/libIGraph/tinyjpeg.c

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/*
* Small jpeg decoder library
*
* Copyright (c) 2006, Luc Saillard <luc@saillard.org>
* 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 author 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.
*
*/

#include "libIGraph.h"

#include "tinyjpeg.h"
#include "tinyjpeg-internal.h"

enum std_markers {
	DQT  = 0xDB, /* Define Quantization Table */
	SOF  = 0xC0, /* Start of Frame (size information) */
	DHT  = 0xC4, /* Huffman Table */
	SOI  = 0xD8, /* Start of Image */
	SOS  = 0xDA, /* Start of Scan */
	RST  = 0xD0, /* Reset Marker d0 -> .. */
	RST7 = 0xD7, /* Reset Marker .. -> d7 */
	EOI  = 0xD9, /* End of Image */
	DRI  = 0xDD, /* Define Restart Interval */
	APP0 = 0xE0,
};

#define cY	0
#define cCb	1
#define cCr	2

#define BLACK_Y 0
#define BLACK_U 127
#define BLACK_V 127

/*#if DEBUG
#define trace(fmt, args...) do { \
fprintf(stderr, fmt, ## args); \
fflush(stderr); \
} while(0)
#else
#define trace(fmt, args...) do { } while (0)
#endif*/
#define error0(fmt) do { \
	snprintf(error_string, sizeof(error_string), fmt); \
	return -1; \
	} while(0)
#define error1(fmt, a) do { \
	snprintf(error_string, sizeof(error_string), fmt, a); \
	return -1; \
	} while(0)
#define error2(fmt, a, b) do { \
	snprintf(error_string, sizeof(error_string), fmt, a, b); \
	return -1; \
	} while(0)
#define error4(fmt, a, b, c, d) do { \
	snprintf(error_string, sizeof(error_string), fmt, a, b, c, d); \
	return -1; \
	} while(0)


#if 0
static char *print_bits(unsigned int value, char *bitstr)
{
	int i, j;
	i=31;
	while (i>0)
	{
		if (value & (1UL<<i))
			break;
		i--;
	}
	j=0;
	while (i>=0)
	{
		bitstr[j++] = (value & (1UL<<i))?'1':'0';
		i--;
	}
	bitstr[j] = 0;
	return bitstr;
}

static void print_next_16bytes(int offset, const unsigned char *stream)
{
	trace("%4.4x: %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x\n",
		offset,
		stream[0], stream[1], stream[2], stream[3], 
		stream[4], stream[5], stream[6], stream[7],
		stream[8], stream[9], stream[10], stream[11], 
		stream[12], stream[13], stream[14], stream[15]);
}

#endif

/* Global variable to return the last error found while deconding */
static char error_string[256];

static const unsigned char zigzag[64] = 
{
	0,  1,  5,  6, 14, 15, 27, 28,
	2,  4,  7, 13, 16, 26, 29, 42,
	3,  8, 12, 17, 25, 30, 41, 43,
	9, 11, 18, 24, 31, 40, 44, 53,
	10, 19, 23, 32, 39, 45, 52, 54,
	20, 22, 33, 38, 46, 51, 55, 60,
	21, 34, 37, 47, 50, 56, 59, 61,
	35, 36, 48, 49, 57, 58, 62, 63
};

/* Set up the standard Huffman tables (cf. JPEG standard section K.3) */
/* IMPORTANT: these are only valid for 8-bit data precision! */
static const unsigned char bits_dc_luminance[17] =
{ 
	0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 
};
static const unsigned char val_dc_luminance[] =
{
	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 
};

static const unsigned char bits_dc_chrominance[17] =
{
	0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 
};
static const unsigned char val_dc_chrominance[] = 
{
	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 
};

static const unsigned char bits_ac_luminance[17] =
{
	0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d 
};
static const unsigned char val_ac_luminance[] =
{
	0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
	0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
	0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
	0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
	0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
	0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
	0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
	0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
	0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
	0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
	0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
	0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
	0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
	0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
	0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
	0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
	0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
	0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
	0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
	0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
	0xf9, 0xfa
};

static const unsigned char bits_ac_chrominance[17] =
{ 
	0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 
};

static const unsigned char val_ac_chrominance[] =
{
	0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
	0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
	0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
	0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
	0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
	0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
	0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
	0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
	0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
	0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
	0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
	0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
	0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
	0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
	0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
	0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
	0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
	0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
	0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
	0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
	0xf9, 0xfa
};


/*
* 4 functions to manage the stream
*
*  fill_nbits: put at least nbits in the reservoir of bits.
*              But convert any 0xff,0x00 into 0xff
*  get_nbits: read nbits from the stream, and put it in result,
*             bits is removed from the stream and the reservoir is filled
*             automaticaly. The result is signed according to the number of
*             bits.
*  look_nbits: read nbits from the stream without marking as read.
*  skip_nbits: read nbits from the stream but do not return the result.
* 
* stream: current pointer in the jpeg data (read bytes per bytes)
* nbits_in_reservoir: number of bits filled into the reservoir
* reservoir: register that contains bits information. Only nbits_in_reservoir
*            is valid.
*                          nbits_in_reservoir
*                        <--    17 bits    -->
*            Ex: 0000 0000 1010 0000 1111 0000   <== reservoir
*                        ^
*                        bit 1
*            To get two bits from this example
*                 result = (reservoir >> 15) & 3
*
*/
#define fill_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted) do { \
	while (nbits_in_reservoir<nbits_wanted) \
{ \
	unsigned char c; \
	if (stream >= priv->stream_end) \
	longjmp(priv->jump_state, -EOI); \
	c = *stream++; \
	reservoir <<= 8; \
	if (c == 0xff && *stream == 0x00) \
	stream++; \
	reservoir |= c; \
	nbits_in_reservoir+=8; \
	} \
	}  while(0);

/* Signed version !!!! */
#define get_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted,result) do { \
	fill_nbits(reservoir,nbits_in_reservoir,stream,(nbits_wanted)); \
	result = ((reservoir)>>(nbits_in_reservoir-(nbits_wanted))); \
	nbits_in_reservoir -= (nbits_wanted);  \
	reservoir &= ((1U<<nbits_in_reservoir)-1); \
	if ((unsigned int)result < (1UL<<((nbits_wanted)-1))) \
	result += (0xFFFFFFFFUL<<(nbits_wanted))+1; \
	}  while(0);

#define look_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted,result) do { \
	fill_nbits(reservoir,nbits_in_reservoir,stream,(nbits_wanted)); \
	result = ((reservoir)>>(nbits_in_reservoir-(nbits_wanted))); \
	}  while(0);

