Add mtar_tell_data() to return offset in data

2 files changed, 13 insertions, 0 deletions

diff --git a/src/microtar.c b/src/microtar.c
index da90d4d..ddd0c0c 100644
--- a/src/microtar.c
+++ b/src/microtar.c
@@ -471,6 +471,18 @@ int mtar_seek_data(mtar_t* tar, int offset, int whence)
     return tseek(tar, newpos);
 }
 
+unsigned mtar_tell_data(mtar_t* tar)
+{
+#ifndef MICROTAR_DISABLE_API_CHECKS
+    if(tar->access != MTAR_READ)
+        return MTAR_EACCESS;
+    if(!(tar->state & S_HEADER_VALID))
+        return MTAR_EAPI;
+#endif
+
+    return tar->pos - data_beg_pos(tar);
+}
+
 int mtar_eof_data(mtar_t* tar)
 {
     /* API usage errors, but just claim EOF. */
diff --git a/src/microtar.h b/src/microtar.h
index 12e43e0..5ccb6df 100644
--- a/src/microtar.h
+++ b/src/microtar.h
@@ -116,6 +116,7 @@ int mtar_find(mtar_t* tar, const char* name);
 
 int mtar_read_data(mtar_t* tar, void* ptr, unsigned size);
 int mtar_seek_data(mtar_t* tar, int offset, int whence);
+unsigned mtar_tell_data(mtar_t* tar);
 int mtar_eof_data(mtar_t* tar);
 
 int mtar_write_header(mtar_t* tar, const mtar_header_t* h);