From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 21:33:14 +0200 Subject: Adding upstream version 115.7.0esr. Signed-off-by: Daniel Baumann --- third_party/jpeg-xl/lib/jpegli/decode_scan.cc | 566 ++++++++++++++++++++++++++ 1 file changed, 566 insertions(+) create mode 100644 third_party/jpeg-xl/lib/jpegli/decode_scan.cc (limited to 'third_party/jpeg-xl/lib/jpegli/decode_scan.cc') diff --git a/third_party/jpeg-xl/lib/jpegli/decode_scan.cc b/third_party/jpeg-xl/lib/jpegli/decode_scan.cc new file mode 100644 index 0000000000..29c0172950 --- /dev/null +++ b/third_party/jpeg-xl/lib/jpegli/decode_scan.cc @@ -0,0 +1,566 @@ +// Copyright (c) the JPEG XL Project Authors. All rights reserved. +// +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#include "lib/jpegli/decode_scan.h" + +#include + +#include + +#include "lib/jpegli/decode_internal.h" +#include "lib/jpegli/error.h" +#include "lib/jxl/base/status.h" + +namespace jpegli { +namespace { + +// Max 14 block per MCU (when 1 channel is subsampled) +// Max 64 nonzero coefficients per block +// Max 16 symbol bits plus 11 extra bits per nonzero symbol +// Max 2 bytes per 8 bits (worst case is all bytes are escaped 0xff) +constexpr int kMaxMCUByteSize = 6048; + +// Helper structure to read bits from the entropy coded data segment. +struct BitReaderState { + BitReaderState(const uint8_t* data, const size_t len, size_t pos) + : data_(data), len_(len), start_pos_(pos) { + Reset(pos); + } + + void Reset(size_t pos) { + pos_ = pos; + val_ = 0; + bits_left_ = 0; + next_marker_pos_ = len_; + FillBitWindow(); + } + + // Returns the next byte and skips the 0xff/0x00 escape sequences. + uint8_t GetNextByte() { + if (pos_ >= next_marker_pos_) { + ++pos_; + return 0; + } + uint8_t c = data_[pos_++]; + if (c == 0xff) { + uint8_t escape = pos_ < len_ ? data_[pos_] : 0; + if (escape == 0) { + ++pos_; + } else { + // 0xff was followed by a non-zero byte, which means that we found the + // start of the next marker segment. + next_marker_pos_ = pos_ - 1; + } + } + return c; + } + + void FillBitWindow() { + if (bits_left_ <= 16) { + while (bits_left_ <= 56) { + val_ <<= 8; + val_ |= (uint64_t)GetNextByte(); + bits_left_ += 8; + } + } + } + + int ReadBits(int nbits) { + FillBitWindow(); + uint64_t val = (val_ >> (bits_left_ - nbits)) & ((1ULL << nbits) - 1); + bits_left_ -= nbits; + return val; + } + + // Sets *pos to the next stream position, and *bit_pos to the bit position + // within the next byte where parsing should continue. + // Returns false if the stream ended too early. + bool FinishStream(size_t* pos, size_t* bit_pos) { + *bit_pos = (8 - (bits_left_ & 7)) & 7; + // Give back some bytes that we did not use. + int unused_bytes_left = DivCeil(bits_left_, 8); + while (unused_bytes_left-- > 0) { + --pos_; + // If we give back a 0 byte, we need to check if it was a 0xff/0x00 escape + // sequence, and if yes, we need to give back one more byte. + if (((pos_ == len_ && pos_ == next_marker_pos_) || + (pos_ > 0 && pos_ < next_marker_pos_ && data_[pos_] == 0)) && + (data_[pos_ - 1] == 0xff)) { + --pos_; + } + } + if (pos_ >= next_marker_pos_) { + *pos = next_marker_pos_; + if (pos_ > next_marker_pos_ || *bit_pos > 0) { + // Data ran out before the scan was complete. + return false; + } + } + *pos = pos_; + return true; + } + + const uint8_t* data_; + const size_t len_; + size_t pos_; + uint64_t val_; + int bits_left_; + size_t next_marker_pos_; + size_t start_pos_; +}; + +// Returns the next Huffman-coded symbol. +int ReadSymbol(const HuffmanTableEntry* table, BitReaderState* br) { + int nbits; + br->FillBitWindow(); + int val = (br->val_ >> (br->bits_left_ - 8)) & 0xff; + table += val; + nbits = table->bits - 8; + if (nbits > 0) { + br->bits_left_ -= 8; + table += table->value; + val = (br->val_ >> (br->bits_left_ - nbits)) & ((1 << nbits) - 1); + table += val; + } + br->bits_left_ -= table->bits; + return table->value; +} + +/** + * Returns the DC diff or AC value for extra bits value x and prefix code s. + * + * CCITT Rec. T.81 (1992 E) + * Table F.1 – Difference magnitude categories for DC coding + * SSSS | DIFF values + * ------+-------------------------- + * 0 | 0 + * 1 | –1, 1 + * 2 | –3, –2, 2, 3 + * 3 | –7..–4, 4..7 + * ......|.......................... + * 11 | –2047..–1024, 1024..2047 + * + * CCITT Rec. T.81 (1992 E) + * Table F.2 – Categories assigned to coefficient values + * [ Same as Table F.1, but does not include SSSS equal to 0 and 11] + * + * + * CCITT Rec. T.81 (1992 E) + * F.1.2.1.1 Structure of DC code table + * For each category,... additional bits... appended... to uniquely identify + * which difference... occurred... When DIFF is positive... SSSS... bits of DIFF + * are appended. When DIFF is negative... SSSS... bits of (DIFF – 1) are + * appended... Most significant bit... is 0 for negative differences and 1 for + * positive differences. + * + * In other words the upper half of extra bits range represents DIFF as is. + * The lower half represents the negative DIFFs with an offset. + */ +int HuffExtend(int x, int s) { + JXL_DASSERT(s >= 1); + int half = 1 << (s - 1); + if (x >= half) { + JXL_DASSERT(x < (1 << s)); + return x; + } else { + return x - (1 << s) + 1; + } +} + +// Decodes one 8x8 block of DCT coefficients from the bit stream. +bool DecodeDCTBlock(const HuffmanTableEntry* dc_huff, + const HuffmanTableEntry* ac_huff, int Ss, int Se, int Al, + int* eobrun, BitReaderState* br, coeff_t* last_dc_coeff, + coeff_t* coeffs) { + // Nowadays multiplication is even faster than variable shift. + int Am = 1 << Al; + bool eobrun_allowed = Ss > 0; + if (Ss == 0) { + int s = ReadSymbol(dc_huff, br); + if (s >= kJpegDCAlphabetSize) { + return false; + } + int diff = 0; + if (s > 0) { + int bits = br->ReadBits(s); + diff = HuffExtend(bits, s); + } + int coeff = diff + *last_dc_coeff; + const int dc_coeff = coeff * Am; + coeffs[0] = dc_coeff; + // TODO(eustas): is there a more elegant / explicit way to check this? + if (dc_coeff != coeffs[0]) { + return false; + } + *last_dc_coeff = coeff; + ++Ss; + } + if (Ss > Se) { + return true; + } + if (*eobrun > 0) { + --(*eobrun); + return true; + } + for (int k = Ss; k <= Se; k++) { + int sr = ReadSymbol(ac_huff, br); + if (sr >= kJpegHuffmanAlphabetSize) { + return false; + } + int r = sr >> 4; + int s = sr & 