/* To speed up the decoding, we assume that the reservoir have enough bit 
* slow version:
* #define skip_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted) do { \
*   fill_nbits(reservoir,nbits_in_reservoir,stream,(nbits_wanted)); \
*   nbits_in_reservoir -= (nbits_wanted); \
*   reservoir &= ((1U<<nbits_in_reservoir)-1); \
* }  while(0);
*/
#define skip_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted) do { \
	nbits_in_reservoir -= (nbits_wanted); \
	reservoir &= ((1U<<nbits_in_reservoir)-1); \
	}  while(0);


#define be16_to_cpu(x) (((x)[0]<<8)|(x)[1])

static void resync(struct jdec_private *priv);

/**
* Get the next (valid) huffman code in the stream.
*
* To speedup the procedure, we look HUFFMAN_HASH_NBITS bits and the code is
* lower than HUFFMAN_HASH_NBITS we have automaticaly the length of the code
* and the value by using two lookup table.
* Else if the value is not found, just search (linear) into an array for each
* bits is the code is present.
*
* If the code is not present for any reason, -1 is return.
*/
static int get_next_huffman_code(struct jdec_private *priv, struct huffman_table *huffman_table)
{
	int value, hcode;
	unsigned int extra_nbits, nbits;
	uint16_t *slowtable;

	look_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, HUFFMAN_HASH_NBITS, hcode);
	value = huffman_table->lookup[hcode];
	if (__likely(value >= 0))
	{ 
		unsigned int code_size = huffman_table->code_size[value];
		skip_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, code_size);
		return value;
	}

	/* Decode more bits each time ... */
	for (extra_nbits=0; extra_nbits<16-HUFFMAN_HASH_NBITS; extra_nbits++)
	{
		nbits = HUFFMAN_HASH_NBITS + 1 + extra_nbits;

		look_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, nbits, hcode);
		slowtable = huffman_table->slowtable[extra_nbits];
		/* Search if the code is in this array */
		while (slowtable[0]) {
			if (slowtable[0] == hcode) {
				skip_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, nbits);
				return slowtable[1];
			}
			slowtable+=2;
		}
	}
	return 0;
}




/**
*
* Decode a single block that contains the DCT coefficients.
* The table coefficients is already dezigzaged at the end of the operation.
*
*/
static void process_Huffman_data_unit(struct jdec_private *priv, int component)
{
	unsigned char j;
	unsigned int huff_code;
	unsigned char size_val, count_0;

	struct component *c = &priv->component_infos[component];
	short int DCT[64];


	/* Initialize the DCT coef table */
	memset(DCT, 0, sizeof(DCT));

	/* DC coefficient decoding */
	huff_code = get_next_huffman_code(priv, c->DC_table);
	//trace("+ %x\n", huff_code);
	if (huff_code) {
		get_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, huff_code, DCT[0]);
		DCT[0] += c->previous_DC;
		c->previous_DC = DCT[0];
	} else {
		DCT[0] = c->previous_DC;
	}

	/* AC coefficient decoding */
	j = 1;
	while (j<64)
	{
		huff_code = get_next_huffman_code(priv, c->AC_table);
		//trace("- %x\n", huff_code);

		size_val = huff_code & 0xF;
		count_0 = huff_code >> 4;

		if (size_val == 0)
		{ /* RLE */
			if (count_0 == 0)
				break;	/* EOB found, go out */
			else if (count_0 == 0xF)
				j += 16;	/* skip 16 zeros */
		}
		else
		{
			j += count_0;	/* skip count_0 zeroes */
			if (__unlikely(j >= 64))
			{
				snprintf(error_string, sizeof(error_string), "Bad huffman data (buffer overflow)");
				break;
			}
			get_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, size_val, DCT[j]);
			j++;
		}
	}

	for (j = 0; j < 64; j++)
		c->DCT[j] = DCT[zigzag[j]];
}

/*
* Takes two array of bits, and build the huffman table for size, and code
* 
* lookup will return the symbol if the code is less or equal than HUFFMAN_HASH_NBITS.
* code_size will be used to known how many bits this symbol is encoded.
* slowtable will be used when the first lookup didn't give the result.
*/
static void build_huffman_table(const unsigned char *bits, const unsigned char *vals, struct huffman_table *table)
{
	unsigned int i, j, code, code_size, val, nbits;
	unsigned char huffsize[HUFFMAN_BITS_SIZE+1], *hz;
	unsigned int huffcode[HUFFMAN_BITS_SIZE+1], *hc;
	int next_free_entry;

	/*
	* Build a temp array 
	*   huffsize[X] => numbers of bits to write vals[X]
	*/
	hz = huffsize;
	for (i=1; i<=16; i++)
	{
		for (j=1; j<=bits[i]; j++)
			*hz++ = i;
	}
	*hz = 0;

	memset(table->lookup, 0xff, sizeof(table->lookup));
	for (i=0; i<(16-HUFFMAN_HASH_NBITS); i++)
		table->slowtable[i][0] = 0;

	/* Build a temp array
	*   huffcode[X] => code used to write vals[X]
	*/
	code = 0;
	hc = huffcode;
	hz = huffsize;
	nbits = *hz;
	while (*hz)
	{
		while (*hz == nbits)
		{
			*hc++ = code++;
			hz++;
		}
		code <<= 1;
		nbits++;
	}

	/*
	* Build the lookup table, and the slowtable if needed.
	*/
	next_free_entry = -1;
	for (i=0; huffsize[i]; i++)
	{
		val = vals[i];
		code = huffcode[i];
		code_size = huffsize[i];

		//trace("val=%2.2x code=%8.8x codesize=%2.2d\n", val, code, code_size);

		table->code_size[val] = code_size;
		if (code_size <= HUFFMAN_HASH_NBITS)
		{
			/*
			* Good: val can be put in the lookup table, so fill all value of this
			* column with value val 
			*/
			int repeat = 1UL<<(HUFFMAN_HASH_NBITS - code_size);
			code <<= HUFFMAN_HASH_NBITS - code_size;
			while ( repeat-- )
				table->lookup[code++] = val;

		}
		else
		{
			/* Perhaps sorting the array will be an optimization */
			uint16_t *slowtable = table->slowtable[code_size-HUFFMAN_HASH_NBITS-1];
			while(slowtable[0])
				slowtable+=2;
			slowtable[0] = code;
			slowtable[1] = val;
			slowtable[2] = 0;
			/* TODO: NEED TO CHECK FOR AN OVERFLOW OF THE TABLE */
		}

	}
}

static void build_default_huffman_tables(struct jdec_private *priv)
{
	if (   (priv->flags & TINYJPEG_FLAGS_MJPEG_TABLE) 
		&& priv->default_huffman_table_initialized)
		return;

	build_huffman_table(bits_dc_luminance, val_dc_luminance, &priv->HTDC[0]);
	build_huffman_table(bits_ac_luminance, val_ac_luminance, &priv->HTAC[0]);

	build_huffman_table(bits_dc_chrominance, val_dc_chrominance, &priv->HTDC[1]);
	build_huffman_table(bits_ac_chrominance, val_ac_chrominance, &priv->HTAC[1]);

	priv->default_huffman_table_initialized = 1;
}



/*******************************************************************************
*
* Colorspace conversion routine
*
*
* Note:
* YCbCr is defined per CCIR 601-1, except that Cb and Cr are
* normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
* The conversion equations to be implemented are therefore
*      R = Y                + 1.40200 * Cr
*      G = Y - 0.34414 * Cb - 0.71414 * Cr
*      B = Y + 1.77200 * Cb
* 
******************************************************************************/

static unsigned char clamp(int i)
{
	if (i<0)
		return 0;
	else if (i>255)
		return 255;
	else
		return i;
}   


