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tjpgd.c
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tjpgd.c
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/*----------------------------------------------------------------------------/
/ TJpgDec - Tiny JPEG Decompressor R0.03 (C)ChaN, 2021
/-----------------------------------------------------------------------------/
/ The TJpgDec is a generic JPEG decompressor module for tiny embedded systems.
/ This is a free software that opened for education, research and commercial
/ developments under license policy of following terms.
/
/ Copyright (C) 2021, ChaN, all right reserved.
/
/ * The TJpgDec module is a free software and there is NO WARRANTY.
/ * No restriction on use. You can use, modify and redistribute it for
/ personal, non-profit or commercial products UNDER YOUR RESPONSIBILITY.
/ * Redistributions of source code must retain the above copyright notice.
/
/-----------------------------------------------------------------------------/
/ Oct 04, 2011 R0.01 First release.
/ Feb 19, 2012 R0.01a Fixed decompression fails when scan starts with an escape seq.
/ Sep 03, 2012 R0.01b Added JD_TBLCLIP option.
/ Mar 16, 2019 R0.01c Supprted stdint.h.
/ Jul 01, 2020 R0.01d Fixed wrong integer type usage.
/ May 08, 2021 R0.02 Supprted grayscale image. Separated configuration options.
/ Jun 11, 2021 R0.02a Some performance improvement.
/ Jul 01, 2021 R0.03 Added JD_FASTDECODE option.
/ Some performance improvement.
/----------------------------------------------------------------------------*/
#include "tjpgd.h"
#if JD_FASTDECODE == 2
#define HUFF_BIT 10 /* Bit length to apply fast huffman decode */
#define HUFF_LEN (1 << HUFF_BIT)
#define HUFF_MASK (HUFF_LEN - 1)
#endif
/*-----------------------------------------------*/
/* Zigzag-order to raster-order conversion table */
/*-----------------------------------------------*/
static const uint8_t Zig[64] = { /* Zigzag-order to raster-order conversion table */
0, 1, 8, 16, 9, 2, 3, 10, 17, 24, 32, 25, 18, 11, 4, 5,
12, 19, 26, 33, 40, 48, 41, 34, 27, 20, 13, 6, 7, 14, 21, 28,
35, 42, 49, 56, 57, 50, 43, 36, 29, 22, 15, 23, 30, 37, 44, 51,
58, 59, 52, 45, 38, 31, 39, 46, 53, 60, 61, 54, 47, 55, 62, 63
};
/*-------------------------------------------------*/
/* Input scale factor of Arai algorithm */
/* (scaled up 16 bits for fixed point operations) */
/*-------------------------------------------------*/
static const uint16_t Ipsf[64] = { /* See also aa_idct.png */
(uint16_t)(1.00000*8192), (uint16_t)(1.38704*8192), (uint16_t)(1.30656*8192), (uint16_t)(1.17588*8192), (uint16_t)(1.00000*8192), (uint16_t)(0.78570*8192), (uint16_t)(0.54120*8192), (uint16_t)(0.27590*8192),
(uint16_t)(1.38704*8192), (uint16_t)(1.92388*8192), (uint16_t)(1.81226*8192), (uint16_t)(1.63099*8192), (uint16_t)(1.38704*8192), (uint16_t)(1.08979*8192), (uint16_t)(0.75066*8192), (uint16_t)(0.38268*8192),
(uint16_t)(1.30656*8192), (uint16_t)(1.81226*8192), (uint16_t)(1.70711*8192), (uint16_t)(1.53636*8192), (uint16_t)(1.30656*8192), (uint16_t)(1.02656*8192), (uint16_t)(0.70711*8192), (uint16_t)(0.36048*8192),
(uint16_t)(1.17588*8192), (uint16_t)(1.63099*8192), (uint16_t)(1.53636*8192), (uint16_t)(1.38268*8192), (uint16_t)(1.17588*8192), (uint16_t)(0.92388*8192), (uint16_t)(0.63638*8192), (uint16_t)(0.32442*8192),
(uint16_t)(1.00000*8192), (uint16_t)(1.38704*8192), (uint16_t)(1.30656*8192), (uint16_t)(1.17588*8192), (uint16_t)(1.00000*8192), (uint16_t)(0.78570*8192), (uint16_t)(0.54120*8192), (uint16_t)(0.27590*8192),
(uint16_t)(0.78570*8192), (uint16_t)(1.08979*8192), (uint16_t)(1.02656*8192), (uint16_t)(0.92388*8192), (uint16_t)(0.78570*8192), (uint16_t)(0.61732*8192), (uint16_t)(0.42522*8192), (uint16_t)(0.21677*8192),
(uint16_t)(0.54120*8192), (uint16_t)(0.75066*8192), (uint16_t)(0.70711*8192), (uint16_t)(0.63638*8192), (uint16_t)(0.54120*8192), (uint16_t)(0.42522*8192), (uint16_t)(0.29290*8192), (uint16_t)(0.14932*8192),