15; + if (s > 0) { + k += r; + if (k > Se) { + return false; + } + if (s + Al >= kJpegDCAlphabetSize) { + return false; + } + int bits = br->ReadBits(s); + int coeff = HuffExtend(bits, s); + coeffs[kJPEGNaturalOrder[k]] = coeff * Am; + } else if (r == 15) { + k += 15; + } else { + *eobrun = 1 << r; + if (r > 0) { + if (!eobrun_allowed) { + return false; + } + *eobrun += br->ReadBits(r); + } + break; + } + } + --(*eobrun); + return true; +} + +bool RefineDCTBlock(const HuffmanTableEntry* ac_huff, int Ss, int Se, int Al, + int* eobrun, BitReaderState* br, coeff_t* coeffs) { + // Nowadays multiplication is even faster than variable shift. + int Am = 1 << Al; + bool eobrun_allowed = Ss > 0; + if (Ss == 0) { + int s = br->ReadBits(1); + coeff_t dc_coeff = coeffs[0]; + dc_coeff |= s * Am; + coeffs[0] = dc_coeff; + ++Ss; + } + if (Ss > Se) { + return true; + } + int p1 = Am; + int m1 = -Am; + int k = Ss; + int r; + int s; + bool in_zero_run = false; + if (*eobrun <= 0) { + for (; k <= Se; k++) { + s = ReadSymbol(ac_huff, br); + if (s >= kJpegHuffmanAlphabetSize) { + return false; + } + r = s >> 4; + s &= 15; + if (s) { + if (s != 1) { + return false; + } + s = br->ReadBits(1) ? p1 : m1; + in_zero_run = false; + } else { + if (r != 15) { + *eobrun = 1 << r; + if (r > 0) { + if (!eobrun_allowed) { + return false; + } + *eobrun += br->ReadBits(r); + } + break; + } + in_zero_run = true; + } + do { + coeff_t thiscoef = coeffs[kJPEGNaturalOrder[k]]; + if (thiscoef != 0) { + if (br->ReadBits(1)) { + if ((thiscoef & p1) == 0) { + if (thiscoef >= 0) { + thiscoef += p1; + } else { + thiscoef += m1; + } + } + } + coeffs[kJPEGNaturalOrder[k]] = thiscoef; + } else { + if (--r < 0) { + break; + } + } + k++; + } while (k <= Se); + if (s) { + if (k > Se) { + return false; + } + coeffs[kJPEGNaturalOrder[k]] = s; + } + } + } + if (in_zero_run) { + return false; + } + if (*eobrun > 0) { + for (; k <= Se; k++) { + coeff_t thiscoef = coeffs[kJPEGNaturalOrder[k]]; + if (thiscoef != 0) { + if (br->ReadBits(1)) { + if ((thiscoef & p1) == 0) { + if (thiscoef >= 0) { + thiscoef += p1; + } else { + thiscoef += m1; + } + } + } + coeffs[kJPEGNaturalOrder[k]] = thiscoef; + } + } + } + --(*eobrun); + return true; +} + +void SaveMCUCodingState(j_decompress_ptr cinfo) { + jpeg_decomp_master* m = cinfo->master; + memcpy(m->mcu_.last_dc_coeff, m->last_dc_coeff_, sizeof(m->last_dc_coeff_)); + m->mcu_.eobrun = m->eobrun_; + size_t offset = 0; + for (int i = 0; i < cinfo->comps_in_scan; ++i) { + const jpeg_component_info* comp = cinfo->cur_comp_info[i]; + int c = comp->component_index; + size_t block_x = m->scan_mcu_col_ * comp->MCU_width; + for (int iy = 0; iy < comp->MCU_height; ++iy) { + size_t block_y = m->scan_mcu_row_ * comp->MCU_height + iy; + size_t biy = block_y % comp->v_samp_factor; + if (block_y >= comp->height_in_blocks) { + continue; + } + size_t nblocks = + std::min(comp->MCU_width, comp->width_in_blocks - block_x); + size_t ncoeffs = nblocks * DCTSIZE2; + coeff_t* coeffs = &m->coeff_rows[c][biy][block_x][0]; + memcpy(&m->mcu_.coeffs[offset], coeffs, ncoeffs * sizeof(coeffs[0])); + offset += ncoeffs; + } + } +} + +void