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virtualx-engine/thirdparty/jpeg-compressor/jpgd.cpp
Rémi Verschelde d09036992c jpgd: Fix detection of SSE2 support with MSVC 
The previous code would always use SSE2 intrinsics, which is not valid
on UWP ARM platforms (and likely not on some x86 platforms either).

The patch has been submitted upstream too:
https://github.com/richgel999/jpeg-compressor/pull/13

(cherry picked from commit 3806efbaa7)
2020-05-07 13:33:39 +02:00

3283 lines
80 KiB
C++
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// jpgd.cpp - C++ class for JPEG decompression. Written by Richard Geldreich <richgel99@gmail.com> between 1994-2020.
// Supports progressive and baseline sequential JPEG image files, and the most common chroma subsampling factors: Y, H1V1, H2V1, H1V2, and H2V2.
// Supports box and linear chroma upsampling.
//
// Released under two licenses. You are free to choose which license you want:
// License 1:
// Public Domain
//
// License 2:
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Alex Evans: Linear memory allocator (taken from jpge.h).
// v1.04, May. 19, 2012: Code tweaks to fix VS2008 static code analysis warnings
// v2.00, March 20, 2020: Fuzzed with zzuf and afl. Fixed several issues, converted most assert()'s to run-time checks. Added chroma upsampling. Removed freq. domain upsampling. gcc/clang warnings.
//
// Important:
// #define JPGD_USE_SSE2 to 0 to completely disable SSE2 usage.
//
#include "jpgd.h"
#include <string.h>
#include <algorithm>
#include <assert.h>
#ifdef _MSC_VER
#pragma warning (disable : 4611) // warning C4611: interaction between '_setjmp' and C++ object destruction is non-portable
#endif
#ifndef JPGD_USE_SSE2
#if defined(__GNUC__)
#if defined(__SSE2__)
#define JPGD_USE_SSE2 (1)
#endif
#elif defined(_MSC_VER)
#if defined(_M_X64)
#define JPGD_USE_SSE2 (1)
#endif
#endif
#endif
#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 };
#if JPGD_USE_SSE2
#include "jpgd_idct.h"
#endif
#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 inline int left_shifti(int val, uint32_t bits)
{
return static_cast<int>(static_cast<uint32_t>(val) << bits);
}
// 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_coeff_t* pSrc)
{
// ACCESS_COL() will be optimized at compile time to either an array access, or 0. Good compilers will then optimize out muls against 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 = left_shifti(ACCESS_COL(0) + ACCESS_COL(4), CONST_BITS);
const int tmp1 = left_shifti(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_coeff_t* pSrc)
{
(void)pTemp;
(void)pSrc;
}
};
template <>
struct Row<1>
{
static void idct(int* pTemp, const jpgd_block_coeff_t* pSrc)
{
const int dcval = left_shifti(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 = left_shifti(ACCESS_ROW(0) + ACCESS_ROW(4), CONST_BITS);
const int tmp1 = left_shifti(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
};
// Scalar "fast pathing" IDCT.
static void idct(const jpgd_block_coeff_t* pSrc_ptr, uint8* pDst_ptr, int block_max_zag, bool use_simd)
{
(void)use_simd;
assert(block_max_zag >= 1);
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;
}
#if JPGD_USE_SSE2
if (use_simd)
{
assert((((uintptr_t)pSrc_ptr) & 15) == 0);
assert((((uintptr_t)pDst_ptr) & 15) == 0);
idctSSEShortU8(pSrc_ptr, pDst_ptr);
return;
}
#endif
int temp[64];
const jpgd_block_coeff_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++;
}
}
// 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)
{
// This could write before the input buffer, but we've placed another array there.
