/*
* 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <errno.h>
#include "tinyjpeg.h"
#include "tinyjpeg-internal.h"
/* 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, -EIO); \
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.
*
*/
void tinyjpeg_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;
/*
* 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.
*/
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 void print_SOF(const unsigned char *stream)
{
#if JPEG_DEBUG
int width, height, nr_components, precision;
const char *nr_components_to_string[] = {
"????",
"Grayscale",
"????",
"YCbCr",
"CYMK"
};
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);
#endif
(void)stream;
}
/*******************************************************************************
*
* 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(float *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
};
const unsigned char *zz = zigzag;
for (i=0; i<8; i++) {
for (j=0; j<8; j++) {
*qtable++ = ref_table[*zz++] * aanscalefactor[i] * aanscalefactor[j];
}
}
}
static int parse_DQT(struct jdec_private *priv, const unsigned char *stream)
{
int qi;
float *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");
if (qi>4)
error("No more 4 quantization table is supported (got %d)\n", qi);
#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)
error("Precision other than 8 is not supported\n");
if (width>JPEG_MAX_WIDTH || height>JPEG_MAX_HEIGHT)
error("Width and Height (%dx%d) seems suspicious\n", width, height);
if (nr_components != 3)
error("We only support YUV images\n");
#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)
error("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)
error("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)
error("We do not support more than 2 AC Huffman table\n");
if ((table>>4)>=4)
error("We do not support more than 2 DC Huffman table\n");
if (cid != priv->component_infos[i].cid)
error("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)
error("No more than %d bytes is allowed to describe a huffman table", HUFFMAN_BITS_SIZE);
if ( (index &0xf) >= HUFFMAN_TABLES)
error("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)
error("Length of DRI marker need to be 4\n");
#endif
priv->restart_interval = be16_to_cpu(stream+2);
#if JPEG_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)
error("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)
error("Wrong Reset marker found, abording");
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))
error("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))
error("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))
error("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))
error("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;
}
/**
* 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,
const struct tinyjpeg_colorspace *pixfmt)
{
int x, y, sx, sy;
int xshift_by_mcu, yshift_by_mcu;
int 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;
convert_colorspace_fct convert_to_pixfmt;
uint8_t *pptr[3];
decode_mcu_table = pixfmt->decode_mcu_table;
/* Fix: check return value */
pixfmt->initialize(priv, bytes_per_blocklines, bytes_per_mcu);
xshift_by_mcu = yshift_by_mcu = 3;
if ((priv->component_infos[cY].Hfactor | priv->component_infos[cY].Vfactor) == 1) {
decode_MCU = decode_mcu_table[0];
convert_to_pixfmt = pixfmt->convert_colorspace[0];
trace("Use decode 1x1 sampling\n");
} else if (priv->component_infos[cY].Hfactor == 1) {
decode_MCU = decode_mcu_table[1];
convert_to_pixfmt = pixfmt->convert_colorspace[1];
yshift_by_mcu = 4;
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 = pixfmt->convert_colorspace[3];
xshift_by_mcu = 4;
yshift_by_mcu = 4;
trace("Use decode 2x2 sampling\n");
} else {
decode_MCU = decode_mcu_table[2];
convert_to_pixfmt = pixfmt->convert_colorspace[2];
xshift_by_mcu = 4;
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] <<= yshift_by_mcu-3;
bytes_per_blocklines[1] <<= yshift_by_mcu-3;
bytes_per_blocklines[2] <<= yshift_by_mcu-3;
bytes_per_mcu[0] <<= xshift_by_mcu-3;
bytes_per_mcu[1] <<= xshift_by_mcu-3;
bytes_per_mcu[2] <<= xshift_by_mcu-3;
xstride_by_mcu = 1 << xshift_by_mcu;
ystride_by_mcu = 1 << yshift_by_mcu;
pptr[0] = priv->components[0];
pptr[1] = priv->components[1];
pptr[2] = priv->components[2];
trace("bpbl = %d, bpmcu = %d\n",
bytes_per_blocklines[0], bytes_per_mcu[0]);
for (y = priv->height; y > 0; y -= ystride_by_mcu)
{
trace("Decoding row %d\n", priv->height-y);
priv->plane[0] = pptr[0]; pptr[0] += bytes_per_blocklines[0];
priv->plane[1] = pptr[1]; pptr[1] += bytes_per_blocklines[1];
priv->plane[2] = pptr[2]; pptr[2] += bytes_per_blocklines[2];
sy = min(y, ystride_by_mcu);
for (x = priv->width; x > 0; x -= xstride_by_mcu)
{
sx = min(x, xstride_by_mcu);
trace("Block size: %dx%d\n", sx, sy);
decode_MCU(priv);
convert_to_pixfmt(priv, sx, sy);
priv->plane[0] += bytes_per_mcu[0];
priv->plane[1] += bytes_per_mcu[1];
priv->plane[2] += bytes_per_mcu[2];
if (priv->restarts_to_go>0)
{
priv->restarts_to_go--;
if (priv->restarts_to_go == 0)
{
priv->stream -= (priv->nbits_in_reservoir/8);
resync(priv);
if (find_next_rst_marker(priv) < 0)
return -1;
}
}
}
}
trace("Input file size: %d\n", priv->stream_length+2);
trace("Input bytes actually read: %d\n", priv->stream - priv->stream_begin + 2);
return 0;
}
const char *tinyjpeg_get_errorstring(struct jdec_private *priv)
{
/* FIXME: the error string must be store in the context */
priv = priv;
return error_string;
}
void tinyjpeg_get_size(struct jdec_private *priv, unsigned int *width, unsigned int *height)
{
*width = priv->width;
*height = priv->height;
}
int tinyjpeg_get_components(struct jdec_private *priv, unsigned char **components, unsigned int ncomponents)
{
unsigned int i;
if (ncomponents > COMPONENTS)
ncomponents = COMPONENTS;
for (i=0; i<ncomponents; i++)
components[i] = priv->components[i];
return 0;
}
int tinyjpeg_set_components(struct jdec_private *priv, unsigned char * const *components, unsigned int ncomponents)
{
unsigned int i;
if (ncomponents > COMPONENTS)
ncomponents = COMPONENTS;
for (i=0; i<ncomponents; i++)
priv->components[i] = components[i];
return 0;
}
int tinyjpeg_get_bytes_per_row(struct jdec_private *priv,
unsigned int *bytes,
unsigned int ncomponents)
{
unsigned int i;
if (ncomponents > COMPONENTS)
ncomponents = COMPONENTS;
for (i=0; i<ncomponents; i++)
bytes[i] = priv->bytes_per_row[i];
return 0;
}
int tinyjpeg_set_bytes_per_row(struct jdec_private *priv,
const unsigned int *bytes,
unsigned int ncomponents)
{
unsigned int i;
if (ncomponents > COMPONENTS)
ncomponents = COMPONENTS;
for (i=0; i<ncomponents; i++)
priv->bytes_per_row[i] = bytes[i];
return 0;
}
int tinyjpeg_set_flags(struct jdec_private *priv, int flags)
{
int oldflags = priv->flags;
priv->flags = flags;
return oldflags;
}