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media/libvpx/vp8/decoder/detokenize.c@ac0c01689b40 (annotated)

media/libvpx/vp8/decoder/detokenize.c

Thu, 15 Jan 2015 15:59:08 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Thu, 15 Jan 2015 15:59:08 +0100

branch

TOR_BUG_9701

changeset 10

ac0c01689b40

permissions

-rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

michael@0	1	/*
michael@0	2	* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
michael@0	3	*
michael@0	4	* Use of this source code is governed by a BSD-style license
michael@0	5	* that can be found in the LICENSE file in the root of the source
michael@0	6	* tree. An additional intellectual property rights grant can be found
michael@0	7	* in the file PATENTS. All contributing project authors may
michael@0	8	* be found in the AUTHORS file in the root of the source tree.
michael@0	9	*/
michael@0	10
michael@0	11
michael@0	12	#include "vp8/common/blockd.h"
michael@0	13	#include "onyxd_int.h"
michael@0	14	#include "vpx_mem/vpx_mem.h"
michael@0	15	#include "vpx_ports/mem.h"
michael@0	16	#include "detokenize.h"
michael@0	17
michael@0	18	void vp8_reset_mb_tokens_context(MACROBLOCKD *x)
michael@0	19	{
michael@0	20	ENTROPY_CONTEXT *a_ctx = ((ENTROPY_CONTEXT *)x->above_context);
michael@0	21	ENTROPY_CONTEXT *l_ctx = ((ENTROPY_CONTEXT *)x->left_context);
michael@0	22
michael@0	23	vpx_memset(a_ctx, 0, sizeof(ENTROPY_CONTEXT_PLANES)-1);
michael@0	24	vpx_memset(l_ctx, 0, sizeof(ENTROPY_CONTEXT_PLANES)-1);
michael@0	25
michael@0	26	/* Clear entropy contexts for Y2 blocks */
michael@0	27	if (!x->mode_info_context->mbmi.is_4x4)
michael@0	28	{
michael@0	29	a_ctx[8] = l_ctx[8] = 0;
michael@0	30	}
michael@0	31	}
michael@0	32
michael@0	33	/*
michael@0	34	------------------------------------------------------------------------------
michael@0	35	Residual decoding (Paragraph 13.2 / 13.3)
michael@0	36	*/
michael@0	37	static const uint8_t kBands[16 + 1] = {
michael@0	38	0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7,
michael@0	39	0 /* extra entry as sentinel */
michael@0	40	};
michael@0	41
michael@0	42	static const uint8_t kCat3[] = { 173, 148, 140, 0 };
michael@0	43	static const uint8_t kCat4[] = { 176, 155, 140, 135, 0 };
michael@0	44	static const uint8_t kCat5[] = { 180, 157, 141, 134, 130, 0 };
michael@0	45	static const uint8_t kCat6[] =
michael@0	46	{ 254, 254, 243, 230, 196, 177, 153, 140, 133, 130, 129, 0 };
michael@0	47	static const uint8_t* const kCat3456[] = { kCat3, kCat4, kCat5, kCat6 };
michael@0	48	static const uint8_t kZigzag[16] = {
michael@0	49	0, 1, 4, 8, 5, 2, 3, 6, 9, 12, 13, 10, 7, 11, 14, 15
michael@0	50	};
michael@0	51
michael@0	52	#define VP8GetBit vp8dx_decode_bool
michael@0	53	#define NUM_PROBAS 11
michael@0	54	#define NUM_CTX 3
michael@0	55
michael@0	56	/* for const-casting */
