Generic I/O for directories: add [read|write]_entries().

Begin conversion to exfat_generic_pread()/exfat_generic_pwrite()
functions for manipulations with directories contents. This simplifies
code a lot.

diff --git a/libexfat/node.c b/libexfat/node.c
index d64ae29..a1f9b17 100644 (file)
--- a/libexfat/node.c
+++ b/libexfat/node.c
@@ -166,6 +166,46 @@ static bool fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
        return true;
 }
 
+static int read_entries(struct exfat* ef, struct exfat_node* dir,
+               struct exfat_entry* entries, int n, off_t offset)
+{
+       ssize_t size;
+
+       if (!(dir->attrib & EXFAT_ATTRIB_DIR))
+               exfat_bug("attempted to read entries from a file");
+
+       size = exfat_generic_pread(ef, dir, entries,
+                       sizeof(struct exfat_entry[n]), offset);
+       if (size == sizeof(struct exfat_entry[n]))
+               return 0; /* success */
+       if (size == 0)
+               return -ENOENT;
+       if (size < 0)
+               return -EIO;
+       exfat_error("read %zd bytes instead of %zu bytes", size,
+                       sizeof(struct exfat_entry[n]));
+       return -EIO;
+}
+
+static int write_entries(struct exfat* ef, struct exfat_node* dir,
+               const struct exfat_entry* entries, int n, off_t offset)
+{
+       ssize_t size;
+
+       if (!(dir->attrib & EXFAT_ATTRIB_DIR))
+               exfat_bug("attempted to write entries into a file");
+
+       size = exfat_generic_pwrite(ef, dir, entries,
+                       sizeof(struct exfat_entry[n]), offset);
+       if (size == sizeof(struct exfat_entry[n]))
+               return 0; /* success */
+       if (size < 0)
+               return -EIO;
+       exfat_error("wrote %zd bytes instead of %zu bytes", size,
+                       sizeof(struct exfat_entry[n]));
+       return -EIO;
+}
+
 static struct exfat_node* allocate_node(void)
 {
        struct exfat_node* node = malloc(sizeof(struct exfat_node));