*(--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;
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;
assert(num_bits <= 16);
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;
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)
{
if (!pH)
stop_decoding(JPGD_DECODE_ERROR);
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
{
unsigned int idx = -(int)(symbol + ((m_bit_buf >> ofs) & 1));
// This should never happen, but to be safe I'm turning these asserts into a run-time check.
if ((idx >= JPGD_HUFF_TREE_MAX_LENGTH) || (ofs < 0))
stop_decoding(JPGD_DECODE_ERROR);
symbol = pH->tree[idx];
ofs--;
} while (symbol < 0);
get_bits_no_markers(8 + (23 - ofs));
}
else
{
assert(symbol < JPGD_HUFF_CODE_SIZE_MAX_LENGTH);
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;
if (!pH)
stop_decoding(JPGD_DECODE_ERROR);
// 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
{
unsigned int idx = -(int)(symbol + ((m_bit_buf >> ofs) & 1));
// This should never happen, but to be safe I'm turning these asserts into a run-time check.
if ((idx >= JPGD_HUFF_TREE_MAX_LENGTH) || (ofs < 0))
stop_decoding(JPGD_DECODE_ERROR);
symbol = pH->tree[idx];
ofs--;
} while (symbol < 0);
get_bits_no_markers(8 + (23 - ofs));
extra_bits = get_bits_no_markers(symbol & 0xF);
}
else
{
if (symbol & 0x8000)
{
//get_bits_no_markers((symbol >> 8) & 31);
assert(((symbol >> 8) & 31) <= 15);
get_bits_no_markers((symbol >> 8) & 15);
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 <= 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, -3, -7, -15, -31, -63, -127, -255, -511, -1023, -2047, -4095, -8191, -16383, -32767 };
//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) };
#define JPGD_HUFF_EXTEND(x, s) (((x) < s_extend_test[s & 15]) ? ((x) + s_extend_offset[s & 15]) : (x))
// Unconditionally frees all allocated m_blocks.
void jpeg_decoder::free_all_blocks()
{
m_pStream = nullptr;
for (mem_block* b = m_pMem_blocks; b; )
{
mem_block* n = b->m_pNext;
jpgd_free(b);
b = n;
}
m_pMem_blocks = nullptr;
}
// 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 = nullptr;
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::alloc_aligned(size_t nSize, uint32_t align, bool zero)
{
assert((align >= 1U) && ((align & (align - 1U)) == 0U));
void *p = alloc(nSize + align - 1U, zero);
p = (void *)( ((uintptr_t)p + (align - 1U)) & ~((uintptr_t)(align - 1U)) );
return p;
}
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);
bool symbol_present[256];
memset(symbol_present, 0, sizeof(symbol_present));
for (i = 0; i < count; i++)
{
const int s = get_bits(8);
// Check for obviously bogus tables.
if (symbol_present[s])
stop_decoding(JPGD_BAD_DHT_COUNTS);
huff_val[i] = static_cast<uint8_t>(s);
symbol_present[s] = true;
}
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);
/* precision: sorry, only 8-bit precision is supported */
if (get_bits(8) != 8)
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);
if (!m_comp_h_samp[i] || !m_comp_v_samp[i] || (m_comp_h_samp[i] > 2) || (m_comp_v_samp[i] > 2))
stop_decoding(JPGD_UNSUPPORTED_SAMP_FACTORS);
m_comp_quant[i] = get_bits(8);
if (m_comp_quant[i] >= JPGD_MAX_QUANT_TABLES)
stop_decoding(JPGD_DECODE_ERROR);
}
}
// 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);
if (ci >= JPGD_MAX_COMPONENTS)
stop_decoding(JPGD_DECODE_ERROR);
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);
if (m_comp_dc_tab[ci] >= JPGD_MAX_HUFF_TABLES)
stop_decoding(JPGD_DECODE_ERROR);
if (m_comp_ac_tab[ci] >= JPGD_MAX_HUFF_TABLES)
stop_decoding(JPGD_DECODE_ERROR);
}
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;
/* read past whatever is num_left */
while (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.
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;
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;
read_sof_marker();
break;
}
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, uint32_t flags)
{
m_flags = flags;
m_pMem_blocks = nullptr;
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;
memset(m_mcu_org, 0, sizeof(m_mcu_org));
m_total_lines_left = 0;
m_mcu_lines_left = 0;
m_num_buffered_scanlines = 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;
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 = nullptr;
m_pSample_buf = nullptr;
m_pSample_buf_prev = nullptr;
m_sample_buf_prev_valid = false;
m_total_bytes_read = 0;
m_pScan_line_0 = nullptr;
m_pScan_line_1 = nullptr;
// 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;
m_has_sse2 = false;
#if JPGD_USE_SSE2
#ifdef _MSC_VER
int cpu_info[4];
__cpuid(cpu_info, 1);
const int cpu_info3 = cpu_info[3];
m_has_sse2 = ((cpu_info3 >> 26U) & 1U) != 0U;
#else
m_has_sse2 = true;
#endif
#endif
}
#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.