michael@0	57	typedef const uint8_t (*ProbaArray)[NUM_CTX][NUM_PROBAS];
michael@0	58
michael@0	59	static int GetSigned(BOOL_DECODER *br, int value_to_sign)
michael@0	60	{
michael@0	61	int split = (br->range + 1) >> 1;
michael@0	62	VP8_BD_VALUE bigsplit = (VP8_BD_VALUE)split << (VP8_BD_VALUE_SIZE - 8);
michael@0	63	int v;
michael@0	64
michael@0	65	if(br->count < 0)
michael@0	66	vp8dx_bool_decoder_fill(br);
michael@0	67
michael@0	68	if ( br->value < bigsplit )
michael@0	69	{
michael@0	70	br->range = split;
michael@0	71	v= value_to_sign;
michael@0	72	}
michael@0	73	else
michael@0	74	{
michael@0	75	br->range = br->range-split;
michael@0	76	br->value = br->value-bigsplit;
michael@0	77	v = -value_to_sign;
michael@0	78	}
michael@0	79	br->range +=br->range;
michael@0	80	br->value +=br->value;
michael@0	81	br->count--;
michael@0	82
michael@0	83	return v;
michael@0	84	}
michael@0	85	/*
michael@0	86	Returns the position of the last non-zero coeff plus one
michael@0	87	(and 0 if there's no coeff at all)
michael@0	88	*/
michael@0	89	static int GetCoeffs(BOOL_DECODER *br, ProbaArray prob,
michael@0	90	int ctx, int n, int16_t* out)
michael@0	91	{
michael@0	92	const uint8_t* p = prob[n][ctx];
michael@0	93	if (!VP8GetBit(br, p[0]))
michael@0	94	{ /* first EOB is more a 'CBP' bit. */
michael@0	95	return 0;
michael@0	96	}
michael@0	97	while (1)
michael@0	98	{
michael@0	99	++n;
michael@0	100	if (!VP8GetBit(br, p[1]))
michael@0	101	{
michael@0	102	p = prob[kBands[n]][0];
michael@0	103	}
michael@0	104	else
michael@0	105	{ /* non zero coeff */
michael@0	106	int v, j;
michael@0	107	if (!VP8GetBit(br, p[2]))
michael@0	108	{
michael@0	109	p = prob[kBands[n]][1];
michael@0	110	v = 1;
michael@0	111	}
michael@0	112	else
michael@0	113	{
michael@0	114	if (!VP8GetBit(br, p[3]))
michael@0	115	{
michael@0	116	if (!VP8GetBit(br, p[4]))
michael@0	117	{
michael@0	118	v = 2;
michael@0	119	}
michael@0	120	else
michael@0	121	{
michael@0	122	v = 3 + VP8GetBit(br, p[5]);
michael@0	123	}
michael@0	124	}
michael@0	125	else
michael@0	126	{
michael@0	127	if (!VP8GetBit(br, p[6]))
michael@0	128	{
michael@0	129	if (!VP8GetBit(br, p[7]))
michael@0	130	{
michael@0	131	v = 5 + VP8GetBit(br, 159);
michael@0	132	} else
michael@0	133	{
michael@0	134	v = 7 + 2 * VP8GetBit(br, 165);
michael@0	135	v += VP8GetBit(br, 145);
michael@0	136	}
michael@0	137	}
michael@0	138	else
michael@0	139	{
michael@0	140	const uint8_t* tab;
michael@0	141	const int bit1 = VP8GetBit(br, p[8]);
michael@0	142	const int bit0 = VP8GetBit(br, p[9 + bit1]);
michael@0	143	const int cat = 2 * bit1 + bit0;
michael@0	144	v = 0;
michael@0	145	for (tab = kCat3456[cat]; *tab; ++tab)
michael@0	146	{
michael@0	147	v += v + VP8GetBit(br, *tab);
michael@0	148	}
michael@0	149	v += 3 + (8 << cat);
michael@0	150	}
michael@0	151	}
michael@0	152	p = prob[kBands[n]][2];
michael@0	153	}