(uint16_t)(0.27590*8192), (uint16_t)(0.38268*8192), (uint16_t)(0.36048*8192), (uint16_t)(0.32442*8192), (uint16_t)(0.27590*8192), (uint16_t)(0.21678*8192), (uint16_t)(0.14932*8192), (uint16_t)(0.07612*8192)
};
/*---------------------------------------------*/
/* Conversion table for fast clipping process */
/*---------------------------------------------*/
#if JD_TBLCLIP
#define BYTECLIP(v) Clip8[(unsigned int)(v) & 0x3FF]
static const uint8_t Clip8[1024] = {
/* 0..255 */
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,
64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95,
96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127,
128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159,
160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191,
192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223,
224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255,
/* 256..511 */
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
/* -512..-257 */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* -256..-1 */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
#else /* JD_TBLCLIP */
static uint8_t BYTECLIP (int val)
{
if (val < 0) return 0;
if (val > 255) return 255;
return (uint8_t)val;
}
#endif
/*-----------------------------------------------------------------------*/
/* Allocate a memory block from memory pool */
/*-----------------------------------------------------------------------*/
static void* alloc_pool ( /* Pointer to allocated memory block (NULL:no memory available) */
JDEC* jd, /* Pointer to the decompressor object */
size_t ndata /* Number of bytes to allocate */
)
{
char *rp = 0;
ndata = (ndata + 3) & ~3; /* Align block size to the word boundary */
if (jd->sz_pool >= ndata) {
jd->sz_pool -= ndata;
rp = (char*)jd->pool; /* Get start of available memory pool */
jd->pool = (void*)(rp + ndata); /* Allocate requierd bytes */
}
return (void*)rp; /* Return allocated memory block (NULL:no memory to allocate) */
}
/*-----------------------------------------------------------------------*/
/* Create de-quantization and prescaling tables with a DQT segment */
/*-----------------------------------------------------------------------*/
static JRESULT create_qt_tbl ( /* 0:OK, !0:Failed */
JDEC* jd, /* Pointer to the decompressor object */
const uint8_t* data, /* Pointer to the quantizer tables */
size_t ndata /* Size of input data */
)
{
unsigned int i, zi;
uint8_t d;
int32_t *pb;
while (ndata) { /* Process all tables in the segment */
if (ndata < 65) return JDR_FMT1; /* Err: table size is unaligned */
ndata -= 65;
d = *data++; /* Get table property */
if (d & 0xF0) return JDR_FMT1; /* Err: not 8-bit resolution */
i = d & 3; /* Get table ID */
pb = alloc_pool(jd, 64 * sizeof (int32_t));/* Allocate a memory block for the table */
if (!pb) return JDR_MEM1; /* Err: not enough memory */
jd->qttbl[i] = pb; /* Register the table */
for (i = 0; i < 64; i++) { /* Load the table */
zi = Zig[i]; /* Zigzag-order to raster-order conversion */
pb[zi] = (int32_t)((uint32_t)*data++ * Ipsf[zi]); /* Apply scale factor of Arai algorithm to the de-quantizers */
}
}
return JDR_OK;
}
/*-----------------------------------------------------------------------*/
/* Create huffman code tables with a DHT segment */
/*-----------------------------------------------------------------------*/
static JRESULT create_huffman_tbl ( /* 0:OK, !0:Failed */
JDEC* jd, /* Pointer to the decompressor object */
const uint8_t* data, /* Pointer to the packed huffman tables */
size_t ndata /* Size of input data */
)
{
unsigned int i, j, b, cls, num;
size_t np;
uint8_t d, *pb, *pd;
uint16_t hc, *ph;
while (ndata) { /* Process all tables in the segment */
if (ndata < 17) return JDR_FMT1; /* Err: wrong data size */
ndata -= 17;
d = *data++; /* Get table number and class */
if (d & 0xEE) return JDR_FMT1; /* Err: invalid class/number */
