android音频解码的源代码（适用于音乐播放器）

/* Copyright (c) 2005, The Musepack Development Team All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the The Musepack Development Team nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /// \file mpc_decoder.c /// Core decoding routines and logic. #include <mpcdec/mpcdec.h> #include <mpcdec/internal.h> #include <mpcdec/requant.h> #include <mpcdec/huffman.h> //SV7 tables extern const HuffmanTyp* mpc_table_HuffQ [2] [8]; extern const HuffmanTyp mpc_table_HuffHdr [10]; extern const HuffmanTyp mpc_table_HuffSCFI [ 4]; extern const HuffmanTyp mpc_table_HuffDSCF [16]; #ifdef MPC_SUPPORT_SV456 //SV4/5/6 tables extern const HuffmanTyp* mpc_table_SampleHuff [18]; extern const HuffmanTyp mpc_table_SCFI_Bundle [ 8]; extern const HuffmanTyp mpc_table_DSCF_Entropie [13]; extern const HuffmanTyp mpc_table_Region_A [16]; extern const HuffmanTyp mpc_table_Region_B [ 8]; extern const HuffmanTyp mpc_table_Region_C [ 4]; #endif #ifndef MPC_LITTLE_ENDIAN #define SWAP(X) mpc_swap32(X) #else #define SWAP(X) (X) #endif //------------------------------------------------------------------------------ // types //------------------------------------------------------------------------------ enum { EQ_TAP = 13, // length of FIR filter for EQ DELAY = ((EQ_TAP + 1) / 2), // delay of FIR FIR_BANDS = 4, // number of subbands to be FIR filtered MEMSIZE = MPC_DECODER_MEMSIZE, // overall buffer size MEMSIZE2 = (MEMSIZE/2), // size of one buffer MEMMASK = (MEMSIZE-1) }; //------------------------------------------------------------------------------ // forward declarations //------------------------------------------------------------------------------ void mpc_decoder_read_bitstream_sv6(mpc_decoder *d, mpc_bool_t seeking); void mpc_decoder_read_bitstream_sv7(mpc_decoder *d, mpc_bool_t seeking); mpc_bool_t mpc_decoder_seek_sample(mpc_decoder *d, mpc_int64_t destsample); void mpc_decoder_requantisierung(mpc_decoder *d, const mpc_int32_t Last_Band); //------------------------------------------------------------------------------ // utility functions //------------------------------------------------------------------------------ static mpc_int32_t f_read(mpc_decoder *d, void *ptr, mpc_int32_t size) { return d->r->read(d->r->data, ptr, size); } static mpc_bool_t f_seek(mpc_decoder *d, mpc_int32_t offset) { return d->r->seek(d->r->data, offset); } static mpc_int32_t f_read_dword(mpc_decoder *d, mpc_uint32_t * ptr, mpc_uint32_t count) { return f_read(d, ptr, count << 2) >> 2; } static void mpc_decoder_seek(mpc_decoder *d, mpc_uint32_t bitpos) { f_seek(d, (bitpos>>5) * 4 + d->MPCHeaderPos); f_read_dword(d, d->Speicher, MEMSIZE); d->dword = SWAP(d->Speicher[d->Zaehler = 0]); d->pos = bitpos & 31; d->WordsRead = bitpos >> 5; } // jump desired number of bits out of the bitstream static void mpc_decoder_bitstream_jump(mpc_decoder *d, const mpc_uint32_t bits) { d->pos += bits; if (d->pos >= 32) { d->Zaehler = (d->Zaehler + (d->pos >> 5)) & MEMMASK; d->dword = SWAP(d->Speicher[d->Zaehler]); d->WordsRead += d->pos >> 5; d->pos &= 31; } } void mpc_decoder_update_buffer(mpc_decoder *d, mpc_uint32_t RING) { if ((RING ^ d->Zaehler) & MEMSIZE2 ) { // update buffer f_read_dword(d, d->Speicher + (RING & MEMSIZE2), MEMSIZE2); } } //------------------------------------------------------------------------------ // huffman & bitstream functions //------------------------------------------------------------------------------ /* F U N C T I O N S */ // resets bitstream decoding static void mpc_decoder_reset_bitstream_decode(mpc_decoder *d) { d->dword = 0; d->pos = 0; d->Zaehler = 0; d->WordsRead = 0; } // reports the number of read bits static mpc_uint32_t mpc_decoder_bits_read(mpc_decoder *d) { return 32 * d->WordsRead + d->pos; } // read desired number of bits out of the bitstream (max 31) static mpc_uint32_t mpc_decoder_bitstream_read(mpc_decoder *d, const mpc_uint32_t bits) { mpc_uint32_t out = d->dword; d->pos += bits; if (d->pos < 32) { out >>= (32 - d->pos); } else { d->dword = SWAP(d->Speicher[d->Zaehler = (d->Zaehler + 1) & MEMMASK]); d->pos -= 32; if (d->pos) { out <<= d->pos; out |= d->dword >> (32 - d->pos); } d->WordsRead++; } return out & ((1 << bits) - 1); } // basic huffman decoding routine // works with maximum lengths up to max_length static mpc_int32_t mpc_decoder_huffman_decode(mpc_decoder *d, const HuffmanTyp *Table, const mpc_uint32_t max_length) { // load preview and decode mpc_uint32_t code = d->dword << d->pos; if (32 - d->pos < max_length) code |= SWAP(d->Speicher[(d->Zaehler + 1) & MEMMASK]) >> (32 - d->pos); while (code < Table->Code) Table++; // set the new position within bitstream without performing a dummy-read if ((d->pos += Table->Length) >= 32) { d->pos -= 32; d->dword = SWAP(d->Speicher[d->Zaehler = (d->Zaehler + 1) & MEMMASK]); d->WordsRead++; } return Table->Value; } // decode SCFI-bundle (sv4,5,6) static void mpc_decoder_scfi_bundle_read(mpc_decoder *d, const HuffmanTyp* Table, mpc_int32_t* SCFI, mpc_bool_t* DSCF) { mpc_uint32_t value = mpc_decoder_huffman_decode(d, Table, 6); *SCFI = value >> 1; *DSCF = value & 1; } static void mpc_decoder_reset_v(mpc_decoder *d) { memset(d->V_L, 0, sizeof d->V_L); memset(d->V_R, 0, sizeof d->V_R); } static void mpc_decoder_reset_synthesis(mpc_decoder *d) { mpc_decoder_reset_v(d); } static void mpc_decoder_reset_y(mpc_decoder *d) { memset(d->Y_L, 0, sizeof d->Y_L); memset(d->Y_R, 0, sizeof d->Y_R); } static void mpc_decoder_reset_globals(mpc_decoder *d) { mpc_decoder_reset_bitstream_decode(d); d->DecodedFrames = 0; d->StreamVersion = 0; d->MS_used = 0; memset(d->Y_L , 0, sizeof d->Y_L ); memset(d->Y_R , 0, sizeof d->Y_R ); memset(d->SCF_Index_L , 0, sizeof d->SCF_Index_L ); memset(d->SCF_Index_R , 0, sizeof d->SCF_Index_R ); memset(d->Res_L , 0, sizeof d->Res_L ); memset(d->Res_R , 0, sizeof d->Res_R ); memset(d->SCFI_L , 0, sizeof d->SCFI_L