RestoreMCUCodingState(j_decompress_ptr cinfo) { + jpeg_decomp_master* m = cinfo->master; + memcpy(m->last_dc_coeff_, m->mcu_.last_dc_coeff, sizeof(m->last_dc_coeff_)); + m->eobrun_ = m->mcu_.eobrun; + size_t offset = 0; + for (int i = 0; i < cinfo->comps_in_scan; ++i) { + const jpeg_component_info* comp = cinfo->cur_comp_info[i]; + int c = comp->component_index; + size_t block_x = m->scan_mcu_col_ * comp->MCU_width; + for (int iy = 0; iy < comp->MCU_height; ++iy) { + size_t block_y = m->scan_mcu_row_ * comp->MCU_height + iy; + size_t biy = block_y % comp->v_samp_factor; + if (block_y >= comp->height_in_blocks) { + continue; + } + size_t nblocks = + std::min(comp->MCU_width, comp->width_in_blocks - block_x); + size_t ncoeffs = nblocks * DCTSIZE2; + coeff_t* coeffs = &m->coeff_rows[c][biy][block_x][0]; + memcpy(coeffs, &m->mcu_.coeffs[offset], ncoeffs * sizeof(coeffs[0])); + offset += ncoeffs; + } + } +} + +bool FinishScan(j_decompress_ptr cinfo, const uint8_t* data, const size_t len, + size_t* pos, size_t* bit_pos) { + jpeg_decomp_master* m = cinfo->master; + if (m->eobrun_ > 0) { + JPEGLI_ERROR("End-of-block run too long."); + } + m->eobrun_ = -1; + memset(m->last_dc_coeff_, 0, sizeof(m->last_dc_coeff_)); + if (*bit_pos == 0) { + return true; + } + if (data[*pos] == 0xff) { + // After last br.FinishStream we checked that there is at least 2 bytes + // in the buffer. + JXL_DASSERT(*pos + 1 < len); + // br.FinishStream would have detected an early marker. + JXL_DASSERT(data[*pos + 1] == 0); + *pos += 2; + } else { + *pos += 1; + } + *bit_pos = 0; + return true; +} + +} // namespace + +void PrepareForiMCURow(j_decompress_ptr cinfo) { + jpeg_decomp_master* m = cinfo->master; + for (int i = 0; i < cinfo->comps_in_scan; ++i) { + const jpeg_component_info* comp = cinfo->cur_comp_info[i]; + int c = comp->component_index; + int by0 = cinfo->input_iMCU_row * comp->v_samp_factor; + int block_rows_left = comp->height_in_blocks - by0; + int max_block_rows = std::min(comp->v_samp_factor, block_rows_left); + int offset = m->streaming_mode_ ? 0 : by0; + m->coeff_rows[c] = (*cinfo->mem->access_virt_barray)( + reinterpret_cast(cinfo), m->coef_arrays[c], offset, + max_block_rows, true); + } +} + +int ProcessScan(j_decompress_ptr cinfo, const uint8_t* const data, + const size_t len, size_t* pos, size_t* bit_pos) { + if (len == 0) { + return kNeedMoreInput; + } + jpeg_decomp_master* m = cinfo->master; + for (;;) { + // Handle the restart intervals. + if (cinfo->restart_interval > 0 && m->restarts_to_go_ == 0) { + if (!FinishScan(cinfo, data, len, pos, bit_pos)) { + return kNeedMoreInput; + } + // Go to the next marker, warn if we had to skip any data. + size_t num_skipped = 0; + while (*pos + 1 < len && (data[*pos] != 0xff || data[*pos + 1] == 0 || + data[*pos + 1] == 0xff)) { + ++(*pos); + ++num_skipped; + } + if (num_skipped > 0) { + JPEGLI_WARN("Skipped %d bytes before restart marker", (int)num_skipped); + } + if (*pos + 2 > len) { + return kNeedMoreInput; + } + cinfo->unread_marker = data[*pos + 1]; + *pos += 2; + return kHandleRestart; + } + + size_t start_pos = *pos; + BitReaderState br(data, len, start_pos); + if (*bit_pos > 