cls = d >> 4; num = d & 0x0F; /* class = dc(0)/ac(1), table number = 0/1 */
pb = alloc_pool(jd, 16); /* Allocate a memory block for the bit distribution table */
if (!pb) return JDR_MEM1; /* Err: not enough memory */
jd->huffbits[num][cls] = pb;
for (np = i = 0; i < 16; i++) { /* Load number of patterns for 1 to 16-bit code */
np += (pb[i] = *data++); /* Get sum of code words for each code */
}
ph = alloc_pool(jd, np * sizeof (uint16_t));/* Allocate a memory block for the code word table */
if (!ph) return JDR_MEM1; /* Err: not enough memory */
jd->huffcode[num][cls] = ph;
hc = 0;
for (j = i = 0; i < 16; i++) { /* Re-build huffman code word table */
b = pb[i];
while (b--) ph[j++] = hc++;
hc <<= 1;
}
if (ndata < np) return JDR_FMT1; /* Err: wrong data size */
ndata -= np;
pd = alloc_pool(jd, np); /* Allocate a memory block for the decoded data */
if (!pd) return JDR_MEM1; /* Err: not enough memory */
jd->huffdata[num][cls] = pd;
for (i = 0; i < np; i++) { /* Load decoded data corresponds to each code word */
d = *data++;
if (!cls && d > 11) return JDR_FMT1;
pd[i] = d;
}
#if JD_FASTDECODE == 2
{ /* Create fast huffman decode table */
unsigned int span, td, ti;
uint16_t *tbl_ac = 0;
uint8_t *tbl_dc = 0;
if (cls) {
tbl_ac = alloc_pool(jd, HUFF_LEN * sizeof (uint16_t)); /* LUT for AC elements */
if (!tbl_ac) return JDR_MEM1; /* Err: not enough memory */
jd->hufflut_ac[num] = tbl_ac;
memset(tbl_ac, 0xFF, HUFF_LEN * sizeof (uint16_t)); /* Default value (0xFFFF: may be long code) */
} else {
tbl_dc = alloc_pool(jd, HUFF_LEN * sizeof (uint8_t)); /* LUT for AC elements */
if (!tbl_dc) return JDR_MEM1; /* Err: not enough memory */
jd->hufflut_dc[num] = tbl_dc;
memset(tbl_dc, 0xFF, HUFF_LEN * sizeof (uint8_t)); /* Default value (0xFF: may be long code) */
}
for (i = b = 0; b < HUFF_BIT; b++) { /* Create LUT */
for (j = pb[b]; j; j--) {
ti = ph[i] << (HUFF_BIT - 1 - b) & HUFF_MASK; /* Index of input pattern for the code */
if (cls) {
td = pd[i++] | ((b + 1) << 8); /* b15..b8: code length, b7..b0: zero run and data length */
for (span = 1 << (HUFF_BIT - 1 - b); span; span--, tbl_ac[ti++] = (uint16_t)td) ;
} else {
td = pd[i++] | ((b + 1) << 4); /* b7..b4: code length, b3..b0: data length */
for (span = 1 << (HUFF_BIT - 1 - b); span; span--, tbl_dc[ti++] = (uint8_t)td) ;
}
}
}
jd->longofs[num][cls] = i; /* Code table offset for long code */
}
#endif
}
return JDR_OK;
}
/*-----------------------------------------------------------------------*/
/* Extract a huffman decoded data from input stream */
/*-----------------------------------------------------------------------*/
static int huffext ( /* >=0: decoded data, <0: error code */
JDEC* jd, /* Pointer to the decompressor object */
unsigned int id, /* Table ID (0:Y, 1:C) */
unsigned int cls /* Table class (0:DC, 1:AC) */
)
{
size_t dc = jd->dctr;
uint8_t *dp = jd->dptr;
unsigned int d, flg = 0;
#if JD_FASTDECODE == 0
uint8_t bm, nd, bl;
const uint8_t *hb = jd->huffbits[id][cls]; /* Bit distribution table */
const uint16_t *hc = jd->huffcode[id][cls]; /* Code word table */
const uint8_t *hd = jd->huffdata[id][cls]; /* Data table */
bm = jd->dbit; /* Bit mask to extract */
d = 0; bl = 16; /* Max code length */
do {
if (!bm) { /* Next byte? */
if (!dc) { /* No input data is available, re-fill input buffer */
dp = jd->inbuf; /* Top of input buffer */
dc = jd->infunc(jd, dp, JD_SZBUF);
if (!dc) return 0 - (int)JDR_INP; /* Err: read error or wrong stream termination */
} else {
dp++; /* Next data ptr */
}
dc--; /* Decrement number of available bytes */
if (flg) { /* In flag sequence? */
flg = 0; /* Exit flag sequence */
if (*dp != 0) return 0 - (int)JDR_FMT1; /* Err: unexpected flag is detected (may be collapted data) */
*dp = 0xFF; /* The flag is a data 0xFF */
} else {
if (*dp == 0xFF) { /* Is start of flag sequence? */
flg = 1; continue; /* Enter flag sequence, get trailing byte */
}
}
bm = 0x80; /* Read from MSB */
}
d <<= 1; /* Get a bit */
if (*dp & bm) d++;