/**
*  YCrCb -> YUV420P (1x1)
*  .---.
*  | 1 |
*  `---'
*/
static void YCrCB_to_YUV420P_1x1(struct jdec_private *priv)
{
	const unsigned char *s, *y;
	unsigned char *p;
	int i,j;

	p = priv->plane[0];
	y = priv->Y;
	for (i=0; i<8; i++)
	{
		memcpy(p, y, 8);
		p+=priv->width;
		y+=8;
	}

	p = priv->plane[1];
	s = priv->Cb;
	for (i=0; i<8; i+=2)
	{
		for (j=0; j<8; j+=2, s+=2)
			*p++ = *s;
		s += 8; /* Skip one line */
		p += priv->width/2 - 4;
	}

	p = priv->plane[2];
	s = priv->Cr;
	for (i=0; i<8; i+=2)
	{
		for (j=0; j<8; j+=2, s+=2)
			*p++ = *s;
		s += 8; /* Skip one line */
		p += priv->width/2 - 4;
	}
}

/**
*  YCrCb -> YUV420P (2x1)
*  .-------.
*  | 1 | 2 |
*  `-------'
*/
static void YCrCB_to_YUV420P_2x1(struct jdec_private *priv)
{
	unsigned char *p;
	const unsigned char *s, *y1;
	unsigned int i;

	p = priv->plane[0];
	y1 = priv->Y;
	for (i=0; i<8; i++)
	{
		memcpy(p, y1, 16);
		p += priv->width;
		y1 += 16;
	}

	p = priv->plane[1];
	s = priv->Cb;
	for (i=0; i<8; i+=2)
	{
		memcpy(p, s, 8);
		s += 16; /* Skip one line */
		p += priv->width/2;
	}

	p = priv->plane[2];
	s = priv->Cr;
	for (i=0; i<8; i+=2)
	{
		memcpy(p, s, 8);
		s += 16; /* Skip one line */
		p += priv->width/2;
	}
}


/**
*  YCrCb -> YUV420P (1x2)
*  .---.
*  | 1 |
*  |---|
*  | 2 |
*  `---'
*/
static void YCrCB_to_YUV420P_1x2(struct jdec_private *priv)
{
	const unsigned char *s, *y;
	unsigned char *p;
	int i,j;

	p = priv->plane[0];
	y = priv->Y;
	for (i=0; i<16; i++)
	{
		memcpy(p, y, 8);
		p+=priv->width;
		y+=8;
	}

	p = priv->plane[1];
	s = priv->Cb;
	for (i=0; i<8; i++)
	{
		for (j=0; j<8; j+=2, s+=2)
			*p++ = *s;
		p += priv->width/2 - 4;
	}

	p = priv->plane[2];
	s = priv->Cr;
	for (i=0; i<8; i++)
	{
		for (j=0; j<8; j+=2, s+=2)
			*p++ = *s;
		p += priv->width/2 - 4;
	}
}

/**
*  YCrCb -> YUV420P (2x2)
*  .-------.
*  | 1 | 2 |
*  |---+---|
*  | 3 | 4 |
*  `-------'
*/
static void YCrCB_to_YUV420P_2x2(struct jdec_private *priv)
{
	unsigned char *p;
	const unsigned char *s, *y1;
	unsigned int i;

	p = priv->plane[0];
	y1 = priv->Y;
	for (i=0; i<16; i++)
	{
		memcpy(p, y1, 16);
		p += priv->width;
		y1 += 16;
	}

	p = priv->plane[1];
	s = priv->Cb;
	for (i=0; i<8; i++)
	{
		memcpy(p, s, 8);
		s += 8;
		p += priv->width/2;
	}

	p = priv->plane[2];
	s = priv->Cr;
	for (i=0; i<8; i++)
	{
		memcpy(p, s, 8);
		s += 8;
		p += priv->width/2;
	}
}

/**
*  YCrCb -> RGB24 (1x1)
*  .---.
*  | 1 |
*  `---'
*/
static void YCrCB_to_RGB24_1x1(struct jdec_private *priv)
{
	const unsigned char *Y, *Cb, *Cr;
	unsigned char *p;
	int i,j;
	int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

	p = priv->plane[0];
	Y = priv->Y;
	Cb = priv->Cb;
	Cr = priv->Cr;
	offset_to_next_row = priv->width*3 - 8*3;
	for (i=0; i<8; i++) {

		for (j=0; j<8; j++) {

			int y, cb, cr;
			int add_r, add_g, add_b;
			int r, g , b;

			y  = (*Y++) << SCALEBITS;
			cb = *Cb++ - 128;
			cr = *Cr++ - 128;
			add_r = FIX(1.40200) * cr + ONE_HALF;
			add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
			add_b = FIX(1.77200) * cb + ONE_HALF;

			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);

		}

		p += offset_to_next_row;
	}

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}

/**
*  YCrCb -> BGR24 (1x1)
*  .---.
*  | 1 |
*  `---'
*/
static void YCrCB_to_BGR24_1x1(struct jdec_private *priv)
{
	const unsigned char *Y, *Cb, *Cr;
	unsigned char *p;
	int i,j;
	int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

	p = priv->plane[0];
	Y = priv->Y;
	Cb = priv->Cb;
	Cr = priv->Cr;
	offset_to_next_row = priv->width*3 - 8*3;
	for (i=0; i<8; i++) {

		for (j=0; j<8; j++) {

			int y, cb, cr;
			int add_r, add_g, add_b;
			int r, g , b;

			y  = (*Y++) << SCALEBITS;
			cb = *Cb++ - 128;
			cr = *Cr++ - 128;
			add_r = FIX(1.40200) * cr + ONE_HALF;
			add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
			add_b = FIX(1.77200) * cb + ONE_HALF;

			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);

		}

		p += offset_to_next_row;
	}

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}


/**
*  YCrCb -> RGB24 (2x1)
*  .-------.
*  | 1 | 2 |
*  `-------'
*/
static void YCrCB_to_RGB24_2x1(struct jdec_private *priv)
{
	const unsigned char *Y, *Cb, *Cr;
	unsigned char *p;
	int i,j;
	int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

	p = priv->plane[0];
	Y = priv->Y;
	Cb = priv->Cb;
	Cr = priv->Cr;
	offset_to_next_row = priv->width*3 - 16*3;
	for (i=0; i<8; i++) {

		for (j=0; j<8; j++) {

			int y, cb, cr;
			int add_r, add_g, add_b;
			int r, g , b;

			y  = (*Y++) << SCALEBITS;
			cb = *Cb++ - 128;
			cr = *Cr++ - 128;
			add_r = FIX(1.40200) * cr + ONE_HALF;
			add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
			add_b = FIX(1.77200) * cb + ONE_HALF;

