Changeset aaf962e6 in mainline for uspace/lib/riff/src/chunk.c

Timestamp:

2020-09-21T21:41:53Z (4 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

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

Children:

ea459d4

Parents:

d145ecb

Message:

Need to be able to skip unknown chunks easily

This is, afterall the whole point of having a self-describing format:
new (optional) chunks types can be inserted without having to modify the
reader.

File:

• uspace/lib/riff/src/chunk.c (modified) (4 diffs)

uspace/lib/riff/src/chunk.c

@@ -39 +39 @@
 #include <macros.h>
 #include <riff/chunk.h>
+#include <stdbool.h>
 #include <stdlib.h>
 
@@ -271 +272 @@
  * @param rchunk RIFF chunk
  * @param v  Place to store value
- * @return EOK on success, EIO on error.
+ * @return EOK on success, ELIMIT if at the end of parent chunk, EIO on error.
  */
 errno_t riff_read_uint32(riff_rchunk_t *rchunk, uint32_t *v)
@@ -295 +296 @@
  * @param rchunk Pointer to chunk structure to fill in
  *
- * @return EOK on success, EIO on error.
+ * @return EOK on success, ELIMIT if at the end of parent chunk,
+ *         EIO on error.
  */
 errno_t riff_rchunk_start(riff_rchunk_t *parent, riff_rchunk_t *rchunk)
@@ -320 +322 @@
 error:
         return rc;
+}
+
+/** Find and start reading RIFF chunk of with specific chunk ID.
+ * Other types of chunks are skipped.
+ *
+ * @param parent Parent chunk
+ * @param rchunk Pointer to chunk structure to fill in
+ *
+ * @return EOK on success, ENOENT chunk was not found and end was reached
+ *         EIO on error.
+ */
+errno_t riff_rchunk_match(riff_rchunk_t *parent, riff_ckid_t ckid,
+    riff_rchunk_t *rchunk)
+{
+        errno_t rc;
+
+        while (true) {
+                rc = riff_rchunk_start(parent, rchunk);
+                if (rc == ELIMIT)
+                        return ENOENT;
+                if (rc != EOK)
+                        return rc;
+
+                if (rchunk->ckid == ckid)
+                        break;
+
+                rc = riff_rchunk_end(rchunk);
+                if (rc != EOK)
+                        return rc;
+        }
+
+        return EOK;
+}
+
+/** Find and start reading RIFF LIST chunk of specified type.
+ * Other chunks or LIST chunks of other type are skipped.
+ *
+ * @param parent Parent chunk
+ * @param rchunk Pointer to chunk structure to fill in
+ *
+ * @return EOK on success, ENOENT chunk was not found and end was reached
+ *         EIO on error.
+ */
+errno_t riff_rchunk_list_match(riff_rchunk_t *parent, riff_ltype_t ltype,
+    riff_rchunk_t *rchunk)
+{
+        errno_t rc;
+        riff_ltype_t rltype;
+
+        while (true) {
+                rc = riff_rchunk_match(parent, CKID_LIST, rchunk);
+                if (rc == ELIMIT)
+                        return ENOENT;
+                if (rc != EOK)
+                        return rc;
+
+                rc = riff_read_uint32(parent, &rltype);
+                if (rc != EOK)
+                        return rc;
+
+                if (rltype == ltype)
+                        break;
+
+                rc = riff_rchunk_end(rchunk);
+                if (rc != EOK)
+                        return rc;
+        }
+
+        return EOK;
 }