Changeset 6fd7062 in mainline

Timestamp:

2011-04-28T12:46:17Z (13 years ago)

Author:

Vojtech Horky <vojtechhorky@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

aa9a53d

Parents:

6cb58e6

Message:

usb_debug_str_buffer() has two internal buffers

So it is possible to use this function twice in printf() statement.

File:

• uspace/lib/usb/src/debug.c (modified) (6 diffs)

uspace/lib/usb/src/debug.c

@@ -158 +158 @@
 
 /** Fibril local storage for the dumped buffer. */
-static fibril_local char buffer_dump[BUFFER_DUMP_LEN];
+static fibril_local char buffer_dump[2][BUFFER_DUMP_LEN];
+/** Fibril local storage for buffer switching. */
+static fibril_local int buffer_dump_index = 0;
 
 /** Dump buffer into string.
@@ -167 +169 @@
  * can not do that) and you do not have to guard it against concurrent
  * calls to it.
- * The only limitation is that each call rewrites the buffer again.
+ * The only limitation is that each second call rewrites the buffer again
+ * (internally, two buffer are used in cyclic manner).
  * Thus, it is necessary to copy the buffer elsewhere (that includes printing
  * to screen or writing to file).
@@ -173 +176 @@
  * that is not a big limitation.
  *
- * @warning You cannot use this function twice in the same printf
+ * @warning You cannot use this function more than twice in the same printf
  * (see detailed explanation).
  *
@@ -185 +188 @@
 {
         /*
-         * Remove previous string (that might also reveal double usage of
-         * this function).
+         * Remove previous string.
          */
-        bzero(buffer_dump, BUFFER_DUMP_LEN);
+        bzero(buffer_dump[buffer_dump_index], BUFFER_DUMP_LEN);
 
         if (buffer == NULL) {
@@ -202 +204 @@
         /* How many bytes are available in the output buffer. */
         size_t buffer_remaining_size = BUFFER_DUMP_LEN - 1 - REMAINDER_STR_LEN;
-        char *it = buffer_dump;
+        char *it = buffer_dump[buffer_dump_index];
 
         size_t index = 0;
@@ -253 +255 @@
         }
 
-        return buffer_dump;
+        /* Next time, use the other buffer. */
+        buffer_dump_index = 1 - buffer_dump_index;
+
+        /* Need to take the old one due to previous line. */
+        return buffer_dump[1 - buffer_dump_index];
 }