libjxl

bitstream.cc (15335B)

---

 // 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/bitstream.h"
 
 #include <cmath>
 
 #include "lib/jpegli/bit_writer.h"
 #include "lib/jpegli/error.h"
 #include "lib/jpegli/memory_manager.h"
 
 namespace jpegli {
 
 void WriteOutput(j_compress_ptr cinfo, const uint8_t* buf, size_t bufsize) {
   size_t pos = 0;
   while (pos < bufsize) {
     if (cinfo->dest->free_in_buffer == 0 &&
         !(*cinfo->dest->empty_output_buffer)(cinfo)) {
       JPEGLI_ERROR("Destination suspension is not supported in markers.");
     }
     size_t len = std::min<size_t>(cinfo->dest->free_in_buffer, bufsize - pos);
     memcpy(cinfo->dest->next_output_byte, buf + pos, len);
     pos += len;
     cinfo->dest->free_in_buffer -= len;
     cinfo->dest->next_output_byte += len;
   }
 }
 
 void WriteOutput(j_compress_ptr cinfo, const std::vector<uint8_t>& bytes) {
   WriteOutput(cinfo, bytes.data(), bytes.size());
 }
 
 void WriteOutput(j_compress_ptr cinfo, std::initializer_list<uint8_t> bytes) {
   WriteOutput(cinfo, bytes.begin(), bytes.size());
 }
 
 void EncodeAPP0(j_compress_ptr cinfo) {
   WriteOutput(cinfo,
               {0xff, 0xe0, 0, 16, 'J', 'F', 'I', 'F', '\0',
                cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
                cinfo->density_unit, static_cast<uint8_t>(cinfo->X_density >> 8),
                static_cast<uint8_t>(cinfo->X_density & 0xff),
                static_cast<uint8_t>(cinfo->Y_density >> 8),
                static_cast<uint8_t>(cinfo->Y_density & 0xff), 0, 0});
 }
 
 void EncodeAPP14(j_compress_ptr cinfo) {
   uint8_t color_transform = cinfo->jpeg_color_space == JCS_YCbCr  ? 1
                             : cinfo->jpeg_color_space == JCS_YCCK ? 2
                                                                   : 0;
   WriteOutput(cinfo, {0xff, 0xee, 0, 14, 'A', 'd', 'o', 'b', 'e', 0, 100, 0, 0,
                       0, 0, color_transform});
 }
 
 void WriteFileHeader(j_compress_ptr cinfo) {
   WriteOutput(cinfo, {0xFF, 0xD8});  // SOI
   if (cinfo->write_JFIF_header) {
     EncodeAPP0(cinfo);
   }
   if (cinfo->write_Adobe_marker) {
     EncodeAPP14(cinfo);
   }
 }
 
 bool EncodeDQT(j_compress_ptr cinfo, bool write_all_tables) {
   uint8_t data[4 + NUM_QUANT_TBLS * (1 + 2 * DCTSIZE2)];  // 520 bytes
   size_t pos = 0;
   data[pos++] = 0xFF;
   data[pos++] = 0xDB;
   pos += 2;  // Length will be filled in later.
 
   int send_table[NUM_QUANT_TBLS] = {};
   if (write_all_tables) {
     for (int i = 0; i < NUM_QUANT_TBLS; ++i) {
       if (cinfo->quant_tbl_ptrs[i]) send_table[i] = 1;
     }
   } else {
     for (int c = 0; c < cinfo->num_components; ++c) {
       send_table[cinfo->comp_info[c].quant_tbl_no] = 1;
     }
   }
 