			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);

			y  = (*Y++) << SCALEBITS;
			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);

		}

		p += offset_to_next_row;
	}

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}

/*
*  YCrCb -> BGR24 (2x1)
*  .-------.
*  | 1 | 2 |
*  `-------'
*/
static void YCrCB_to_BGR24_2x1(struct jdec_private *priv)
{
	const unsigned char *Y, *Cb, *Cr;
	unsigned char *p;
	int i,j;
	int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

	p = priv->plane[0];
	Y = priv->Y;
	Cb = priv->Cb;
	Cr = priv->Cr;
	offset_to_next_row = priv->width*3 - 16*3;
	for (i=0; i<8; i++) {

		for (j=0; j<8; j++) {

			int y, cb, cr;
			int add_r, add_g, add_b;
			int r, g , b;

			cb = *Cb++ - 128;
			cr = *Cr++ - 128;
			add_r = FIX(1.40200) * cr + ONE_HALF;
			add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
			add_b = FIX(1.77200) * cb + ONE_HALF;

			y  = (*Y++) << SCALEBITS;
			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);

			y  = (*Y++) << SCALEBITS;
			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);

		}

		p += offset_to_next_row;
	}

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}

/**
*  YCrCb -> RGB24 (1x2)
*  .---.
*  | 1 |
*  |---|
*  | 2 |
*  `---'
*/
static void YCrCB_to_RGB24_1x2(struct jdec_private *priv)
{
	const unsigned char *Y, *Cb, *Cr;
	unsigned char *p, *p2;
	int i,j;
	int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

	p = priv->plane[0];
	p2 = priv->plane[0] + priv->width*3;
	Y = priv->Y;
	Cb = priv->Cb;
	Cr = priv->Cr;
	offset_to_next_row = 2*priv->width*3 - 8*3;
	for (i=0; i<8; i++) {

		for (j=0; j<8; j++) {

			int y, cb, cr;
			int add_r, add_g, add_b;
			int r, g , b;

			cb = *Cb++ - 128;
			cr = *Cr++ - 128;
			add_r = FIX(1.40200) * cr + ONE_HALF;
			add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
			add_b = FIX(1.77200) * cb + ONE_HALF;

			y  = (*Y++) << SCALEBITS;
			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);

			y  = (Y[8-1]) << SCALEBITS;
			r = (y + add_r) >> SCALEBITS;
			*p2++ = clamp(r);
			g = (y + add_g) >> SCALEBITS;
			*p2++ = clamp(g);
			b = (y + add_b) >> SCALEBITS;
			*p2++ = clamp(b);

		}
		Y += 8;
		p += offset_to_next_row;
		p2 += offset_to_next_row;
	}

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}

/*
*  YCrCb -> BGR24 (1x2)
*  .---.
*  | 1 |
*  |---|
*  | 2 |
*  `---'
*/
static void YCrCB_to_BGR24_1x2(struct jdec_private *priv)
{
	const unsigned char *Y, *Cb, *Cr;
	unsigned char *p, *p2;
	int i,j;
	int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

	p = priv->plane[0];
	p2 = priv->plane[0] + priv->width*3;
	Y = priv->Y;
	Cb = priv->Cb;
	Cr = priv->Cr;
	offset_to_next_row = 2*priv->width*3 - 8*3;
	for (i=0; i<8; i++) {

		for (j=0; j<8; j++) {

			int y, cb, cr;
			int add_r, add_g, add_b;
			int r, g , b;

			cb = *Cb++ - 128;
			cr = *Cr++ - 128;
			add_r = FIX(1.40200) * cr + ONE_HALF;
			add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
			add_b = FIX(1.77200) * cb + ONE_HALF;

			y  = (*Y++) << SCALEBITS;
			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);

			y  = (Y[8-1]) << SCALEBITS;
			b = (y + add_b) >> SCALEBITS;
			*p2++ = clamp(b);
			g = (y + add_g) >> SCALEBITS;
			*p2++ = clamp(g);
			r = (y + add_r) >> SCALEBITS;
			*p2++ = clamp(r);

		}
		Y += 8;
		p += offset_to_next_row;
		p2 += offset_to_next_row;
	}

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}


/**
*  YCrCb -> RGB24 (2x2)
*  .-------.
*  | 1 | 2 |
*  |---+---|
*  | 3 | 4 |
*  `-------'
*/
static void YCrCB_to_RGB24_2x2(struct jdec_private *priv)
{
	const unsigned char *Y, *Cb, *Cr;
	unsigned char *p, *p2;
	int i,j;
	int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

	p = priv->plane[0];
	p2 = priv->plane[0] + priv->width*3;
	Y = priv->Y;
	Cb = priv->Cb;
	Cr = priv->Cr;
	offset_to_next_row = (priv->width*3*2) - 16*3;
	for (i=0; i<8; i++) {

		for (j=0; j<8; j++) {

			int y, cb, cr;
			int add_r, add_g, add_b;
			int r, g , b;

			cb = *Cb++ - 128;
			cr = *Cr++ - 128;
			add_r = FIX(1.40200) * cr + ONE_HALF;
			add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
			add_b = FIX(1.77200) * cb + ONE_HALF;

			y  = (*Y++) << SCALEBITS;
			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);

			y  = (*Y++) << SCALEBITS;
			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);

			y  = (Y[16-2]) << SCALEBITS;
			r = (y + add_r) >> SCALEBITS;
			*p2++ = clamp(r);
			g = (y + add_g) >> SCALEBITS;
			*p2++ = clamp(g);
			b = (y + add_b) >> SCALEBITS;
			*p2++ = clamp(b);

			y  = (Y[16-1]) << SCALEBITS;
			r = (y + add_r) >> SCALEBITS;
			*p2++ = clamp(r);
			g = (y + add_g) >> SCALEBITS;
			*p2++ = clamp(g);
			b = (y + add_b) >> SCALEBITS;
			*p2++ = clamp(b);
		}
		Y  += 16;
		p  += offset_to_next_row;
		p2 += offset_to_next_row;
	}

