[xiph-commits] r8897 - trunk/oggdsf/src/lib/core/ogg/libOOOgg

ozone at motherfish-iii.xiph.org ozone at motherfish-iii.xiph.org
Wed Feb 9 20:33:24 PST 2005


Author: ozone
Date: 2005-02-09 20:33:21 -0800 (Wed, 09 Feb 2005)
New Revision: 8897

Modified:
   trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPage.cpp
   trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPage.h
   trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPaginator.cpp
Log:
oggdsf:
 * Added OggPage::computeAndSetCRCChecksum() method

Modified: trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPage.cpp
===================================================================
--- trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPage.cpp	2005-02-10 03:36:29 UTC (rev 8896)
+++ trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPage.cpp	2005-02-10 04:33:21 UTC (rev 8897)
@@ -32,12 +32,84 @@
 #include "stdafx.h"
 #include <libOOOgg/OggPage.h>
 //LEACK CHECKED::: 20041018 - OK.
+
+
+// Checksum tables from libogg
+static unsigned long crc_lookup[256]={
+  0x00000000,0x04c11db7,0x09823b6e,0x0d4326d9,
+  0x130476dc,0x17c56b6b,0x1a864db2,0x1e475005,
+  0x2608edb8,0x22c9f00f,0x2f8ad6d6,0x2b4bcb61,
+  0x350c9b64,0x31cd86d3,0x3c8ea00a,0x384fbdbd,
+  0x4c11db70,0x48d0c6c7,0x4593e01e,0x4152fda9,
+  0x5f15adac,0x5bd4b01b,0x569796c2,0x52568b75,
+  0x6a1936c8,0x6ed82b7f,0x639b0da6,0x675a1011,
+  0x791d4014,0x7ddc5da3,0x709f7b7a,0x745e66cd,
+  0x9823b6e0,0x9ce2ab57,0x91a18d8e,0x95609039,
+  0x8b27c03c,0x8fe6dd8b,0x82a5fb52,0x8664e6e5,
+  0xbe2b5b58,0xbaea46ef,0xb7a96036,0xb3687d81,
+  0xad2f2d84,0xa9ee3033,0xa4ad16ea,0xa06c0b5d,
+  0xd4326d90,0xd0f37027,0xddb056fe,0xd9714b49,
+  0xc7361b4c,0xc3f706fb,0xceb42022,0xca753d95,
+  0xf23a8028,0xf6fb9d9f,0xfbb8bb46,0xff79a6f1,
+  0xe13ef6f4,0xe5ffeb43,0xe8bccd9a,0xec7dd02d,
+  0x34867077,0x30476dc0,0x3d044b19,0x39c556ae,
+  0x278206ab,0x23431b1c,0x2e003dc5,0x2ac12072,
+  0x128e9dcf,0x164f8078,0x1b0ca6a1,0x1fcdbb16,
+  0x018aeb13,0x054bf6a4,0x0808d07d,0x0cc9cdca,
+  0x7897ab07,0x7c56b6b0,0x71159069,0x75d48dde,
+  0x6b93dddb,0x6f52c06c,0x6211e6b5,0x66d0fb02,
+  0x5e9f46bf,0x5a5e5b08,0x571d7dd1,0x53dc6066,
+  0x4d9b3063,0x495a2dd4,0x44190b0d,0x40d816ba,
+  0xaca5c697,0xa864db20,0xa527fdf9,0xa1e6e04e,
+  0xbfa1b04b,0xbb60adfc,0xb6238b25,0xb2e29692,
+  0x8aad2b2f,0x8e6c3698,0x832f1041,0x87ee0df6,
+  0x99a95df3,0x9d684044,0x902b669d,0x94ea7b2a,
+  0xe0b41de7,0xe4750050,0xe9362689,0xedf73b3e,
+  0xf3b06b3b,0xf771768c,0xfa325055,0xfef34de2,
+  0xc6bcf05f,0xc27dede8,0xcf3ecb31,0xcbffd686,
+  0xd5b88683,0xd1799b34,0xdc3abded,0xd8fba05a,
+  0x690ce0ee,0x6dcdfd59,0x608edb80,0x644fc637,
+  0x7a089632,0x7ec98b85,0x738aad5c,0x774bb0eb,
+  0x4f040d56,0x4bc510e1,0x46863638,0x42472b8f,
+  0x5c007b8a,0x58c1663d,0x558240e4,0x51435d53,
+  0x251d3b9e,0x21dc2629,0x2c9f00f0,0x285e1d47,
+  0x36194d42,0x32d850f5,0x3f9b762c,0x3b5a6b9b,
+  0x0315d626,0x07d4cb91,0x0a97ed48,0x0e56f0ff,
+  0x1011a0fa,0x14d0bd4d,0x19939b94,0x1d528623,
+  0xf12f560e,0xf5ee4bb9,0xf8ad6d60,0xfc6c70d7,
+  0xe22b20d2,0xe6ea3d65,0xeba91bbc,0xef68060b,
+  0xd727bbb6,0xd3e6a601,0xdea580d8,0xda649d6f,
+  0xc423cd6a,0xc0e2d0dd,0xcda1f604,0xc960ebb3,
+  0xbd3e8d7e,0xb9ff90c9,0xb4bcb610,0xb07daba7,
+  0xae3afba2,0xaafbe615,0xa7b8c0cc,0xa379dd7b,
+  0x9b3660c6,0x9ff77d71,0x92b45ba8,0x9675461f,
+  0x8832161a,0x8cf30bad,0x81b02d74,0x857130c3,
+  0x5d8a9099,0x594b8d2e,0x5408abf7,0x50c9b640,
+  0x4e8ee645,0x4a4ffbf2,0x470cdd2b,0x43cdc09c,
+  0x7b827d21,0x7f436096,0x7200464f,0x76c15bf8,
+  0x68860bfd,0x6c47164a,0x61043093,0x65c52d24,
+  0x119b4be9,0x155a565e,0x18197087,0x1cd86d30,
+  0x029f3d35,0x065e2082,0x0b1d065b,0x0fdc1bec,
+  0x3793a651,0x3352bbe6,0x3e119d3f,0x3ad08088,
+  0x2497d08d,0x2056cd3a,0x2d15ebe3,0x29d4f654,
+  0xc5a92679,0xc1683bce,0xcc2b1d17,0xc8ea00a0,
+  0xd6ad50a5,0xd26c4d12,0xdf2f6bcb,0xdbee767c,
+  0xe3a1cbc1,0xe760d676,0xea23f0af,0xeee2ed18,
+  0xf0a5bd1d,0xf464a0aa,0xf9278673,0xfde69bc4,
+  0x89b8fd09,0x8d79e0be,0x803ac667,0x84fbdbd0,
+  0x9abc8bd5,0x9e7d9662,0x933eb0bb,0x97ffad0c,
+  0xafb010b1,0xab710d06,0xa6322bdf,0xa2f33668,
+  0xbcb4666d,0xb8757bda,0xb5365d03,0xb1f740b4
+};
+
+// End libogg tables
+
+
 OggPage::OggPage(void)
 {
-	mHeader = new OggPageHeader;			//Deleted in destructor.
-	
-	
+	mHeader = new OggPageHeader;			//Deleted in destructor.	
 }
+
 OggPage::~OggPage(void)
 {
 	delete mHeader;
@@ -106,8 +178,41 @@
 	}
 }
 
