add a new function for buffer

MPEGGroup · Dec 6, 2023 · 340b122 · 340b122
1 parent 2a0e1a3
commit 340b122
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Showing 4 changed files with 55 additions and 1 deletion.
diff --git a/IsoLib/libisomediafile/src/MP4FileMappingInputStream.c b/IsoLib/libisomediafile/src/MP4FileMappingInputStream.c
@@ -158,6 +158,29 @@ static MP4Err skipData(struct MP4InputStreamRecord *s, u64 bytes, char *msg)
   return err;
 }
 
+static MP4Err rewindData(struct MP4InputStreamRecord *s, u64 bytes, char *msg)
+{
+  MP4Err err;
+  MP4FileMappingInputStreamPtr self = (MP4FileMappingInputStreamPtr)s;
+
+  err = MP4NoErr;
+
+  CHECK_AVAIL(bytes)
+  self->available += bytes;
+  self->current_offset -= bytes;
+
+  if(msg && self->debugging)
+  {
+    doIndent(s);
+    fprintf(stdout, "%s = [%lld bytes of data rewinded]\n", msg, bytes);
+  }
+
+bail:
+  TEST_RETURN(err);
+
+  return err;
+}
+
 static MP4Err readData(struct MP4InputStreamRecord *s, u64 bytes, char *outData, char *msg)
 {
   MP4Err err;
@@ -223,6 +246,7 @@ MP4Err MP4CreateFileMappingInputStream(struct FileMappingObjectRecord *mapping,
   is->read32               = read32;
   is->readData             = readData;
   is->skipData             = skipData;
+  is->rewindData           = rewindData;
   is->getStreamOffset      = getStreamOffset;
   is->getFileMappingObject = getFileMappingObject;
   is->mapping              = mapping;

diff --git a/IsoLib/libisomediafile/src/MP4Impl.h b/IsoLib/libisomediafile/src/MP4Impl.h
@@ -236,6 +236,11 @@ derivative works. Copyright (c) 1999.
     }                                                                               \
   }
 
+#define REWIND_DATA(length, var)                           \
+  err = inputStream->rewindData(inputStream, length, var); \
+  if(err) goto bail;                                       \
+  self->bytesRead -= length;
+
 #define PUTBYTES(src, len)                    \
   if((self->bytesWritten + len) > self->size) \
   {                                           \

diff --git a/IsoLib/libisomediafile/src/MP4InputStream.h b/IsoLib/libisomediafile/src/MP4InputStream.h
@@ -41,7 +41,8 @@ derivative works. Copyright (c) 1999.
   MP4Err (*read32)(struct MP4InputStreamRecord * self, u32 * outVal, char *msg);               \
   MP4Err (*readData)(struct MP4InputStreamRecord * self, u64 bytes, char *outData, char *msg); \
   u64 (*getStreamOffset)(struct MP4InputStreamRecord * self);                                  \
-  MP4Err (*skipData)(struct MP4InputStreamRecord * self, u64 bytes, char *msg);
+  MP4Err (*skipData)(struct MP4InputStreamRecord * self, u64 bytes, char *msg);                \
+  MP4Err (*rewindData)(struct MP4InputStreamRecord * self, u64 bytes, char *msg);
 
 typedef struct MP4InputStreamRecord
 {

diff --git a/IsoLib/libisomediafile/src/MP4MemoryInputStream.c b/IsoLib/libisomediafile/src/MP4MemoryInputStream.c
@@ -168,6 +168,29 @@ static MP4Err skipData(struct MP4InputStreamRecord *s, u64 bytes, char *msg)
   return err;
 }
 
+static MP4Err rewindData(struct MP4InputStreamRecord *s, u64 bytes, char *msg)
+{
+  MP4Err err;
+  MP4FileMappingInputStreamPtr self = (MP4FileMappingInputStreamPtr)s;
+
+  err = MP4NoErr;
+
+  CHECK_AVAIL(bytes)
+  self->available += bytes;
+  self->current_offset -= bytes;
+
+  if(msg && self->debugging)
+  {
+    doIndent(s);
+    fprintf(stdout, "%s = [%lld bytes of data rewinded]\n", msg, bytes);
+  }
+
+bail:
+  TEST_RETURN(err);
+
+  return err;
+}
+
 static MP4Err readData(struct MP4InputStreamRecord *s, u64 bytes, char *outData, char *msg)
 {
   MP4Err err;
@@ -221,6 +244,7 @@ MP4Err MP4CreateMemoryInputStream(char *base, u32 size, MP4InputStreamPtr *outSt
   is->read32               = read32;
   is->readData             = readData;
   is->skipData             = skipData;
+  is->rewindData           = rewindData;
   is->getStreamOffset      = getStreamOffset;
   is->msg                  = msg;
   is->getFileMappingObject = getFileMappingObject;