ref: f7e5af47f117be34669dc1e532d525dcbbff73f0
dir: /jpc_mqdec.h/
/* * Copyright (c) 1999-2000 Image Power, Inc. and the University of * British Columbia. * Copyright (c) 2001-2003 Michael David Adams. * All rights reserved. */ /* __START_OF_JASPER_LICENSE__ * * JasPer License Version 2.0 * * Copyright (c) 2001-2006 Michael David Adams * Copyright (c) 1999-2000 Image Power, Inc. * Copyright (c) 1999-2000 The University of British Columbia * * All rights reserved. * * Permission is hereby granted, free of charge, to any person (the * "User") obtaining a copy of this software and associated documentation * files (the "Software"), to deal in the Software without restriction, * including without limitation the rights to use, copy, modify, merge, * publish, distribute, and/or sell copies of the Software, and to permit * persons to whom the Software is furnished to do so, subject to the * following conditions: * * 1. The above copyright notices and this permission notice (which * includes the disclaimer below) shall be included in all copies or * substantial portions of the Software. * * 2. The name of a copyright holder shall not be used to endorse or * promote products derived from the Software without specific prior * written permission. * * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS * LICENSE. NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER * THIS DISCLAIMER. THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS * "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A * PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN NO * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. NO ASSURANCES ARE * PROVIDED BY THE COPYRIGHT HOLDERS THAT THE SOFTWARE DOES NOT INFRINGE * THE PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER ENTITY. * EACH COPYRIGHT HOLDER DISCLAIMS ANY LIABILITY TO THE USER FOR CLAIMS * BROUGHT BY ANY OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL * PROPERTY RIGHTS OR OTHERWISE. AS A CONDITION TO EXERCISING THE RIGHTS * GRANTED HEREUNDER, EACH USER HEREBY ASSUMES SOLE RESPONSIBILITY TO SECURE * ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY. THE SOFTWARE * IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL * SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES, * AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL * SYSTEMS, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH * THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH, * PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH * RISK ACTIVITIES"). THE COPYRIGHT HOLDERS SPECIFICALLY DISCLAIM ANY * EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES. * * __END_OF_JASPER_LICENSE__ */ /* * MQ Arithmetic Decoder * * $Id$ */ #ifndef JPC_MQDEC_H #define JPC_MQDEC_H /******************************************************************************\ * Includes. \******************************************************************************/ #include "jasper/jas_types.h" #include "jasper/jas_stream.h" #include "jpc_mqcod.h" /******************************************************************************\ * Types. \******************************************************************************/ /* MQ arithmetic decoder. */ typedef struct { /* The C register. */ uint_least32_t creg; /* The A register. */ uint_least32_t areg; /* The CT register. */ uint_least32_t ctreg; /* The current context. */ const jpc_mqstate_t **curctx; /* The per-context information. */ const jpc_mqstate_t **ctxs; /* The maximum number of contexts. */ unsigned maxctxs; /* The stream from which to read data. */ jas_stream_t *in; /* The last character read. */ jas_uchar inbuffer; /* The EOF indicator. */ bool eof; } jpc_mqdec_t; /******************************************************************************\ * Functions/macros for construction and destruction. \******************************************************************************/ /* Create a MQ decoder. */ jpc_mqdec_t *jpc_mqdec_create(unsigned maxctxs, jas_stream_t *in); /* Destroy a MQ decoder. */ void jpc_mqdec_destroy(jpc_mqdec_t *dec); /******************************************************************************\ * Functions/macros for initialization. \******************************************************************************/ /* Set the input stream associated with a MQ decoder. */ void jpc_mqdec_setinput(jpc_mqdec_t *dec, jas_stream_t *in); /* Initialize a MQ decoder. */ void jpc_mqdec_init(jpc_mqdec_t *dec); /******************************************************************************\ * Functions/macros for manipulating contexts. \******************************************************************************/ /* Set the current context for a MQ decoder. */ static inline void jpc_mqdec_setcurctx(jpc_mqdec_t *dec, unsigned ctxno) { dec->curctx = &dec->ctxs[ctxno]; } /* Set the state information for all contexts of a MQ decoder. */ void jpc_mqdec_setctxs(const jpc_mqdec_t *dec, unsigned numctxs, const jpc_mqctx_t *ctxs); /******************************************************************************\ * Functions/macros for decoding bits. \******************************************************************************/ /* Decode a symbol. */ #ifdef NDEBUG #define jpc_mqdec_getbit(dec) \ jpc_mqdec_getbit_macro(dec) #else #define jpc_mqdec_getbit(dec) \ jpc_mqdec_getbit_func(dec) #endif /* Decode a symbol (assuming an unskewed probability distribution). */ #ifdef NDEBUG #define jpc_mqdec_getbitnoskew(dec) \ jpc_mqdec_getbit_macro(dec) #else #define jpc_mqdec_getbitnoskew(dec) \ jpc_mqdec_getbit_func(dec) #endif /******************************************************************************\ * Functions/macros for debugging. \******************************************************************************/ /* Dump the MQ decoder state for debugging. */ void jpc_mqdec_dump(const jpc_mqdec_t *dec); /******************************************************************************\ * EVERYTHING BELOW THIS POINT IS IMPLEMENTATION SPECIFIC AND NOT PART OF THE * APPLICATION INTERFACE. DO NOT RELY ON ANY OF THE INTERNAL FUNCTIONS/MACROS * GIVEN BELOW. \******************************************************************************/ bool jpc_mqdec_mpsexchrenormd(jpc_mqdec_t *dec); bool jpc_mqdec_lpsexchrenormd(jpc_mqdec_t *dec); JAS_FORCE_INLINE static bool jpc_mqdec_getbit_macro(jpc_mqdec_t *dec) { const jpc_mqstate_t *const state = *dec->curctx; dec->areg -= state->qeval; if (dec->creg >= (uint_least32_t)state->qeval << 16) { dec->creg -= (uint_least32_t)state->qeval << 16; return dec->areg & 0x8000 ? state->mps : jpc_mqdec_mpsexchrenormd(dec); } else { return jpc_mqdec_lpsexchrenormd(dec); } } JAS_FORCE_INLINE static bool jpc_mqdec_mpsexchange(uint_least32_t areg, uint_least32_t delta, const jpc_mqstate_t **curctx) { if (areg < delta) { const jpc_mqstate_t *state = *curctx; /* LPS decoded. */ *curctx = state->nlps; return !state->mps; } else { const jpc_mqstate_t *state = *curctx; /* MPS decoded. */ *curctx = state->nmps; return state->mps; } } JAS_FORCE_INLINE static bool jpc_mqdec_lpsexchange(uint_least32_t *areg_p, uint_least32_t delta, const jpc_mqstate_t **curctx) { if (*areg_p >= delta) { const jpc_mqstate_t *state = *curctx; *areg_p = delta; *curctx = state->nlps; return !state->mps; } else { const jpc_mqstate_t *state = *curctx; *areg_p = delta; *curctx = state->nmps; return state->mps; } } bool jpc_mqdec_getbit_func(jpc_mqdec_t *dec); #endif