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_coeff_t* pSrc_ptr = m_pMCU_coefficients;
if (mcu_row * m_blocks_per_mcu >= m_max_blocks_per_row)
stop_decoding(JPGD_DECODE_ERROR);
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], ((m_flags & cFlagDisableSIMD) == 0) && m_has_sse2);
pSrc_ptr += 64;
pDst_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_coeff_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];
if (m_comp_quant[component_id] >= JPGD_MAX_QUANT_TABLES)
stop_decoding(JPGD_DECODE_ERROR);
q = m_quant[m_comp_quant[component_id]];
p = m_pMCU_coefficients + 64 * mcu_block;
jpgd_block_coeff_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_coeff_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_coeff_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_coeff_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];
}
}
}
}
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_coeff_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];
if (m_comp_quant[component_id] >= JPGD_MAX_QUANT_TABLES)
stop_decoding(JPGD_DECODE_ERROR);
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);
if (s >= 16)
stop_decoding(JPGD_DECODE_ERROR);
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_coeff_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);
if (k >= 64)
stop_decoding(JPGD_DECODE_ERROR);
p[g_ZAG[k]] = static_cast<jpgd_block_coeff_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--)
{
if (kt > 63)
stop_decoding(JPGD_DECODE_ERROR);
p[g_ZAG[kt++]] = 0;
}
}
k += 16 - 1; // - 1 because the loop counter is k
if (p[g_ZAG[k & 63]] != 0)
stop_decoding(JPGD_DECODE_ERROR);
}
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++;
}
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 (2x1:1:1, 4 m_blocks per MCU) to RGB
void jpeg_decoder::H2V1ConvertFiltered()
{
const uint BLOCKS_PER_MCU = 4;
int row = m_max_mcu_y_size - m_mcu_lines_left;
uint8* d0 = m_pScan_line_0;
const int half_image_x_size = (m_image_x_size >> 1) - 1;
const int row_x8 = row * 8;
for (int x = 0; x < m_image_x_size; x++)
{
int y = m_pSample_buf[check_sample_buf_ofs((x >> 4) * BLOCKS_PER_MCU * 64 + ((x & 8) ? 64 : 0) + (x & 7) + row_x8)];
int c_x0 = (x - 1) >> 1;
int c_x1 = JPGD_MIN(c_x0 + 1, half_image_x_size);
c_x0 = JPGD_MAX(c_x0, 0);
int a = (c_x0 >> 3) * BLOCKS_PER_MCU * 64 + (c_x0 & 7) + row_x8 + 128;
int cb0 = m_pSample_buf[check_sample_buf_ofs(a)];
int cr0 = m_pSample_buf[check_sample_buf_ofs(a + 64)];
int b = (c_x1 >> 3) * BLOCKS_PER_MCU * 64 + (c_x1 & 7) + row_x8 + 128;
int cb1 = m_pSample_buf[check_sample_buf_ofs(b)];
int cr1 = m_pSample_buf[check_sample_buf_ofs(b + 64)];
int w0 = (x & 1) ? 3 : 1;
int w1 = (x & 1) ? 1 : 3;
int cb = (cb0 * w0 + cb1 * w1 + 2) >> 2;
int cr = (cr0 * w0 + cr1 * w1 + 2) >> 2;
int rc = m_crr[cr];
int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
int bc = m_cbb[cb];
d0[0] = clamp(y + rc);
d0[1] = clamp(y + gc);
d0[2] = clamp(y + bc);
d0[3] = 255;
d0 += 4;
}
}
// 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 H2V1 (1x2:1:1, 4 m_blocks per MCU) to RGB
void jpeg_decoder::H1V2ConvertFiltered()
{
const uint BLOCKS_PER_MCU = 4;
int y = m_image_y_size - m_total_lines_left;
int row = y & 15;
const int half_image_y_size = (m_image_y_size >> 1) - 1;
uint8* d0 = m_pScan_line_0;
const int w0 = (row & 1) ? 3 : 1;
const int w1 = (row & 1) ? 1 : 3;