bm >>= 1;
for (nd = *hb++; nd; nd--) { /* Search the code word in this bit length */
if (d == *hc++) { /* Matched? */
jd->dbit = bm; jd->dctr = dc; jd->dptr = dp;
return *hd; /* Return the decoded data */
}
hd++;
}
bl--;
} while (bl);
#else
const uint8_t *hb, *hd;
const uint16_t *hc;
unsigned int nc, bl, wbit = jd->dbit % 32;
uint32_t w = jd->wreg & ((1UL << wbit) - 1);
while (wbit < 16) { /* Prepare 16 bits into the working register */
if (jd->marker) {
d = 0xFF; /* Input stream has stalled for a marker. Generate stuff bits */
} else {
if (!dc) { /* Buffer empty, re-fill input buffer */
dp = jd->inbuf; /* Top of input buffer */
dc = jd->infunc(jd, dp, JD_SZBUF);
if (!dc) return 0 - (int)JDR_INP; /* Err: read error or wrong stream termination */
}
d = *dp++; dc--;
if (flg) { /* In flag sequence? */
flg = 0; /* Exit flag sequence */
if (d != 0) jd->marker = d; /* Not an escape of 0xFF but a marker */
d = 0xFF;
} else {
if (d == 0xFF) { /* Is start of flag sequence? */
flg = 1; continue; /* Enter flag sequence, get trailing byte */
}
}
}
w = w << 8 | d; /* Shift 8 bits in the working register */
wbit += 8;
}
jd->dctr = dc; jd->dptr = dp;
jd->wreg = w;
#if JD_FASTDECODE == 2
/* Table serch for the short codes */
d = (unsigned int)(w >> (wbit - HUFF_BIT)); /* Short code as table index */
if (cls) { /* AC element */
d = jd->hufflut_ac[id][d]; /* Table decode */
if (d != 0xFFFF) { /* It is done if hit in short code */
jd->dbit = wbit - (d >> 8); /* Snip the code length */
return d & 0xFF; /* b7..0: zero run and following data bits */
}
} else { /* DC element */
d = jd->hufflut_dc[id][d]; /* Table decode */
if (d != 0xFF) { /* It is done if hit in short code */
jd->dbit = wbit - (d >> 4); /* Snip the code length */
return d & 0xF; /* b3..0: following data bits */
}
}
/* Incremental serch for the codes longer than HUFF_BIT */
hb = jd->huffbits[id][cls] + HUFF_BIT; /* Bit distribution table */
hc = jd->huffcode[id][cls] + jd->longofs[id][cls]; /* Code word table */
hd = jd->huffdata[id][cls] + jd->longofs[id][cls]; /* Data table */
bl = HUFF_BIT + 1;
#else
/* Incremental serch for all codes */
hb = jd->huffbits[id][cls]; /* Bit distribution table */
hc = jd->huffcode[id][cls]; /* Code word table */
hd = jd->huffdata[id][cls]; /* Data table */
bl = 1;
#endif
for ( ; bl <= 16; bl++) { /* Incremental search */
nc = *hb++;
if (nc) {
d = w >> (wbit - bl);
do { /* Search the code word in this bit length */
if (d == *hc++) { /* Matched? */
jd->dbit = wbit - bl; /* Snip the huffman code */
return *hd; /* Return the decoded data */
}
hd++;
} while (--nc);
}
}
#endif
return 0 - (int)JDR_FMT1; /* Err: code not found (may be collapted data) */
}
/*-----------------------------------------------------------------------*/
/* Extract N bits from input stream */
/*-----------------------------------------------------------------------*/
static int bitext ( /* >=0: extracted data, <0: error code */
JDEC* jd, /* Pointer to the decompressor object */
unsigned int nbit /* Number of bits to extract (1 to 16) */
)
{
size_t dc = jd->dctr;
uint8_t *dp = jd->dptr;
unsigned int d, flg = 0;
#if JD_FASTDECODE == 0
uint8_t mbit = jd->dbit;
d = 0;
do {
if (!mbit) { /* Next byte? */
if (!dc) { /* No input data is available, re-fill input buffer */
dp = jd->inbuf; /* Top of input buffer */
dc = jd->infunc(jd, dp, JD_SZBUF);
if (!dc) return 0 - (int)JDR_INP; /* Err: read error or wrong stream termination */
} else {
dp++; /* Next data ptr */
}
dc--; /* Decrement number of available bytes */
if (flg) { /* In flag sequence? */
flg = 0; /* Exit flag sequence */
if (*dp != 0) return 0 - (int)JDR_FMT1; /* Err: unexpected flag is detected (may be collapted data) */
*dp = 0xFF; /* The flag is a data 0xFF */
} else {
if (*dp == 0xFF) { /* Is start of flag sequence? */
flg = 1; continue; /* Enter flag sequence */
}
}
mbit = 0x80; /* Read from MSB */
}
d <<= 1; /* Get a bit */
if (*dp & mbit) d |= 1;
mbit >>= 1;