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}


/*
*  YCrCb -> BGR24 (2x2)
*  .-------.
*  | 1 | 2 |
*  |---+---|
*  | 3 | 4 |
*  `-------'
*/
static void YCrCB_to_BGR24_2x2(struct jdec_private *priv)
{
	const unsigned char *Y, *Cb, *Cr;
	unsigned char *p, *p2;
	int i,j;
	int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

	p = priv->plane[0];
	p2 = priv->plane[0] + priv->width*3;
	Y = priv->Y;
	Cb = priv->Cb;
	Cr = priv->Cr;
	offset_to_next_row = (priv->width*3*2) - 16*3;
	for (i=0; i<8; i++) {

		for (j=0; j<8; j++) {

			int y, cb, cr;
			int add_r, add_g, add_b;
			int r, g , b;

			cb = *Cb++ - 128;
			cr = *Cr++ - 128;
			add_r = FIX(1.40200) * cr + ONE_HALF;
			add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
			add_b = FIX(1.77200) * cb + ONE_HALF;

			y  = (*Y++) << SCALEBITS;
			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);

			y  = (*Y++) << SCALEBITS;
			b = (y + add_b) >> SCALEBITS;
			*p++ = clamp(b);
			g = (y + add_g) >> SCALEBITS;
			*p++ = clamp(g);
			r = (y + add_r) >> SCALEBITS;
			*p++ = clamp(r);

			y  = (Y[16-2]) << SCALEBITS;
			b = (y + add_b) >> SCALEBITS;
			*p2++ = clamp(b);
			g = (y + add_g) >> SCALEBITS;
			*p2++ = clamp(g);
			r = (y + add_r) >> SCALEBITS;
			*p2++ = clamp(r);

			y  = (Y[16-1]) << SCALEBITS;
			b = (y + add_b) >> SCALEBITS;
			*p2++ = clamp(b);
			g = (y + add_g) >> SCALEBITS;
			*p2++ = clamp(g);
			r = (y + add_r) >> SCALEBITS;
			*p2++ = clamp(r);
		}
		Y  += 16;
		p  += offset_to_next_row;
		p2 += offset_to_next_row;
	}

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}



/**
*  YCrCb -> Grey (1x1)
*  .---.
*  | 1 |
*  `---'
*/
static void YCrCB_to_Grey_1x1(struct jdec_private *priv)
{
	const unsigned char *y;
	unsigned char *p;
	unsigned int i;
	int offset_to_next_row;

	p = priv->plane[0];
	y = priv->Y;
	offset_to_next_row = priv->width;

	for (i=0; i<8; i++) {
		memcpy(p, y, 8);
		y+=8;
		p += offset_to_next_row;
	}
}

/**
*  YCrCb -> Grey (2x1)
*  .-------.
*  | 1 | 2 |
*  `-------'
*/
static void YCrCB_to_Grey_2x1(struct jdec_private *priv)
{
	const unsigned char *y;
	unsigned char *p;
	unsigned int i;

	p = priv->plane[0];
	y = priv->Y;

	for (i=0; i<8; i++) {
		memcpy(p, y, 16);
		y += 16;
		p += priv->width;
	}
}


/**
*  YCrCb -> Grey (1x2)
*  .---.
*  | 1 |
*  |---|
*  | 2 |
*  `---'
*/
static void YCrCB_to_Grey_1x2(struct jdec_private *priv)
{
	const unsigned char *y;
	unsigned char *p;
	unsigned int i;

	p = priv->plane[0];
	y = priv->Y;

	for (i=0; i<16; i++) {
		memcpy(p, y, 8);
		y += 8;
		p += priv->width;
	}
}

/**
*  YCrCb -> Grey (2x2)
*  .-------.
*  | 1 | 2 |
*  |---+---|
*  | 3 | 4 |
*  `-------'
*/
static void YCrCB_to_Grey_2x2(struct jdec_private *priv)
{
	const unsigned char *y;
	unsigned char *p;
	unsigned int i;

	p = priv->plane[0];
	y = priv->Y;

	for (i=0; i<16; i++) {
		memcpy(p, y, 16);
		y += 16;
		p += priv->width;
	}
}


/*
* Decode all the 3 components for 1x1 
*/
static void decode_MCU_1x1_3planes(struct jdec_private *priv)
{
	// Y
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y, 8);

	// Cb
	process_Huffman_data_unit(priv, cCb);
	IDCT(&priv->component_infos[cCb], priv->Cb, 8);

	// Cr
	process_Huffman_data_unit(priv, cCr);
	IDCT(&priv->component_infos[cCr], priv->Cr, 8);
}

/*
* Decode a 1x1 directly in 1 color
*/
static void decode_MCU_1x1_1plane(struct jdec_private *priv)
{
	// Y
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y, 8);

	// Cb
	process_Huffman_data_unit(priv, cCb);
	IDCT(&priv->component_infos[cCb], priv->Cb, 8);

	// Cr
	process_Huffman_data_unit(priv, cCr);
	IDCT(&priv->component_infos[cCr], priv->Cr, 8);
}


/*
* Decode a 2x1
*  .-------.
*  | 1 | 2 |
*  `-------'
*/
static void decode_MCU_2x1_3planes(struct jdec_private *priv)
{
	// Y
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y, 16);
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y+8, 16);

	// Cb
	process_Huffman_data_unit(priv, cCb);
	IDCT(&priv->component_infos[cCb], priv->Cb, 8);

	// Cr
	process_Huffman_data_unit(priv, cCr);
	IDCT(&priv->component_infos[cCr], priv->Cr, 8);
}

/*
* Decode a 2x1
*  .-------.
*  | 1 | 2 |
*  `-------'
*/
static void decode_MCU_2x1_1plane(struct jdec_private *priv)
{
	// Y
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y, 16);
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y+8, 16);

	// Cb
	process_Huffman_data_unit(priv, cCb);

	// Cr
	process_Huffman_data_unit(priv, cCr);
}


/*
* Decode a 2x2
*  .-------.
*  | 1 | 2 |
*  |---+---|
*  | 3 | 4 |
*  `-------'
*/
static void decode_MCU_2x2_3planes(struct jdec_private *priv)
{
	// Y
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y, 16);
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y+8, 16);
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y+64*2, 16);
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y+64*2+8, 16);

	// Cb
	process_Huffman_data_unit(priv, cCb);
	IDCT(&priv->component_infos[cCb], priv->Cb, 8);

	// Cr
	process_Huffman_data_unit(priv, cCr);
	IDCT(&priv->component_infos[cCr], priv->Cr, 8);
}

/*
* Decode a 2x2 directly in GREY format (8bits)
*  .-------.
*  | 1 | 2 |
*  |---+---|
*  | 3 | 4 |
*  `-------'
*/
static void decode_MCU_2x2_1plane(struct jdec_private *priv)
{
	// Y
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y, 16);
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y+8, 16);
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y+64*2, 16);
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y+64*2+8, 16);

	// Cb
	process_Huffman_data_unit(priv, cCb);

	// Cr
	process_Huffman_data_unit(priv, cCr);
}

/*
* Decode a 1x2 mcu
*  .---.
*  | 1 |
*  |---|
*  | 2 |
*  `---'
*/
static void decode_MCU_1x2_3planes(struct jdec_private *priv)
{
	// Y
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y, 8);
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y+64, 8);

