From f40bfc9267b13b54e6379dfe7539447662879d24 Mon Sep 17 00:00:00 2001 From: Sean Bartell Date: Sat, 25 Jun 2011 21:32:25 -0400 Subject: Add codecs to librbcodec. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Change-Id: Id7f4717d51ed02d67cb9f9cb3c0ada4a81843f97 Reviewed-on: http://gerrit.rockbox.org/137 Reviewed-by: Nils Wallménius Tested-by: Nils Wallménius --- lib/rbcodec/codecs/demac/libdemac/entropy.c | 464 ++++++++++++++++++++++++++++ 1 file changed, 464 insertions(+) create mode 100644 lib/rbcodec/codecs/demac/libdemac/entropy.c (limited to 'lib/rbcodec/codecs/demac/libdemac/entropy.c') diff --git a/lib/rbcodec/codecs/demac/libdemac/entropy.c b/lib/rbcodec/codecs/demac/libdemac/entropy.c new file mode 100644 index 0000000000..1cef979808 --- /dev/null +++ b/lib/rbcodec/codecs/demac/libdemac/entropy.c @@ -0,0 +1,464 @@ +/* + +libdemac - A Monkey's Audio decoder + +$Id$ + +Copyright (C) Dave Chapman 2007 + +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 +along with this program; if not, write to the Free Software +Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110, USA + +*/ + +#include +#include + +#include "parser.h" +#include "entropy.h" +#include "demac_config.h" + +#define MODEL_ELEMENTS 64 + +/* + The following counts arrays for use with the range decoder are + hard-coded in the Monkey's Audio decoder. +*/ + +static const int counts_3970[65] ICONST_ATTR_DEMAC = +{ + 0,14824,28224,39348,47855,53994,58171,60926, + 62682,63786,64463,64878,65126,65276,65365,65419, + 65450,65469,65480,65487,65491,65493,65494,65495, + 65496,65497,65498,65499,65500,65501,65502,65503, + 65504,65505,65506,65507,65508,65509,65510,65511, + 65512,65513,65514,65515,65516,65517,65518,65519, + 65520,65521,65522,65523,65524,65525,65526,65527, + 65528,65529,65530,65531,65532,65533,65534,65535, + 65536 +}; + +/* counts_diff_3970[i] = counts_3970[i+1] - counts_3970[i] */ +static const int counts_diff_3970[64] ICONST_ATTR_DEMAC = +{ + 14824,13400,11124,8507,6139,4177,2755,1756, + 1104,677,415,248,150,89,54,31, + 19,11,7,4,2,1,1,1, + 1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1 +}; + +static const int counts_3980[65] ICONST_ATTR_DEMAC = +{ + 0,19578,36160,48417,56323,60899,63265,64435, + 64971,65232,65351,65416,65447,65466,65476,65482, + 65485,65488,65490,65491,65492,65493,65494,65495, + 65496,65497,65498,65499,65500,65501,65502,65503, + 65504,65505,65506,65507,65508,65509,65510,65511, + 65512,65513,65514,65515,65516,65517,65518,65519, + 65520,65521,65522,65523,65524,65525,65526,65527, + 65528,65529,65530,65531,65532,65533,65534,65535, + 65536 +}; + +/* counts_diff_3980[i] = counts_3980[i+1] - counts_3980[i] */ + +static const int counts_diff_3980[64] ICONST_ATTR_DEMAC = +{ + 19578,16582,12257,7906,4576,2366,1170,536, + 261,119,65,31,19,10,6,3, + 3,2,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1 +}; + +/* + +Range decoder adapted from rangecod.c included in: + + http://www.compressconsult.com/rangecoder/rngcod13.zip + + rangecod.c range encoding + + (c) Michael Schindler + 1997, 1998, 1999, 2000 + http://www.compressconsult.com/ + michael@compressconsult.com + + 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. + + +The encoding functions were removed, and functions turned into "static +inline" functions. Some minor cosmetic changes were made (e.g. turning +pre-processor symbols into upper-case, removing the rc parameter from +each function (and the RNGC macro)). + +*/ + +/* BITSTREAM READING FUNCTIONS */ + +/* We deal with the input data one byte at a time - to ensure + functionality on CPUs of any endianness regardless of any requirements + for aligned reads. +*/ + +static unsigned char* bytebuffer IBSS_ATTR_DEMAC; +static int bytebufferoffset IBSS_ATTR_DEMAC; + +static inline void skip_byte(void) +{ + bytebufferoffset--; + bytebuffer += bytebufferoffset & 4; + bytebufferoffset &= 3; +} + +static inline int read_byte(void) +{ + int