nbit--;
} while (nbit);
jd->dbit = mbit; jd->dctr = dc; jd->dptr = dp;
return (int)d;
#else
unsigned int wbit = jd->dbit % 32;
uint32_t w = jd->wreg & ((1UL << wbit) - 1);
while (wbit < nbit) { /* Prepare nbit bits into the working register */
if (jd->marker) {
d = 0xFF; /* Input stream stalled, generate stuff bits */
} else {
if (!dc) { /* Buffer empty, re-fill input buffer */
dp = jd->inbuf; /* Top of input buffer */
dc = jd->infunc(jd, dp, JD_SZBUF);
if (!dc) return 0 - (int)JDR_INP; /* Err: read error or wrong stream termination */
}
d = *dp++; dc--;
if (flg) { /* In flag sequence? */
flg = 0; /* Exit flag sequence */
if (d != 0) jd->marker = d; /* Not an escape of 0xFF but a marker */
d = 0xFF;
} else {
if (d == 0xFF) { /* Is start of flag sequence? */
flg = 1; continue; /* Enter flag sequence, get trailing byte */
}
}
}
w = w << 8 | d; /* Get 8 bits into the working register */
wbit += 8;
}
jd->wreg = w; jd->dbit = wbit - nbit;
jd->dctr = dc; jd->dptr = dp;
return (int)(w >> ((wbit - nbit) % 32));
#endif
}
/*-----------------------------------------------------------------------*/
/* Process restart interval */
/*-----------------------------------------------------------------------*/
static JRESULT restart (
JDEC* jd, /* Pointer to the decompressor object */
uint16_t rstn /* Expected restert sequense number */
)
{
unsigned int i;
uint8_t *dp = jd->dptr;
size_t dc = jd->dctr;
#if JD_FASTDECODE == 0
uint16_t d = 0;
/* Get two bytes from the input stream */
for (i = 0; i < 2; i++) {
if (!dc) { /* No input data is available, re-fill input buffer */
dp = jd->inbuf;
dc = jd->infunc(jd, dp, JD_SZBUF);
if (!dc) return JDR_INP;
} else {
dp++;
}
dc--;
d = d << 8 | *dp; /* Get a byte */
}
jd->dptr = dp; jd->dctr = dc; jd->dbit = 0;
/* Check the marker */
if ((d & 0xFFD8) != 0xFFD0 || (d & 7) != (rstn & 7)) {
return JDR_FMT1; /* Err: expected RSTn marker is not detected (may be collapted data) */
}
#else
uint16_t marker;
if (jd->marker) { /* Generate a maker if it has been detected */
marker = 0xFF00 | jd->marker;
jd->marker = 0;
} else {
marker = 0;
for (i = 0; i < 2; i++) { /* Get a restart marker */
if (!dc) { /* No input data is available, re-fill input buffer */
dp = jd->inbuf;
dc = jd->infunc(jd, dp, JD_SZBUF);
if (!dc) return JDR_INP;
}
marker = (marker << 8) | *dp++; /* Get a byte */
dc--;
}
jd->dptr = dp; jd->dctr = dc;
}
/* Check the marker */
if ((marker & 0xFFD8) != 0xFFD0 || (marker & 7) != (rstn & 7)) {
return JDR_FMT1; /* Err: expected RSTn marker was not detected (may be collapted data) */
}
jd->dbit = 0; /* Discard stuff bits */
#endif
jd->dcv[2] = jd->dcv[1] = jd->dcv[0] = 0; /* Reset DC offset */
return JDR_OK;
}
/*-----------------------------------------------------------------------*/
/* Apply Inverse-DCT in Arai Algorithm (see also aa_idct.png) */
/*-----------------------------------------------------------------------*/
static void block_idct (
int32_t* src, /* Input block data (de-quantized and pre-scaled for Arai Algorithm) */
jd_yuv_t* dst /* Pointer to the destination to store the block as byte array */
)
{
const int32_t M13 = (int32_t)(1.41421*4096), M2 = (int32_t)(1.08239*4096), M4 = (int32_t)(2.61313*4096), M5 = (int32_t)(1.84776*4096);
int32_t v0, v1, v2, v3, v4, v5, v6, v7;
int32_t t10, t11, t12, t13;
int i;
/* Process columns */
for (i = 0; i < 8; i++) {
v0 = src[8 * 0]; /* Get even elements */
v1 = src[8 * 2];
v2 = src[8 * 4];
v3 = src[8 * 6];
t10 = v0 + v2; /* Process the even elements */
t12 = v0 - v2;
t11 = (v1 - v3) * M13 >> 12;
v3 += v1;
t11 -= v3;
v0 = t10 + v3;
v3 = t10 - v3;
v1 = t11 + t12;
v2 = t12 - t11;
v4 = src[8 * 7]; /* Get odd elements */
v5 = src[8 * 1];
v6 = src[8 * 5];
v7 = src[8 * 3];
t10 = v5 - v4; /* Process the odd elements */
t11 = v5 + v4;
t12 = v6 - v7;
v7 += v6;
v5 = (t11 - v7) * M13 >> 12;
v7 += t11;
t13 = (t10 + t12) * M5 >> 12;
v4 = t13 - (t10 * M2 >> 12);
v6 = t13 - (t12 * M4 >> 12) - v7;
v5 -= v6;
v4 -= v5;
