// jpgd.cpp - C++ class for JPEG decompression.
// Public domain, Rich Geldreich <richgel99@gmail.com>
// Alex Evans: Linear memory allocator (taken from jpge.h).
// v1.04, May. 19, 2012: Code tweaks to fix VS2008 static code analysis warnings (all looked harmless)
//
// Supports progressive and baseline sequential JPEG image files, and the most common chroma subsampling factors: Y, H1V1, H2V1, H1V2, and H2V2.
//
// Chroma upsampling quality: H2V2 is upsampled in the frequency domain, H2V1 and H1V2 are upsampled using point sampling.
// Chroma upsampling reference: "Fast Scheme for Image Size Change in the Compressed Domain"
// http://vision.ai.uiuc.edu/~dugad/research/dct/index.html
#include "jpgd.h"
#include <string.h>
#include <assert.h>
#define JPGD_ASSERT(x) assert(x)
#ifdef _MSC_VER
#pragma warning (disable : 4611) // warning C4611: interaction between '_setjmp' and C++ object destruction is non-portable
#endif
// Set to 1 to enable freq. domain chroma upsampling on images using H2V2 subsampling (0=faster nearest neighbor sampling).
// This is slower, but results in higher quality on images with highly saturated colors.
#define JPGD_SUPPORT_FREQ_DOMAIN_UPSAMPLING 1
#define JPGD_TRUE (1)
#define JPGD_FALSE (0)
#define JPGD_MAX(a,b) (((a)>(b)) ? (a) : (b))
#define JPGD_MIN(a,b) (((a)<(b)) ? (a) : (b))
namespace jpgd {
static inline void *jpgd_malloc(size_t nSize) { return malloc(nSize); }
static inline void jpgd_free(void *p) { free(p); }
// DCT coefficients are stored in this sequence.
static int g_ZAG[64] = { 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 };
enum JPEG_MARKER
{
M_SOF0 = 0xC0, M_SOF1 = 0xC1, M_SOF2 = 0xC2, M_SOF3 = 0xC3, M_SOF5 = 0xC5, M_SOF6 = 0xC6, M_SOF7 = 0xC7, M_JPG = 0xC8,
M_SOF9 = 0xC9, M_SOF10 = 0xCA, M_SOF11 = 0xCB, M_SOF13 = 0xCD, M_SOF14 = 0xCE, M_SOF15 = 0xCF, M_DHT = 0xC4, M_DAC = 0xCC,
M_RST0 = 0xD0, M_RST1 = 0xD1, M_RST2 = 0xD2, M_RST3 = 0xD3, M_RST4 = 0xD4, M_RST5 = 0xD5, M_RST6 = 0xD6, M_RST7 = 0xD7,
M_SOI = 0xD8, M_EOI = 0xD9, M_SOS = 0xDA, M_DQT = 0xDB, M_DNL = 0xDC, M_DRI = 0xDD, M_DHP = 0xDE, M_EXP = 0xDF,
M_APP0 = 0xE0, M_APP15 = 0xEF, M_JPG0 = 0xF0, M_JPG13 = 0xFD, M_COM = 0xFE, M_TEM = 0x01, M_ERROR = 0x100, RST0 = 0xD0
};
enum JPEG_SUBSAMPLING { JPGD_GRAYSCALE = 0, JPGD_YH1V1, JPGD_YH2V1, JPGD_YH1V2, JPGD_YH2V2 };
#define CONST_BITS 13
#define PASS1_BITS 2
#define SCALEDONE ((int32)1)
#define FIX_0_298631336 ((int32)2446) /* FIX(0.298631336) */
#define FIX_0_390180644 ((int32)3196) /* FIX(0.390180644) */
#define FIX_0_541196100 ((int32)4433) /* FIX(0.541196100) */
#define FIX_0_765366865 ((int32)6270) /* FIX(0.765366865) */
#define FIX_0_899976223 ((int32)7373) /* FIX(0.899976223) */
#define FIX_1_175875602 ((int32)9633) /* FIX(1.175875602) */
#define FIX_1_501321110 ((int32)12299) /* FIX(1.501321110) */
#define FIX_1_847759065 ((int32)15137) /* FIX(1.847759065) */
#define FIX_1_961570560 ((int32)16069) /* FIX(1.961570560) */
#define FIX_2_053119869 ((int32)16819) /* FIX(2.053119869) */
#define FIX_2_562915447 ((int32)20995) /* FIX(2.562915447) */
#define FIX_3_072711026 ((int32)25172) /* FIX(3.072711026) */
#define DESCALE(x,n) (((x) + (SCALEDONE << ((n)-1))) >> (n))
#define DESCALE_ZEROSHIFT(x,n) (((x) + (128 << (n)) + (SCALEDONE << ((n)-1))) >> (n))
#define MULTIPLY(var, cnst) ((var) * (cnst))
#define CLAMP(i) ((static_cast<uint>(i) > 255) ? (((~i) >> 31) & 0xFF) : (i))
static const char *err_reason;
// Compiler creates a fast path 1D IDCT for X non-zero columns
template <int NONZERO_COLS>
struct Row
{
static void idct(int* pTemp, const jpgd_block_t* pSrc)
{
// ACCESS_COL() will be optimized at compile time to either an array access, or 0.
#define ACCESS_COL(x) (((x) < NONZERO_COLS) ? (int)pSrc[x] : 0)
const int z2 = ACCESS_COL(2), z3 = ACCESS_COL(6);
const int z1 = MULTIPLY(z2 + z3, FIX_0_541196100);
const int tmp2 = z1 + MULTIPLY(z3, - FIX_1_847759065);
const int tmp3 = z1 + MULTIPLY(z2, FIX_0_765366865);
const int tmp0 = (ACCESS_COL(0) + ACCESS_COL(4)) << CONST_BITS;
const int tmp1 = (ACCESS_COL(0) - ACCESS_COL(4)) << CONST_BITS;
const int tmp10 = tmp0 + tmp3, tmp13 = tmp0 - tmp3, tmp11 = tmp1 + tmp2, tmp12 = tmp1 - tmp2;
const int atmp0 = ACCESS_COL(7), atmp1 = ACCESS_COL(5), atmp2 = ACCESS_COL(3), atmp3 = ACCESS_COL(1);
const int bz1 = atmp0 + atmp3, bz2 = atmp1 + atmp2, bz3 = atmp0 + atmp2, bz4 = atmp1 + atmp3;
const int bz5 = MULTIPLY(bz3 + bz4, FIX_1_175875602);
const int az1 = MULTIPLY(bz1, - FIX_0_899976223);
const int az2 = MULTIPLY(bz2, - FIX_2_562915447);
const int az3 = MULTIPLY(bz3, - FIX_1_961570560) + bz5;
const int az4 = MULTIPLY(bz4, - FIX_0_390180644) + bz5;
const int btmp0 = MULTIPLY(atmp0, FIX_0_298631336) + az1 + az3;
const int btmp1 = MULTIPLY(atmp1, FIX_2_053119869) + az2 + az4;
const int btmp2 = MULTIPLY(atmp2, FIX_3_072711026) + az2 + az3;
const int btmp3 = MULTIPLY(atmp3, FIX_1_501321110) + az1 + az4;
pTemp[0] = DESCALE(tmp10 + btmp3, CONST_BITS-PASS1_BITS);
pTemp[7] = DESCALE(tmp10 - btmp3, CONST_BITS-PASS1_BITS);
pTemp[1] = DESCALE(tmp11 + btmp2, CONST_BITS-PASS1_BITS);
pTemp[6] = DESCALE(tmp11 - btmp2, CONST_BITS-PASS1_BITS);
pTemp[2] = DESCALE(tmp12 + btmp1, CONST_BITS-PASS1_BITS);
pTemp[5] = DESCALE(tmp12 - btmp1, CONST_BITS-PASS1_BITS);
pTemp[3] = DESCALE(tmp13 + btmp0, CONST_BITS-PASS1_BITS);
pTemp[4] = DESCALE(tmp13 - btmp0, CONST_BITS-PASS1_BITS);
}
};
template <>
struct Row<0>
{
static void idct(int* pTemp, const jpgd_block_t* pSrc)
{
#ifdef _MSC_VER
pTemp; pSrc;
#endif
}
};
template <>
struct Row<1>
{
static void idct(int* pTemp, const jpgd_block_t* pSrc)
{
const int dcval = (pSrc[0] << PASS1_BITS);
pTemp[0] = dcval;
pTemp[1] = dcval;
pTemp[2] = dcval;
pTemp[3] = dcval;
pTemp[4] = dcval;
pTemp[5] = dcval;
pTemp[6] = dcval;
pTemp[7] = dcval;
}
};
// Compiler creates a fast path 1D IDCT for X non-zero rows
template <int NONZERO_ROWS>
struct Col
{
static void idct(uint8* pDst_ptr, const int* pTemp)
{
// ACCESS_ROW() will be optimized at compile time to either an array access, or 0.
#define ACCESS_ROW(x) (((x) < NONZERO_ROWS) ? pTemp[x * 8] : 0)
const int z2 = ACCESS_ROW(2);
const int z3 = ACCESS_ROW(6);
const int z1 = MULTIPLY(z2 + z3, FIX_0_541196100);
const int tmp2 = z1 + MULTIPLY(z3, - FIX_1_847759065);
const int tmp3 = z1 + MULTIPLY(z2, FIX_0_765366865);
const int tmp0 = (ACCESS_ROW(0) + ACCESS_ROW(4)) << CONST_BITS;
const int tmp1 = (ACCESS_ROW(0) - ACCESS_ROW(4)) << CONST_BITS;
const int tmp10 = tmp0 + tmp3, tmp13 = tmp0 - tmp3, tmp11 = tmp1 + tmp2, tmp12 = tmp1 - tmp2;
const int atmp0 = ACCESS_ROW(7), atmp1 = ACCESS_ROW(5), atmp2 = ACCESS_ROW(3), atmp3 = ACCESS_ROW(1);
const int bz1 = atmp0 + atmp3, bz2 = atmp1 + atmp2, bz3 = atmp0 + atmp2, bz4 = atmp1 + atmp3;
const int bz5 = MULTIPLY(bz3 + bz4, FIX_1_175875602);
const int az1 = MULTIPLY(bz1, - FIX_0_899976223);
const int az2 = MULTIPLY(bz2, - FIX_2_562915447);
const int az3 = MULTIPLY(bz3, - FIX_1_961570560) + bz5;
const int az4 = MULTIPLY(bz4, - FIX_0_390180644) + bz5;
const int btmp0 = MULTIPLY(atmp0, FIX_0_298631336) + az1 + az3;
const int btmp1 = MULTIPLY(atmp1, FIX_2_053119869) + az2 + az4;
const int btmp2 = MULTIPLY(atmp2, FIX_3_072711026) + az2 + az3;
const int btmp3 = MULTIPLY(atmp3, FIX_1_501321110) + az1 + az4;
int i = DESCALE_ZEROSHIFT(tmp10 + btmp3, CONST_BITS+PASS1_BITS+3);
pDst_ptr[8*0] = (uint8)CLAMP(i);
i = DESCALE_ZEROSHIFT(tmp10 - btmp3, CONST_BITS+PASS1_BITS+3);
pDst_ptr[8*7] = (uint8)CLAMP(i);
i = DESCALE_ZEROSHIFT(tmp11 + btmp2, CONST_BITS+PASS1_BITS+3);
pDst_ptr[8*1] = (uint8)CLAMP(i);
i = DESCALE_ZEROSHIFT(tmp11 - btmp2, CONST_BITS+PASS1_BITS+3);
pDst_ptr[8*6] = (uint8)CLAMP(i);
i = DESCALE_ZEROSHIFT(tmp12 + btmp1, CONST_BITS+PASS1_BITS+3);
pDst_ptr[8*2] = (uint8)CLAMP(i);
i = DESCALE_ZEROSHIFT(tmp12 - btmp1, CONST_BITS+PASS1_BITS+3);
pDst_ptr[8*5] = (uint8)CLAMP(i);
i = DESCALE_ZEROSHIFT(tmp13 + btmp0, CONST_BITS+PASS1_BITS+3);
pDst_ptr[8*3] = (uint8)CLAMP(i);
i = DESCALE_ZEROSHIFT(tmp13 - btmp0, CONST_BITS+PASS1_BITS+3);
pDst_ptr[8*4] = (uint8)CLAMP(i);
}
};
template <>
struct Col<1>
{
static void idct(uint8* pDst_ptr, const int* pTemp)
{
int dcval = DESCALE_ZEROSHIFT(pTemp[0], PASS1_BITS+3);
const uint8 dcval_clamped = (uint8)CLAMP(dcval);
pDst_ptr[0*8] = dcval_clamped;
pDst_ptr[1*8] = dcval_clamped;
pDst_ptr[2*8] = dcval_clamped;
pDst_ptr[3*8] = dcval_clamped;
pDst_ptr[4*8] = dcval_clamped;
pDst_ptr[5*8] = dcval_clamped;
pDst_ptr[6*8] = dcval_clamped;
pDst_ptr[7*8] = dcval_clamped;
}
};
static const uint8 s_idct_row_table[] =
{
1,0,0,0,0,0,0,0, 2,0,0,0,0,0,0,0, 2,1,0,0,0,0,0,0, 2,1,1,0,0,0,0,0, 2,2,1,0,0,0,0,0, 3,2,1,0,0,0,0,0, 4,2,1,0,0,0,0,0, 4,3,1,0,0,0,0,0,
4,3,2,0,0,0,0,0, 4,3,2,1,0,0,0,0, 4,3,2,1,1,0,0,0, 4,3,2,2,1,0,0,0, 4,3,3,2,1,0,0,0, 4,4,3,2,1,0,0,0, 5,4,3,2,1,0,0,0, 6,4,3,2,1,0,0,0,
6,5,3,2,1,0,0,0, 6,5,4,2,1,0,0,0, 6,5,4,3,1,0,0,0, 6,5,4,3,2,0,0,0, 6,5,4,3,2,1,0,0, 6,5,4,3,2,1,1,0, 6,5,4,3,2,2,1,0, 6,5,4,3,3,2,1,0,
6,5,4,4,3,2,1,0, 6,5,5,4,3,2,1,0, 6,6,5,4,3,2,1,0, 7,6,5,4,3,2,1,0, 8,6,5,4,3,2,1,0, 8,7,5,4,3,2,1,0, 8,7,6,4,3,2,1,0, 8,7,6,5,3,2,1,0,
8,7,6,5,4,2,1,0, 8,7,6,5,4,3,1,0, 8,7,6,5,4,3,2,0, 8,7,6,5,4,3,2,1, 8,7,6,5,4,3,2,2, 8,7,6,5,4,3,3,2, 8,7,6,5,4,4,3,2, 8,7,6,5,5,4,3,2,
8,7,6,6,5,4,3,2, 8,7,7,6,5,4,3,2, 8,8,7,6,5,4,3,2, 8,8,8,6,5,4,3,2, 8,8,8,7,5,4,3,2, 8,8,8,7,6,4,3,2, 8,8,8,7,6,5,3,2, 8,8,8,7,6,5,4,2,
8,8,8,7,6,5,4,3, 8,8,8,7,6,5,4,4, 8,8,8,7,6,5,5,4, 8,8,8,7,6,6,5,4, 8,8,8,7,7,6,5,4, 8,8,8,8,7,6,5,4, 8,8,8,8,8,6,5,4, 8,8,8,8,8,7,5,4,
8,8,8,8,8,7,6,4, 8,8,8,8,8,7,6,5, 8,8,8,8,8,7,6,6, 8,8,8,8,8,7,7,6, 8,8,8,8,8,8,7,6, 8,8,8,8,8,8,8,6, 8,8,8,8,8,8,8,7, 8,8,8,8,8,8,8,8,
};
static const uint8 s_idct_col_table[] = { 1, 1, 2, 3, 3, 3, 3, 3, 3, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 };
