IOB_MODE_SCRIPT:
         if (context.args == NULL)
-            return -2;
+            return IOB_ERROR_BAD_ARG;
         input = fopen(context.args, "r");
         if (input == NULL)
-            return -4;
+            return IOB_ERROR_CANNOT_OPEN_FILE;
+        state = IOB_STATE_READY;
+        return 0;
 
-    IOB_MODE_CMD:
+    case IOB_MODE_CMD:
         if (context.args != NULL)
-            return -2;
+            return IOB_ERROR_BAD_ARG;
-        else
+        state = IOB_STATE_READY;
-            return 0;
+        return 0;
 
     default:
-        return -1;
+        return IOB_ERROR_BAD_ARG;
+    }
+}
+
+void iob_close(void)
+{
+    fclose(input);
+    if ((context.mode == IOB_MODE_STDIN || context.mode == IOB_MODE_SCRIPT)
+        && stream_buf != NULL)
+    {
+        free(stream_buf);
+        stream_buf_size = 0;
+    }
+    state = IOB_STATE_NOT_INITIALIZED;
+}
+
+ssize_t stream_read(char **stream)
+{
+    // Check args
+    if (stream == NULL)
+        return IOB_ERROR_BAD_ARG;
+
+    // Check env
+    if (state == IOB_STATE_NOT_INITIALIZED)
+        return IOB_ERROR_MODULE_NOT_INITIALIZED;
+    if (state == IOB_STATE_FINISHED)
+        return 0;
+    if (state == IOB_STATE_ERROR)
+        return IOB_ERROR_GENERIC;
+
+    // Use input
+    if (context.mode == IOB_MODE_STDIN || context.mode == IOB_MODE_SCRIPT)
+    {
+        ssize_t nread = getline(&stream_buf, &stream_buf_size, input);
+        if (nread == -1)
+        {
+            state = IOB_STATE_FINISHED;
+            return 0;
+        }
+        else if (nread < 0)
+            state = IOB_STATE_ERROR;
+
+        return nread;
+    }
+    // Use args
+    else if (context.mode == IOB_MODE_CMD)
+    {
+        *stream = context.args;
+        return strlen(context.args);
+    }
+    else
+    {
+        *stream = NULL;
+        return IOB_ERROR_GENERIC;
     }
 }

src/io_backend/io_backend.h

@@ -3,6 +3,13 @@
 
 #include <sys/types.h>
 
+// Error codes
+#define IOB_ERROR_GENERIC -1
+#define IOB_ERROR_BAD_ARG -2
+#define IOB_ERROR_MODULE_NOT_INITIALIZED -3
+#define IOB_ERROR_MODULE_ALREADY_INITALIZED -4
+#define IOB_ERROR_CANNOT_OPEN_FILE -5
+
 enum iob_mode {
     IOB_MODE_NULL = 0,
     IOB_MODE_STDIN,
@@ -10,11 +17,18 @@ enum iob_mode {
     IOB_MODE_CMD
 };
 
+enum iob_state {
+    IOB_STATE_NOT_INITIALIZED,
+    IOB_STATE_READY,
+    IOB_STATE_FINISHED,
+    IOB_STATE_ERROR
+};
+
 /* @struct iob_context
  * @var mode
  * @var args contains
- *        the script name when mode is set to IOB_SCRIPT,
+ *        the script name when mode is set to IOB_MODE_SCRIPT,
- *        the command to execute when mode is set to IOB_CMD,
+ *        the command to execute when mode is set to IOB_MODE_CMD
  */
 struct iob_context {
     enum iob_mode mode;
@@ -29,14 +43,16 @@ struct iob_context {
  */
 int iob_init(struct iob_context *context);
 
-/* @brief Closes the opened buffers and exits the modules gracefully
+/* @brief Closes the opened buffers and the module gracefully
  */
 void iob_close(void);
 
 /* @brief reads at most one line of the input and stores it into *stream
  *
  * @param stream is a pointer that will be set to a string to parse
- * @return the number of read characters if positive, the error code otherwise
+ * @return the number of read characters if positive,
+ *         zero if finished (reached EOF),
+ *         the error code otherwise
  */
 ssize_t stream_read(char** stream);