src[8 * 0] = v0 + v7; /* Write-back transformed values */
src[8 * 7] = v0 - v7;
src[8 * 1] = v1 + v6;
src[8 * 6] = v1 - v6;
src[8 * 2] = v2 + v5;
src[8 * 5] = v2 - v5;
src[8 * 3] = v3 + v4;
src[8 * 4] = v3 - v4;
src++; /* Next column */
}
/* Process rows */
src -= 8;
for (i = 0; i < 8; i++) {
v0 = src[0] + (128L << 8); /* Get even elements (remove DC offset (-128) here) */
v1 = src[2];
v2 = src[4];
v3 = src[6];
t10 = v0 + v2; /* Process the even elements */
t12 = v0 - v2;
t11 = (v1 - v3) * M13 >> 12;
v3 += v1;
t11 -= v3;
v0 = t10 + v3;
v3 = t10 - v3;
v1 = t11 + t12;
v2 = t12 - t11;
v4 = src[7]; /* Get odd elements */
v5 = src[1];
v6 = src[5];
v7 = src[3];
t10 = v5 - v4; /* Process the odd elements */
t11 = v5 + v4;
t12 = v6 - v7;
v7 += v6;
v5 = (t11 - v7) * M13 >> 12;
v7 += t11;
t13 = (t10 + t12) * M5 >> 12;
v4 = t13 - (t10 * M2 >> 12);
v6 = t13 - (t12 * M4 >> 12) - v7;
v5 -= v6;
v4 -= v5;
/* Descale the transformed values 8 bits and output a row */
#if JD_FASTDECODE >= 1
dst[0] = (int16_t)((v0 + v7) >> 8);
dst[7] = (int16_t)((v0 - v7) >> 8);
dst[1] = (int16_t)((v1 + v6) >> 8);
dst[6] = (int16_t)((v1 - v6) >> 8);
dst[2] = (int16_t)((v2 + v5) >> 8);
dst[5] = (int16_t)((v2 - v5) >> 8);
dst[3] = (int16_t)((v3 + v4) >> 8);
dst[4] = (int16_t)((v3 - v4) >> 8);
#else
dst[0] = BYTECLIP((v0 + v7) >> 8);
dst[7] = BYTECLIP((v0 - v7) >> 8);
dst[1] = BYTECLIP((v1 + v6) >> 8);
dst[6] = BYTECLIP((v1 - v6) >> 8);
dst[2] = BYTECLIP((v2 + v5) >> 8);
dst[5] = BYTECLIP((v2 - v5) >> 8);
dst[3] = BYTECLIP((v3 + v4) >> 8);
dst[4] = BYTECLIP((v3 - v4) >> 8);
#endif
dst += 8; src += 8; /* Next row */
}
}
/*-----------------------------------------------------------------------*/
/* Load all blocks in an MCU into working buffer */
/*-----------------------------------------------------------------------*/
static JRESULT mcu_load (
JDEC* jd /* Pointer to the decompressor object */
)
{
int32_t *tmp = (int32_t*)jd->workbuf; /* Block working buffer for de-quantize and IDCT */
int d, e;
unsigned int blk, nby, i, bc, z, id, cmp;
jd_yuv_t *bp;
const int32_t *dqf;
nby = jd->msx * jd->msy; /* Number of Y blocks (1, 2 or 4) */
bp = jd->mcubuf; /* Pointer to the first block of MCU */
for (blk = 0; blk < nby + 2; blk++) { /* Get nby Y blocks and two C blocks */
cmp = (blk < nby) ? 0 : blk - nby + 1; /* Component number 0:Y, 1:Cb, 2:Cr */
if (cmp && jd->ncomp != 3) { /* Clear C blocks if not exist (monochrome image) */
for (i = 0; i < 64; bp[i++] = 128) ;
} else { /* Load Y/C blocks from input stream */
id = cmp ? 1 : 0; /* Huffman table ID of this component */
/* Extract a DC element from input stream */
d = huffext(jd, id, 0); /* Extract a huffman coded data (bit length) */
if (d < 0) return (JRESULT)(0 - d); /* Err: invalid code or input */
bc = (unsigned int)d;
d = jd->dcv[cmp]; /* DC value of previous block */
if (bc) { /* If there is any difference from previous block */
e = bitext(jd, bc); /* Extract data bits */
if (e < 0) return (JRESULT)(0 - e); /* Err: input */
bc = 1 << (bc - 1); /* MSB position */
if (!(e & bc)) e -= (bc << 1) - 1; /* Restore negative value if needed */
d += e; /* Get current value */
jd->dcv[cmp] = (int16_t)d; /* Save current DC value for next block */
}
dqf = jd->qttbl[jd->qtid[cmp]]; /* De-quantizer table ID for this component */
tmp[0] = d * dqf[0] >> 8; /* De-quantize, apply scale factor of Arai algorithm and descale 8 bits */
/* Extract following 63 AC elements from input stream */
memset(&tmp[1], 0, 63 * sizeof (int32_t)); /* Initialize all AC elements */
z = 1; /* Top of the AC elements (in zigzag-order) */
do {
d = huffext(jd, id, 1); /* Extract a huffman coded value (zero runs and bit length) */
if (d == 0) break; /* EOB? */
if (d < 0) return (JRESULT)(0 - d); /* Err: invalid code or input error */
bc = (unsigned int)d;
z += bc >> 4; /* Skip leading zero run */
if (z >= 64) return JDR_FMT1; /* Too long zero run */
if (bc &= 0x0F) { /* Bit length? */