void idct(const jpgd_block_t* pSrc_ptr, uint8* pDst_ptr, int block_max_zag)
{
JPGD_ASSERT(block_max_zag >= 1);
JPGD_ASSERT(block_max_zag <= 64);
if (block_max_zag <= 1)
{
int k = ((pSrc_ptr[0] + 4) >> 3) + 128;
k = CLAMP(k);
k = k | (k<<8);
k = k | (k<<16);
for (int i = 8; i > 0; i--)
{
*(int*)&pDst_ptr[0] = k;
*(int*)&pDst_ptr[4] = k;
pDst_ptr += 8;
}
return;
}
int temp[64];
const jpgd_block_t* pSrc = pSrc_ptr;
int* pTemp = temp;
const uint8* pRow_tab = &s_idct_row_table[(block_max_zag - 1) * 8];
int i;
for (i = 8; i > 0; i--, pRow_tab++)
{
switch (*pRow_tab)
{
case 0: Row<0>::idct(pTemp, pSrc); break;
case 1: Row<1>::idct(pTemp, pSrc); break;
case 2: Row<2>::idct(pTemp, pSrc); break;
case 3: Row<3>::idct(pTemp, pSrc); break;
case 4: Row<4>::idct(pTemp, pSrc); break;
case 5: Row<5>::idct(pTemp, pSrc); break;
case 6: Row<6>::idct(pTemp, pSrc); break;
case 7: Row<7>::idct(pTemp, pSrc); break;
case 8: Row<8>::idct(pTemp, pSrc); break;
}
pSrc += 8;
pTemp += 8;
}
pTemp = temp;
const int nonzero_rows = s_idct_col_table[block_max_zag - 1];
for (i = 8; i > 0; i--)
{
switch (nonzero_rows)
{
case 1: Col<1>::idct(pDst_ptr, pTemp); break;
case 2: Col<2>::idct(pDst_ptr, pTemp); break;
case 3: Col<3>::idct(pDst_ptr, pTemp); break;
case 4: Col<4>::idct(pDst_ptr, pTemp); break;
case 5: Col<5>::idct(pDst_ptr, pTemp); break;
case 6: Col<6>::idct(pDst_ptr, pTemp); break;
case 7: Col<7>::idct(pDst_ptr, pTemp); break;
case 8: Col<8>::idct(pDst_ptr, pTemp); break;
}
pTemp++;
pDst_ptr++;
}
}
void idct_4x4(const jpgd_block_t* pSrc_ptr, uint8* pDst_ptr)
{
int temp[64];
int* pTemp = temp;
const jpgd_block_t* pSrc = pSrc_ptr;
for (int i = 4; i > 0; i--)
{
Row<4>::idct(pTemp, pSrc);
pSrc += 8;
pTemp += 8;
}
pTemp = temp;
for (int i = 8; i > 0; i--)
{
Col<4>::idct(pDst_ptr, pTemp);
pTemp++;
pDst_ptr++;
}
}
// Retrieve one character from the input stream.
inline uint jpeg_decoder::get_char()
{
// Any bytes remaining in buffer?
if (!m_in_buf_left)
{
// Try to get more bytes.
prep_in_buffer();
// Still nothing to get?
if (!m_in_buf_left)
{
// Pad the end of the stream with 0xFF 0xD9 (EOI marker)
int t = m_tem_flag;
m_tem_flag ^= 1;
if (t)
return 0xD9;
else
return 0xFF;
}
}
uint c = *m_pIn_buf_ofs++;
m_in_buf_left--;
return c;
}
// Same as previous method, except can indicate if the character is a pad character or not.
inline uint jpeg_decoder::get_char(bool *pPadding_flag)
{
if (!m_in_buf_left)
{
prep_in_buffer();
if (!m_in_buf_left)
{
*pPadding_flag = true;
int t = m_tem_flag;
m_tem_flag ^= 1;
if (t)
return 0xD9;
else
return 0xFF;
}
}
*pPadding_flag = false;
uint c = *m_pIn_buf_ofs++;
m_in_buf_left--;
return c;
}
// Inserts a previously retrieved character back into the input buffer.
inline void jpeg_decoder::stuff_char(uint8 q)
{
*(--m_pIn_buf_ofs) = q;
m_in_buf_left++;
}
// Retrieves one character from the input stream, but does not read past markers. Will continue to return 0xFF when a marker is encountered.
inline uint8 jpeg_decoder::get_octet()
{
bool padding_flag;
int c = get_char(&padding_flag);
if (c == 0xFF)
{
if (padding_flag)
return 0xFF;
c = get_char(&padding_flag);
if (padding_flag)
{
stuff_char(0xFF);
return 0xFF;
}
if (c == 0x00)
return 0xFF;
else
{
stuff_char(static_cast<uint8>(c));
stuff_char(0xFF);
return 0xFF;
}
}
return static_cast<uint8>(c);
}
// Retrieves a variable number of bits from the input stream. Does not recognize markers.
inline uint jpeg_decoder::get_bits(int num_bits)
{
if (!num_bits)
return 0;
uint i = m_bit_buf >> (32 - num_bits);
if ((m_bits_left -= num_bits) <= 0)
{
m_bit_buf <<= (num_bits += m_bits_left);
uint c1 = get_char();
uint c2 = get_char();
m_bit_buf = (m_bit_buf & 0xFFFF0000) | (c1 << 8) | c2;
m_bit_buf <<= -m_bits_left;
m_bits_left += 16;
JPGD_ASSERT(m_bits_left >= 0);
}
else
m_bit_buf <<= num_bits;
return i;
}
// Retrieves a variable number of bits from the input stream. Markers will not be read into the input bit buffer. Instead, an infinite number of all 1's will be returned when a marker is encountered.
inline uint jpeg_decoder::get_bits_no_markers(int num_bits)
{
if (!num_bits)
return 0;
uint i = m_bit_buf >> (32 - num_bits);
if ((m_bits_left -= num_bits) <= 0)
{
m_bit_buf <<= (num_bits += m_bits_left);
if ((m_in_buf_left < 2) || (m_pIn_buf_ofs[0] == 0xFF) || (m_pIn_buf_ofs[1] == 0xFF))
{
uint c1 = get_octet();
uint c2 = get_octet();
m_bit_buf |= (c1 << 8) | c2;
}
else
{
m_bit_buf |= ((uint)m_pIn_buf_ofs[0] << 8) | m_pIn_buf_ofs[1];
m_in_buf_left -= 2;
m_pIn_buf_ofs += 2;
}
m_bit_buf <<= -m_bits_left;
m_bits_left += 16;
JPGD_ASSERT(m_bits_left >= 0);
}
else
m_bit_buf <<= num_bits;
return i;
}
// Decodes a Huffman encoded symbol.
inline int jpeg_decoder::huff_decode(huff_tables *pH)
{
int symbol;
// Check first 8-bits: do we have a complete symbol?
if ((symbol = pH->look_up[m_bit_buf >> 24]) < 0)
{
// Decode more bits, use a tree traversal to find symbol.
int ofs = 23;
do
{
symbol = pH->tree[-(int)(symbol + ((m_bit_buf >> ofs) & 1))];
ofs--;
} while (symbol < 0);
get_bits_no_markers(8 + (23 - ofs));
}
else
get_bits_no_markers(pH->code_size[symbol]);
return symbol;
}
// Decodes a Huffman encoded symbol.
inline int jpeg_decoder::huff_decode(huff_tables *pH, int& extra_bits)
{
int symbol;
// Check first 8-bits: do we have a complete symbol?
if ((symbol = pH->look_up2[m_bit_buf >> 24]) < 0)
{
// Use a tree traversal to find symbol.
int ofs = 23;
do
{
symbol = pH->tree[-(int)(symbol + ((m_bit_buf >> ofs) & 1))];
ofs--;
} while (symbol < 0);
get_bits_no_markers(8 + (23 - ofs));
extra_bits = get_bits_no_markers(symbol & 0xF);
}
else
{
JPGD_ASSERT(((symbol >> 8) & 31) == pH->code_size[symbol & 255] + ((symbol & 0x8000) ? (symbol & 15) : 0));
if (symbol & 0x8000)
{
get_bits_no_markers((symbol >> 8) & 31);
extra_bits = symbol >> 16;
}
else
{
int code_size = (symbol >> 8) & 31;
int num_extra_bits = symbol & 0xF;
int bits = code_size + num_extra_bits;
if (bits <= (m_bits_left + 16))
extra_bits = get_bits_no_markers(bits) & ((1 << num_extra_bits) - 1);
else
{
get_bits_no_markers(code_size);
extra_bits = get_bits_no_markers(num_extra_bits);
}
}
symbol &= 0xFF;
}
return symbol;
}
// Tables and macro used to fully decode the DPCM differences.
static const int s_extend_test[16] = { 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080, 0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000 };
static const int s_extend_offset[16] = { 0, ((-1)<<1) + 1, ((-1)<<2) + 1, ((-1)<<3) + 1, ((-1)<<4) + 1, ((-1)<<5) + 1, ((-1)<<6) + 1, ((-1)<<7) + 1, ((-1)<<8) + 1, ((-1)<<9) + 1, ((-1)<<10) + 1, ((-1)<<11) + 1, ((-1)<<12) + 1, ((-1)<<13) + 1, ((-1)<<14) + 1, ((-1)<<15) + 1 };
static const int s_extend_mask[] = { 0, (1<<0), (1<<1), (1<<2), (1<<3), (1<<4), (1<<5), (1<<6), (1<<7), (1<<8), (1<<9), (1<<10), (1<<11), (1<<12), (1<<13), (1<<14), (1<<15), (1<<16) };
// The logical AND's in this macro are to shut up static code analysis (aren't really necessary - couldn't find another way to do this)
#define JPGD_HUFF_EXTEND(x, s) (((x) < s_extend_test[s & 15]) ? ((x) + s_extend_offset[s & 15]) : (x))
// Clamps a value between 0-255.
inline uint8 jpeg_decoder::clamp(int i)
{
if (static_cast<uint>(i) > 255)
i = (((~i) >> 31) & 0xFF);
return static_cast<uint8>(i);
}
namespace DCT_Upsample
{
struct Matrix44
{
typedef int Element_Type;
enum { NUM_ROWS = 4, NUM_COLS = 4 };
Element_Type v[NUM_ROWS][NUM_COLS];
inline int rows() const { return NUM_ROWS; }
inline int cols() const { return NUM_COLS; }
inline const Element_Type & at(int r, int c) const { return v[r][c]; }
inline Element_Type & at(int r, int c) { return v[r][c]; }
inline Matrix44() { }
inline Matrix44& operator += (const Matrix44& a)
{
for (int r = 0; r < NUM_ROWS; r++)
{
at(r, 0) += a.at(r, 0);
at(r, 1) += a.at(r, 1);
at(r, 2) += a.at(r, 2);
at(r, 3) += a.at(r, 3);
}
return *this;
}
inline Matrix44& operator -= (const Matrix44& a)
{
for (int r = 0; r < NUM_ROWS; r++)
{
at(r, 0) -= a.at(r, 0);
at(r, 1) -= a.at(r, 1);
at(r, 2) -= a.at(r, 2);
at(r, 3) -= a.at(r, 3);
}
return *this;
}
friend inline Matrix44 operator + (const Matrix44& a, const Matrix44& b)
{
Matrix44 ret;
for (int r = 0; r < NUM_ROWS; r++)
{
ret.at(r, 0) = a.at(r, 0) + b.at(r, 0);
ret.at(r, 1) = a.at(r, 1) + b.at(r, 1);
ret.at(r, 2) = a.at(r, 2) + b.at(r, 2);
ret.at(r, 3) = a.at(r, 3) + b.at(r, 3);
}
return ret;
}
friend inline Matrix44 operator - (const Matrix44& a, const Matrix44& b)
{
Matrix44 ret;
for (int r = 0; r < NUM_ROWS; r++)
{
ret.at(r, 0) = a.at(r, 0) - b.at(r, 0);
ret.at(r, 1) = a.at(r, 1) - b.at(r, 1);
ret.at(r, 2) = a.at(r, 2) - b.at(r, 2);
ret.at(r, 3) = a.at(r, 3) - b.at(r, 3);
}
return ret;
}
static inline void add_and_store(jpgd_block_t* pDst, const Matrix44& a, const Matrix44& b)
{
for (int r = 0; r < 4; r++)
{
pDst[0*8 + r] = static_cast<jpgd_block_t>(a.at(r, 0) + b.at(r, 0));
pDst[1*8 + r] = static_cast<jpgd_block_t>(a.at(r, 1) + b.at(r, 1));
pDst[2*8 + r] = static_cast<jpgd_block_t>(a.at(r, 2) + b.at(r, 2));
pDst[3*8 + r] = static_cast<jpgd_block_t>(a.at(r, 3) + b.at(r, 3));
}
}
static inline void sub_and_store(jpgd_block_t* pDst, const Matrix44& a, const Matrix44& b)
{
for (int r = 0; r < 4; r++)
{
pDst[0*8 + r] = static_cast<jpgd_block_t>(a.at(r, 0) - b.at(r, 0));
pDst[1*8 + r] = static_cast<jpgd_block_t>(a.at(r, 1) - b.at(r, 1));
pDst[2*8 + r] = static_cast<jpgd_block_t>(a.at(r, 2) - b.at(r, 2));
pDst[3*8 + r] = static_cast<jpgd_block_t>(a.at(r, 3) - b.at(r, 3));
}
}
};
const int FRACT_BITS = 10;
const int SCALE = 1 << FRACT_BITS;
typedef int Temp_Type;
#define D(i) (((i) + (SCALE >> 1)) >> FRACT_BITS)
#define F(i) ((int)((i) * SCALE + .5f))
// Any decent C++ compiler will optimize this at compile time to a 0, or an array access.