	// Cb
	process_Huffman_data_unit(priv, cCb);
	IDCT(&priv->component_infos[cCb], priv->Cb, 8);

	// Cr
	process_Huffman_data_unit(priv, cCr);
	IDCT(&priv->component_infos[cCr], priv->Cr, 8);
}

/*
* Decode a 1x2 mcu
*  .---.
*  | 1 |
*  |---|
*  | 2 |
*  `---'
*/
static void decode_MCU_1x2_1plane(struct jdec_private *priv)
{
	// Y
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y, 8);
	process_Huffman_data_unit(priv, cY);
	IDCT(&priv->component_infos[cY], priv->Y+64, 8);

	// Cb
	process_Huffman_data_unit(priv, cCb);

	// Cr
	process_Huffman_data_unit(priv, cCr);
}

static void print_SOF(const unsigned char *stream)
{
	int width, height, nr_components, precision;
#if DEBUG
	const char *nr_components_to_string[] = {
		"????",
		"Grayscale",
		"????",
		"YCbCr",
		"CYMK"
	};
#endif

	precision = stream[2];
	height = be16_to_cpu(stream+3);
	width  = be16_to_cpu(stream+5);
	nr_components = stream[7];

	/*trace("> SOF marker\n");
	trace("Size:%dx%d nr_components:%d (%s)  precision:%d\n", 
	width, height,
	nr_components, nr_components_to_string[nr_components],
	precision);*/
}

/*******************************************************************************
*
* JPEG/JFIF Parsing functions
*
* Note: only a small subset of the jpeg file format is supported. No markers,
* nor progressive stream is supported.
*
******************************************************************************/

static void build_quantization_table(int *qtable, const unsigned char *ref_table)
{
	/* Taken from libjpeg. Copyright Independent JPEG Group's LLM idct.
	* For float AA&N IDCT method, divisors are equal to quantization
	* coefficients scaled by scalefactor[row]*scalefactor[col], where
	*   scalefactor[0] = 1
	*   scalefactor[k] = cos(k*PI/16) * sqrt(2)    for k=1..7
	* We apply a further scale factor of 8.
	* What's actually stored is 1/divisor so that the inner loop can
	* use a multiplication rather than a division.
	*/
	int i, j;
	/*static const double aanscalefactor[8] = {
	1.0, 1.387039845, 1.306562965, 1.175875602,
	1.0, 0.785694958, 0.541196100, 0.275899379
	};*/
	static const int aanscalefactor[8] = {
		DCT_FIX(1.0), DCT_FIX(1.387039845), DCT_FIX(1.306562965), DCT_FIX(1.175875602),
		DCT_FIX(1.0), DCT_FIX(0.785694958), DCT_FIX(0.541196100), DCT_FIX(0.275899379)
	};
	const unsigned char *zz = zigzag;

	for (i=0; i<8; i++) {
		for (j=0; j<8; j++) {
			//*qtable++ = (float)(ref_table[*zz++] * aanscalefactor[i] * aanscalefactor[j]);
			//float f = (float)(ref_table[*zz++] * aanscalefactor[i] * aanscalefactor[j]);
			int value = ref_table[*zz++];
			value *= aanscalefactor[i];
			value *= aanscalefactor[j];
			*qtable++ = DCT_DESCALE1(value);
		}
	}

}

static int parse_DQT(struct jdec_private *priv, const unsigned char *stream)
{
	int qi;
	int *table;
	const unsigned char *dqt_block_end;

	//trace("> DQT marker\n");
	dqt_block_end = stream + be16_to_cpu(stream);
	stream += 2;	/* Skip length */

	while (stream < dqt_block_end)
	{
		qi = *stream++;
#if SANITY_CHECK
		if (qi>>4) {
			//error("16 bits quantization table is not supported\n");
			snprintf(error_string, sizeof(error_string), "16 bits quantization table is not supported\n");
			return -1;
		}
		if (qi>4) {
			//error("No more 4 quantization table is supported (got %d)\n", qi);
			snprintf(error_string, sizeof(error_string), "No more 4 quantization table is supported (got %d)\n", qi);
			return -1;
		}
#endif
		table = priv->Q_tables[qi];
		build_quantization_table(table, stream);
		stream += 64;
	}
	//trace("< DQT marker\n");
	return 0;
}

static int parse_SOF(struct jdec_private *priv, const unsigned char *stream)
{
	int i, width, height, nr_components, cid, sampling_factor;
	int Q_table;
	struct component *c;

	//  trace("> SOF marker\n");
	print_SOF(stream);

	height = be16_to_cpu(stream+3);
	width  = be16_to_cpu(stream+5);
	nr_components = stream[7];
#if SANITY_CHECK
	if (stream[2] != 8) {
		error0("Precision other than 8 is not supported\n");
	}
	if (width>JPEG_MAX_WIDTH || height>JPEG_MAX_HEIGHT)
		error2("Width and Height (%dx%d) seems suspicious\n", width, height);
	if (nr_components != 3)
		error0("We only support YUV images\n");
	if (height%16)
		error1("Height need to be a multiple of 16 (current height is %d)\n", height);
	if (width%16)
		error1("Width need to be a multiple of 16 (current Width is %d)\n", width);
#endif
	stream += 8;
	for (i=0; i<nr_components; i++) {
		cid = *stream++;
		sampling_factor = *stream++;
		Q_table = *stream++;
		c = &priv->component_infos[i];
#if SANITY_CHECK
		c->cid = cid;
		if (Q_table >= COMPONENTS)
			error2("Bad Quantization table index (got %d, max allowed %d)\n", Q_table, COMPONENTS-1);
#endif
		c->Vfactor = sampling_factor&0xf;
		c->Hfactor = sampling_factor>>4;
		c->Q_table = priv->Q_tables[Q_table];
		//trace("Component:%d  factor:%dx%d  Quantization table:%d\n",
		//    cid, c->Hfactor, c->Hfactor, Q_table );

	}
	priv->width = width;
	priv->height = height;

	//trace("< SOF marker\n");

	return 0;
}

static int parse_SOS(struct jdec_private *priv, const unsigned char *stream)
{
	unsigned int i, cid, table;
	unsigned int nr_components = stream[2];

	//  trace("> SOS marker\n");