+/* n.b. This code is _duplicated_ in OggPaginator::setChecksum(), since I
+   (andre) didn't want to risk unstabilising any existing code.  Zen, if feel
+   like replacing OggPaginator::setChecksum() with an indirection to this,
+   go for it. */
+void OggPage::computeAndSetCRCChecksum()
+{
+	unsigned long locChecksum = 0;
+	unsigned long locTemp = 0;
+	unsigned char* locHeaderBuff = new unsigned char[300];
 
+	// Set the checksum to NULL for the checksumming process.
+	header()->setCRCChecksum((unsigned long)0);
+	header()->rawData(locHeaderBuff, 300);
 
+	for(unsigned long i = 0; i < headerSize(); i++) {
+		//Create the index we use for the lookup
+		locTemp = ((locChecksum >> 24) & 0xff) ^ locHeaderBuff[i];
+		//XOR the lookup value with the the current checksum shifted left 8 bits.
+		locChecksum=(locChecksum << 8) ^ crc_lookup[locTemp];
+	}
+
+	unsigned char* locBuff = NULL;
+	for(unsigned long i = 0; i < numPackets(); i++) {
+		locBuff = getPacket(i)->packetData();			//View only don't delete.
+
+		for (unsigned long j = 0; j < getPacket(i)->packetSize(); j++) {
+			locTemp = ((locChecksum >> 24) & 0xff) ^ locBuff[j];
+            locChecksum = (locChecksum << 8) ^ crc_lookup[locTemp];
+		}
+	}
+
+	header()->setCRCChecksum(locChecksum);
+}
+
+
 unsigned long OggPage::pageSize()
 {
 	return mHeader->pageSize();

Modified: trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPage.h
===================================================================
--- trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPage.h	2005-02-10 03:36:29 UTC (rev 8896)
+++ trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPage.h	2005-02-10 04:33:21 UTC (rev 8897)
@@ -80,6 +80,9 @@
 	/// Creates a buffer of size pageSize and returns you a pointer to keep.
 	unsigned char* createRawPageData();
 
+	/// (Re-)compute the page's checksum and set it
+	void computeAndSetCRCChecksum();
+
 protected:
 	//Member data of packets and header.
 	vector<StampedOggPacket*> mPacketList;

Modified: trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPaginator.cpp
===================================================================
--- trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPaginator.cpp	2005-02-10 03:36:29 UTC (rev 8896)
+++ trunk/oggdsf/src/lib/core/ogg/libOOOgg/OggPaginator.cpp	2005-02-10 04:33:21 UTC (rev 8897)
@@ -174,9 +174,22 @@
 
 bool OggPaginator::setChecksum() 
 {
-		unsigned long locChecksum = 0;
-		unsigned long locTemp = 0;
+	unsigned long locChecksum = 0;
+	unsigned long locTemp = 0;
 
+	/* Note: now that there's a OggPage::computeAndSetCRCChecksum() function,
+	   we can just use that instead of setting the checksum ourselves.  i.e.
+
+		if (mPendingPage != NULL) {
+			mPendingPage->computeAndSetCRCChecksum();
+			return true;
+		} else {
+			return false;
+		}
+
+	   Zen, if you'd like to make the changes here, feel free.
+	 */
+
 	if (mPendingPage != NULL) {
 		//Set the checksum to NULL for the checksumming process.
 		mPendingPage->header()->setCRCChecksum((unsigned long)0);



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