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Diffstat (limited to 'thirdparty/basis_universal/encoder/jpgd.cpp')
| -rw-r--r-- | thirdparty/basis_universal/encoder/jpgd.cpp | 3241 |
1 files changed, 3241 insertions, 0 deletions
diff --git a/thirdparty/basis_universal/encoder/jpgd.cpp b/thirdparty/basis_universal/encoder/jpgd.cpp new file mode 100644 index 0000000000..460834409d --- /dev/null +++ b/thirdparty/basis_universal/encoder/jpgd.cpp @@ -0,0 +1,3241 @@ +// 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. +// +#ifdef _MSC_VER +#ifndef BASISU_NO_ITERATOR_DEBUG_LEVEL +#if defined(_DEBUG) || defined(DEBUG) +#define _ITERATOR_DEBUG_LEVEL 1 +#define _SECURE_SCL 1 +#else +#define _SECURE_SCL 0 +#define _ITERATOR_DEBUG_LEVEL 0 +#endif +#endif +#endif + +#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 + +#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 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_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_t* pSrc) + { + (void)pTemp; + (void)pSrc; + } + }; + + template <> + struct Row<1> + { + static void idct(int* pTemp, const jpgd_block_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_t* pSrc_ptr, uint8* pDst_ptr, int block_max_zag) + { + 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; + } + + 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++; + } + } + + // 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, ((int)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); + + 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; + } + +#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_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]); + 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_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_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]; + } + } + } + } + + 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]; + 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_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_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 & cFlagLinearChromaFiltering) && ((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 & cFlagLinearChromaFiltering) && ((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 & cFlagLinearChromaFiltering) + { + 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 & cFlagLinearChromaFiltering) + 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(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_DECODE_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_pSample_buf = (uint8*)alloc(m_max_blocks_per_row * 64); + m_pSample_buf_prev = (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) + { + if ((block_x >= cb->block_num_x) || (block_y >= cb->block_num_y)) + stop_decoding(JPGD_DECODE_ERROR); + + 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) + { + 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_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++) + { + 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_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_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_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], 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 |