   bool is_baseline = true;
   for (int i = 0; i < NUM_QUANT_TBLS; ++i) {
     if (!send_table[i]) continue;
     JQUANT_TBL* quant_table = cinfo->quant_tbl_ptrs[i];
     if (quant_table == nullptr) {
       JPEGLI_ERROR("Missing quant table %d", i);
     }
     int precision = 0;
     for (UINT16 q : quant_table->quantval) {
       if (q > 255) {
         precision = 1;
         is_baseline = false;
       }
     }
     if (quant_table->sent_table) {
       continue;
     }
     data[pos++] = (precision << 4) + i;
     for (size_t j = 0; j < DCTSIZE2; ++j) {
       int val_idx = kJPEGNaturalOrder[j];
       int val = quant_table->quantval[val_idx];
       if (val == 0) {
         JPEGLI_ERROR("Invalid quantval 0.");
       }
       if (precision) {
         data[pos++] = val >> 8;
       }
       data[pos++] = val & 0xFFu;
     }
     quant_table->sent_table = TRUE;
   }
   if (pos > 4) {
     data[2] = (pos - 2) >> 8u;
     data[3] = (pos - 2) & 0xFFu;
     WriteOutput(cinfo, data, pos);
   }
   return is_baseline;
 }
 
 void EncodeSOF(j_compress_ptr cinfo, bool is_baseline) {
   if (cinfo->data_precision != kJpegPrecision) {
     JPEGLI_ERROR("Unsupported data precision %d", cinfo->data_precision);
   }
   const uint8_t marker = cinfo->progressive_mode ? 0xc2
                          : is_baseline           ? 0xc0
                                                  : 0xc1;
   const size_t n_comps = cinfo->num_components;
   const size_t marker_len = 8 + 3 * n_comps;
   std::vector<uint8_t> data(marker_len + 2);
   size_t pos = 0;
   data[pos++] = 0xFF;
   data[pos++] = marker;
   data[pos++] = marker_len >> 8u;
   data[pos++] = marker_len & 0xFFu;
   data[pos++] = kJpegPrecision;
   data[pos++] = cinfo->image_height >> 8u;
   data[pos++] = cinfo->image_height & 0xFFu;
   data[pos++] = cinfo->image_width >> 8u;
   data[pos++] = cinfo->image_width & 0xFFu;
   data[pos++] = n_comps;
   for (size_t i = 0; i < n_comps; ++i) {
     jpeg_component_info* comp = &cinfo->comp_info[i];
     data[pos++] = comp->component_id;
     data[pos++] = ((comp->h_samp_factor << 4u) | (comp->v_samp_factor));
     const uint32_t quant_idx = comp->quant_tbl_no;
     if (cinfo->quant_tbl_ptrs[quant_idx] == nullptr) {
       JPEGLI_ERROR("Invalid component quant table index %u.", quant_idx);
     }
     data[pos++] = quant_idx;
   }
   WriteOutput(cinfo, data);
 }
 
 void WriteFrameHeader(j_compress_ptr cinfo) {
   jpeg_comp_master* m = cinfo->master;
   bool is_baseline = EncodeDQT(cinfo, /*write_all_tables=*/false);
   if (cinfo->progressive_mode || cinfo->arith_code ||
       cinfo->data_precision != 8) {
     is_baseline = false;
   }
   for (size_t i = 0; i < m->num_huffman_tables; ++i) {
     int slot_id = m->slot_id_map[i];
     if (slot_id > 0x11 || (slot_id > 0x01 && slot_id < 0x10)) {
       is_baseline = false;
     }
   }
   EncodeSOF(cinfo, is_baseline);
 }
 
 void EncodeDRI(j_compress_ptr cinfo) {
   WriteOutput(cinfo, {0xFF, 0xDD, 0, 4,
                       static_cast<uint8_t>(cinfo->restart_interval >> 8),
                       static_cast<uint8_t>(cinfo->restart_interval & 0xFF)});
 }
 