int c_y0 = (y - 1) >> 1;
int c_y1 = JPGD_MIN(c_y0 + 1, half_image_y_size);
const uint8_t* p_YSamples = m_pSample_buf;
const uint8_t* p_C0Samples = m_pSample_buf;
if ((c_y0 >= 0) && (((row & 15) == 0) || ((row & 15) == 15)) && (m_total_lines_left > 1))
{
assert(y > 0);
assert(m_sample_buf_prev_valid);
if ((row & 15) == 15)
p_YSamples = m_pSample_buf_prev;
p_C0Samples = m_pSample_buf_prev;
}
const int y_sample_base_ofs = ((row & 8) ? 64 : 0) + (row & 7) * 8;
const int y0_base = (c_y0 & 7) * 8 + 128;
const int y1_base = (c_y1 & 7) * 8 + 128;
for (int x = 0; x < m_image_x_size; x++)
{
const int base_ofs = (x >> 3) * BLOCKS_PER_MCU * 64 + (x & 7);
int y_sample = p_YSamples[check_sample_buf_ofs(base_ofs + y_sample_base_ofs)];
int a = base_ofs + y0_base;
int cb0_sample = p_C0Samples[check_sample_buf_ofs(a)];
int cr0_sample = p_C0Samples[check_sample_buf_ofs(a + 64)];
int b = base_ofs + y1_base;
int cb1_sample = m_pSample_buf[check_sample_buf_ofs(b)];
int cr1_sample = m_pSample_buf[check_sample_buf_ofs(b + 64)];
int cb = (cb0_sample * w0 + cb1_sample * w1 + 2) >> 2;
int cr = (cr0_sample * w0 + cr1_sample * w1 + 2) >> 2;
int rc = m_crr[cr];
int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
int bc = m_cbb[cb];
d0[0] = clamp(y_sample + rc);
d0[1] = clamp(y_sample + gc);
d0[2] = clamp(y_sample + bc);
d0[3] = 255;
d0 += 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;
}
}
uint32_t jpeg_decoder::H2V2ConvertFiltered()
{
const uint BLOCKS_PER_MCU = 6;
int y = m_image_y_size - m_total_lines_left;
int row = y & 15;
const int half_image_y_size = (m_image_y_size >> 1) - 1;
uint8* d0 = m_pScan_line_0;
int c_y0 = (y - 1) >> 1;
int c_y1 = JPGD_MIN(c_y0 + 1, half_image_y_size);
const uint8_t* p_YSamples = m_pSample_buf;
const uint8_t* p_C0Samples = m_pSample_buf;
if ((c_y0 >= 0) && (((row & 15) == 0) || ((row & 15) == 15)) && (m_total_lines_left > 1))
{
assert(y > 0);
assert(m_sample_buf_prev_valid);
if ((row & 15) == 15)
p_YSamples = m_pSample_buf_prev;
p_C0Samples = m_pSample_buf_prev;
}
const int y_sample_base_ofs = ((row & 8) ? 128 : 0) + (row & 7) * 8;
const int y0_base = (c_y0 & 7) * 8 + 256;
const int y1_base = (c_y1 & 7) * 8 + 256;
const int half_image_x_size = (m_image_x_size >> 1) - 1;
static const uint8_t s_muls[2][2][4] =
{
{ { 1, 3, 3, 9 }, { 3, 9, 1, 3 }, },
{ { 3, 1, 9, 3 }, { 9, 3, 3, 1 } }
};
if (((row & 15) >= 1) && ((row & 15) <= 14))
{
assert((row & 1) == 1);
assert(((y + 1 - 1) >> 1) == c_y0);
assert(p_YSamples == m_pSample_buf);
assert(p_C0Samples == m_pSample_buf);
uint8* d1 = m_pScan_line_1;
const int y_sample_base_ofs1 = (((row + 1) & 8) ? 128 : 0) + ((row + 1) & 7) * 8;
for (int x = 0; x < m_image_x_size; x++)
{
int k = (x >> 4) * BLOCKS_PER_MCU * 64 + ((x & 8) ? 64 : 0) + (x & 7);
int y_sample0 = p_YSamples[check_sample_buf_ofs(k + y_sample_base_ofs)];
int y_sample1 = p_YSamples[check_sample_buf_ofs(k + y_sample_base_ofs1)];
int c_x0 = (x - 1) >> 1;
int c_x1 = JPGD_MIN(c_x0 + 1, half_image_x_size);
c_x0 = JPGD_MAX(c_x0, 0);
int a = (c_x0 >> 3) * BLOCKS_PER_MCU * 64 + (c_x0 & 7);
int cb00_sample = p_C0Samples[check_sample_buf_ofs(a + y0_base)];
int cr00_sample = p_C0Samples[check_sample_buf_ofs(a + y0_base + 64)];
int cb01_sample = m_pSample_buf[check_sample_buf_ofs(a + y1_base)];
int cr01_sample = m_pSample_buf[check_sample_buf_ofs(a + y1_base + 64)];
