WebSVN – HelenOS – Diff – /trunk/uspace/lib/libfs/libfs.c

+}
 #define RD_BASE     1024    // FIXME
 #define RD_READ_BLOCK   (RD_BASE + 1)
+/** Read data from a block device.
+ *
+ * @param phone     Phone to be used to communicate with the device.
+ * @param buffer    Communication buffer shared with the device.
+ * @param bufpos    Pointer to the first unread valid offset within the
+ *          communication buffer.
+ * @param buflen    Pointer to the number of unread bytes that are ready in
+ *          the communication buffer.
+ * @param pos       Device position to be read.
+ * @param dst       Destination buffer.
+ * @param size      Size of the destination buffer.
+ * @param block_size    Block size to be used for the transfer.
+ *
+ * @return      True on success, false on failure.
+ */
-bool libfs_blockread(int phone, void *buffer, size_t *bufpos, size_t *buflen,
+bool libfs_blockread(int phone, void *buffer, off_t *bufpos, size_t *buflen,
-    size_t *pos, void *dst, size_t size, size_t block_size)
+    off_t *pos, void *dst, size_t size, size_t block_size)
+{
-    size_t offset = 0;
+    off_t offset = 0;
     size_t left = size;
     while (left > 0) {
         size_t rd;
             rd = left;
         else
             rd = *buflen - *bufpos;
         if (rd > 0) {
+            /*
+             * Copy the contents of the communication buffer to the
+             * destination buffer.
+             */
             memcpy(dst + offset, buffer + *bufpos, rd);
             offset += rd;
             *bufpos += rd;
             *pos += rd;
             left -= rd;
+        }
         if (*bufpos == *buflen) {
+            /* Refill the communication buffer with a new block. */
             ipcarg_t retval;
             int rc = async_req_2_1(phone, RD_READ_BLOCK,
                 *pos / block_size, block_size, &retval);
             if ((rc != EOK) || (retval != EOK))
                 return false;

Subversion Repositories HelenOS

(root)/trunk/uspace/lib/libfs/libfs.c – Rev 3251 → 3252