#if SANITY_CHECK
	if (nr_components != 3)
		error0("We only support YCbCr image\n");
#endif

	stream += 3;
	for (i=0;i<nr_components;i++) {
		cid = *stream++;
		table = *stream++;
#if SANITY_CHECK
		if ((table&0xf)>=4)
			error0("We do not support more than 2 AC Huffman table\n");
		if ((table>>4)>=4)
			error0("We do not support more than 2 DC Huffman table\n");
		if (cid != priv->component_infos[i].cid)
			error4("SOS cid order (%d:%d) isn't compatible with the SOF marker (%d:%d)\n",
			i, cid, i, priv->component_infos[i].cid);
		//trace("ComponentId:%d  tableAC:%d tableDC:%d\n", cid, table&0xf, table>>4);
#endif
		priv->component_infos[i].AC_table = &priv->HTAC[table&0xf];
		priv->component_infos[i].DC_table = &priv->HTDC[table>>4];
	}
	priv->stream = stream+3;
	//trace("< SOS marker\n");
	return 0;
}

static int parse_DHT(struct jdec_private *priv, const unsigned char *stream)
{
	unsigned int count, i;
	unsigned char huff_bits[17];
	int length, index;

	length = be16_to_cpu(stream) - 2;
	stream += 2;	/* Skip length */

	// trace("> DHT marker (length=%d)\n", length);

	while (length>0) {
		index = *stream++;

		/* We need to calculate the number of bytes 'vals' will takes */
		huff_bits[0] = 0;
		count = 0;
		for (i=1; i<17; i++) {
			huff_bits[i] = *stream++;
			count += huff_bits[i];
		}
#if SANITY_CHECK
		if (count >= HUFFMAN_BITS_SIZE)
			error1("No more than %d bytes is allowed to describe a huffman table", HUFFMAN_BITS_SIZE);
		if ( (index &0xf) >= HUFFMAN_TABLES)
			error2("No more than %d Huffman tables is supported (got %d)\n", HUFFMAN_TABLES, index&0xf);
		//trace("Huffman table %s[%d] length=%d\n", (index&0xf0)?"AC":"DC", index&0xf, count);
#endif

		if (index & 0xf0 )
			build_huffman_table(huff_bits, stream, &priv->HTAC[index&0xf]);
		else
			build_huffman_table(huff_bits, stream, &priv->HTDC[index&0xf]);

		length -= 1;
		length -= 16;
		length -= count;
		stream += count;
	}
	//trace("< DHT marker\n");
	return 0;
}

static int parse_DRI(struct jdec_private *priv, const unsigned char *stream)
{
	unsigned int length;

	// trace("> DRI marker\n");

	length = be16_to_cpu(stream);

#if SANITY_CHECK
	if (length != 4)
		error0("Length of DRI marker need to be 4\n");
#endif

	priv->restart_interval = be16_to_cpu(stream+2);

#if DEBUG
	trace("Restart interval = %d\n", priv->restart_interval);
#endif

	//trace("< DRI marker\n");

	return 0;
}



static void resync(struct jdec_private *priv)
{
	int i;

	/* Init DC coefficients */
	for (i=0; i<COMPONENTS; i++)
		priv->component_infos[i].previous_DC = 0;

	priv->reservoir = 0;
	priv->nbits_in_reservoir = 0;
	if (priv->restart_interval > 0)
		priv->restarts_to_go = priv->restart_interval;
	else
		priv->restarts_to_go = -1;
}

static int find_next_rst_marker(struct jdec_private *priv)
{
	int rst_marker_found = 0;
	int marker;
	const unsigned char *stream = priv->stream;

	/* Parse marker */
	while (!rst_marker_found)
	{
		while (*stream++ != 0xff)
		{
			if (stream >= priv->stream_end)
				error0("EOF while search for a RST marker.");
		}
		/* Skip any padding ff byte (this is normal) */
		while (*stream == 0xff)
			stream++;

		marker = *stream++;
		if ((RST+priv->last_rst_marker_seen) == marker)
			rst_marker_found = 1;
		else if (marker >= RST && marker <= RST7)
			error0("Wrong Reset marker found, aborting");
		else if (marker == EOI)
			return 0;
	}
	// trace("RST Marker %d found at offset %d\n", priv->last_rst_marker_seen, stream - priv->stream_begin);

	priv->stream = stream;
	priv->last_rst_marker_seen++;
	priv->last_rst_marker_seen &= 7;

	return 0;
}

static int parse_JFIF(struct jdec_private *priv, const unsigned char *stream)
{
	int chuck_len;
	int marker;
	int sos_marker_found = 0;
	int dht_marker_found = 0;
	const unsigned char *next_chunck;

	/* Parse marker */
	while (!sos_marker_found)
	{
		if (*stream++ != 0xff)
			goto bogus_jpeg_format;
		/* Skip any padding ff byte (this is normal) */
		while (*stream == 0xff)
			stream++;

		marker = *stream++;
		chuck_len = be16_to_cpu(stream);
		next_chunck = stream + chuck_len;
		switch (marker)
		{
		case SOF:
			if (parse_SOF(priv, stream) < 0)
				return -1;
			break;
		case DQT:
			if (parse_DQT(priv, stream) < 0)
				return -1;
			break;
		case SOS:
			if (parse_SOS(priv, stream) < 0)
				return -1;
			sos_marker_found = 1;
			break;
		case DHT:
			if (parse_DHT(priv, stream) < 0)
				return -1;
			dht_marker_found = 1;
			break;
		case DRI:
			if (parse_DRI(priv, stream) < 0)
				return -1;
			break;
		default:
			// trace("> Unknown marker %2.2x\n", marker);
			break;
		}

		stream = next_chunck;
	}

	if (!dht_marker_found) {
		//trace("No Huffman table loaded, using the default one\n");
		build_default_huffman_tables(priv);
	}

#ifdef SANITY_CHECK
	if (   (priv->component_infos[cY].Hfactor < priv->component_infos[cCb].Hfactor)
		|| (priv->component_infos[cY].Hfactor < priv->component_infos[cCr].Hfactor))
		error0("Horizontal sampling factor for Y should be greater than horitontal sampling factor for Cb or Cr\n");
	if (   (priv->component_infos[cY].Vfactor < priv->component_infos[cCb].Vfactor)
		|| (priv->component_infos[cY].Vfactor < priv->component_infos[cCr].Vfactor))
		error0("Vertical sampling factor for Y should be greater than vertical sampling factor for Cb or Cr\n");
	if (   (priv->component_infos[cCb].Hfactor!=1) 
		|| (priv->component_infos[cCr].Hfactor!=1)
		|| (priv->component_infos[cCb].Vfactor!=1)
		|| (priv->component_infos[cCr].Vfactor!=1))
		error0("Sampling other than 1x1 for Cr and Cb is not supported");
#endif

	return 0;
bogus_jpeg_format:
	//trace("Bogus jpeg format\n");
	return -1;
}

/*******************************************************************************
*
* Functions exported of the library.
*
* Note: Some applications can access directly to internal pointer of the
* structure. It's is not recommended, but if you have many images to
* uncompress with the same parameters, some functions can be called to speedup
* the decoding.
*
******************************************************************************/

/**
* Allocate a new tinyjpeg decoder object.
*
* Before calling any other functions, an object need to be called.
*/
struct jdec_private *tinyjpeg_init(void)
{
	struct jdec_private *priv;

	priv = (struct jdec_private *)calloc(1, sizeof(struct jdec_private));
	if (priv == NULL)
		return NULL;
	return priv;
}