int b = (c_x1 >> 3) * BLOCKS_PER_MCU * 64 + (c_x1 & 7);
int cb10_sample = p_C0Samples[check_sample_buf_ofs(b + y0_base)];
int cr10_sample = p_C0Samples[check_sample_buf_ofs(b + y0_base + 64)];
int cb11_sample = m_pSample_buf[check_sample_buf_ofs(b + y1_base)];
int cr11_sample = m_pSample_buf[check_sample_buf_ofs(b + y1_base + 64)];
{
const uint8_t* pMuls = &s_muls[row & 1][x & 1][0];
int cb = (cb00_sample * pMuls[0] + cb01_sample * pMuls[1] + cb10_sample * pMuls[2] + cb11_sample * pMuls[3] + 8) >> 4;
int cr = (cr00_sample * pMuls[0] + cr01_sample * pMuls[1] + cr10_sample * pMuls[2] + cr11_sample * pMuls[3] + 8) >> 4;
int rc = m_crr[cr];
int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
int bc = m_cbb[cb];
d0[0] = clamp(y_sample0 + rc);
d0[1] = clamp(y_sample0 + gc);
d0[2] = clamp(y_sample0 + bc);
d0[3] = 255;
d0 += 4;
}
{
const uint8_t* pMuls = &s_muls[(row + 1) & 1][x & 1][0];
int cb = (cb00_sample * pMuls[0] + cb01_sample * pMuls[1] + cb10_sample * pMuls[2] + cb11_sample * pMuls[3] + 8) >> 4;
int cr = (cr00_sample * pMuls[0] + cr01_sample * pMuls[1] + cr10_sample * pMuls[2] + cr11_sample * pMuls[3] + 8) >> 4;
int rc = m_crr[cr];
int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
int bc = m_cbb[cb];
d1[0] = clamp(y_sample1 + rc);
d1[1] = clamp(y_sample1 + gc);
d1[2] = clamp(y_sample1 + bc);
d1[3] = 255;
d1 += 4;
}
if (((x & 1) == 1) && (x < m_image_x_size - 1))
{
const int nx = x + 1;
assert(c_x0 == (nx - 1) >> 1);
k = (nx >> 4) * BLOCKS_PER_MCU * 64 + ((nx & 8) ? 64 : 0) + (nx & 7);
y_sample0 = p_YSamples[check_sample_buf_ofs(k + y_sample_base_ofs)];
y_sample1 = p_YSamples[check_sample_buf_ofs(k + y_sample_base_ofs1)];
{
const uint8_t* pMuls = &s_muls[row & 1][nx & 1][0];
int cb = (cb00_sample * pMuls[0] + cb01_sample * pMuls[1] + cb10_sample * pMuls[2] + cb11_sample * pMuls[3] + 8) >> 4;
int cr = (cr00_sample * pMuls[0] + cr01_sample * pMuls[1] + cr10_sample * pMuls[2] + cr11_sample * pMuls[3] + 8) >> 4;
int rc = m_crr[cr];
int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
int bc = m_cbb[cb];
d0[0] = clamp(y_sample0 + rc);
d0[1] = clamp(y_sample0 + gc);
d0[2] = clamp(y_sample0 + bc);
d0[3] = 255;
d0 += 4;
}
{
const uint8_t* pMuls = &s_muls[(row + 1) & 1][nx & 1][0];
int cb = (cb00_sample * pMuls[0] + cb01_sample * pMuls[1] + cb10_sample * pMuls[2] + cb11_sample * pMuls[3] + 8) >> 4;
int cr = (cr00_sample * pMuls[0] + cr01_sample * pMuls[1] + cr10_sample * pMuls[2] + cr11_sample * pMuls[3] + 8) >> 4;
int rc = m_crr[cr];
int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
int bc = m_cbb[cb];
d1[0] = clamp(y_sample1 + rc);
d1[1] = clamp(y_sample1 + gc);
d1[2] = clamp(y_sample1 + bc);
d1[3] = 255;
d1 += 4;
}
++x;
}
}
return 2;
}
else
{
for (int x = 0; x < m_image_x_size; x++)
{
int y_sample = p_YSamples[check_sample_buf_ofs((x >> 4) * BLOCKS_PER_MCU * 64 + ((x & 8) ? 64 : 0) + (x & 7) + y_sample_base_ofs)];
int c_x0 = (x - 1) >> 1;
int c_x1 = JPGD_MIN(c_x0 + 1, half_image_x_size);
c_x0 = JPGD_MAX(c_x0, 0);
int a = (c_x0 >> 3) * BLOCKS_PER_MCU * 64 + (c_x0 & 7);
int cb00_sample = p_C0Samples[check_sample_buf_ofs(a + y0_base)];
int cr00_sample = p_C0Samples[check_sample_buf_ofs(a + y0_base + 64)];
int cb01_sample = m_pSample_buf[check_sample_buf_ofs(a + y1_base)];
int cr01_sample = m_pSample_buf[check_sample_buf_ofs(a + y1_base + 64)];