0) { + br.ReadBits(*bit_pos); + } + if (start_pos + kMaxMCUByteSize > len) { + SaveMCUCodingState(cinfo); + } + + // Decode one MCU. + HWY_ALIGN_MAX coeff_t dummy_block[DCTSIZE2]; + bool scan_ok = true; + for (int i = 0; i < cinfo->comps_in_scan; ++i) { + const jpeg_component_info* comp = cinfo->cur_comp_info[i]; + int c = comp->component_index; + const HuffmanTableEntry* dc_lut = + &m->dc_huff_lut_[comp->dc_tbl_no * kJpegHuffmanLutSize]; + const HuffmanTableEntry* ac_lut = + &m->ac_huff_lut_[comp->ac_tbl_no * kJpegHuffmanLutSize]; + for (int iy = 0; iy < comp->MCU_height; ++iy) { + size_t block_y = m->scan_mcu_row_ * comp->MCU_height + iy; + int biy = block_y % comp->v_samp_factor; + for (int ix = 0; ix < comp->MCU_width; ++ix) { + size_t block_x = m->scan_mcu_col_ * comp->MCU_width + ix; + coeff_t* coeffs; + if (block_x >= comp->width_in_blocks || + block_y >= comp->height_in_blocks) { + // Note that it is OK that dummy_block is uninitialized because + // it will never be used in any branches, even in the RefineDCTBlock + // case, because only DC scans can be interleaved and we don't use + // the zero-ness of the DC coeff in the DC refinement code-path. + coeffs = dummy_block; + } else { + coeffs = &m->coeff_rows[c][biy][block_x][0]; + } + if (cinfo->Ah == 0) { + if (!DecodeDCTBlock(dc_lut, ac_lut, cinfo->Ss, cinfo->Se, cinfo->Al, + &m->eobrun_, &br, + &m->last_dc_coeff_[comp->component_index], + coeffs)) { + scan_ok = false; + } + } else { + if (!RefineDCTBlock(ac_lut, cinfo->Ss, cinfo->Se, cinfo->Al, + &m->eobrun_, &br, coeffs)) { + scan_ok = false; + } + } + } + } + } + size_t new_pos; + size_t new_bit_pos; + bool stream_ok = br.FinishStream(&new_pos, &new_bit_pos); + if (new_pos + 2 > len) { + // If reading stopped within the last two bytes, we have to request more + // input even if FinishStream() returned true, since the Huffman code + // reader could have peaked ahead some bits past the current input chunk + // and thus the last prefix code length could have been wrong. We can do + // this because a valid JPEG bit stream has two extra bytes at the end. + RestoreMCUCodingState(cinfo); + return kNeedMoreInput; + } + *pos = new_pos; + *bit_pos = new_bit_pos; + if (!stream_ok) { + // We hit a marker during parsing. + JXL_DASSERT(data[*pos] == 0xff); + JXL_DASSERT(data[*pos + 1] != 0); + RestoreMCUCodingState(cinfo); + JPEGLI_WARN("Incomplete scan detected."); + return JPEG_SCAN_COMPLETED; + } + if (!scan_ok) { + JPEGLI_ERROR("Failed to decode DCT block"); + } + if (m->restarts_to_go_ > 0) { + --m->restarts_to_go_; + } + ++m->scan_mcu_col_; + if (m->scan_mcu_col_ == cinfo->MCUs_per_row) { + ++m->scan_mcu_row_; + m->scan_mcu_col_ = 0; + if (m->scan_mcu_row_ == cinfo->MCU_rows_in_scan) { + if (!FinishScan(cinfo, data, len, pos, bit_pos)) { + return kNeedMoreInput; + } + break; + } else if ((m->scan_mcu_row_ % m->mcu_rows_per_iMCU_row_) == 0) { + // Current iMCU row is done. + break; + } + } + } + ++cinfo->input_iMCU_row; + if (cinfo->input_iMCU_row < cinfo->total_iMCU_rows) { + PrepareForiMCURow(cinfo); + return JPEG_ROW_COMPLETED; + } + return JPEG_SCAN_COMPLETED; +} + +} // namespace jpegli -- cgit v1.2.3