#define AT(c, r) ((((c)>=NUM_COLS)||((r)>=NUM_ROWS)) ? 0 : pSrc[(c)+(r)*8])
// NUM_ROWS/NUM_COLS = # of non-zero rows/cols in input matrix
template<int NUM_ROWS, int NUM_COLS>
struct P_Q
{
static void calc(Matrix44& P, Matrix44& Q, const jpgd_block_t* pSrc)
{
// 4x8 = 4x8 times 8x8, matrix 0 is constant
const Temp_Type X000 = AT(0, 0);
const Temp_Type X001 = AT(0, 1);
const Temp_Type X002 = AT(0, 2);
const Temp_Type X003 = AT(0, 3);
const Temp_Type X004 = AT(0, 4);
const Temp_Type X005 = AT(0, 5);
const Temp_Type X006 = AT(0, 6);
const Temp_Type X007 = AT(0, 7);
const Temp_Type X010 = D(F(0.415735f) * AT(1, 0) + F(0.791065f) * AT(3, 0) + F(-0.352443f) * AT(5, 0) + F(0.277785f) * AT(7, 0));
const Temp_Type X011 = D(F(0.415735f) * AT(1, 1) + F(0.791065f) * AT(3, 1) + F(-0.352443f) * AT(5, 1) + F(0.277785f) * AT(7, 1));
const Temp_Type X012 = D(F(0.415735f) * AT(1, 2) + F(0.791065f) * AT(3, 2) + F(-0.352443f) * AT(5, 2) + F(0.277785f) * AT(7, 2));
const Temp_Type X013 = D(F(0.415735f) * AT(1, 3) + F(0.791065f) * AT(3, 3) + F(-0.352443f) * AT(5, 3) + F(0.277785f) * AT(7, 3));
const Temp_Type X014 = D(F(0.415735f) * AT(1, 4) + F(0.791065f) * AT(3, 4) + F(-0.352443f) * AT(5, 4) + F(0.277785f) * AT(7, 4));
const Temp_Type X015 = D(F(0.415735f) * AT(1, 5) + F(0.791065f) * AT(3, 5) + F(-0.352443f) * AT(5, 5) + F(0.277785f) * AT(7, 5));
const Temp_Type X016 = D(F(0.415735f) * AT(1, 6) + F(0.791065f) * AT(3, 6) + F(-0.352443f) * AT(5, 6) + F(0.277785f) * AT(7, 6));
const Temp_Type X017 = D(F(0.415735f) * AT(1, 7) + F(0.791065f) * AT(3, 7) + F(-0.352443f) * AT(5, 7) + F(0.277785f) * AT(7, 7));
const Temp_Type X020 = AT(4, 0);
const Temp_Type X021 = AT(4, 1);
const Temp_Type X022 = AT(4, 2);
const Temp_Type X023 = AT(4, 3);
const Temp_Type X024 = AT(4, 4);
const Temp_Type X025 = AT(4, 5);
const Temp_Type X026 = AT(4, 6);
const Temp_Type X027 = AT(4, 7);
const Temp_Type X030 = D(F(0.022887f) * AT(1, 0) + F(-0.097545f) * AT(3, 0) + F(0.490393f) * AT(5, 0) + F(0.865723f) * AT(7, 0));
const Temp_Type X031 = D(F(0.022887f) * AT(1, 1) + F(-0.097545f) * AT(3, 1) + F(0.490393f) * AT(5, 1) + F(0.865723f) * AT(7, 1));
const Temp_Type X032 = D(F(0.022887f) * AT(1, 2) + F(-0.097545f) * AT(3, 2) + F(0.490393f) * AT(5, 2) + F(0.865723f) * AT(7, 2));
const Temp_Type X033 = D(F(0.022887f) * AT(1, 3) + F(-0.097545f) * AT(3, 3) + F(0.490393f) * AT(5, 3) + F(0.865723f) * AT(7, 3));
const Temp_Type X034 = D(F(0.022887f) * AT(1, 4) + F(-0.097545f) * AT(3, 4) + F(0.490393f) * AT(5, 4) + F(0.865723f) * AT(7, 4));
const Temp_Type X035 = D(F(0.022887f) * AT(1, 5) + F(-0.097545f) * AT(3, 5) + F(0.490393f) * AT(5, 5) + F(0.865723f) * AT(7, 5));
const Temp_Type X036 = D(F(0.022887f) * AT(1, 6) + F(-0.097545f) * AT(3, 6) + F(0.490393f) * AT(5, 6) + F(0.865723f) * AT(7, 6));
const Temp_Type X037 = D(F(0.022887f) * AT(1, 7) + F(-0.097545f) * AT(3, 7) + F(0.490393f) * AT(5, 7) + F(0.865723f) * AT(7, 7));
// 4x4 = 4x8 times 8x4, matrix 1 is constant
P.at(0, 0) = X000;
P.at(0, 1) = D(X001 * F(0.415735f) + X003 * F(0.791065f) + X005 * F(-0.352443f) + X007 * F(0.277785f));
P.at(0, 2) = X004;
P.at(0, 3) = D(X001 * F(0.022887f) + X003 * F(-0.097545f) + X005 * F(0.490393f) + X007 * F(0.865723f));
P.at(1, 0) = X010;
P.at(1, 1) = D(X011 * F(0.415735f) + X013 * F(0.791065f) + X015 * F(-0.352443f) + X017 * F(0.277785f));
P.at(1, 2) = X014;
P.at(1, 3) = D(X011 * F(0.022887f) + X013 * F(-0.097545f) + X015 * F(0.490393f) + X017 * F(0.865723f));
P.at(2, 0) = X020;
P.at(2, 1) = D(X021 * F(0.415735f) + X023 * F(0.791065f) + X025 * F(-0.352443f) + X027 * F(0.277785f));
P.at(2, 2) = X024;
P.at(2, 3) = D(X021 * F(0.022887f) + X023 * F(-0.097545f) + X025 * F(0.490393f) + X027 * F(0.865723f));
P.at(3, 0) = X030;
P.at(3, 1) = D(X031 * F(0.415735f) + X033 * F(0.791065f) + X035 * F(-0.352443f) + X037 * F(0.277785f));
P.at(3, 2) = X034;
P.at(3, 3) = D(X031 * F(0.022887f) + X033 * F(-0.097545f) + X035 * F(0.490393f) + X037 * F(0.865723f));
// 40 muls 24 adds
// 4x4 = 4x8 times 8x4, matrix 1 is constant
Q.at(0, 0) = D(X001 * F(0.906127f) + X003 * F(-0.318190f) + X005 * F(0.212608f) + X007 * F(-0.180240f));
Q.at(0, 1) = X002;
Q.at(0, 2) = D(X001 * F(-0.074658f) + X003 * F(0.513280f) + X005 * F(0.768178f) + X007 * F(-0.375330f));
Q.at(0, 3) = X006;
Q.at(1, 0) = D(X011 * F(0.906127f) + X013 * F(-0.318190f) + X015 * F(0.212608f) + X017 * F(-0.180240f));
Q.at(1, 1) = X012;
Q.at(1, 2) = D(X011 * F(-0.074658f) + X013 * F(0.513280f) + X015 * F(0.768178f) + X017 * F(-0.375330f));
Q.at(1, 3) = X016;
Q.at(2, 0) = D(X021 * F(0.906127f) + X023 * F(-0.318190f) + X025 * F(0.212608f) + X027 * F(-0.180240f));
Q.at(2, 1) = X022;
Q.at(2, 2) = D(X021 * F(-0.074658f) + X023 * F(0.513280f) + X025 * F(0.768178f) + X027 * F(-0.375330f));
Q.at(2, 3) = X026;
Q.at(3, 0) = D(X031 * F(0.906127f) + X033 * F(-0.318190f) + X035 * F(0.212608f) + X037 * F(-0.180240f));
Q.at(3, 1) = X032;
Q.at(3, 2) = D(X031 * F(-0.074658f) + X033 * F(0.513280f) + X035 * F(0.768178f) + X037 * F(-0.375330f));
Q.at(3, 3) = X036;
// 40 muls 24 adds
}
};
template<int NUM_ROWS, int NUM_COLS>
struct R_S
{
static void calc(Matrix44& R, Matrix44& S, const jpgd_block_t* pSrc)
{
// 4x8 = 4x8 times 8x8, matrix 0 is constant
const Temp_Type X100 = D(F(0.906127f) * AT(1, 0) + F(-0.318190f) * AT(3, 0) + F(0.212608f) * AT(5, 0) + F(-0.180240f) * AT(7, 0));
const Temp_Type X101 = D(F(0.906127f) * AT(1, 1) + F(-0.318190f) * AT(3, 1) + F(0.212608f) * AT(5, 1) + F(-0.180240f) * AT(7, 1));
const Temp_Type X102 = D(F(0.906127f) * AT(1, 2) + F(-0.318190f) * AT(3, 2) + F(0.212608f) * AT(5, 2) + F(-0.180240f) * AT(7, 2));
const Temp_Type X103 = D(F(0.906127f) * AT(1, 3) + F(-0.318190f) * AT(3, 3) + F(0.212608f) * AT(5, 3) + F(-0.180240f) * AT(7, 3));
const Temp_Type X104 = D(F(0.906127f) * AT(1, 4) + F(-0.318190f) * AT(3, 4) + F(0.212608f) * AT(5, 4) + F(-0.180240f) * AT(7, 4));
const Temp_Type X105 = D(F(0.906127f) * AT(1, 5) + F(-0.318190f) * AT(3, 5) + F(0.212608f) * AT(5, 5) + F(-0.180240f) * AT(7, 5));
const Temp_Type X106 = D(F(0.906127f) * AT(1, 6) + F(-0.318190f) * AT(3, 6) + F(0.212608f) * AT(5, 6) + F(-0.180240f) * AT(7, 6));
const Temp_Type X107 = D(F(0.906127f) * AT(1, 7) + F(-0.318190f) * AT(3, 7) + F(0.212608f) * AT(5, 7) + F(-0.180240f) * AT(7, 7));
const Temp_Type X110 = AT(2, 0);
const Temp_Type X111 = AT(2, 1);
const Temp_Type X112 = AT(2, 2);
const Temp_Type X113 = AT(2, 3);
const Temp_Type X114 = AT(2, 4);
const Temp_Type X115 = AT(2, 5);
const Temp_Type X116 = AT(2, 6);
const Temp_Type X117 = AT(2, 7);
const Temp_Type X120 = D(F(-0.074658f) * AT(1, 0) + F(0.513280f) * AT(3, 0) + F(0.768178f) * AT(5, 0) + F(-0.375330f) * AT(7, 0));
const Temp_Type X121 = D(F(-0.074658f) * AT(1, 1) + F(0.513280f) * AT(3, 1) + F(0.768178f) * AT(5, 1) + F(-0.375330f) * AT(7, 1));
const Temp_Type X122 = D(F(-0.074658f) * AT(1, 2) + F(0.513280f) * AT(3, 2) + F(0.768178f) * AT(5, 2) + F(-0.375330f) * AT(7, 2));
const Temp_Type X123 = D(F(-0.074658f) * AT(1, 3) + F(0.513280f) * AT(3, 3) + F(0.768178f) * AT(5, 3) + F(-0.375330f) * AT(7, 3));
const Temp_Type X124 = D(F(-0.074658f) * AT(1, 4) + F(0.513280f) * AT(3, 4) + F(0.768178f) * AT(5, 4) + F(-0.375330f) * AT(7, 4));
const Temp_Type X125 = D(F(-0.074658f) * AT(1, 5) + F(0.513280f) * AT(3, 5) + F(0.768178f) * AT(5, 5) + F(-0.375330f) * AT(7, 5));
const Temp_Type X126 = D(F(-0.074658f) * AT(1, 6) + F(0.513280f) * AT(3, 6) + F(0.768178f) * AT(5, 6) + F(-0.375330f) * AT(7, 6));
const Temp_Type X127 = D(F(-0.074658f) * AT(1, 7) + F(0.513280f) * AT(3, 7) + F(0.768178f) * AT(5, 7) + F(-0.375330f) * AT(7, 7));
const Temp_Type X130 = AT(6, 0);
const Temp_Type X131 = AT(6, 1);
const Temp_Type X132 = AT(6, 2);
const Temp_Type X133 = AT(6, 3);
const Temp_Type X134 = AT(6, 4);
const Temp_Type X135 = AT(6, 5);
const Temp_Type X136 = AT(6, 6);
const Temp_Type X137 = AT(6, 7);
// 80 muls 48 adds
// 4x4 = 4x8 times 8x4, matrix 1 is constant
R.at(0, 0) = X100;
R.at(0, 1) = D(X101 * F(0.415735f) + X103 * F(0.791065f) + X105 * F(-0.352443f) + X107 * F(0.277785f));
R.at(0, 2) = X104;
R.at(0, 3) = D(X101 * F(0.022887f) + X103 * F(-0.097545f) + X105 * F(0.490393f) + X107 * F(0.865723f));
R.at(1, 0) = X110;
R.at(1, 1) = D(X111 * F(0.415735f) + X113 * F(0.791065f) + X115 * F(-0.352443f) + X117 * F(0.277785f));
R.at(1, 2) = X114;
R.at(1, 3) = D(X111 * F(0.022887f) + X113 * F(-0.097545f) + X115 * F(0.490393f) + X117 * F(0.865723f));
R.at(2, 0) = X120;
R.at(2, 1) = D(X121 * F(0.415735f) + X123 * F(0.791065f) + X125 * F(-0.352443f) + X127 * F(0.277785f));
R.at(2, 2) = X124;
R.at(2, 3) = D(X121 * F(0.022887f) + X123 * F(-0.097545f) + X125 * F(0.490393f) + X127 * F(0.865723f));
R.at(3, 0) = X130;
R.at(3, 1) = D(X131 * F(0.415735f) + X133 * F(0.791065f) + X135 * F(-0.352443f) + X137 * F(0.277785f));
R.at(3, 2) = X134;
R.at(3, 3) = D(X131 * F(0.022887f) + X133 * F(-0.097545f) + X135 * F(0.490393f) + X137 * F(0.865723f));
// 40 muls 24 adds
// 4x4 = 4x8 times 8x4, matrix 1 is constant
S.at(0, 0) = D(X101 * F(0.906127f) + X103 * F(-0.318190f) + X105 * F(0.212608f) + X107 * F(-0.180240f));
S.at(0, 1) = X102;
S.at(0, 2) = D(X101 * F(-0.074658f) + X103 * F(0.513280f) + X105 * F(0.768178f) + X107 * F(-0.375330f));
S.at(0, 3) = X106;
S.at(1, 0) = D(X111 * F(0.906127f) + X113 * F(-0.318190f) + X115 * F(0.212608f) + X117 * F(-0.180240f));
S.at(1, 1) = X112;
S.at(1, 2) = D(X111 * F(-0.074658f) + X113 * F(0.513280f) + X115 * F(0.768178f) + X117 * F(-0.375330f));
S.at(1, 3) = X116;
S.at(2, 0) = D(X121 * F(0.906127f) + X123 * F(-0.318190f) + X125 * F(0.212608f) + X127 * F(-0.180240f));
S.at(2, 1) = X122;
S.at(2, 2) = D(X121 * F(-0.074658f) + X123 * F(0.513280f) + X125 * F(0.768178f) + X127 * F(-0.375330f));
S.at(2, 3) = X126;
S.at(3, 0) = D(X131 * F(0.906127f) + X133 * F(-0.318190f) + X135 * F(0.212608f) + X137 * F(-0.180240f));
S.at(3, 1) = X132;
S.at(3, 2) = D(X131 * F(-0.074658f) + X133 * F(0.513280f) + X135 * F(0.768178f) + X137 * F(-0.375330f));
S.at(3, 3) = X136;
// 40 muls 24 adds
}
};
} // end namespace DCT_Upsample
// Unconditionally frees all allocated m_blocks.