/**
* Free a tinyjpeg object.
*
* No others function can be called after this one.
*/
void tinyjpeg_free(struct jdec_private *priv)
{
	int i;
	for (i=0; i<COMPONENTS; i++) {
		if (priv->components[i])
			free(priv->components[i]);
		priv->components[i] = NULL;
	}
	free(priv);
}

/**
* Initialize the tinyjpeg object and prepare the decoding of the stream.
*
* Check if the jpeg can be decoded with this jpeg decoder.
* Fill some table used for preprocessing.
*/
int tinyjpeg_parse_header(struct jdec_private *priv, const unsigned char *buf, unsigned int size)
{
	int ret;

	/* Identify the file */
	if ((buf[0] != 0xFF) || (buf[1] != SOI))
		error0("Not a JPG file ?\n");

	priv->stream_begin = buf+2;
	priv->stream_length = size-2;
	priv->stream_end = priv->stream_begin + priv->stream_length;

	ret = parse_JFIF(priv, priv->stream_begin);

	return ret;
}

static const decode_MCU_fct decode_mcu_3comp_table[4] = {
	decode_MCU_1x1_3planes,
	decode_MCU_1x2_3planes,
	decode_MCU_2x1_3planes,
	decode_MCU_2x2_3planes,
};

static const decode_MCU_fct decode_mcu_1comp_table[4] = {
	decode_MCU_1x1_1plane,
	decode_MCU_1x2_1plane,
	decode_MCU_2x1_1plane,
	decode_MCU_2x2_1plane,
};

static const convert_colorspace_fct convert_colorspace_yuv420p[4] = {
	YCrCB_to_YUV420P_1x1,
	YCrCB_to_YUV420P_1x2,
	YCrCB_to_YUV420P_2x1,
	YCrCB_to_YUV420P_2x2,
};

static const convert_colorspace_fct convert_colorspace_rgb24[4] = {
	YCrCB_to_RGB24_1x1,
	YCrCB_to_RGB24_1x2,
	YCrCB_to_RGB24_2x1,
	YCrCB_to_RGB24_2x2,
};

static const convert_colorspace_fct convert_colorspace_bgr24[4] = {
	YCrCB_to_BGR24_1x1,
	YCrCB_to_BGR24_1x2,
	YCrCB_to_BGR24_2x1,
	YCrCB_to_BGR24_2x2,
};

static const convert_colorspace_fct convert_colorspace_grey[4] = {
	YCrCB_to_Grey_1x1,
	YCrCB_to_Grey_1x2,
	YCrCB_to_Grey_2x1,
	YCrCB_to_Grey_2x2,
};

/**
* Decode and convert the jpeg image into @pixfmt@ image
*
* Note: components will be automaticaly allocated if no memory is attached.
*/
int tinyjpeg_decode(struct jdec_private *priv, int pixfmt)
{
	unsigned int x, y, xstride_by_mcu, ystride_by_mcu;
	unsigned int bytes_per_blocklines[3], bytes_per_mcu[3];
	decode_MCU_fct decode_MCU;
	const decode_MCU_fct *decode_mcu_table;
	const convert_colorspace_fct *colorspace_array_conv;
	convert_colorspace_fct convert_to_pixfmt;

	if (setjmp(priv->jump_state))
		return -1;

	/* To keep gcc happy initialize some array */
	bytes_per_mcu[1] = 0;
	bytes_per_mcu[2] = 0;
	bytes_per_blocklines[1] = 0;
	bytes_per_blocklines[2] = 0;

	decode_mcu_table = decode_mcu_3comp_table;
	switch (pixfmt) {
case TINYJPEG_FMT_YUV420P:
	colorspace_array_conv = convert_colorspace_yuv420p;
	if (priv->components[0] == NULL)
		priv->components[0] = (uint8_t *)malloc(priv->width * priv->height);
	if (priv->components[1] == NULL)
		priv->components[1] = (uint8_t *)malloc(priv->width * priv->height/4);
	if (priv->components[2] == NULL)
		priv->components[2] = (uint8_t *)malloc(priv->width * priv->height/4);
	bytes_per_blocklines[0] = priv->width;
	bytes_per_blocklines[1] = priv->width/4;
	bytes_per_blocklines[2] = priv->width/4;
	bytes_per_mcu[0] = 8;
	bytes_per_mcu[1] = 4;
	bytes_per_mcu[2] = 4;
	break;

case TINYJPEG_FMT_RGB24:
	colorspace_array_conv = convert_colorspace_rgb24;
	if (priv->components[0] == NULL)
		priv->components[0] = (uint8_t *)malloc(priv->width * priv->height * 3);
	bytes_per_blocklines[0] = priv->width * 3;
	bytes_per_mcu[0] = 3*8;
	break;

case TINYJPEG_FMT_BGR24:
	colorspace_array_conv = convert_colorspace_bgr24;
	if (priv->components[0] == NULL)
		priv->components[0] = (uint8_t *)malloc(priv->width * priv->height * 3);
	bytes_per_blocklines[0] = priv->width * 3;
	bytes_per_mcu[0] = 3*8;
	break;

case TINYJPEG_FMT_GREY:
	decode_mcu_table = decode_mcu_1comp_table;
	colorspace_array_conv = convert_colorspace_grey;
	if (priv->components[0] == NULL)
		priv->components[0] = (uint8_t *)malloc(priv->width * priv->height);
	bytes_per_blocklines[0] = priv->width;
	bytes_per_mcu[0] = 8;
	break;

default:
	//       trace("Bad pixel format\n");
	return -1;
	}

	xstride_by_mcu = ystride_by_mcu = 8;
	if ((priv->component_infos[cY].Hfactor | priv->component_infos[cY].Vfactor) == 1) {
		decode_MCU = decode_mcu_table[0];
		convert_to_pixfmt = colorspace_array_conv[0];
		//     trace("Use decode 1x1 sampling\n");
	} else if (priv->component_infos[cY].Hfactor == 1) {
		decode_MCU = decode_mcu_table[1];
		convert_to_pixfmt = colorspace_array_conv[1];
		ystride_by_mcu = 16;
		//     trace("Use decode 1x2 sampling (not supported)\n");
	} else if (priv->component_infos[cY].Vfactor == 2) {
		decode_MCU = decode_mcu_table[3];
		convert_to_pixfmt = colorspace_array_conv[3];
		xstride_by_mcu = 16;
		ystride_by_mcu = 16;
		//     trace("Use decode 2x2 sampling\n");
	} else {
		decode_MCU = decode_mcu_table[2];
		convert_to_pixfmt = colorspace_array_conv[2];
		xstride_by_mcu = 16;
		//     trace("Use decode 2x1 sampling\n");
	}

	resync(priv);

	/* Don't forget to that block can be either 8 or 16 lines */
	bytes_per_blocklines[0] *= ystride_by_mcu;
	bytes_per_blocklines[1] *= ystride_by_…