Create libioutil, implement a filewriter

libioutil/filewriter.c

@@ -0,0 +1,83 @@
+#include <desc.h>
+#include <filewriter.h>
+#include <path_defs.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include <system.h>
+#include <write_file.h>
+
+int filewriter_init (struct filewriter* fw, const char* volume, const char* path, uint32_t flags) {
+  memset (fw, 0, sizeof (*fw));
+  strncpy (fw->volume, volume, VOLUME_MAX);
+  strncpy (fw->path, path, PATH_MAX);
+  fw->flags = flags;
+
+  int ret;
+  struct desc desc;
+
+  if ((ret = volume_open (fw->volume)) < 0)
+    return -FW_VOLUME_OPEN_ERROR;
+
+  if ((fw->flags & FW_CREATE_FILE)) {
+    if ((ret = create_file (fw->path)) < 0) {
+      volume_close ();
+      return -FW_CREATE_FILE_ERROR;
+    }
+  }
+
+  if ((ret = describe (fw->path, &desc)) < 0) {
+    volume_close ();
+    return -FW_DESC_ERROR;
+  }
+
+  if (desc.type != FS_FILE)
+    return -FW_NOT_FILE;
+
+  fw->file_size = desc.size;
+  fw->flags |= FW_OPEN;
+
+  if ((fw->flags & FW_APPEND))
+    fw->write_cursor = desc.size;
+
+  return FW_OK;
+}
+
+int filewriter_fini (struct filewriter* fw) {
+  if ((fw->flags & FW_OPEN)) {
+    volume_close ();
+    fw->flags &= ~FW_OPEN;
+  }
+
+  return FW_OK;
+}
+
+int filewriter_write (struct filewriter* fw, uint8_t* buffer, size_t buffer_size) {
+  if (!(fw->flags & FW_OPEN))
+    return -FW_VOLUME_NOT_OPENED;
+
+  struct desc desc;
+  int ret;
+
+  if ((fw->flags & FW_APPEND)) {
+    if ((ret = describe (fw->path, &desc)) < 0)
+      return -FW_DESC_ERROR;
+
+    fw->file_size = desc.size;
+    fw->write_cursor = fw->file_size;
+  }
+
+  if (buffer_size > 0) {
+    if (!(fw->flags & FW_APPEND) && !(fw->write_cursor + buffer_size <= fw->file_size))
+      return -FW_CURSOR_OOB;
+
+    uint32_t flags = (fw->flags & FW_APPEND) ? WF_APPEND : 0;
+    if ((ret = write_file (fw->path, fw->write_cursor, buffer, buffer_size, flags)) < 0)
+      return -FW_WRITE_ERROR;
+
+    fw->write_cursor += buffer_size;
+  }
+
+  return FW_OK;
+}