void jpeg_decoder::free_all_blocks()
{
m_pStream = NULL;
for (mem_block *b = m_pMem_blocks; b; )
{
mem_block *n = b->m_pNext;
jpgd_free(b);
b = n;
}
m_pMem_blocks = NULL;
}
// This method handles all errors. It will never return.
// It could easily be changed to use C++ exceptions.
JPGD_NORETURN void jpeg_decoder::stop_decoding(jpgd_status status)
{
m_error_code = status;
free_all_blocks();
longjmp(m_jmp_state, status);
}
void *jpeg_decoder::alloc(size_t nSize, bool zero)
{
nSize = (JPGD_MAX(nSize, 1) + 3) & ~3;
char *rv = NULL;
for (mem_block *b = m_pMem_blocks; b; b = b->m_pNext)
{
if ((b->m_used_count + nSize) <= b->m_size)
{
rv = b->m_data + b->m_used_count;
b->m_used_count += nSize;
break;
}
}
if (!rv)
{
int capacity = JPGD_MAX(32768 - 256, (nSize + 2047) & ~2047);
mem_block *b = (mem_block*)jpgd_malloc(sizeof(mem_block) + capacity);
if (!b) { stop_decoding(JPGD_NOTENOUGHMEM); }
b->m_pNext = m_pMem_blocks; m_pMem_blocks = b;
b->m_used_count = nSize;
b->m_size = capacity;
rv = b->m_data;
}
if (zero) memset(rv, 0, nSize);
return rv;
}
void jpeg_decoder::word_clear(void *p, uint16 c, uint n)
{
uint8 *pD = (uint8*)p;
const uint8 l = c & 0xFF, h = (c >> 8) & 0xFF;
while (n)
{
pD[0] = l; pD[1] = h; pD += 2;
n--;
}
}
// Refill the input buffer.
// This method will sit in a loop until (A) the buffer is full or (B)
// the stream's read() method reports and end of file condition.
void jpeg_decoder::prep_in_buffer()
{
m_in_buf_left = 0;
m_pIn_buf_ofs = m_in_buf;
if (m_eof_flag)
return;
do
{
int bytes_read = m_pStream->read(m_in_buf + m_in_buf_left, JPGD_IN_BUF_SIZE - m_in_buf_left, &m_eof_flag);
if (bytes_read == -1)
stop_decoding(JPGD_STREAM_READ);
m_in_buf_left += bytes_read;
} while ((m_in_buf_left < JPGD_IN_BUF_SIZE) && (!m_eof_flag));
m_total_bytes_read += m_in_buf_left;
// Pad the end of the block with M_EOI (prevents the decompressor from going off the rails if the stream is invalid).
// (This dates way back to when this decompressor was written in C/asm, and the all-asm Huffman decoder did some fancy things to increase perf.)
word_clear(m_pIn_buf_ofs + m_in_buf_left, 0xD9FF, 64);
}
// Read a Huffman code table.
void jpeg_decoder::read_dht_marker()
{
int i, index, count;
uint8 huff_num[17];
uint8 huff_val[256];
uint num_left = get_bits(16);
if (num_left < 2)
stop_decoding(JPGD_BAD_DHT_MARKER);
num_left -= 2;
while (num_left)
{
index = get_bits(8);
huff_num[0] = 0;
count = 0;
for (i = 1; i <= 16; i++)
{
huff_num[i] = static_cast<uint8>(get_bits(8));
count += huff_num[i];
}
if (count > 255)
stop_decoding(JPGD_BAD_DHT_COUNTS);
for (i = 0; i < count; i++)
huff_val[i] = static_cast<uint8>(get_bits(8));
i = 1 + 16 + count;
if (num_left < (uint)i)
stop_decoding(JPGD_BAD_DHT_MARKER);
num_left -= i;
if ((index & 0x10) > 0x10)
stop_decoding(JPGD_BAD_DHT_INDEX);
index = (index & 0x0F) + ((index & 0x10) >> 4) * (JPGD_MAX_HUFF_TABLES >> 1);
if (index >= JPGD_MAX_HUFF_TABLES)
stop_decoding(JPGD_BAD_DHT_INDEX);
if (!m_huff_num[index])
m_huff_num[index] = (uint8 *)alloc(17);
if (!m_huff_val[index])
m_huff_val[index] = (uint8 *)alloc(256);
m_huff_ac[index] = (index & 0x10) != 0;
memcpy(m_huff_num[index], huff_num, 17);
memcpy(m_huff_val[index], huff_val, 256);
}
}
// Read a quantization table.
void jpeg_decoder::read_dqt_marker()
{
int n, i, prec;
uint num_left;
uint temp;
num_left = get_bits(16);
if (num_left < 2)
stop_decoding(JPGD_BAD_DQT_MARKER);
num_left -= 2;
while (num_left)
{
n = get_bits(8);
prec = n >> 4;
n &= 0x0F;
if (n >= JPGD_MAX_QUANT_TABLES)
stop_decoding(JPGD_BAD_DQT_TABLE);
if (!m_quant[n])
m_quant[n] = (jpgd_quant_t *)alloc(64 * sizeof(jpgd_quant_t));
// read quantization entries, in zag order
for (i = 0; i < 64; i++)
{
temp = get_bits(8);
if (prec)
temp = (temp << 8) + get_bits(8);
m_quant[n][i] = static_cast<jpgd_quant_t>(temp);
}
i = 64 + 1;
if (prec)
i += 64;
if (num_left < (uint)i)
stop_decoding(JPGD_BAD_DQT_LENGTH);
num_left -= i;
}
}
// Read the start of frame (SOF) marker.
void jpeg_decoder::read_sof_marker()
{
int i;
uint num_left;
num_left = get_bits(16);
if (get_bits(8) != 8) /* precision: sorry, only 8-bit precision is supported right now */
stop_decoding(JPGD_BAD_PRECISION);
m_image_y_size = get_bits(16);
if ((m_image_y_size < 1) || (m_image_y_size > JPGD_MAX_HEIGHT))
stop_decoding(JPGD_BAD_HEIGHT);
m_image_x_size = get_bits(16);
if ((m_image_x_size < 1) || (m_image_x_size > JPGD_MAX_WIDTH))
stop_decoding(JPGD_BAD_WIDTH);
m_comps_in_frame = get_bits(8);
if (m_comps_in_frame > JPGD_MAX_COMPONENTS)
stop_decoding(JPGD_TOO_MANY_COMPONENTS);
if (num_left != (uint)(m_comps_in_frame * 3 + 8))
stop_decoding(JPGD_BAD_SOF_LENGTH);
for (i = 0; i < m_comps_in_frame; i++)
{
m_comp_ident[i] = get_bits(8);
m_comp_h_samp[i] = get_bits(4);
m_comp_v_samp[i] = get_bits(4);
m_comp_quant[i] = get_bits(8);
}
}
// Used to skip unrecognized markers.
void jpeg_decoder::skip_variable_marker()
{
uint num_left;
num_left = get_bits(16);
if (num_left < 2)
stop_decoding(JPGD_BAD_VARIABLE_MARKER);
num_left -= 2;
while (num_left)
{
get_bits(8);
num_left--;
}
}
// Read a define restart interval (DRI) marker.
void jpeg_decoder::read_dri_marker()
{
if (get_bits(16) != 4)
stop_decoding(JPGD_BAD_DRI_LENGTH);
m_restart_interval = get_bits(16);
}
// Read a start of scan (SOS) marker.
void jpeg_decoder::read_sos_marker()
{
uint num_left;
int i, ci, n, c, cc;
num_left = get_bits(16);
n = get_bits(8);
m_comps_in_scan = n;
num_left -= 3;
if ( (num_left != (uint)(n * 2 + 3)) || (n < 1) || (n > JPGD_MAX_COMPS_IN_SCAN) )
stop_decoding(JPGD_BAD_SOS_LENGTH);
for (i = 0; i < n; i++)
{
cc = get_bits(8);
c = get_bits(8);
num_left -= 2;
for (ci = 0; ci < m_comps_in_frame; ci++)
if (cc == m_comp_ident[ci])
break;
if (ci >= m_comps_in_frame)
stop_decoding(JPGD_BAD_SOS_COMP_ID);
m_comp_list[i] = ci;
m_comp_dc_tab[ci] = (c >> 4) & 15;
m_comp_ac_tab[ci] = (c & 15) + (JPGD_MAX_HUFF_TABLES >> 1);
}
m_spectral_start = get_bits(8);
m_spectral_end = get_bits(8);
m_successive_high = get_bits(4);
m_successive_low = get_bits(4);
if (!m_progressive_flag)
{
m_spectral_start = 0;
m_spectral_end = 63;
}
num_left -= 3;
while (num_left) /* read past whatever is num_left */
{
get_bits(8);
num_left--;
}
}
// Finds the next marker.
int jpeg_decoder::next_marker()
{
uint c, bytes;
bytes = 0;
do
{
do
{
bytes++;
c = get_bits(8);
} while (c != 0xFF);
do
{
c = get_bits(8);
} while (c == 0xFF);
} while (c == 0);
// If bytes > 0 here, there where extra bytes before the marker (not good).
return c;
}
// Process markers. Returns when an SOFx, SOI, EOI, or SOS marker is
// encountered.
int jpeg_decoder::process_markers()
{
int c;
for ( ; ; )
{
c = next_marker();
switch (c)
{
case M_SOF0:
case M_SOF1:
case M_SOF2:
case M_SOF3:
case M_SOF5:
case M_SOF6:
case M_SOF7:
// case M_JPG:
case M_SOF9:
case M_SOF10:
case M_SOF11:
case M_SOF13:
case M_SOF14:
case M_SOF15:
case M_SOI:
case M_EOI:
case M_SOS:
{
return c;
}
case M_DHT:
{
read_dht_marker();
break;
}
// No arithmitic support - dumb patents!
case M_DAC:
{
stop_decoding(JPGD_NO_ARITHMITIC_SUPPORT);
break;
}
case M_DQT:
{
read_dqt_marker();
break;
}
case M_DRI:
{
read_dri_marker();
break;
}
//case M_APP0: /* no need to read the JFIF marker */
case M_JPG:
case M_RST0: /* no parameters */
case M_RST1:
case M_RST2:
case M_RST3:
case M_RST4:
case M_RST5:
case M_RST6:
case M_RST7:
case M_TEM:
{
stop_decoding(JPGD_UNEXPECTED_MARKER);
break;
}
default: /* must be DNL, DHP, EXP, APPn, JPGn, COM, or RESn or APP0 */
{
skip_variable_marker();
break;
}
}
}
}
// Finds the start of image (SOI) marker.