d = bitext(jd, bc); /* Extract data bits */
if (d < 0) return (JRESULT)(0 - d); /* Err: input device */
bc = 1 << (bc - 1); /* MSB position */
if (!(d & bc)) d -= (bc << 1) - 1; /* Restore negative value if needed */
i = Zig[z]; /* Get raster-order index */
tmp[i] = d * dqf[i] >> 8; /* De-quantize, apply scale factor of Arai algorithm and descale 8 bits */
}
} while (++z < 64); /* Next AC element */
if (JD_FORMAT != 2 || !cmp) { /* C components may not be processed if in grayscale output */
if (z == 1 || (JD_USE_SCALE && jd->scale == 3)) { /* If no AC element or scale ratio is 1/8, IDCT can be ommited and the block is filled with DC value */
d = (jd_yuv_t)((*tmp / 256) + 128);
if (JD_FASTDECODE >= 1) {
for (i = 0; i < 64; bp[i++] = d) ;
} else {
memset(bp, d, 64);
}
} else {
block_idct(tmp, bp); /* Apply IDCT and store the block to the MCU buffer */
}
}
}
bp += 64; /* Next block */
}
return JDR_OK; /* All blocks have been loaded successfully */
}
/*-----------------------------------------------------------------------*/
/* Output an MCU: Convert YCrCb to RGB and output it in RGB form */
/*-----------------------------------------------------------------------*/
static JRESULT mcu_output (
JDEC* jd, /* Pointer to the decompressor object */
int (*outfunc)(JDEC*, void*, JRECT*), /* RGB output function */
unsigned int x, /* MCU location in the image */
unsigned int y /* MCU location in the image */
)
{
const int CVACC = (sizeof (int) > 2) ? 1024 : 128; /* Adaptive accuracy for both 16-/32-bit systems */
unsigned int ix, iy, mx, my, rx, ry;
int yy, cb, cr;
jd_yuv_t *py, *pc;
uint8_t *pix;
JRECT rect;
mx = jd->msx * 8; my = jd->msy * 8; /* MCU size (pixel) */
rx = (x + mx <= jd->width) ? mx : jd->width - x; /* Output rectangular size (it may be clipped at right/bottom end of image) */
ry = (y + my <= jd->height) ? my : jd->height - y;
if (JD_USE_SCALE) {
rx >>= jd->scale; ry >>= jd->scale;
if (!rx || !ry) return JDR_OK; /* Skip this MCU if all pixel is to be rounded off */
x >>= jd->scale; y >>= jd->scale;
}
rect.left = x; rect.right = x + rx - 1; /* Rectangular area in the frame buffer */
rect.top = y; rect.bottom = y + ry - 1;
if (!JD_USE_SCALE || jd->scale != 3) { /* Not for 1/8 scaling */
pix = (uint8_t*)jd->workbuf;
if (JD_FORMAT != 2) { /* RGB output (build an RGB MCU from Y/C component) */
for (iy = 0; iy < my; iy++) {
pc = py = jd->mcubuf;
if (my == 16) { /* Double block height? */
pc += 64 * 4 + (iy >> 1) * 8;
if (iy >= 8) py += 64;
} else { /* Single block height */
pc += mx * 8 + iy * 8;
}
py += iy * 8;
for (ix = 0; ix < mx; ix++) {
cb = pc[0] - 128; /* Get Cb/Cr component and remove offset */
cr = pc[64] - 128;
if (mx == 16) { /* Double block width? */
if (ix == 8) py += 64 - 8; /* Jump to next block if double block heigt */
pc += ix & 1; /* Step forward chroma pointer every two pixels */
} else { /* Single block width */
pc++; /* Step forward chroma pointer every pixel */
}
yy = *py++; /* Get Y component */
*pix++ = /*R*/ BYTECLIP(yy + ((int)(1.402 * CVACC) * cr) / CVACC);
*pix++ = /*G*/ BYTECLIP(yy - ((int)(0.344 * CVACC) * cb + (int)(0.714 * CVACC) * cr) / CVACC);
*pix++ = /*B*/ BYTECLIP(yy + ((int)(1.772 * CVACC) * cb) / CVACC);
}
}
} else { /* Monochrome output (build a grayscale MCU from Y comopnent) */
for (iy = 0; iy < my; iy++) {
py = jd->mcubuf + iy * 8;
if (my == 16) { /* Double block height? */
if (iy >= 8) py += 64;
}
for (ix = 0; ix < mx; ix++) {
if (mx == 16) { /* Double block width? */
if (ix == 8) py += 64 - 8; /* Jump to next block if double block height */
}
*pix++ = (uint8_t)*py++; /* Get and store a Y value as grayscale */
}
}
}
/* Descale the MCU rectangular if needed */
if (JD_USE_SCALE && jd->scale) {
unsigned int x, y, r, g, b, s, w, a;
uint8_t *op;
/* Get averaged RGB value of each square correcponds to a pixel */
s = jd->scale * 2; /* Number of shifts for averaging */
w = 1 << jd->scale; /* Width of square */