int b = (c_x1 >> 3) * BLOCKS_PER_MCU * 64 + (c_x1 & 7);
int cb10_sample = p_C0Samples[check_sample_buf_ofs(b + y0_base)];
int cr10_sample = p_C0Samples[check_sample_buf_ofs(b + y0_base + 64)];
int cb11_sample = m_pSample_buf[check_sample_buf_ofs(b + y1_base)];
int cr11_sample = m_pSample_buf[check_sample_buf_ofs(b + y1_base + 64)];
const uint8_t* pMuls = &s_muls[row & 1][x & 1][0];
int cb = (cb00_sample * pMuls[0] + cb01_sample * pMuls[1] + cb10_sample * pMuls[2] + cb11_sample * pMuls[3] + 8) >> 4;
int cr = (cr00_sample * pMuls[0] + cr01_sample * pMuls[1] + cr10_sample * pMuls[2] + cr11_sample * pMuls[3] + 8) >> 4;
int rc = m_crr[cr];
int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
int bc = m_cbb[cb];
d0[0] = clamp(y_sample + rc);
d0[1] = clamp(y_sample + gc);
d0[2] = clamp(y_sample + bc);
d0[3] = 255;
d0 += 4;
}
return 1;
}
}
// 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;
}
}
// 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_next_mcu_row()
{
if (::setjmp(m_jmp_state))
return JPGD_FAILED;
const bool chroma_y_filtering = ((m_flags & cFlagBoxChromaFiltering) == 0) && ((m_scan_type == JPGD_YH2V2) || (m_scan_type == JPGD_YH1V2));
if (chroma_y_filtering)
{
std::swap(m_pSample_buf, m_pSample_buf_prev);
m_sample_buf_prev_valid = true;
}
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;
return 0;
}
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;
const bool chroma_y_filtering = ((m_flags & cFlagBoxChromaFiltering) == 0) && ((m_scan_type == JPGD_YH2V2) || (m_scan_type == JPGD_YH1V2));
bool get_another_mcu_row = false;
bool got_mcu_early = false;
if (chroma_y_filtering)
{
if (m_total_lines_left == m_image_y_size)
get_another_mcu_row = true;
else if ((m_mcu_lines_left == 1) && (m_total_lines_left > 1))
{
get_another_mcu_row = true;
got_mcu_early = true;
}
}
else
{
get_another_mcu_row = (m_mcu_lines_left == 0);
}
if (get_another_mcu_row)
{
int status = decode_next_mcu_row();
if (status != 0)
return status;
}
switch (m_scan_type)
{
case JPGD_YH2V2:
{
if ((m_flags & cFlagBoxChromaFiltering) == 0)
{
if (m_num_buffered_scanlines == 1)
{
*pScan_line = m_pScan_line_1;
}
else if (m_num_buffered_scanlines == 0)
{
m_num_buffered_scanlines = H2V2ConvertFiltered();
*pScan_line = m_pScan_line_0;
}
m_num_buffered_scanlines--;
}
else
{
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:
{
if ((m_flags & cFlagBoxChromaFiltering) == 0)
H2V1ConvertFiltered();
else
H2V1Convert();
*pScan_line = m_pScan_line_0;
break;
}
case JPGD_YH1V2:
{
if (chroma_y_filtering)
{
H1V2ConvertFiltered();
*pScan_line = m_pScan_line_0;
}
else
{
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;
if (!got_mcu_early)
{
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[258];
uint huffcode[258];
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++)
{
if (p >= 257)
stop_decoding(JPGD_DECODE_ERROR);
huffsize[p++] = static_cast<uint8>(l);
}
}
assert(p < 258);
huffsize[p] = 0;
lastp = p;
code = 0;
si = huffsize[0];
p = 0;
while (huffsize[p])
{
while (huffsize[p] == si)
{
if (p >= 257)
stop_decoding(JPGD_DECODE_ERROR);
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];
assert(i < JPGD_HUFF_CODE_SIZE_MAX_LENGTH);
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--)
{
if (code >= 256)
stop_decoding(JPGD_DECODE_ERROR);
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));
