From 559af022041942be21d7cabd398639f4d6db52ea Mon Sep 17 00:00:00 2001
From: Dean Camera <dean@fourwalledcubicle.com>
Date: Tue, 22 Jun 2010 07:55:02 +0000
Subject: [PATCH] Use a bitmask instead of an array of bools in the SDP UUID
List matching algorithm to reduce the compiled code size and stack used.
---
Demos/Host/Incomplete/BluetoothHost/Lib/SDP.c | 33 +++++++++----------
Demos/Host/Incomplete/BluetoothHost/Lib/SDP.h | 2 +-
2 files changed, 17 insertions(+), 18 deletions(-)
diff --git a/Demos/Host/Incomplete/BluetoothHost/Lib/SDP.c b/Demos/Host/Incomplete/BluetoothHost/Lib/SDP.c
index 0daf8e24e..d01225152 100644
--- a/Demos/Host/Incomplete/BluetoothHost/Lib/SDP.c
+++ b/Demos/Host/Incomplete/BluetoothHost/Lib/SDP.c
@@ -458,27 +458,20 @@ static void* SDP_GetAttributeValue(const ServiceAttributeTable_t* AttributeTable
static bool SDP_SearchServiceTable(uint8_t UUIDList[][UUID_SIZE_BYTES], const uint8_t TotalUUIDs,
const ServiceAttributeTable_t* CurrAttributeTable)
{
- bool UUIDMatch[TotalUUIDs];
-
- /* Set all the match flags to false (not matched) before starting the search */
- memset(UUIDMatch, false, sizeof(UUIDMatch));
-
const void* CurrAttribute;
+ uint16_t UUIDMatchFlags = 0;
/* Search through the current attribute table, checking each attribute value for UUID matches */
while ((CurrAttribute = pgm_read_ptr(&CurrAttributeTable->Data)) != NULL)
{
- SDP_CheckUUIDMatch(UUIDList, TotalUUIDs, UUIDMatch, CurrAttribute);
+ SDP_CheckUUIDMatch(UUIDList, TotalUUIDs, &UUIDMatchFlags, CurrAttribute);
CurrAttributeTable++;
}
/* Determine how many UUID matches in the list we have found */
- uint8_t UUIDMatches = 0;
- for (uint8_t i = 0; i < TotalUUIDs; i++)
- {
- if (UUIDMatch[i])
- UUIDMatches++;
- }
+ uint8_t UUIDMatches;
+ for (UUIDMatches = 0; UUIDMatchFlags; UUIDMatches++)
+ UUIDMatchFlags &= (UUIDMatchFlags - 1);
/* If all UUIDs have been matched to the current service, return true */
return (UUIDMatches == TotalUUIDs);
@@ -494,7 +487,7 @@ static bool SDP_SearchServiceTable(uint8_t UUIDList[][UUID_SIZE_BYTES], const ui
*
* \return True if all the UUIDs given in the UUID list appear in the given attribute table, false otherwise
*/
-static void SDP_CheckUUIDMatch(uint8_t UUIDList[][UUID_SIZE_BYTES], const uint8_t TotalUUIDs, bool UUIDMatch[],
+static void SDP_CheckUUIDMatch(uint8_t UUIDList[][UUID_SIZE_BYTES], const uint8_t TotalUUIDs, uint16_t* UUIDMatchFlags,
const void* CurrAttribute)
{
uint8_t CurrAttributeType = (pgm_read_byte(CurrAttribute) & ~0x07);
@@ -502,16 +495,20 @@ static void SDP_CheckUUIDMatch(uint8_t UUIDList[][UUID_SIZE_BYTES], const uint8_
/* Check the data type of the current attribute value - if UUID, compare, if Sequence, unwrap and recurse */
if (CurrAttributeType == SDP_DATATYPE_UUID)
{
+ uint16_t CurrUUIDMatchMask = (1 << 0);
+
/* Look for matches in the UUID list against the current attribute UUID value */
for (uint8_t i = 0; i < TotalUUIDs; i++)
{
/* Check if the current unmatched UUID is identical to the search UUID */
- if (!(UUIDMatch[i]) && !(memcmp_P(UUIDList[i], (CurrAttribute + 1), UUID_SIZE_BYTES)))
+ if (!(*UUIDMatchFlags & CurrUUIDMatchMask) && !(memcmp_P(UUIDList[i], (CurrAttribute + 1), UUID_SIZE_BYTES)))
{
/* Indicate match found for the current attribute UUID and early-abort */
- UUIDMatch[i] = true;
+ *UUIDMatchFlags |= CurrUUIDMatchMask;
break;
}
+
+ CurrUUIDMatchMask <<= 1;
}
}
else if (CurrAttributeType == SDP_DATATYPE_Sequence)
@@ -527,8 +524,10 @@ static void SDP_CheckUUIDMatch(uint8_t UUIDList[][UUID_SIZE_BYTES], const uint8_
uint8_t InnerHeaderSize;
uint16_t InnerSize = SDP_GetLocalAttributeContainerSize(CurrAttribute, &InnerHeaderSize);
- SDP_CheckUUIDMatch(UUIDList, TotalUUIDs, UUIDMatch, CurrAttribute);
-
+ /* Recursively search of the next element in the sequence, trying to match UUIDs with the UUID list */
+ SDP_CheckUUIDMatch(UUIDList, TotalUUIDs, UUIDMatchFlags, CurrAttribute);
+
+ /* Skip to the next element in the sequence */
SequenceSize -= InnerHeaderSize + InnerSize;
CurrAttribute += InnerHeaderSize + InnerSize;
}
diff --git a/Demos/Host/Incomplete/BluetoothHost/Lib/SDP.h b/Demos/Host/Incomplete/BluetoothHost/Lib/SDP.h
index c52477527..e7d02b0ab 100644
--- a/Demos/Host/Incomplete/BluetoothHost/Lib/SDP.h
+++ b/Demos/Host/Incomplete/BluetoothHost/Lib/SDP.h
@@ -218,7 +218,7 @@
static bool SDP_SearchServiceTable(uint8_t UUIDList[][UUID_SIZE_BYTES], const uint8_t TotalUUIDs,
const ServiceAttributeTable_t* CurrAttributeTable);
- static void SDP_CheckUUIDMatch(uint8_t UUIDList[][UUID_SIZE_BYTES], const uint8_t TotalUUIDs, bool UUIDMatch[],
+ static void SDP_CheckUUIDMatch(uint8_t UUIDList[][UUID_SIZE_BYTES], const uint8_t TotalUUIDs, uint16_t* UUIDMatchFlags,
const void* CurrAttribute);
static uint8_t SDP_GetAttributeList(uint16_t AttributeList[][2], const void** const CurrentParameter);
--
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