// This code is rather defensive: it only checks the first 512 bytes to avoid
// false positives.
void jpeg_decoder::locate_soi_marker()
{
uint lastchar, thischar;
uint bytesleft;
lastchar = get_bits(8);
thischar = get_bits(8);
/* ok if it's a normal JPEG file without a special header */
if ((lastchar == 0xFF) && (thischar == M_SOI))
return;
bytesleft = 4096; //512;
for ( ; ; )
{
if (--bytesleft == 0)
stop_decoding(JPGD_NOT_JPEG);
lastchar = thischar;
thischar = get_bits(8);
if (lastchar == 0xFF)
{
if (thischar == M_SOI)
break;
else if (thischar == M_EOI) // get_bits will keep returning M_EOI if we read past the end
stop_decoding(JPGD_NOT_JPEG);
}
}
// Check the next character after marker: if it's not 0xFF, it can't be the start of the next marker, so the file is bad.
thischar = (m_bit_buf >> 24) & 0xFF;
if (thischar != 0xFF)
stop_decoding(JPGD_NOT_JPEG);
}
// Find a start of frame (SOF) marker.
void jpeg_decoder::locate_sof_marker()
{
locate_soi_marker();
int c = process_markers();
switch (c)
{
case M_SOF2:
m_progressive_flag = JPGD_TRUE;
case M_SOF0: /* baseline DCT */
case M_SOF1: /* extended sequential DCT */
{
read_sof_marker();
break;
}
case M_SOF9: /* Arithmitic coding */
{
stop_decoding(JPGD_NO_ARITHMITIC_SUPPORT);
break;
}
default:
{
stop_decoding(JPGD_UNSUPPORTED_MARKER);
break;
}
}
}
// Find a start of scan (SOS) marker.
int jpeg_decoder::locate_sos_marker()
{
int c;
c = process_markers();
if (c == M_EOI)
return JPGD_FALSE;
else if (c != M_SOS)
stop_decoding(JPGD_UNEXPECTED_MARKER);
read_sos_marker();
return JPGD_TRUE;
}
// Reset everything to default/uninitialized state.
void jpeg_decoder::init(jpeg_decoder_stream *pStream)
{
m_pMem_blocks = NULL;
m_error_code = JPGD_SUCCESS;
m_ready_flag = false;
m_image_x_size = m_image_y_size = 0;
m_pStream = pStream;
m_progressive_flag = JPGD_FALSE;
memset(m_huff_ac, 0, sizeof(m_huff_ac));
memset(m_huff_num, 0, sizeof(m_huff_num));
memset(m_huff_val, 0, sizeof(m_huff_val));
memset(m_quant, 0, sizeof(m_quant));
m_scan_type = 0;
m_comps_in_frame = 0;
memset(m_comp_h_samp, 0, sizeof(m_comp_h_samp));
memset(m_comp_v_samp, 0, sizeof(m_comp_v_samp));
memset(m_comp_quant, 0, sizeof(m_comp_quant));
memset(m_comp_ident, 0, sizeof(m_comp_ident));
memset(m_comp_h_blocks, 0, sizeof(m_comp_h_blocks));
memset(m_comp_v_blocks, 0, sizeof(m_comp_v_blocks));
m_comps_in_scan = 0;
memset(m_comp_list, 0, sizeof(m_comp_list));
memset(m_comp_dc_tab, 0, sizeof(m_comp_dc_tab));
memset(m_comp_ac_tab, 0, sizeof(m_comp_ac_tab));
m_spectral_start = 0;
m_spectral_end = 0;
m_successive_low = 0;
m_successive_high = 0;
m_max_mcu_x_size = 0;
m_max_mcu_y_size = 0;
m_blocks_per_mcu = 0;
m_max_blocks_per_row = 0;
m_mcus_per_row = 0;
m_mcus_per_col = 0;
m_expanded_blocks_per_component = 0;
m_expanded_blocks_per_mcu = 0;
m_expanded_blocks_per_row = 0;
m_freq_domain_chroma_upsample = false;
memset(m_mcu_org, 0, sizeof(m_mcu_org));
m_total_lines_left = 0;
m_mcu_lines_left = 0;
m_real_dest_bytes_per_scan_line = 0;
m_dest_bytes_per_scan_line = 0;
m_dest_bytes_per_pixel = 0;
memset(m_pHuff_tabs, 0, sizeof(m_pHuff_tabs));
memset(m_dc_coeffs, 0, sizeof(m_dc_coeffs));
memset(m_ac_coeffs, 0, sizeof(m_ac_coeffs));
memset(m_block_y_mcu, 0, sizeof(m_block_y_mcu));
m_eob_run = 0;
memset(m_block_y_mcu, 0, sizeof(m_block_y_mcu));
m_pIn_buf_ofs = m_in_buf;
m_in_buf_left = 0;
m_eof_flag = false;
m_tem_flag = 0;
memset(m_in_buf_pad_start, 0, sizeof(m_in_buf_pad_start));
memset(m_in_buf, 0, sizeof(m_in_buf));
memset(m_in_buf_pad_end, 0, sizeof(m_in_buf_pad_end));
m_restart_interval = 0;
m_restarts_left = 0;
m_next_restart_num = 0;
m_max_mcus_per_row = 0;
m_max_blocks_per_mcu = 0;
m_max_mcus_per_col = 0;
memset(m_last_dc_val, 0, sizeof(m_last_dc_val));
m_pMCU_coefficients = NULL;
m_pSample_buf = NULL;
m_total_bytes_read = 0;
m_pScan_line_0 = NULL;
m_pScan_line_1 = NULL;
// Ready the input buffer.
prep_in_buffer();
// Prime the bit buffer.
m_bits_left = 16;
m_bit_buf = 0;
get_bits(16);
get_bits(16);
for (int i = 0; i < JPGD_MAX_BLOCKS_PER_MCU; i++)
m_mcu_block_max_zag[i] = 64;
}
#define SCALEBITS 16
#define ONE_HALF ((int) 1 << (SCALEBITS-1))
#define FIX(x) ((int) ((x) * (1L<<SCALEBITS) + 0.5f))
// Create a few tables that allow us to quickly convert YCbCr to RGB.
void jpeg_decoder::create_look_ups()
{
for (int i = 0; i <= 255; i++)
{
int k = i - 128;
m_crr[i] = ( FIX(1.40200f) * k + ONE_HALF) >> SCALEBITS;
m_cbb[i] = ( FIX(1.77200f) * k + ONE_HALF) >> SCALEBITS;
m_crg[i] = (-FIX(0.71414f)) * k;
m_cbg[i] = (-FIX(0.34414f)) * k + ONE_HALF;
}
}
// This method throws back into the stream any bytes that where read
// into the bit buffer during initial marker scanning.
void jpeg_decoder::fix_in_buffer()
{
// In case any 0xFF's where pulled into the buffer during marker scanning.
JPGD_ASSERT((m_bits_left & 7) == 0);
if (m_bits_left == 16)
stuff_char( (uint8)(m_bit_buf & 0xFF));
if (m_bits_left >= 8)
stuff_char( (uint8)((m_bit_buf >> 8) & 0xFF));
stuff_char((uint8)((m_bit_buf >> 16) & 0xFF));
stuff_char((uint8)((m_bit_buf >> 24) & 0xFF));
m_bits_left = 16;
get_bits_no_markers(16);
get_bits_no_markers(16);
}
void jpeg_decoder::transform_mcu(int mcu_row)
{
jpgd_block_t* pSrc_ptr = m_pMCU_coefficients;
uint8* pDst_ptr = m_pSample_buf + mcu_row * m_blocks_per_mcu * 64;
for (int mcu_block = 0; mcu_block < m_blocks_per_mcu; mcu_block++)
{
idct(pSrc_ptr, pDst_ptr, m_mcu_block_max_zag[mcu_block]);
pSrc_ptr += 64;
pDst_ptr += 64;
}
}
static const uint8 s_max_rc[64] =
{
17, 18, 34, 50, 50, 51, 52, 52, 52, 68, 84, 84, 84, 84, 85, 86, 86, 86, 86, 86,
102, 118, 118, 118, 118, 118, 118, 119, 120, 120, 120, 120, 120, 120, 120, 136,
136, 136, 136, 136, 136, 136, 136, 136, 136, 136, 136, 136, 136, 136, 136, 136,
136, 136, 136, 136, 136, 136, 136, 136, 136, 136, 136, 136
};
void jpeg_decoder::transform_mcu_expand(int mcu_row)
{
jpgd_block_t* pSrc_ptr = m_pMCU_coefficients;
uint8* pDst_ptr = m_pSample_buf + mcu_row * m_expanded_blocks_per_mcu * 64;
// Y IDCT
int mcu_block;
for (mcu_block = 0; mcu_block < m_expanded_blocks_per_component; mcu_block++)
{
idct(pSrc_ptr, pDst_ptr, m_mcu_block_max_zag[mcu_block]);
pSrc_ptr += 64;
pDst_ptr += 64;
}
// Chroma IDCT, with upsampling
jpgd_block_t temp_block[64];
for (int i = 0; i < 2; i++)
{
DCT_Upsample::Matrix44 P, Q, R, S;
JPGD_ASSERT(m_mcu_block_max_zag[mcu_block] >= 1);
JPGD_ASSERT(m_mcu_block_max_zag[mcu_block] <= 64);
int max_zag = m_mcu_block_max_zag[mcu_block++] - 1;
if (max_zag <= 0) max_zag = 0; // should never happen, only here to shut up static analysis
switch (s_max_rc[max_zag])
{
case 1*16+1:
DCT_Upsample::P_Q<1, 1>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<1, 1>::calc(R, S, pSrc_ptr);
break;
case 1*16+2:
DCT_Upsample::P_Q<1, 2>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<1, 2>::calc(R, S, pSrc_ptr);
break;
case 2*16+2:
DCT_Upsample::P_Q<2, 2>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<2, 2>::calc(R, S, pSrc_ptr);
break;
case 3*16+2:
DCT_Upsample::P_Q<3, 2>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<3, 2>::calc(R, S, pSrc_ptr);
break;
case 3*16+3:
DCT_Upsample::P_Q<3, 3>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<3, 3>::calc(R, S, pSrc_ptr);
break;
case 3*16+4:
DCT_Upsample::P_Q<3, 4>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<3, 4>::calc(R, S, pSrc_ptr);
break;
case 4*16+4:
DCT_Upsample::P_Q<4, 4>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<4, 4>::calc(R, S, pSrc_ptr);
break;
case 5*16+4:
DCT_Upsample::P_Q<5, 4>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<5, 4>::calc(R, S, pSrc_ptr);
break;
case 5*16+5:
DCT_Upsample::P_Q<5, 5>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<5, 5>::calc(R, S, pSrc_ptr);
break;
case 5*16+6:
DCT_Upsample::P_Q<5, 6>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<5, 6>::calc(R, S, pSrc_ptr);
break;
case 6*16+6:
DCT_Upsample::P_Q<6, 6>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<6, 6>::calc(R, S, pSrc_ptr);
break;
case 7*16+6:
DCT_Upsample::P_Q<7, 6>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<7, 6>::calc(R, S, pSrc_ptr);
break;
case 7*16+7:
DCT_Upsample::P_Q<7, 7>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<7, 7>::calc(R, S, pSrc_ptr);
break;
case 7*16+8:
DCT_Upsample::P_Q<7, 8>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<7, 8>::calc(R, S, pSrc_ptr);
break;
case 8*16+8:
DCT_Upsample::P_Q<8, 8>::calc(P, Q, pSrc_ptr);
DCT_Upsample::R_S<8, 8>::calc(R, S, pSrc_ptr);
break;
default:
JPGD_ASSERT(false);
}
DCT_Upsample::Matrix44 a(P + Q); P -= Q;
DCT_Upsample::Matrix44& b = P;
DCT_Upsample::Matrix44 c(R + S); R -= S;
DCT_Upsample::Matrix44& d = R;
DCT_Upsample::Matrix44::add_and_store(temp_block, a, c);
idct_4x4(temp_block, pDst_ptr);
pDst_ptr += 64;
DCT_Upsample::Matrix44::sub_and_store(temp_block, a, c);
idct_4x4(temp_block, pDst_ptr);
pDst_ptr += 64;
DCT_Upsample::Matrix44::add_and_store(temp_block, b, d);
idct_4x4(temp_block, pDst_ptr);
pDst_ptr += 64;
DCT_Upsample::Matrix44::sub_and_store(temp_block, b, d);
idct_4x4(temp_block, pDst_ptr);
pDst_ptr += 64;
pSrc_ptr += 64;
}
}
// Loads and dequantizes the next row of (already decoded) coefficients.
// Progressive images only.
void jpeg_decoder::load_next_row()
{
int i;
jpgd_block_t *p;
jpgd_quant_t *q;
int mcu_row, mcu_block, row_block = 0;
int component_num, component_id;
int block_x_mcu[JPGD_MAX_COMPONENTS];
memset(block_x_mcu, 0, JPGD_MAX_COMPONENTS * sizeof(int));
for (mcu_row = 0; mcu_row < m_mcus_per_row; mcu_row++)
{
int block_x_mcu_ofs = 0, block_y_mcu_ofs = 0;
for (mcu_block = 0; mcu_block < m_blocks_per_mcu; mcu_block++)
{
component_id = m_mcu_org[mcu_block];
q = m_quant[m_comp_quant[component_id]];
p = m_pMCU_coefficients + 64 * mcu_block;
jpgd_block_t* pAC = coeff_buf_getp(m_ac_coeffs[component_id], block_x_mcu[component_id] + block_x_mcu_ofs, m_block_y_mcu[component_id] + block_y_mcu_ofs);
jpgd_block_t* pDC = coeff_buf_getp(m_dc_coeffs[component_id], block_x_mcu[component_id] + block_x_mcu_ofs, m_block_y_mcu[component_id] + block_y_mcu_ofs);
p[0] = pDC[0];
memcpy(&p[1], &pAC[1], 63 * sizeof(jpgd_block_t));
for (i = 63; i > 0; i--)
if (p[g_ZAG[i]])
break;
m_mcu_block_max_zag[mcu_block] = i + 1;
for ( ; i >= 0; i--)
if (p[g_ZAG[i]])
p[g_ZAG[i]] = static_cast<jpgd_block_t>(p[g_ZAG[i]] * q[i]);
row_block++;
if (m_comps_in_scan == 1)
block_x_mcu[component_id]++;
else
{
if (++block_x_mcu_ofs == m_comp_h_samp[component_id])
{
block_x_mcu_ofs = 0;
if (++block_y_mcu_ofs == m_comp_v_samp[component_id])
{
block_y_mcu_ofs = 0;
block_x_mcu[component_id] += m_comp_h_samp[component_id];
}
}
}
}
if (m_freq_domain_chroma_upsample)
transform_mcu_expand(mcu_row);
else
transform_mcu(mcu_row);
}
if (m_comps_in_scan == 1)
m_block_y_mcu[m_comp_list[0]]++;
else
{
for (component_num = 0; component_num < m_comps_in_scan; component_num++)
{
component_id = m_comp_list[component_num];
m_block_y_mcu[component_id] += m_comp_v_samp[component_id];
}
}
}
// Restart interval processing.
void jpeg_decoder::process_restart()
{
int i;
int c = 0;
// Align to a byte boundry
// FIXME: Is this really necessary? get_bits_no_markers() never reads in markers!