if (extra_bits > 0x7FFF)
stop_decoding(JPGD_DECODE_ERROR);
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--;
unsigned int idx = -currententry - 1;
if (idx >= JPGD_HUFF_TREE_MAX_LENGTH)
stop_decoding(JPGD_DECODE_ERROR);
if (pH->tree[idx] == 0)
{
pH->tree[idx] = nextfreeentry;
currententry = nextfreeentry;
nextfreeentry -= 2;
}
else
{
currententry = pH->tree[idx];
}
code <<= 1;
}
if ((code & 0x8000) == 0)
currententry--;
if ((-currententry - 1) >= JPGD_HUFF_TREE_MAX_LENGTH)
stop_decoding(JPGD_DECODE_ERROR);
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]]] == nullptr)
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]]] == nullptr))
stop_decoding(JPGD_UNDEFINED_HUFF_TABLE);
if ((m_spectral_end > 0) && (m_huff_num[m_comp_ac_tab[m_comp_list[i]]] == nullptr))
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.
bool 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;
}
}
if (m_blocks_per_mcu > m_max_blocks_per_mcu)
return false;
for (int mcu_block = 0; mcu_block < m_blocks_per_mcu; mcu_block++)
{
int comp_id = m_mcu_org[mcu_block];
if (comp_id >= JPGD_MAX_QUANT_TABLES)
return false;
}
return true;
}
// Starts a new scan.
int jpeg_decoder::init_scan()
{
if (!locate_sos_marker())
return JPGD_FALSE;
if (!calc_mcu_block_order())
return JPGD_FALSE;
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_aligned(m_dest_bytes_per_scan_line, true);
if ((m_scan_type == JPGD_YH1V2) || (m_scan_type == JPGD_YH2V2))
m_pScan_line_1 = (uint8*)alloc_aligned(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_DECODE_ERROR);
// Allocate the coefficient buffer, enough for one MCU
m_pMCU_coefficients = (jpgd_block_coeff_t *)alloc_aligned(m_max_blocks_per_mcu * 64 * sizeof(jpgd_block_coeff_t));
for (i = 0; i < m_max_blocks_per_mcu; i++)
m_mcu_block_max_zag[i] = 64;
m_pSample_buf = (uint8*)alloc_aligned(m_max_blocks_per_row * 64);
m_pSample_buf_prev = (uint8*)alloc_aligned(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_coeff_t);
cb->pData = (uint8*)alloc(cb->block_size * block_num_x * block_num_y, true);
return cb;
}
inline jpgd_block_coeff_t* jpeg_decoder::coeff_buf_getp(coeff_buf* cb, int block_x, int block_y)
{
if ((block_x >= cb->block_num_x) || (block_y >= cb->block_num_y))
stop_decoding(JPGD_DECODE_ERROR);
return (jpgd_block_coeff_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_coeff_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)
{
if (s >= 16)
pD->stop_decoding(JPGD_DECODE_ERROR);
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_coeff_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_coeff_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_coeff_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++)
{
unsigned int idx = pD->m_comp_ac_tab[component_id];
if (idx >= JPGD_MAX_HUFF_TABLES)
pD->stop_decoding(JPGD_DECODE_ERROR);
s = pD->huff_decode(pD->m_pHuff_tabs[idx]);
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_coeff_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;
int m1 = static_cast<int>((UINT32_MAX << pD->m_successive_low));
jpgd_block_coeff_t* p = pD->coeff_buf_getp(pD->m_ac_coeffs[component_id], block_x, block_y);
if (pD->m_spectral_end > 63)
pD->stop_decoding(JPGD_DECODE_ERROR);
k = pD->m_spectral_start;
if (pD->m_eob_run == 0)
{
for (; k <= pD->m_spectral_end; k++)
{
unsigned int idx = pD->m_comp_ac_tab[component_id];
