1cd1e66ed3
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@25676 a1c6a512-1295-4272-9138-f99709370657
175 lines
6.3 KiB
C
175 lines
6.3 KiB
C
/*
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Copyright (c) 2007-2009, The Musepack Development Team
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following
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disclaimer in the documentation and/or other materials provided
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with the distribution.
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* Neither the name of the The Musepack Development Team nor the
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names of its contributors may be used to endorse or promote
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products derived from this software without specific prior
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written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#define MAX_ENUM 32
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MPC_API int mpc_bits_get_block(mpc_bits_reader * r, mpc_block * p_block);
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mpc_int32_t mpc_bits_golomb_dec(mpc_bits_reader * r, const mpc_uint_t k);
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MPC_API unsigned int mpc_bits_get_size(mpc_bits_reader * r, mpc_uint64_t * p_size);
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mpc_uint32_t mpc_bits_log_dec(mpc_bits_reader * r, mpc_uint_t max);
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extern const mpc_uint32_t Cnk [MAX_ENUM / 2][MAX_ENUM];
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extern const mpc_uint8_t Cnk_len [MAX_ENUM / 2][MAX_ENUM];
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extern const mpc_uint32_t Cnk_lost[MAX_ENUM / 2][MAX_ENUM];
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// can read up to 31 bits
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static mpc_inline mpc_uint32_t mpc_bits_read(mpc_bits_reader * r, const unsigned int nb_bits)
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{
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mpc_uint32_t ret;
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r->buff -= (int)(r->count - nb_bits) >> 3;
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r->count = (r->count - nb_bits) & 0x07;
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ret = (r->buff[0] | (r->buff[-1] << 8)) >> r->count;
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if (nb_bits > (16 - r->count)) {
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ret |= (mpc_uint32_t)((r->buff[-2] << 16) | (r->buff[-3] << 24)) >> r->count;
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if (nb_bits > 24 && r->count != 0)
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ret |= r->buff[-4] << (32 - r->count);
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}
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return ret & ((1 << nb_bits) - 1);
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}
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#if defined(CPU_COLDFIRE)
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/* rockbox: This is specific code to optimize demux performance on Coldfire
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* CPUs. Coldfire CPUs are very sensible to RAM accesses. As the bitstream
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* buffer does not fit into IRAM the read accesses to the uint8 buffer are very
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* expensive in terms of CPU cycles.
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* The following code uses two variables in IRAM. The variable last_code keeps
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* the 4-byte value of buf[0]<<16 | buf[1]<<8 | buf[2]. As long as buf[0] will
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* read from the same address the following code will avoid re-reading of the
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* buffers. If buf[0] did advance to the next uint8-entry since the last call
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* the following will only need to load 1 uint8-entry instead of 3.
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*/
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static mpc_inline mpc_uint16_t get_code_from_buffer(mpc_bits_reader *r)
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{
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/* Buffer advanced by 1 entry since last call */
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if (r->buff == r->buffered_addr + 1) {
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r->buffered_code = (r->buffered_code<<8) | r->buff[2];
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r->buffered_addr = r->buff;
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}
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/* Buffer must be fully re-read */
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else if (r->buff != r->buffered_addr) {
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r->buffered_code = (r->buff[0] << 16) | (r->buff[1] << 8) | r->buff[2];
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r->buffered_addr = r->buff;
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}
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return (mpc_uint16_t)((r->buffered_code >> r->count) & 0xFFFF);
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}
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#else
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/* Use the decoder's default implementation. This is faster on non-Coldfire targets */
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#define get_code_from_buffer(r) (mpc_uint16_t)((((r->buff[0] << 16) | (r->buff[1] << 8) | r->buff[2]) >> r->count) & 0xFFFF);
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#endif
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// basic huffman decoding routine
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// works with maximum lengths up to 16
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static mpc_inline mpc_int32_t mpc_bits_huff_dec(mpc_bits_reader * r, const mpc_huffman *Table)
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{
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const mpc_uint16_t code = get_code_from_buffer(r);
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while (code < Table->Code) Table++;
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r->buff -= (int)(r->count - Table->Length) >> 3;
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r->count = (r->count - Table->Length) & 0x07;
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return Table->Value;
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}
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static mpc_inline mpc_int32_t mpc_bits_can_dec(mpc_bits_reader * r, const mpc_can_data *can)
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{
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const mpc_uint16_t code = get_code_from_buffer(r);
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const mpc_huff_lut tmp = can->lut[code >> (16 - LUT_DEPTH)];
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const mpc_huffman * Table;
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if (tmp.Length != 0) {
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r->buff -= (int)(r->count - tmp.Length) >> 3;
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r->count = (r->count - tmp.Length) & 0x07;
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return tmp.Value;
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}
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Table = can->table + (unsigned char)tmp.Value;
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while (code < Table->Code) Table++;
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r->buff -= (int)(r->count - Table->Length) >> 3;
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r->count = (r->count - Table->Length) & 0x07;
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return can->sym[(Table->Value - (code >> (16 - Table->Length))) & 0xFF] ;
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}
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// LUT-based huffman decoding routine
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// works with maximum lengths up to 16
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static mpc_inline mpc_int32_t mpc_bits_huff_lut(mpc_bits_reader * r, const mpc_lut_data *lut)
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{
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const mpc_uint16_t code = get_code_from_buffer(r);
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const mpc_huff_lut tmp = lut->lut[code >> (16 - LUT_DEPTH)];
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const mpc_huffman * Table;
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if (tmp.Length != 0) {
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r->buff -= (int)(r->count - tmp.Length) >> 3;
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r->count = (r->count - tmp.Length) & 0x07;
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return tmp.Value;
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}
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Table = lut->table + (unsigned char)tmp.Value;
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while (code < Table->Code) Table++;
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r->buff -= (int)(r->count - Table->Length) >> 3;
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r->count = (r->count - Table->Length) & 0x07;
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return Table->Value;
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}
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static mpc_inline mpc_uint32_t mpc_bits_enum_dec(mpc_bits_reader * r, mpc_uint_t k, mpc_uint_t n)
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{
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mpc_uint32_t bits = 0;
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mpc_uint32_t code;
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const mpc_uint32_t * C = Cnk[k-1];
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code = mpc_bits_read(r, Cnk_len[k-1][n-1] - 1);
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if (code >= Cnk_lost[k-1][n-1])
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code = ((code << 1) | mpc_bits_read(r, 1)) - Cnk_lost[k-1][n-1];
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do {
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n--;
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if (code >= C[n]) {
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bits |= 1 << n;
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code -= C[n];
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C -= MAX_ENUM;
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k--;
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}
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} while(k > 0);
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return bits;
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}
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