add helper tu_desc_find/find2/find3

2 files changed, 48 insertions, 0 deletions

diff --git a/src/common/tusb_types.h b/src/common/tusb_types.h
index 32cdba450..82798a484 100644
--- a/src/common/tusb_types.h
+++ b/src/common/tusb_types.h
@@ -543,22 +543,35 @@ TU_ATTR_ALWAYS_INLINE static inline const char *tu_edpt_type_str(tusb_xfer_type_
 //--------------------------------------------------------------------+
 // Descriptor helper
 //--------------------------------------------------------------------+
+
+// return next descriptor
 TU_ATTR_ALWAYS_INLINE static inline uint8_t const * tu_desc_next(void const* desc)
 {
   uint8_t const* desc8 = (uint8_t const*) desc;
   return desc8 + desc8[DESC_OFFSET_LEN];
 }
 
+// get descriptor type
 TU_ATTR_ALWAYS_INLINE static inline uint8_t tu_desc_type(void const* desc)
 {
   return ((uint8_t const*) desc)[DESC_OFFSET_TYPE];
 }
 
+// get descriptor length
 TU_ATTR_ALWAYS_INLINE static inline uint8_t tu_desc_len(void const* desc)
 {
   return ((uint8_t const*) desc)[DESC_OFFSET_LEN];
 }
 
+// find descriptor that match byte1 (type)
+uint8_t const * tu_desc_find(uint8_t const* desc, uint8_t const* end, uint8_t byte1);
+
+// find descriptor that match byte1 (type) and byte2
+uint8_t const * tu_desc_find2(uint8_t const* desc, uint8_t const* end, uint8_t byte1, uint8_t byte2);
+
+// find descriptor that match byte1 (type) and byte2
+uint8_t const * tu_desc_find3(uint8_t const* desc, uint8_t const* end, uint8_t byte1, uint8_t byte2, uint8_t byte3);
+
 #ifdef __cplusplus
  }
 #endif
diff --git a/src/tusb.c b/src/tusb.c
index a5c820b8d..44b34b0e6 100644
--- a/src/tusb.c
+++ b/src/tusb.c
@@ -74,6 +74,41 @@ bool tusb_inited(void)
 }
 
 //--------------------------------------------------------------------+
+// Descriptor helper
+//--------------------------------------------------------------------+
+
+uint8_t const * tu_desc_find(uint8_t const* desc, uint8_t const* end, uint8_t byte1)
+{
+  while(desc+1 < end)
+  {
+    if ( desc[1] == byte1 ) return desc;
+    desc += desc[DESC_OFFSET_LEN];
+  }
+  return NULL;
+}
+
+uint8_t const * tu_desc_find2(uint8_t const* desc, uint8_t const* end, uint8_t byte1, uint8_t byte2)
+{
+  while(desc+2 < end)
+  {
+    if ( desc[1] == byte1 && desc[2] == byte2) return desc;
+    desc += desc[DESC_OFFSET_LEN];
+  }
+  return NULL;
+}
+
+uint8_t const * tu_desc_find3(uint8_t const* desc, uint8_t const* end, uint8_t byte1, uint8_t byte2, uint8_t byte3)
+{
+  while(desc+3 < end)
+  {
+    if (desc[1] == byte1 && desc[2] == byte2 && desc[3] == byte3) return desc;
+    desc += desc[DESC_OFFSET_LEN];
+  }
+  return NULL;
+}
+
+
+//--------------------------------------------------------------------+
 // Endpoint Helper for both Host and Device stack
 //--------------------------------------------------------------------+