if (idx >= JPGD_MAX_HUFF_TABLES)
pD->stop_decoding(JPGD_DECODE_ERROR);
s = pD->huff_decode(pD->m_pHuff_tabs[idx]);
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_coeff_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_coeff_t>(*this_coef + p1);
else
*this_coef = static_cast<jpgd_block_coeff_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_coeff_t>(s);
}
}
}
if (pD->m_eob_run > 0)
{
for (; k <= pD->m_spectral_end; k++)
{
jpgd_block_coeff_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_coeff_t>(*this_coef + p1);
else
*this_coef = static_cast<jpgd_block_coeff_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], block_y_mcu[JPGD_MAX_COMPONENTS];
memset(block_y_mcu, 0, sizeof(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, 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)
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];
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);
}
// See https://libjpeg-turbo.org/pmwiki/uploads/About/TwoIssueswiththeJPEGStandard.pdf
uint32_t total_scans = 0;
const uint32_t MAX_SCANS_TO_PROCESS = 1000;
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);
total_scans++;
if (total_scans > MAX_SCANS_TO_PROCESS)
stop_decoding(JPGD_TOO_MANY_SCANS);
}
m_comps_in_scan = m_comps_in_frame;
for (i = 0; i < m_comps_in_frame; i++)
m_comp_list[i] = i;
if (!calc_mcu_block_order())
stop_decoding(JPGD_DECODE_ERROR);
}
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, uint32_t flags)
{
init(pStream, flags);
locate_sof_marker();
}
jpeg_decoder::jpeg_decoder(jpeg_decoder_stream* pStream, uint32_t flags)
{
if (::setjmp(m_jmp_state))
return;
decode_init(pStream, flags);
}
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 = nullptr;
m_eof_flag = false;
m_error_flag = false;
}
void jpeg_decoder_file_stream::close()
{
if (m_pFile)
{
fclose(m_pFile);
m_pFile = nullptr;
}
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 = nullptr;
fopen_s(&m_pFile, Pfilename, "rb");
#else
m_pFile = fopen(Pfilename, "rb");
#endif
return m_pFile != nullptr;
}
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, uint32_t flags)
{
if (!actual_comps)
return nullptr;
*actual_comps = 0;
if ((!pStream) || (!width) || (!height) || (!req_comps))
return nullptr;
if ((req_comps != 1) && (req_comps != 3) && (req_comps != 4))
return nullptr;
jpeg_decoder decoder(pStream, flags);
if (decoder.get_error_code() != JPGD_SUCCESS)
return nullptr;
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)
return nullptr;
const int dst_bpl = image_width * req_comps;
uint8* pImage_data = (uint8*)jpgd_malloc(dst_bpl * image_height);
if (!pImage_data)
return nullptr;
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);
return nullptr;
}
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;
}
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, uint32_t flags)
{
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, flags);
}
unsigned char* decompress_jpeg_image_from_file(const char* pSrc_filename, int* width, int* height, int* actual_comps, int req_comps, uint32_t flags)
{
jpgd::jpeg_decoder_file_stream file_stream;
if (!file_stream.open(pSrc_filename))
return nullptr;
return decompress_jpeg_image_from_stream(&file_stream, width, height, actual_comps, req_comps, flags);
}
} // namespace jpgd
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