From f606afeffffcfffba837ad1350bcda7b458b4031 Mon Sep 17 00:00:00 2001 From: Dean Camera Date: Mon, 31 May 2010 06:55:23 +0000 Subject: Remove void* arithmetic in the USB_GetNextDescriptor() static inline function, to make the header file C++ compatible once again. Implement workaround for an obscure GCC bug which can cause incorrect code generation under some circumstances when the void* is re-cast. --- LUFA/Drivers/USB/HighLevel/ConfigDescriptor.c | 4 +- LUFA/Drivers/USB/HighLevel/ConfigDescriptor.h | 107 ++++++++++++++------------ 2 files changed, 61 insertions(+), 50 deletions(-) (limited to 'LUFA/Drivers/USB/HighLevel') diff --git a/LUFA/Drivers/USB/HighLevel/ConfigDescriptor.c b/LUFA/Drivers/USB/HighLevel/ConfigDescriptor.c index 07a3d4292..ffac8ae0f 100644 --- a/LUFA/Drivers/USB/HighLevel/ConfigDescriptor.c +++ b/LUFA/Drivers/USB/HighLevel/ConfigDescriptor.c @@ -114,13 +114,13 @@ void USB_GetNextDescriptorOfTypeAfter(uint16_t* const BytesRem, USB_GetNextDescriptorOfType(BytesRem, CurrConfigLoc, Type); } -uint8_t USB_GetNextDescriptorComp(uint16_t* BytesRem, void** CurrConfigLoc, ConfigComparatorPtr_t const ComparatorRoutine) +uint8_t USB_GetNextDescriptorComp(uint16_t* BytesRem, void** const CurrConfigLoc, ConfigComparatorPtr_t const ComparatorRoutine) { uint8_t ErrorCode; while (*BytesRem) { - void* PrevDescLoc = *CurrConfigLoc; + uint8_t* PrevDescLoc = *CurrConfigLoc; uint16_t PrevBytesRem = *BytesRem; USB_GetNextDescriptor(BytesRem, CurrConfigLoc); diff --git a/LUFA/Drivers/USB/HighLevel/ConfigDescriptor.h b/LUFA/Drivers/USB/HighLevel/ConfigDescriptor.h index 211128ca2..87610c7ba 100644 --- a/LUFA/Drivers/USB/HighLevel/ConfigDescriptor.h +++ b/LUFA/Drivers/USB/HighLevel/ConfigDescriptor.h @@ -119,49 +119,6 @@ * \see \ref USB_GetNextDescriptorComp function for more details */ typedef uint8_t (* ConfigComparatorPtr_t)(void*); - - /* Function Prototypes: */ - /** Searches for the next descriptor in the given configuration descriptor using a premade comparator - * function. The routine updates the position and remaining configuration descriptor bytes values - * automatically. If a comparator routine fails a search, the descriptor pointer is retreated back - * so that the next descriptor search invocation will start from the descriptor which first caused the - * original search to fail. This behaviour allows for one comparator to be used immediately after another - * has failed, starting the second search from the descriptor which failed the first. - * - * Comparator functions should be standard functions which accept a pointer to the header of the current - * descriptor inside the configuration descriptor which is being compared, and should return a value from - * the \ref DSearch_Return_ErrorCodes_t enum as a uint8_t value. - * - * \note This function is available in USB Host mode only. - * - * \param[in,out] BytesRem Pointer to an int storing the remaining bytes in the configuration descriptor - * \param[in,out] CurrConfigLoc Pointer to the current position in the configuration descriptor - * \param[in] ComparatorRoutine Name of the comparator search function to use on the configuration descriptor - * - * \return Value of one of the members of the \ref DSearch_Comp_Return_ErrorCodes_t enum - * - * Usage Example: - * \code - * uint8_t EndpointSearcher(void* CurrentDescriptor); // Comparator Prototype - * - * uint8_t EndpointSearcher(void* CurrentDescriptor) - * { - * if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Endpoint) - * return DESCRIPTOR_SEARCH_Found; - * else - * return DESCRIPTOR_SEARCH_NotFound; - * } - * - * //... - * // After retrieving configuration descriptor: - * if (USB_Host_GetNextDescriptorComp(&BytesRemaining, &CurrentConfigLoc, EndpointSearcher) == - * Descriptor_Search_Comp_Found) - * { - * // Do something with the endpoint