ch = bytebuffer[bytebufferoffset]; + + skip_byte(); + + return ch; +} + +/* RANGE DECODING FUNCTIONS */ + +/* SIZE OF RANGE ENCODING CODE VALUES. */ + +#define CODE_BITS 32 +#define TOP_VALUE ((unsigned int)1 << (CODE_BITS-1)) +#define SHIFT_BITS (CODE_BITS - 9) +#define EXTRA_BITS ((CODE_BITS-2) % 8 + 1) +#define BOTTOM_VALUE (TOP_VALUE >> 8) + +struct rangecoder_t +{ + uint32_t low; /* low end of interval */ + uint32_t range; /* length of interval */ + uint32_t help; /* bytes_to_follow resp. intermediate value */ + unsigned int buffer; /* buffer for input/output */ +}; + +static struct rangecoder_t rc IBSS_ATTR_DEMAC; + +/* Start the decoder */ +static inline void range_start_decoding(void) +{ + rc.buffer = read_byte(); + rc.low = rc.buffer >> (8 - EXTRA_BITS); + rc.range = (uint32_t) 1 << EXTRA_BITS; +} + +static inline void range_dec_normalize(void) +{ + while (rc.range <= BOTTOM_VALUE) + { + rc.buffer = (rc.buffer << 8) | read_byte(); + rc.low = (rc.low << 8) | ((rc.buffer >> 1) & 0xff); + rc.range <<= 8; + } +} + +/* Calculate culmulative frequency for next symbol. Does NO update!*/ +/* tot_f is the total frequency */ +/* or: totf is (code_value)1<> shift; + return UDIV32(rc.low, rc.help); +} + + +/* Update decoding state */ +/* sy_f is the interval length (frequency of the symbol) */ +/* lt_f is the lower end (frequency sum of < symbols) */ +static inline void range_decode_update(int sy_f, int lt_f) +{ + rc.low -= rc.help * lt_f; + rc.range = rc.help * sy_f; +} + + +/* Decode a byte/short without modelling */ +static inline unsigned char decode_byte(void) +{ int tmp = range_decode_culshift(8); + range_decode_update( 1,tmp); + return tmp; +} + +static inline unsigned short range_decode_short(void) +{ int tmp = range_decode_culshift(16); + range_decode_update( 1,tmp); + return tmp; +} + +/* Decode n bits (n <= 16) without modelling - based on range_decode_short */ +static inline int range_decode_bits(int n) +{ int tmp = range_decode_culshift(n); + range_decode_update( 1,tmp); + return tmp; +} + + +/* Finish decoding */ +static inline void range_done_decoding(void) +{ range_dec_normalize(); /* normalize to use up all bytes */ +} + +/* + range_get_symbol_* functions based on main decoding loop in simple_d.c from + http://www.compressconsult.com/rangecoder/rngcod13.zip + (c) Michael Schindler +*/ + +static inline int range_get_symbol_3980(void) +{ + int symbol, cf; + + cf = range_decode_culshift(16); + + /* figure out the symbol inefficiently; a binary search would be much better */ + for (symbol = 0; counts_3980[symbol+1] <= cf; symbol++); + + range_decode_update(counts_diff_3980[symbol],counts_3980[symbol]); + + return symbol; +} + +static inline int range_get_symbol_3970(void) +{ + int symbol, cf; + + cf = range_decode_culshift(16); + + /* figure out the symbol inefficiently; a binary search would be much better */ + for (symbol = 0; counts_3970[symbol+1] <= cf; symbol++); + + range_decode_update(counts_diff_3970[symbol],counts_3970[symbol]); + + return symbol; +} + +/* MAIN DECODING FUNCTIONS */ + +struct rice_t +{ + uint32_t k; + uint32_t ksum; +}; + +static struct rice_t riceX IBSS_ATTR_DEMAC; +static struct rice_t riceY IBSS_ATTR_DEMAC; + +static inline void update_rice(struct rice_t* rice, int x) +{ + rice->ksum += ((x + 1) / 2) - ((rice->ksum + 16) >> 5); + + if (UNLIKELY(rice->k == 0)) { + rice->k = 1; + } else { + uint32_t lim = 1 << (rice->k + 4); + if (UNLIKELY(rice->ksum < lim)) { + rice->k--; + } else if (UNLIKELY(rice->ksum >= 2 * lim)) { + rice->k++; + } + } +} + +static inline int entropy_decode3980(struct rice_t* rice) +{ + int base, x, pivot, overflow; + + pivot = rice->ksum >> 5; + if (UNLIKELY(pivot == 0)) + pivot=1; + + overflow = range_get_symbol_3980(); + + if (UNLIKELY(overflow == (MODEL_ELEMENTS-1))) { + overflow = range_decode_short() << 16; + overflow |= range_decode_short(); + } + + if (pivot >= 0x10000) { + /* Codepath