//get_bits_no_markers(m_bits_left & 7);
// Let's scan a little bit to find the marker, but not _too_ far.
// 1536 is a "fudge factor" that determines how much to scan.
for (i = 1536; i > 0; i--)
if (get_char() == 0xFF)
break;
if (i == 0)
stop_decoding(JPGD_BAD_RESTART_MARKER);
for ( ; i > 0; i--)
if ((c = get_char()) != 0xFF)
break;
if (i == 0)
stop_decoding(JPGD_BAD_RESTART_MARKER);
// Is it the expected marker? If not, something bad happened.
if (c != (m_next_restart_num + M_RST0))
stop_decoding(JPGD_BAD_RESTART_MARKER);
// Reset each component's DC prediction values.
memset(&m_last_dc_val, 0, m_comps_in_frame * sizeof(uint));
m_eob_run = 0;
m_restarts_left = m_restart_interval;
m_next_restart_num = (m_next_restart_num + 1) & 7;
// Get the bit buffer going again...
m_bits_left = 16;
get_bits_no_markers(16);
get_bits_no_markers(16);
}
static inline int dequantize_ac(int c, int q) { c *= q; return c; }
// Decodes and dequantizes the next row of coefficients.
void jpeg_decoder::decode_next_row()
{
int row_block = 0;
for (int mcu_row = 0; mcu_row < m_mcus_per_row; mcu_row++)
{
if ((m_restart_interval) && (m_restarts_left == 0))
process_restart();
jpgd_block_t* p = m_pMCU_coefficients;
for (int mcu_block = 0; mcu_block < m_blocks_per_mcu; mcu_block++, p += 64)
{
int component_id = m_mcu_org[mcu_block];
jpgd_quant_t* q = m_quant[m_comp_quant[component_id]];
int r, s;
s = huff_decode(m_pHuff_tabs[m_comp_dc_tab[component_id]], r);
s = JPGD_HUFF_EXTEND(r, s);
m_last_dc_val[component_id] = (s += m_last_dc_val[component_id]);
p[0] = static_cast<jpgd_block_t>(s * q[0]);
int prev_num_set = m_mcu_block_max_zag[mcu_block];
huff_tables *pH = m_pHuff_tabs[m_comp_ac_tab[component_id]];
int k;
for (k = 1; k < 64; k++)
{
int extra_bits;
s = huff_decode(pH, extra_bits);
r = s >> 4;
s &= 15;
if (s)
{
if (r)
{
if ((k + r) > 63)
stop_decoding(JPGD_DECODE_ERROR);
if (k < prev_num_set)
{
int n = JPGD_MIN(r, prev_num_set - k);
int kt = k;
while (n--)
p[g_ZAG[kt++]] = 0;
}
k += r;
}
s = JPGD_HUFF_EXTEND(extra_bits, s);
JPGD_ASSERT(k < 64);
p[g_ZAG[k]] = static_cast<jpgd_block_t>(dequantize_ac(s, q[k])); //s * q[k];
}
else
{
if (r == 15)
{
if ((k + 16) > 64)
stop_decoding(JPGD_DECODE_ERROR);
if (k < prev_num_set)
{
int n = JPGD_MIN(16, prev_num_set - k);
int kt = k;
while (n--)
{
JPGD_ASSERT(kt <= 63);
p[g_ZAG[kt++]] = 0;
}
}
k += 16 - 1; // - 1 because the loop counter is k
JPGD_ASSERT(p[g_ZAG[k]] == 0);
}
else
break;
}
}
if (k < prev_num_set)
{
int kt = k;
while (kt < prev_num_set)
p[g_ZAG[kt++]] = 0;
}
m_mcu_block_max_zag[mcu_block] = k;
row_block++;
}
if (m_freq_domain_chroma_upsample)
transform_mcu_expand(mcu_row);
else
transform_mcu(mcu_row);
m_restarts_left--;
}
}
// YCbCr H1V1 (1x1:1:1, 3 m_blocks per MCU) to RGB
void jpeg_decoder::H1V1Convert()
{
int row = m_max_mcu_y_size - m_mcu_lines_left;
uint8 *d = m_pScan_line_0;
uint8 *s = m_pSample_buf + row * 8;
for (int i = m_max_mcus_per_row; i > 0; i--)
{
for (int j = 0; j < 8; j++)
{
int y = s[j];
int cb = s[64+j];
int cr = s[128+j];
d[0] = clamp(y + m_crr[cr]);
d[1] = clamp(y + ((m_crg[cr] + m_cbg[cb]) >> 16));
d[2] = clamp(y + m_cbb[cb]);
d[3] = 255;
d += 4;
}
s += 64*3;
}
}
// YCbCr H2V1 (2x1:1:1, 4 m_blocks per MCU) to RGB
void jpeg_decoder::H2V1Convert()
{
int row = m_max_mcu_y_size - m_mcu_lines_left;
uint8 *d0 = m_pScan_line_0;
uint8 *y = m_pSample_buf + row * 8;
uint8 *c = m_pSample_buf + 2*64 + row * 8;
for (int i = m_max_mcus_per_row; i > 0; i--)
{
for (int l = 0; l < 2; l++)
{
for (int j = 0; j < 4; j++)
{
int cb = c[0];
int cr = c[64];
int rc = m_crr[cr];
int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
int bc = m_cbb[cb];
int yy = y[j<<1];
d0[0] = clamp(yy+rc);
d0[1] = clamp(yy+gc);
d0[2] = clamp(yy+bc);
d0[3] = 255;
yy = y[(j<<1)+1];
d0[4] = clamp(yy+rc);
d0[5] = clamp(yy+gc);
d0[6] = clamp(yy+bc);
d0[7] = 255;
d0 += 8;
c++;
}
y += 64;
}
y += 64*4 - 64*2;
c += 64*4 - 8;
}
}
// YCbCr H2V1 (1x2:1:1, 4 m_blocks per MCU) to RGB
void jpeg_decoder::H1V2Convert()
{
int row = m_max_mcu_y_size - m_mcu_lines_left;
uint8 *d0 = m_pScan_line_0;
uint8 *d1 = m_pScan_line_1;
uint8 *y;
uint8 *c;
if (row < 8)
y = m_pSample_buf + row * 8;
else
y = m_pSample_buf + 64*1 + (row & 7) * 8;
c = m_pSample_buf + 64*2 + (row >> 1) * 8;
for (int i = m_max_mcus_per_row; i > 0; i--)
{
for (int j = 0; j < 8; j++)
{
int cb = c[0+j];
int cr = c[64+j];
int rc = m_crr[cr];
int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
int bc = m_cbb[cb];
int yy = y[j];
d0[0] = clamp(yy+rc);
d0[1] = clamp(yy+gc);
d0[2] = clamp(yy+bc);
d0[3] = 255;
yy = y[8+j];
d1[0] = clamp(yy+rc);
d1[1] = clamp(yy+gc);
d1[2] = clamp(yy+bc);
d1[3] = 255;
d0 += 4;
d1 += 4;
}
y += 64*4;
c += 64*4;
}
}
// YCbCr H2V2 (2x2:1:1, 6 m_blocks per MCU) to RGB
void jpeg_decoder::H2V2Convert()
{
int row = m_max_mcu_y_size - m_mcu_lines_left;
uint8 *d0 = m_pScan_line_0;
uint8 *d1 = m_pScan_line_1;
uint8 *y;
uint8 *c;
if (row < 8)
y = m_pSample_buf + row * 8;
else
y = m_pSample_buf + 64*2 + (row & 7) * 8;
c = m_pSample_buf + 64*4 + (row >> 1) * 8;
for (int i = m_max_mcus_per_row; i > 0; i--)
{
for (int l = 0; l < 2; l++)
{
for (int j = 0; j < 8; j += 2)
{
int cb = c[0];
int cr = c[64];
int rc = m_crr[cr];
int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
int bc = m_cbb[cb];
int yy = y[j];
d0[0] = clamp(yy+rc);
d0[1] = clamp(yy+gc);
d0[2] = clamp(yy+bc);
d0[3] = 255;
yy = y[j+1];
d0[4] = clamp(yy+rc);
d0[5] = clamp(yy+gc);
d0[6] = clamp(yy+bc);
d0[7] = 255;
yy = y[j+8];
d1[0] = clamp(yy+rc);
d1[1] = clamp(yy+gc);
d1[2] = clamp(yy+bc);
d1[3] = 255;
yy = y[j+8+1];
d1[4] = clamp(yy+rc);
d1[5] = clamp(yy+gc);
d1[6] = clamp(yy+bc);
d1[7] = 255;
d0 += 8;
d1 += 8;
c++;
}
y += 64;
}
y += 64*6 - 64*2;
c += 64*6 - 8;
}
}
// Y (1 block per MCU) to 8-bit grayscale
void jpeg_decoder::gray_convert()
{
int row = m_max_mcu_y_size - m_mcu_lines_left;
uint8 *d = m_pScan_line_0;
uint8 *s = m_pSample_buf + row * 8;
for (int i = m_max_mcus_per_row; i > 0; i--)
{
*(uint *)d = *(uint *)s;
*(uint *)(&d[4]) = *(uint *)(&s[4]);
s += 64;
d += 8;
}
}
void jpeg_decoder::expanded_convert()
{
int row = m_max_mcu_y_size - m_mcu_lines_left;
uint8* Py = m_pSample_buf + (row / 8) * 64 * m_comp_h_samp[0] + (row & 7) * 8;
uint8* d = m_pScan_line_0;
for (int i = m_max_mcus_per_row; i > 0; i--)
{
for (int k = 0; k < m_max_mcu_x_size; k += 8)
{
const int Y_ofs = k * 8;
const int Cb_ofs = Y_ofs + 64 * m_expanded_blocks_per_component;
const int Cr_ofs = Y_ofs + 64 * m_expanded_blocks_per_component * 2;
for (int j = 0; j < 8; j++)
{
int y = Py[Y_ofs + j];
int cb = Py[Cb_ofs + j];
int cr = Py[Cr_ofs + j];
d[0] = clamp(y + m_crr[cr]);
d[1] = clamp(y + ((m_crg[cr] + m_cbg[cb]) >> 16));
d[2] = clamp(y + m_cbb[cb]);
d[3] = 255;
d += 4;
}
}
Py += 64 * m_expanded_blocks_per_mcu;
}
}
// Find end of image (EOI) marker, so we can return to the user the exact size of the input stream.
void jpeg_decoder::find_eoi()
{
if (!m_progressive_flag)
{
// Attempt to read the EOI marker.
//get_bits_no_markers(m_bits_left & 7);
// Prime the bit buffer
m_bits_left = 16;
get_bits(16);
get_bits(16);
// The next marker _should_ be EOI
process_markers();
}
m_total_bytes_read -= m_in_buf_left;
}
int jpeg_decoder::decode(const void** pScan_line, uint* pScan_line_len)
{
if ((m_error_code) || (!m_ready_flag))
return JPGD_FAILED;
if (m_total_lines_left == 0)
return JPGD_DONE;
if (m_mcu_lines_left == 0)
{
if (setjmp(m_jmp_state))
return JPGD_FAILED;
if (m_progressive_flag)
load_next_row();
else
decode_next_row();
// Find the EOI marker if that was the last row.
if (m_total_lines_left <= m_max_mcu_y_size)
find_eoi();
m_mcu_lines_left = m_max_mcu_y_size;
}
if (m_freq_domain_chroma_upsample)
{
expanded_convert();
*pScan_line = m_pScan_line_0;
}
else
{
switch (m_scan_type)
{
case JPGD_YH2V2:
{
if ((m_mcu_lines_left & 1) == 0)
{
H2V2Convert();
*pScan_line = m_pScan_line_0;
}
else
*pScan_line = m_pScan_line_1;
break;
}
case JPGD_YH2V1:
{
H2V1Convert();
*pScan_line = m_pScan_line_0;
break;
}
case JPGD_YH1V2:
{
if ((m_mcu_lines_left & 1) == 0)
{
H1V2Convert();
*pScan_line = m_pScan_line_0;
}
else
*pScan_line = m_pScan_line_1;
break;
}
case JPGD_YH1V1:
{
H1V1Convert();
*pScan_line = m_pScan_line_0;
break;
}
case JPGD_GRAYSCALE:
{
gray_convert();
*pScan_line = m_pScan_line_0;
break;
}
}
}
*pScan_line_len = m_real_dest_bytes_per_scan_line;
m_mcu_lines_left--;
m_total_lines_left--;
return JPGD_SUCCESS;
}
// Creates the tables needed for efficient Huffman decoding.
