can be of use later

ttalib-1.1/BitReader.h

@@ -0,0 +1,199 @@
+/*
+ * BitReader.h
+ *
+ * Description: Bit reader internal interface
+ *
+ * Copyright (c) 2004 Alexander Djourik. All rights reserved.
+ * Copyright (c) 2004 Pavel Zhilin. All rights reserved.
+ *
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * aint with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Please see the file COPYING in this directory for full copyright
+ * information.
+ */
+
+#pragma once
+#include <windows.h>
+#include "TTACommon.h"
+#include "TTAError.h"
+#include "crc32.h"
+
+namespace TTALib 
+{
+	class BitReader
+	{
+	protected:	
+		HANDLE hInFile;
+
+		unsigned char bit_buffer[BIT_BUFFER_SIZE + 8];
+		unsigned char *bit_buffer_end;
+
+		unsigned long frame_crc32;
+		unsigned long bit_count;
+		unsigned long bit_cache;
+		unsigned char *bitpos;
+
+		unsigned long *st;
+		unsigned long next_frame_pos;
+
+	public:
+		BitReader(HANDLE fd) :
+			frame_crc32(0xFFFFFFFFUL), hInFile (fd),
+			bit_count(0), bit_cache(0), bit_buffer_end(bit_buffer + BIT_BUFFER_SIZE),
+			bitpos(bit_buffer_end), input_byte_count (0)
+		{			
+		}
+
+		virtual ~BitReader(void) {}
+
+		virtual void GetHeader (TTAHeader *ttahdr)
+		{
+			unsigned long result, checksum;
+
+			if (!ReadFile(hInFile, ttahdr, sizeof(TTAHeader), &result, NULL) ||
+				result != sizeof (TTAHeader))
+			{
+				throw TTAException (READ_ERROR);
+			} else input_byte_count += sizeof(*ttahdr);
+
+			// check for supported formats
+			if (ENDSWAP_INT32(ttahdr->TTAid) != TTA1_SIGN) 
+				throw TTAException (FORMAT_ERROR);
+
+			checksum = crc32((unsigned char *) ttahdr, sizeof(TTAHeader) - sizeof(long));
+			if (checksum != ttahdr->CRC32) 
+				throw TTAException (FILE_ERROR);
+
+			ttahdr->AudioFormat = ENDSWAP_INT16(ttahdr->AudioFormat); 
+			ttahdr->NumChannels = ENDSWAP_INT16(ttahdr->NumChannels);
+			ttahdr->BitsPerSample = ENDSWAP_INT16(ttahdr->BitsPerSample);
+			ttahdr->SampleRate = ENDSWAP_INT32(ttahdr->SampleRate);
+			ttahdr->DataLength = ENDSWAP_INT32(ttahdr->DataLength);
+		}
+
+		virtual bool GetSeekTable (unsigned long *seek_table, long st_size)
+		{
+			unsigned long result, checksum;
+			bool st_state = false;
+		
+			if (!ReadFile(hInFile, seek_table, st_size * sizeof(long), &result, NULL) ||
+				result != st_size * sizeof(long))
+				throw TTAException (READ_ERROR);
+			else input_byte_count += st_size * sizeof(long);
+
+			checksum = crc32((unsigned char *) seek_table, (st_size - 1) * sizeof(long));
+			if (checksum == ENDSWAP_INT32(seek_table[st_size - 1]))
+				st_state = true;
+
+			for (st = seek_table; st < (seek_table + st_size); st++)
+				*st = ENDSWAP_INT32(*st);
+						
+			next_frame_pos = SetFilePointer (hInFile, 0, NULL, FILE_CURRENT);
+			st = seek_table;
+
+			return st_state;
+		}
+
+		virtual void GetBinary(unsigned long *value, unsigned long bits) {
+			while (bit_count < bits) {
+				if (bitpos == bit_buffer_end) {
+					unsigned long result;			 
+					if (!ReadFile (hInFile, bit_buffer, BIT_BUFFER_SIZE, &result, NULL))
+						throw TTAException (READ_ERROR);
+					input_byte_count += result;
+					bitpos = bit_buffer;
+				}
+
+				UPDATE_CRC32(*bitpos, frame_crc32);
+				bit_cache |= *bitpos << bit_count;
+				bit_count += 8;
+				bitpos++;
+			}
+
+			*value = bit_cache & bit_mask[bits];
+			bit_cache >>= bits;
+			bit_count -= bits;
+			bit_cache &= bit_mask[bit_count];
+		}
+
+		virtual void GetUnary(unsigned long *value) 
+		{
+			*value = 0;
+
+			while (!(bit_cache ^ bit_mask[bit_count])) {
+				if (bitpos == bit_buffer_end) {
+					unsigned long result;			 
+					if (!ReadFile (hInFile, bit_buffer, BIT_BUFFER_SIZE, &result, NULL)) 
+						throw TTAException (READ_ERROR);
+					input_byte_count += result;
+					bitpos = bit_buffer;
+				}
+
+				*value += bit_count;
+				bit_cache = *bitpos++;
+				UPDATE_CRC32(bit_cache, frame_crc32);
+				bit_count = 8;
+			}
+
+			while (bit_cache & 1) {
+				(*value)++;
+				bit_cache >>= 1;
+				bit_count--;
+			}
+
+			bit_cache >>= 1;
+			bit_count--;
+		}
+
+		virtual int Done ()
+		{
+			unsigned long crc32, rbytes, result;
+			frame_crc32 ^= 0xFFFFFFFFUL;
+
+	  		next_frame_pos += *st++;
+
+			rbytes = bit_buffer_end - bitpos;
+			if (rbytes < sizeof(long)) {
+				CopyMemory(bit_buffer, bitpos, 4);
+				if (!ReadFile(hInFile, bit_buffer + rbytes,
+					BIT_BUFFER_SIZE - rbytes, &result, NULL))
+					throw TTAException (READ_ERROR);
+				input_byte_count += result;
+				bitpos = bit_buffer;
+			}
+
+			CopyMemory(&crc32, bitpos, 4);
+			crc32 = ENDSWAP_INT32(crc32);
+			bitpos += sizeof(long);
+			result = (crc32 != frame_crc32);
+
+			bit_cache = bit_count = 0;
+			frame_crc32 = 0xFFFFFFFFUL;
+
+			return result;
+		}
+
+		virtual void SkipFrame ()
+		{
+			SetFilePointer(hInFile, next_frame_pos, NULL, FILE_BEGIN);
+			bitpos = bit_buffer_end;
+		}
+
+		unsigned long input_byte_count;
+	};
+};