descriptor - * } - * \endcode - */ - uint8_t USB_GetNextDescriptorComp(uint16_t* BytesRem, void** CurrConfigLoc, ConfigComparatorPtr_t const ComparatorRoutine); /* Enums: */ /** Enum for the possible return codes of the \ref USB_Host_GetDeviceConfigDescriptor() function. */ @@ -257,7 +214,59 @@ const uint8_t AfterType) ATTR_NON_NULL_PTR_ARG(1) ATTR_NON_NULL_PTR_ARG(2); + /** Searches for the next descriptor in the given configuration descriptor using a premade comparator + * function. The routine updates the position and remaining configuration descriptor bytes values + * automatically. If a comparator routine fails a search, the descriptor pointer is retreated back + * so that the next descriptor search invocation will start from the descriptor which first caused the + * original search to fail. This behaviour allows for one comparator to be used immediately after another + * has failed, starting the second search from the descriptor which failed the first. + * + * Comparator functions should be standard functions which accept a pointer to the header of the current + * descriptor inside the configuration descriptor which is being compared, and should return a value from + * the \ref DSearch_Return_ErrorCodes_t enum as a uint8_t value. + * + * \note This function is available in USB Host mode only. + * + * \param[in,out] BytesRem Pointer to an int storing the remaining bytes in the configuration descriptor + * \param[in,out] CurrConfigLoc Pointer to the current position in the configuration descriptor + * \param[in] ComparatorRoutine Name of the comparator search function to use on the configuration descriptor + * + * \return Value of one of the members of the \ref DSearch_Comp_Return_ErrorCodes_t enum + * + * Usage Example: + * \code + * uint8_t EndpointSearcher(void* CurrentDescriptor); // Comparator Prototype + * + * uint8_t EndpointSearcher(void* CurrentDescriptor) + * { + * if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Endpoint) + * return DESCRIPTOR_SEARCH_Found; + * else + * return DESCRIPTOR_SEARCH_NotFound; + * } + * + * //... + * // After retrieving configuration descriptor: + * if (USB_Host_GetNextDescriptorComp(&BytesRemaining, &CurrentConfigLoc, EndpointSearcher) == + * Descriptor_Search_Comp_Found) + * { + * // Do something with the endpoint descriptor + * } + * \endcode + */ + uint8_t USB_GetNextDescriptorComp(uint16_t* BytesRem, void** const CurrConfigLoc, ConfigComparatorPtr_t const ComparatorRoutine); + /* Inline Functions: */ + #if !defined(__DOXYGEN__) + static inline void USB_GetNextDescriptorST(uint16_t* const BytesRem, uint8_t** CurrConfigLoc) + { + uint16_t CurrDescriptorSize = DESCRIPTOR_CAST(*CurrConfigLoc, USB_Descriptor_Header_t).Size; + + *CurrConfigLoc += CurrDescriptorSize; + *BytesRem -= CurrDescriptorSize; + } + #endif + /** Skips over the current sub-descriptor inside the configuration descriptor, so that the pointer then points to the next sub-descriptor. The bytes remaining value is automatically decremented. * @@ -268,12 +277,14 @@ ATTR_NON_NULL_PTR_ARG(1) ATTR_NON_NULL_PTR_ARG(2); static inline void USB_GetNextDescriptor(uint16_t* const BytesRem, void** CurrConfigLoc) { - uint16_t CurrDescriptorSize = DESCRIPTOR_CAST(*CurrConfigLoc, USB_Descriptor_Header_t).Size; - - *CurrConfigLoc += CurrDescriptorSize; - *BytesRem -= CurrDescriptorSize; + /* Horrible workaround for a bug in GCC - in some circumstances, the code generated for the strongly-typed + * (uint8_t**) cast to avoid void pointer arithmetic (which is not allowed in C++) causes incorrect code to + * be generated. Performing the cast and using a secondary inline routine show here seems to avoid the + * problem. + */ + USB_GetNextDescriptorST(BytesRem, (uint8_t**)CurrConfigLoc); } - + /* Disable C linkage for C++ Compilers: */ #if defined(__cplusplus) } -- cgit v1.2.3