void jpeg_decoder::make_huff_table(int index, huff_tables *pH)
{
int p, i, l, si;
uint8 huffsize[257];
uint huffcode[257];
uint code;
uint subtree;
int code_size;
int lastp;
int nextfreeentry;
int currententry;
pH->ac_table = m_huff_ac[index] != 0;
p = 0;
for (l = 1; l <= 16; l++)
{
for (i = 1; i <= m_huff_num[index][l]; i++)
{
JPGD_ASSERT(p < 257);
huffsize[p++] = static_cast<uint8>(l);
}
}
huffsize[p] = 0;
lastp = p;
code = 0;
si = huffsize[0];
p = 0;
while (huffsize[p])
{
while (huffsize[p] == si)
{
JPGD_ASSERT(p < 257);
huffcode[p++] = code;
code++;
}
code <<= 1;
si++;
}
memset(pH->look_up, 0, sizeof(pH->look_up));
memset(pH->look_up2, 0, sizeof(pH->look_up2));
memset(pH->tree, 0, sizeof(pH->tree));
memset(pH->code_size, 0, sizeof(pH->code_size));
nextfreeentry = -1;
p = 0;
while (p < lastp)
{
i = m_huff_val[index][p];
code = huffcode[p];
code_size = huffsize[p];
pH->code_size[i] = static_cast<uint8>(code_size);
if (code_size <= 8)
{
code <<= (8 - code_size);
for (l = 1 << (8 - code_size); l > 0; l--)
{
JPGD_ASSERT(i < 256);
pH->look_up[code] = i;
bool has_extrabits = false;
int extra_bits = 0;
int num_extra_bits = i & 15;
int bits_to_fetch = code_size;
if (num_extra_bits)
{
int total_codesize = code_size + num_extra_bits;
if (total_codesize <= 8)
{
has_extrabits = true;
extra_bits = ((1 << num_extra_bits) - 1) & (code >> (8 - total_codesize));
JPGD_ASSERT(extra_bits <= 0x7FFF);
bits_to_fetch += num_extra_bits;
}
}
if (!has_extrabits)
pH->look_up2[code] = i | (bits_to_fetch << 8);
else
pH->look_up2[code] = i | 0x8000 | (extra_bits << 16) | (bits_to_fetch << 8);
code++;
}
}
else
{
subtree = (code >> (code_size - 8)) & 0xFF;
currententry = pH->look_up[subtree];
if (currententry == 0)
{
pH->look_up[subtree] = currententry = nextfreeentry;
pH->look_up2[subtree] = currententry = nextfreeentry;
nextfreeentry -= 2;
}
code <<= (16 - (code_size - 8));
for (l = code_size; l > 9; l--)
{
if ((code & 0x8000) == 0)
currententry--;
if (pH->tree[-currententry - 1] == 0)
{
pH->tree[-currententry - 1] = nextfreeentry;
currententry = nextfreeentry;
nextfreeentry -= 2;
}
else
currententry = pH->tree[-currententry - 1];
code <<= 1;
}
if ((code & 0x8000) == 0)
currententry--;
pH->tree[-currententry - 1] = i;
}
p++;
}
}
// Verifies the quantization tables needed for this scan are available.
void jpeg_decoder::check_quant_tables()
{
for (int i = 0; i < m_comps_in_scan; i++)
if (m_quant[m_comp_quant[m_comp_list[i]]] == NULL)
stop_decoding(JPGD_UNDEFINED_QUANT_TABLE);
}
// Verifies that all the Huffman tables needed for this scan are available.
void jpeg_decoder::check_huff_tables()
{
for (int i = 0; i < m_comps_in_scan; i++)
{
if ((m_spectral_start == 0) && (m_huff_num[m_comp_dc_tab[m_comp_list[i]]] == NULL))
stop_decoding(JPGD_UNDEFINED_HUFF_TABLE);
if ((m_spectral_end > 0) && (m_huff_num[m_comp_ac_tab[m_comp_list[i]]] == NULL))
stop_decoding(JPGD_UNDEFINED_HUFF_TABLE);
}
for (int i = 0; i < JPGD_MAX_HUFF_TABLES; i++)
if (m_huff_num[i])
{
if (!m_pHuff_tabs[i])
m_pHuff_tabs[i] = (huff_tables *)alloc(sizeof(huff_tables));
make_huff_table(i, m_pHuff_tabs[i]);
}
}
// Determines the component order inside each MCU.
// Also calcs how many MCU's are on each row, etc.
void jpeg_decoder::calc_mcu_block_order()
{
int component_num, component_id;
int max_h_samp = 0, max_v_samp = 0;
for (component_id = 0; component_id < m_comps_in_frame; component_id++)
{
if (m_comp_h_samp[component_id] > max_h_samp)
max_h_samp = m_comp_h_samp[component_id];
if (m_comp_v_samp[component_id] > max_v_samp)
max_v_samp = m_comp_v_samp[component_id];
}
for (component_id = 0; component_id < m_comps_in_frame; component_id++)
{
m_comp_h_blocks[component_id] = ((((m_image_x_size * m_comp_h_samp[component_id]) + (max_h_samp - 1)) / max_h_samp) + 7) / 8;
m_comp_v_blocks[component_id] = ((((m_image_y_size * m_comp_v_samp[component_id]) + (max_v_samp - 1)) / max_v_samp) + 7) / 8;
}
if (m_comps_in_scan == 1)
{
m_mcus_per_row = m_comp_h_blocks[m_comp_list[0]];
m_mcus_per_col = m_comp_v_blocks[m_comp_list[0]];
}
else
{
m_mcus_per_row = (((m_image_x_size + 7) / 8) + (max_h_samp - 1)) / max_h_samp;
m_mcus_per_col = (((m_image_y_size + 7) / 8) + (max_v_samp - 1)) / max_v_samp;
}
if (m_comps_in_scan == 1)
{
m_mcu_org[0] = m_comp_list[0];
m_blocks_per_mcu = 1;
}
else
{
m_blocks_per_mcu = 0;
for (component_num = 0; component_num < m_comps_in_scan; component_num++)
{
int num_blocks;
component_id = m_comp_list[component_num];
num_blocks = m_comp_h_samp[component_id] * m_comp_v_samp[component_id];
while (num_blocks--)
m_mcu_org[m_blocks_per_mcu++] = component_id;
}
}
}
// Starts a new scan.
int jpeg_decoder::init_scan()
{
if (!locate_sos_marker())
return JPGD_FALSE;
calc_mcu_block_order();
check_huff_tables();
check_quant_tables();
memset(m_last_dc_val, 0, m_comps_in_frame * sizeof(uint));
m_eob_run = 0;
if (m_restart_interval)
{
m_restarts_left = m_restart_interval;
m_next_restart_num = 0;
}
fix_in_buffer();
return JPGD_TRUE;
}
// Starts a frame. Determines if the number of components or sampling factors
// are supported.
void jpeg_decoder::init_frame()
{
int i;
if (m_comps_in_frame == 1)
{
if ((m_comp_h_samp[0] != 1) || (m_comp_v_samp[0] != 1))
stop_decoding(JPGD_UNSUPPORTED_SAMP_FACTORS);
m_scan_type = JPGD_GRAYSCALE;
m_max_blocks_per_mcu = 1;
m_max_mcu_x_size = 8;
m_max_mcu_y_size = 8;
}
else if (m_comps_in_frame == 3)
{
if ( ((m_comp_h_samp[1] != 1) || (m_comp_v_samp[1] != 1)) ||
((m_comp_h_samp[2] != 1) || (m_comp_v_samp[2] != 1)) )
stop_decoding(JPGD_UNSUPPORTED_SAMP_FACTORS);
if ((m_comp_h_samp[0] == 1) && (m_comp_v_samp[0] == 1))
{
m_scan_type = JPGD_YH1V1;
m_max_blocks_per_mcu = 3;
m_max_mcu_x_size = 8;
m_max_mcu_y_size = 8;
}
else if ((m_comp_h_samp[0] == 2) && (m_comp_v_samp[0] == 1))
{
m_scan_type = JPGD_YH2V1;
m_max_blocks_per_mcu = 4;
m_max_mcu_x_size = 16;
m_max_mcu_y_size = 8;
}
else if ((m_comp_h_samp[0] == 1) && (m_comp_v_samp[0] == 2))
{
m_scan_type = JPGD_YH1V2;
m_max_blocks_per_mcu = 4;
m_max_mcu_x_size = 8;
m_max_mcu_y_size = 16;
}
else if ((m_comp_h_samp[0] == 2) && (m_comp_v_samp[0] == 2))
{
m_scan_type = JPGD_YH2V2;
m_max_blocks_per_mcu = 6;
m_max_mcu_x_size = 16;
m_max_mcu_y_size = 16;
}
else
stop_decoding(JPGD_UNSUPPORTED_SAMP_FACTORS);
}
else
stop_decoding(JPGD_UNSUPPORTED_COLORSPACE);
m_max_mcus_per_row = (m_image_x_size + (m_max_mcu_x_size - 1)) / m_max_mcu_x_size;
m_max_mcus_per_col = (m_image_y_size + (m_max_mcu_y_size - 1)) / m_max_mcu_y_size;
// These values are for the *destination* pixels: after conversion.
if (m_scan_type == JPGD_GRAYSCALE)
m_dest_bytes_per_pixel = 1;
else
m_dest_bytes_per_pixel = 4;
m_dest_bytes_per_scan_line = ((m_image_x_size + 15) & 0xFFF0) * m_dest_bytes_per_pixel;
m_real_dest_bytes_per_scan_line = (m_image_x_size * m_dest_bytes_per_pixel);
// Initialize two scan line buffers.
m_pScan_line_0 = (uint8 *)alloc(m_dest_bytes_per_scan_line, true);
if ((m_scan_type == JPGD_YH1V2) || (m_scan_type == JPGD_YH2V2))
m_pScan_line_1 = (uint8 *)alloc(m_dest_bytes_per_scan_line, true);
m_max_blocks_per_row = m_max_mcus_per_row * m_max_blocks_per_mcu;
// Should never happen
if (m_max_blocks_per_row > JPGD_MAX_BLOCKS_PER_ROW)
stop_decoding(JPGD_ASSERTION_ERROR);
// Allocate the coefficient buffer, enough for one MCU
m_pMCU_coefficients = (jpgd_block_t*)alloc(m_max_blocks_per_mcu * 64 * sizeof(jpgd_block_t));
for (i = 0; i < m_max_blocks_per_mcu; i++)
m_mcu_block_max_zag[i] = 64;
m_expanded_blocks_per_component = m_comp_h_samp[0] * m_comp_v_samp[0];
m_expanded_blocks_per_mcu = m_expanded_blocks_per_component * m_comps_in_frame;
m_expanded_blocks_per_row = m_max_mcus_per_row * m_expanded_blocks_per_mcu;
// Freq. domain chroma upsampling is only supported for H2V2 subsampling factor (the most common one I've seen).
m_freq_domain_chroma_upsample = false;
#if JPGD_SUPPORT_FREQ_DOMAIN_UPSAMPLING
m_freq_domain_chroma_upsample = (m_expanded_blocks_per_mcu == 4*3);
#endif
if (m_freq_domain_chroma_upsample)
m_pSample_buf = (uint8 *)alloc(m_expanded_blocks_per_row * 64);
else
m_pSample_buf = (uint8 *)alloc(m_max_blocks_per_row * 64);
m_total_lines_left = m_image_y_size;
m_mcu_lines_left = 0;
create_look_ups();
}
// The coeff_buf series of methods originally stored the coefficients
// into a "virtual" file which was located in EMS, XMS, or a disk file. A cache
// was used to make this process more efficient. Now, we can store the entire
// thing in RAM.
jpeg_decoder::coeff_buf* jpeg_decoder::coeff_buf_open(int block_num_x, int block_num_y, int block_len_x, int block_len_y)
{
coeff_buf* cb = (coeff_buf*)alloc(sizeof(coeff_buf));
cb->block_num_x = block_num_x;
cb->block_num_y = block_num_y;
cb->block_len_x = block_len_x;
cb->block_len_y = block_len_y;
cb->block_size = (block_len_x * block_len_y) * sizeof(jpgd_block_t);
cb->pData = (uint8 *)alloc(cb->block_size * block_num_x * block_num_y, true);
return cb;
}
inline jpgd_block_t *jpeg_decoder::coeff_buf_getp(coeff_buf *cb, int block_x, int block_y)
{
JPGD_ASSERT((block_x < cb->block_num_x) && (block_y < cb->block_num_y));
return (jpgd_block_t *)(cb->pData + block_x * cb->block_size + block_y * (cb->block_size * cb->block_num_x));
}
// The following methods decode the various types of m_blocks encountered
// in progressively encoded images.