michael@0	154	j = kZigzag[n - 1];
michael@0	155
michael@0	156	out[j] = GetSigned(br, v);
michael@0	157
michael@0	158	if (n == 16 || !VP8GetBit(br, p[0]))
michael@0	159	{ /* EOB */
michael@0	160	return n;
michael@0	161	}
michael@0	162	}
michael@0	163	if (n == 16)
michael@0	164	{
michael@0	165	return 16;
michael@0	166	}
michael@0	167	}
michael@0	168	}
michael@0	169
michael@0	170	int vp8_decode_mb_tokens(VP8D_COMP *dx, MACROBLOCKD *x)
michael@0	171	{
michael@0	172	BOOL_DECODER *bc = x->current_bc;
michael@0	173	const FRAME_CONTEXT * const fc = &dx->common.fc;
michael@0	174	char *eobs = x->eobs;
michael@0	175
michael@0	176	int i;
michael@0	177	int nonzeros;
michael@0	178	int eobtotal = 0;
michael@0	179
michael@0	180	short *qcoeff_ptr;
michael@0	181	ProbaArray coef_probs;
michael@0	182	ENTROPY_CONTEXT *a_ctx = ((ENTROPY_CONTEXT *)x->above_context);
michael@0	183	ENTROPY_CONTEXT *l_ctx = ((ENTROPY_CONTEXT *)x->left_context);
michael@0	184	ENTROPY_CONTEXT *a;
michael@0	185	ENTROPY_CONTEXT *l;
michael@0	186	int skip_dc = 0;
michael@0	187
michael@0	188	qcoeff_ptr = &x->qcoeff[0];
michael@0	189
michael@0	190	if (!x->mode_info_context->mbmi.is_4x4)
michael@0	191	{
michael@0	192	a = a_ctx + 8;
michael@0	193	l = l_ctx + 8;
michael@0	194
michael@0	195	coef_probs = fc->coef_probs [1];
michael@0	196
michael@0	197	nonzeros = GetCoeffs(bc, coef_probs, (*a + *l), 0, qcoeff_ptr + 24 * 16);
michael@0	198	*a = *l = (nonzeros > 0);
michael@0	199
michael@0	200	eobs[24] = nonzeros;
michael@0	201	eobtotal += nonzeros - 16;
michael@0	202
michael@0	203	coef_probs = fc->coef_probs [0];
michael@0	204	skip_dc = 1;
michael@0	205	}
michael@0	206	else
michael@0	207	{
michael@0	208	coef_probs = fc->coef_probs [3];
michael@0	209	skip_dc = 0;
michael@0	210	}
michael@0	211
michael@0	212	for (i = 0; i < 16; ++i)
michael@0	213	{
michael@0	214	a = a_ctx + (i&3);
michael@0	215	l = l_ctx + ((i&0xc)>>2);
michael@0	216
michael@0	217	nonzeros = GetCoeffs(bc, coef_probs, (*a + *l), skip_dc, qcoeff_ptr);
michael@0	218	*a = *l = (nonzeros > 0);
michael@0	219
michael@0	220	nonzeros += skip_dc;
michael@0	221	eobs[i] = nonzeros;
michael@0	222	eobtotal += nonzeros;
michael@0	223	qcoeff_ptr += 16;
michael@0	224	}
michael@0	225
michael@0	226	coef_probs = fc->coef_probs [2];
michael@0	227
michael@0	228	a_ctx += 4;
michael@0	229	l_ctx += 4;
michael@0	230	for (i = 16; i < 24; ++i)
michael@0	231	{
michael@0	232	a = a_ctx + ((i > 19)<<1) + (i&1);
michael@0	233	l = l_ctx + ((i > 19)<<1) + ((i&3)>1);
michael@0	234
michael@0	235	nonzeros = GetCoeffs(bc, coef_probs, (*a + *l), 0, qcoeff_ptr);
michael@0	236	*a = *l = (nonzeros > 0);
michael@0	237
michael@0	238	eobs[i] = nonzeros;
michael@0	239	eobtotal += nonzeros;
michael@0	240	qcoeff_ptr += 16;
michael@0	241	}
michael@0	242
michael@0	243	return eobtotal;
michael@0	244	}
michael@0	245