for 24-bit streams */ + int nbits, lo_bits, base_hi, base_lo; + + /* Count the number of bits in pivot */ + nbits = 17; /* We know there must be at least 17 bits */ + while ((pivot >> nbits) > 0) { nbits++; } + + /* base_lo is the low (nbits-16) bits of base + base_hi is the high 16 bits of base + */ + lo_bits = (nbits - 16); + + base_hi = range_decode_culfreq((pivot >> lo_bits) + 1); + range_decode_update(1, base_hi); + + base_lo = range_decode_culshift(lo_bits); + range_decode_update(1, base_lo); + + base = (base_hi << lo_bits) + base_lo; + } else { + /* Codepath for 16-bit streams */ + base = range_decode_culfreq(pivot); + range_decode_update(1, base); + } + + x = base + (overflow * pivot); + update_rice(rice, x); + + /* Convert to signed */ + if (x & 1) + return (x >> 1) + 1; + else + return -(x >> 1); +} + + +static inline int entropy_decode3970(struct rice_t* rice) +{ + int x, tmpk; + + int overflow = range_get_symbol_3970(); + + if (UNLIKELY(overflow == (MODEL_ELEMENTS - 1))) { + tmpk = range_decode_bits(5); + overflow = 0; + } else { + tmpk = (rice->k < 1) ? 0 : rice->k - 1; + } + + if (tmpk <= 16) { + x = range_decode_bits(tmpk); + } else { + x = range_decode_short(); + x |= (range_decode_bits(tmpk - 16) << 16); + } + x += (overflow << tmpk); + + update_rice(rice, x); + + /* Convert to signed */ + if (x & 1) + return (x >> 1) + 1; + else + return -(x >> 1); +} + +void init_entropy_decoder(struct ape_ctx_t* ape_ctx, + unsigned char* inbuffer, int* firstbyte, + int* bytesconsumed) +{ + bytebuffer = inbuffer; + bytebufferoffset = *firstbyte; + + /* Read the CRC */ + ape_ctx->CRC = read_byte(); + ape_ctx->CRC = (ape_ctx->CRC << 8) | read_byte(); + ape_ctx->CRC = (ape_ctx->CRC << 8) | read_byte(); + ape_ctx->CRC = (ape_ctx->CRC << 8) | read_byte(); + + /* Read the frame flags if they exist */ + ape_ctx->frameflags = 0; + if ((ape_ctx->fileversion > 3820) && (ape_ctx->CRC & 0x80000000)) { + ape_ctx->CRC &= ~0x80000000; + + ape_ctx->frameflags = read_byte(); + ape_ctx->frameflags = (ape_ctx->frameflags << 8) | read_byte(); + ape_ctx->frameflags = (ape_ctx->frameflags << 8) | read_byte(); + ape_ctx->frameflags = (ape_ctx->frameflags << 8) | read_byte(); + } + /* Keep a count of the blocks decoded in this frame */ + ape_ctx->blocksdecoded = 0; + + /* Initialise the rice structs */ + riceX.k = 10; + riceX.ksum = (1 << riceX.k) * 16; + riceY.k = 10; + riceY.ksum = (1 << riceY.k) * 16; + + /* The first 8 bits of input are ignored. */ + skip_byte(); + + range_start_decoding(); + + /* Return the new state of the buffer */ + *bytesconsumed = (intptr_t)bytebuffer - (intptr_t)inbuffer; + *firstbyte = bytebufferoffset; +} + +void ICODE_ATTR_DEMAC entropy_decode(struct ape_ctx_t* ape_ctx, + unsigned char* inbuffer, int* firstbyte, + int* bytesconsumed, + int32_t* decoded0, int32_t* decoded1, + int blockstodecode) +{ + bytebuffer = inbuffer; + bytebufferoffset = *firstbyte; + + ape_ctx->blocksdecoded += blockstodecode; + + if ((ape_ctx->frameflags & APE_FRAMECODE_LEFT_SILENCE) + && ((ape_ctx->frameflags & APE_FRAMECODE_RIGHT_SILENCE) + || (decoded1 == NULL))) { + /* We are pure silence, just memset the output buffer. */ + memset(decoded0, 0, blockstodecode * sizeof(int32_t)); + if (decoded1 != NULL) + memset(decoded1, 0, blockstodecode * sizeof(int32_t)); + } else { + if (ape_ctx->fileversion > 3970) { + while (LIKELY(blockstodecode--)) { + *(decoded0++) = entropy_decode3980(&riceY); + if (decoded1 != NULL) + *(decoded1++) = entropy_decode3980(&riceX); + } + } else { + while (LIKELY(blockstodecode--)) { + *(decoded0++) = entropy_decode3970(&riceY); + if (decoded1 != NULL) + *(decoded1++) = entropy_decode3970(&riceX); + } + } + } + + if (ape_ctx->blocksdecoded == ape_ctx->currentframeblocks) + { + range_done_decoding(); + } + + /* Return the new state of the buffer */ + *bytesconsumed = bytebuffer - inbuffer; + *firstbyte = bytebufferoffset; +} -- cgit v1.2.3