a = (mx - w) * (JD_FORMAT != 2 ? 3 : 1); /* Bytes to skip for next line in the square */
op = (uint8_t*)jd->workbuf;
for (iy = 0; iy < my; iy += w) {
for (ix = 0; ix < mx; ix += w) {
pix = (uint8_t*)jd->workbuf + (iy * mx + ix) * (JD_FORMAT != 2 ? 3 : 1);
r = g = b = 0;
for (y = 0; y < w; y++) { /* Accumulate RGB value in the square */
for (x = 0; x < w; x++) {
r += *pix++; /* Accumulate R or Y (monochrome output) */
if (JD_FORMAT != 2) { /* RGB output? */
g += *pix++; /* Accumulate G */
b += *pix++; /* Accumulate B */
}
}
pix += a;
} /* Put the averaged pixel value */
*op++ = (uint8_t)(r >> s); /* Put R or Y (monochrome output) */
if (JD_FORMAT != 2) { /* RGB output? */
*op++ = (uint8_t)(g >> s); /* Put G */
*op++ = (uint8_t)(b >> s); /* Put B */
}
}
}
}
} else { /* For only 1/8 scaling (left-top pixel in each block are the DC value of the block) */
/* Build a 1/8 descaled RGB MCU from discrete comopnents */
pix = (uint8_t*)jd->workbuf;
pc = jd->mcubuf + mx * my;
cb = pc[0] - 128; /* Get Cb/Cr component and restore right level */
cr = pc[64] - 128;
for (iy = 0; iy < my; iy += 8) {
py = jd->mcubuf;
if (iy == 8) py += 64 * 2;
for (ix = 0; ix < mx; ix += 8) {
yy = *py; /* Get Y component */
py += 64;
if (JD_FORMAT != 2) {
*pix++ = /*R*/ BYTECLIP(yy + ((int)(1.402 * CVACC) * cr / CVACC));
*pix++ = /*G*/ BYTECLIP(yy - ((int)(0.344 * CVACC) * cb + (int)(0.714 * CVACC) * cr) / CVACC);
*pix++ = /*B*/ BYTECLIP(yy + ((int)(1.772 * CVACC) * cb / CVACC));
} else {
*pix++ = yy;
}
}
}
}
/* Squeeze up pixel table if a part of MCU is to be truncated */
mx >>= jd->scale;
if (rx < mx) { /* Is the MCU spans rigit edge? */
uint8_t *s, *d;
unsigned int x, y;
s = d = (uint8_t*)jd->workbuf;
for (y = 0; y < ry; y++) {
for (x = 0; x < rx; x++) { /* Copy effective pixels */
*d++ = *s++;
if (JD_FORMAT != 2) {
*d++ = *s++;
*d++ = *s++;
}
}
s += (mx - rx) * (JD_FORMAT != 2 ? 3 : 1); /* Skip truncated pixels */
}
}
/* Convert RGB888 to RGB565 if needed */
if (JD_FORMAT == 1) {
uint8_t *s = (uint8_t*)jd->workbuf;
uint16_t w, *d = (uint16_t*)s;
unsigned int n = rx * ry;
do {
w = (*s++ & 0xF8) << 8; /* RRRRR----------- */
w |= (*s++ & 0xFC) << 3; /* -----GGGGGG----- */
w |= *s++ >> 3; /* -----------BBBBB */
*d++ = w;
} while (--n);
}
/* Output the rectangular */
return outfunc(jd, jd->workbuf, &rect) ? JDR_OK : JDR_INTR;
}
/*-----------------------------------------------------------------------*/
/* Analyze the JPEG image and Initialize decompressor object */
/*-----------------------------------------------------------------------*/
#define LDB_WORD(ptr) (uint16_t)(((uint16_t)*((uint8_t*)(ptr))<<8)|(uint16_t)*(uint8_t*)((ptr)+1))
JRESULT jd_prepare (
JDEC* jd, /* Blank decompressor object */
size_t (*infunc)(JDEC*, uint8_t*, size_t), /* JPEG strem input function */
void* pool, /* Working buffer for the decompression session */
size_t sz_pool, /* Size of working buffer */
void* dev /* I/O device identifier for the session */
)
{
uint8_t *seg, b;
uint16_t marker;
unsigned int n, i, ofs;
size_t len;
JRESULT rc;
memset(jd, 0, sizeof (JDEC)); /* Clear decompression object (this might be a problem if machine's null pointer is not all bits zero) */
jd->pool = pool; /* Work memroy */
jd->sz_pool = sz_pool; /* Size of given work memory */
jd->infunc = infunc; /* Stream input function */
jd->device = dev; /* I/O device identifier */
jd->inbuf = seg = alloc_pool(jd, JD_SZBUF); /* Allocate stream input buffer */
if (!seg) return JDR_MEM1;
ofs = marker = 0; /* Find SOI marker */
do {
if (jd->infunc(jd, seg, 1) != 1) return JDR_INP; /* Err: SOI was not detected */
ofs++;
marker = marker << 8 | seg[0];
} while (marker != 0xFFD8);
for (;;) { /* Parse JPEG segments */
/* Get a JPEG marker */
if (jd->infunc(jd, seg, 4) != 4) return JDR_INP;
marker = LDB_WORD(seg); /* Marker */
len = LDB_WORD(seg + 2); /* Length field */
if (len <= 2 || (marker >> 8) != 0xFF) return JDR_FMT1;
len -= 2; /* Segent content size */
ofs += 4 + len; /* Number of bytes loaded */