void jpeg_decoder::decode_block_dc_first(jpeg_decoder *pD, int component_id, int block_x, int block_y)
{
int s, r;
jpgd_block_t *p = pD->coeff_buf_getp(pD->m_dc_coeffs[component_id], block_x, block_y);
if ((s = pD->huff_decode(pD->m_pHuff_tabs[pD->m_comp_dc_tab[component_id]])) != 0)
{
r = pD->get_bits_no_markers(s);
s = JPGD_HUFF_EXTEND(r, s);
}
pD->m_last_dc_val[component_id] = (s += pD->m_last_dc_val[component_id]);
p[0] = static_cast<jpgd_block_t>(s << pD->m_successive_low);
}
void jpeg_decoder::decode_block_dc_refine(jpeg_decoder *pD, int component_id, int block_x, int block_y)
{
if (pD->get_bits_no_markers(1))
{
jpgd_block_t *p = pD->coeff_buf_getp(pD->m_dc_coeffs[component_id], block_x, block_y);
p[0] |= (1 << pD->m_successive_low);
}
}
void jpeg_decoder::decode_block_ac_first(jpeg_decoder *pD, int component_id, int block_x, int block_y)
{
int k, s, r;
if (pD->m_eob_run)
{
pD->m_eob_run--;
return;
}
jpgd_block_t *p = pD->coeff_buf_getp(pD->m_ac_coeffs[component_id], block_x, block_y);
for (k = pD->m_spectral_start; k <= pD->m_spectral_end; k++)
{
s = pD->huff_decode(pD->m_pHuff_tabs[pD->m_comp_ac_tab[component_id]]);
r = s >> 4;
s &= 15;
if (s)
{
if ((k += r) > 63)
pD->stop_decoding(JPGD_DECODE_ERROR);
r = pD->get_bits_no_markers(s);
s = JPGD_HUFF_EXTEND(r, s);
p[g_ZAG[k]] = static_cast<jpgd_block_t>(s << pD->m_successive_low);
}
else
{
if (r == 15)
{
if ((k += 15) > 63)
pD->stop_decoding(JPGD_DECODE_ERROR);
}
else
{
pD->m_eob_run = 1 << r;
if (r)
pD->m_eob_run += pD->get_bits_no_markers(r);
pD->m_eob_run--;
break;
}
}
}
}
void jpeg_decoder::decode_block_ac_refine(jpeg_decoder *pD, int component_id, int block_x, int block_y)
{
int s, k, r;
int p1 = 1 << pD->m_successive_low;
int m1 = (-1) << pD->m_successive_low;
jpgd_block_t *p = pD->coeff_buf_getp(pD->m_ac_coeffs[component_id], block_x, block_y);
JPGD_ASSERT(pD->m_spectral_end <= 63);
k = pD->m_spectral_start;
if (pD->m_eob_run == 0)
{
for ( ; k <= pD->m_spectral_end; k++)
{
s = pD->huff_decode(pD->m_pHuff_tabs[pD->m_comp_ac_tab[component_id]]);
r = s >> 4;
s &= 15;
if (s)
{
if (s != 1)
pD->stop_decoding(JPGD_DECODE_ERROR);
if (pD->get_bits_no_markers(1))
s = p1;
else
s = m1;
}
else
{
if (r != 15)
{
pD->m_eob_run = 1 << r;
if (r)
pD->m_eob_run += pD->get_bits_no_markers(r);
break;
}
}
do
{
jpgd_block_t *this_coef = p + g_ZAG[k & 63];
if (*this_coef != 0)
{
if (pD->get_bits_no_markers(1))
{
if ((*this_coef & p1) == 0)
{
if (*this_coef >= 0)
*this_coef = static_cast<jpgd_block_t>(*this_coef + p1);
else
*this_coef = static_cast<jpgd_block_t>(*this_coef + m1);
}
}
}
else
{
if (--r < 0)
break;
}
k++;
} while (k <= pD->m_spectral_end);
if ((s) && (k < 64))
{
p[g_ZAG[k]] = static_cast<jpgd_block_t>(s);
}
}
}
if (pD->m_eob_run > 0)
{
for ( ; k <= pD->m_spectral_end; k++)
{
jpgd_block_t *this_coef = p + g_ZAG[k & 63]; // logical AND to shut up static code analysis
if (*this_coef != 0)
{
if (pD->get_bits_no_markers(1))
{
if ((*this_coef & p1) == 0)
{
if (*this_coef >= 0)
*this_coef = static_cast<jpgd_block_t>(*this_coef + p1);
else
*this_coef = static_cast<jpgd_block_t>(*this_coef + m1);
}
}
}
}
pD->m_eob_run--;
}
}
// Decode a scan in a progressively encoded image.
void jpeg_decoder::decode_scan(pDecode_block_func decode_block_func)
{
int mcu_row, mcu_col, mcu_block;
int block_x_mcu[JPGD_MAX_COMPONENTS], m_block_y_mcu[JPGD_MAX_COMPONENTS];
memset(m_block_y_mcu, 0, sizeof(m_block_y_mcu));
for (mcu_col = 0; mcu_col < m_mcus_per_col; mcu_col++)
{
int component_num, component_id;
memset(block_x_mcu, 0, sizeof(block_x_mcu));
for (mcu_row = 0; mcu_row < m_mcus_per_row; mcu_row++)
{
int block_x_mcu_ofs = 0, block_y_mcu_ofs = 0;
if ((m_restart_interval) && (m_restarts_left == 0))
process_restart();
for (mcu_block = 0; mcu_block < m_blocks_per_mcu; mcu_block++)
{
component_id = m_mcu_org[mcu_block];
decode_block_func(this, component_id, block_x_mcu[component_id] + block_x_mcu_ofs, m_block_y_mcu[component_id] + block_y_mcu_ofs);
if (m_comps_in_scan == 1)
block_x_mcu[component_id]++;
else
{
if (++block_x_mcu_ofs == m_comp_h_samp[component_id])
{
block_x_mcu_ofs = 0;
if (++block_y_mcu_ofs == m_comp_v_samp[component_id])
{
block_y_mcu_ofs = 0;
block_x_mcu[component_id] += m_comp_h_samp[component_id];
}
}
}
}
m_restarts_left--;
}
if (m_comps_in_scan == 1)
m_block_y_mcu[m_comp_list[0]]++;
else
{
for (component_num = 0; component_num < m_comps_in_scan; component_num++)
{
component_id = m_comp_list[component_num];
m_block_y_mcu[component_id] += m_comp_v_samp[component_id];
}
}
}
}
// Decode a progressively encoded image.
void jpeg_decoder::init_progressive()
{
int i;
if (m_comps_in_frame == 4)
stop_decoding(JPGD_UNSUPPORTED_COLORSPACE);
// Allocate the coefficient buffers.
for (i = 0; i < m_comps_in_frame; i++)
{
m_dc_coeffs[i] = coeff_buf_open(m_max_mcus_per_row * m_comp_h_samp[i], m_max_mcus_per_col * m_comp_v_samp[i], 1, 1);
m_ac_coeffs[i] = coeff_buf_open(m_max_mcus_per_row * m_comp_h_samp[i], m_max_mcus_per_col * m_comp_v_samp[i], 8, 8);
}
for ( ; ; )
{
int dc_only_scan, refinement_scan;
pDecode_block_func decode_block_func;
if (!init_scan())
break;
dc_only_scan = (m_spectral_start == 0);
refinement_scan = (m_successive_high != 0);
if ((m_spectral_start > m_spectral_end) || (m_spectral_end > 63))
stop_decoding(JPGD_BAD_SOS_SPECTRAL);
if (dc_only_scan)
{
if (m_spectral_end)
stop_decoding(JPGD_BAD_SOS_SPECTRAL);
}
else if (m_comps_in_scan != 1) /* AC scans can only contain one component */
stop_decoding(JPGD_BAD_SOS_SPECTRAL);
if ((refinement_scan) && (m_successive_low != m_successive_high - 1))
stop_decoding(JPGD_BAD_SOS_SUCCESSIVE);
if (dc_only_scan)
{
if (refinement_scan)
decode_block_func = decode_block_dc_refine;
else
decode_block_func = decode_block_dc_first;
}
else
{
if (refinement_scan)
decode_block_func = decode_block_ac_refine;
else
decode_block_func = decode_block_ac_first;
}
decode_scan(decode_block_func);
m_bits_left = 16;
get_bits(16);
get_bits(16);
}
m_comps_in_scan = m_comps_in_frame;
for (i = 0; i < m_comps_in_frame; i++)
m_comp_list[i] = i;
calc_mcu_block_order();
}
void jpeg_decoder::init_sequential()
{
if (!init_scan())
stop_decoding(JPGD_UNEXPECTED_MARKER);
}
void jpeg_decoder::decode_start()
{
init_frame();
if (m_progressive_flag)
init_progressive();
else
init_sequential();
}
void jpeg_decoder::decode_init(jpeg_decoder_stream *pStream)
{
init(pStream);
locate_sof_marker();
}
jpeg_decoder::jpeg_decoder(jpeg_decoder_stream *pStream)
{
if (setjmp(m_jmp_state))
return;
decode_init(pStream);
}
int jpeg_decoder::begin_decoding()
{
if (m_ready_flag)
return JPGD_SUCCESS;
if (m_error_code)
return JPGD_FAILED;
if (setjmp(m_jmp_state))
return JPGD_FAILED;
decode_start();
m_ready_flag = true;
return JPGD_SUCCESS;
}
jpeg_decoder::~jpeg_decoder()
{
free_all_blocks();
}
jpeg_decoder_file_stream::jpeg_decoder_file_stream()
{
m_pFile = NULL;
m_eof_flag = false;
m_error_flag = false;
}
void jpeg_decoder_file_stream::close()
{
if (m_pFile)
{
fclose(m_pFile);
m_pFile = NULL;
}
m_eof_flag = false;
m_error_flag = false;
}
jpeg_decoder_file_stream::~jpeg_decoder_file_stream()
{
close();
}
bool jpeg_decoder_file_stream::open(const char *Pfilename)
{
close();
m_eof_flag = false;
m_error_flag = false;
#if defined(_MSC_VER)
m_pFile = NULL;
fopen_s(&m_pFile, Pfilename, "rb");
#else
m_pFile = fopen(Pfilename, "rb");
#endif
return m_pFile != NULL;
}
int jpeg_decoder_file_stream::read(uint8 *pBuf, int max_bytes_to_read, bool *pEOF_flag)
{
if (!m_pFile)
return -1;
if (m_eof_flag)
{
*pEOF_flag = true;
return 0;
}
if (m_error_flag)
return -1;
int bytes_read = static_cast<int>(fread(pBuf, 1, max_bytes_to_read, m_pFile));
if (bytes_read < max_bytes_to_read)
{
if (ferror(m_pFile))
{
m_error_flag = true;
return -1;
}
m_eof_flag = true;
*pEOF_flag = true;
}
return bytes_read;
}
bool jpeg_decoder_mem_stream::open(const uint8 *pSrc_data, uint size)
{
close();
m_pSrc_data = pSrc_data;
m_ofs = 0;
m_size = size;
return true;
}
int jpeg_decoder_mem_stream::read(uint8 *pBuf, int max_bytes_to_read, bool *pEOF_flag)
{
*pEOF_flag = false;
if (!m_pSrc_data)
return -1;
uint bytes_remaining = m_size - m_ofs;
if ((uint)max_bytes_to_read > bytes_remaining)
{
max_bytes_to_read = bytes_remaining;
*pEOF_flag = true;
}
memcpy(pBuf, m_pSrc_data + m_ofs, max_bytes_to_read);
m_ofs += max_bytes_to_read;
return max_bytes_to_read;
}
unsigned char *decompress_jpeg_image_from_stream(jpeg_decoder_stream *pStream, int *width, int *height, int *actual_comps, int req_comps)
{
if (!actual_comps) {
err_reason = "no actual_comps";
return NULL;
}
*actual_comps = 0;
if (!pStream) {
err_reason = "stream == NULL";
return NULL;
}
if (!width) {
err_reason = "width == NULL";
return NULL;
}
if (!height) {
err_reason = "height == NULL";
return NULL;
}
if ((req_comps != 1) && (req_comps != 3) && (req_comps != 4)) {
err_reason = "req_comps not 1, 3 or 4";
return NULL;
}
jpeg_decoder decoder(pStream);
if (decoder.get_error_code() != JPGD_SUCCESS) {
err_reason = "decoder init failed for stream";
return NULL;
}
const int image_width = decoder.get_width(), image_height = decoder.get_height();
*width = image_width;
*height = image_height;
*actual_comps = decoder.get_num_components();
if (decoder.begin_decoding() != JPGD_SUCCESS) {
err_reason = "begin decoding failed";
return NULL;
}
const int dst_bpl = image_width * req_comps;
uint8 *pImage_data = (uint8*)jpgd_malloc(dst_bpl * image_height);
if (!pImage_data) {
err_reason = "image data == NULL";
return NULL;
}
for (int y = 0; y < image_height; y++)
{
const uint8* pScan_line;
uint scan_line_len;
if (decoder.decode((const void**)&pScan_line, &scan_line_len) != JPGD_SUCCESS)
{
jpgd_free(pImage_data);
err_reason = "line scanning failed";
return NULL;
}
uint8 *pDst = pImage_data + y * dst_bpl;
if (((req_comps == 1) && (decoder.get_num_components() == 1)) || ((req_comps == 4) && (decoder.get_num_components() == 3)))
memcpy(pDst, pScan_line, dst_bpl);
else if (decoder.get_num_components() == 1)
{
if (req_comps == 3)
{
for (int x = 0; x < image_width; x++)
{
uint8 luma = pScan_line[x];
pDst[0] = luma;
pDst[1] = luma;
pDst[2] = luma;
pDst += 3;
}
}
else
{
for (int x = 0; x < image_width; x++)
{
uint8 luma = pScan_line[x];
pDst[0] = luma;
pDst[1] = luma;
pDst[2] = luma;
pDst[3] = 255;
pDst += 4;
}
}
}
else if (decoder.get_num_components() == 3)
{
if (req_comps == 1)
{
const int YR = 19595, YG = 38470, YB = 7471;
for (int x = 0; x < image_width; x++)
{
int r = pScan_line[x*4+0];
int g = pScan_line[x*4+1];
int b = pScan_line[x*4+2];
*pDst++ = static_cast<uint8>((r * YR + g * YG + b * YB + 32768) >> 16);
}
}
else
{
for (int x = 0; x < image_width; x++)
{
pDst[0] = pScan_line[x*4+0];
pDst[1] = pScan_line[x*4+1];
pDst[2] = pScan_line[x*4+2];
pDst += 3;
}
}
}
}
return pImage_data;
}
const char *failure_reason(void)
{
return err_reason;
}
unsigned char *decompress_jpeg_image_from_memory(const unsigned char *pSrc_data, int src_data_size, int *width, int *height, int *actual_comps, int req_comps)
{
jpgd::jpeg_decoder_mem_stream mem_stream(pSrc_data, src_data_size);
return decompress_jpeg_image_from_stream(&mem_stream, width, height, actual_comps, req_comps);
}
unsigned char *decompress_jpeg_image_from_file(const char *pSrc_filename, int *width, int *height, int *actual_comps, int req_comps)
{
jpgd::jpeg_decoder_file_stream file_stream;
if (!file_stream.open(pSrc_filename))
return NULL;
return decompress_jpeg_image_from_stream(&file_stream, width, height, actual_comps, req_comps);
}
} // namespace jpgd