 void EncodeDHT(j_compress_ptr cinfo, size_t offset, size_t num) {
   jpeg_comp_master* m = cinfo->master;
   size_t marker_len = 2;
   for (size_t i = 0; i < num; ++i) {
     const JHUFF_TBL& table = m->huffman_tables[offset + i];
     if (table.sent_table) continue;
     marker_len += kJpegHuffmanMaxBitLength + 1;
     for (size_t j = 0; j <= kJpegHuffmanMaxBitLength; ++j) {
       marker_len += table.bits[j];
     }
   }
   std::vector<uint8_t> data(marker_len + 2);
   size_t pos = 0;
   data[pos++] = 0xFF;
   data[pos++] = 0xC4;
   data[pos++] = marker_len >> 8u;
   data[pos++] = marker_len & 0xFFu;
   for (size_t i = 0; i < num; ++i) {
     const JHUFF_TBL& table = m->huffman_tables[offset + i];
     if (table.sent_table) continue;
     size_t total_count = 0;
     for (size_t i = 0; i <= kJpegHuffmanMaxBitLength; ++i) {
       total_count += table.bits[i];
     }
     data[pos++] = m->slot_id_map[offset + i];
     for (size_t i = 1; i <= kJpegHuffmanMaxBitLength; ++i) {
       data[pos++] = table.bits[i];
     }
     for (size_t i = 0; i < total_count; ++i) {
       data[pos++] = table.huffval[i];
     }
   }
   if (marker_len > 2) {
     WriteOutput(cinfo, data);
   }
 }
 
 void EncodeSOS(j_compress_ptr cinfo, int scan_index) {
   jpeg_comp_master* m = cinfo->master;
   const jpeg_scan_info* scan_info = &cinfo->scan_info[scan_index];
   const size_t marker_len = 6 + 2 * scan_info->comps_in_scan;
   std::vector<uint8_t> data(marker_len + 2);
   size_t pos = 0;
   data[pos++] = 0xFF;
   data[pos++] = 0xDA;
   data[pos++] = marker_len >> 8u;
   data[pos++] = marker_len & 0xFFu;
   data[pos++] = scan_info->comps_in_scan;
   for (int i = 0; i < scan_info->comps_in_scan; ++i) {
     int comp_idx = scan_info->component_index[i];
     data[pos++] = cinfo->comp_info[comp_idx].component_id;
     int dc_slot_id = m->slot_id_map[m->context_map[comp_idx]];
     int ac_context = m->ac_ctx_offset[scan_index] + i;
     int ac_slot_id = m->slot_id_map[m->context_map[ac_context]];
     data[pos++] = (dc_slot_id << 4u) + (ac_slot_id - 16);
   }
   data[pos++] = scan_info->Ss;
   data[pos++] = scan_info->Se;
   data[pos++] = ((scan_info->Ah << 4u) | (scan_info->Al));
   WriteOutput(cinfo, data);
 }
 
 void WriteScanHeader(j_compress_ptr cinfo, int scan_index) {
   jpeg_comp_master* m = cinfo->master;
   const jpeg_scan_info* scan_info = &cinfo->scan_info[scan_index];
   cinfo->restart_interval = m->scan_token_info[scan_index].restart_interval;
   if (cinfo->restart_interval != m->last_restart_interval) {
     EncodeDRI(cinfo);
     m->last_restart_interval = cinfo->restart_interval;
   }
   size_t num_dht = 0;
   if (scan_index == 0) {
     // For the first scan we emit all DC and at most 4 AC Huffman codes.
     for (size_t i = 0, num_ac = 0; i < m->num_huffman_tables; ++i) {
       if (m->slot_id_map[i] >= 16 && num_ac++ >= 4) break;
       ++num_dht;
     }
   } else if (scan_info->Ss > 0) {
     // For multi-scan sequential and progressive DC scans we have already
     // emitted all Huffman codes that we need before the first scan. For
     // progressive AC scans we only need at most one new Huffman code.
     if (m->context_map[m->ac_ctx_offset[scan_index]] == m->next_dht_index) {
       num_dht = 1;
     }
   }
   if (num_dht > 0) {
     EncodeDHT(cinfo, m->next_dht_index, num_dht);
     m->next_dht_index += num_dht;
   }
   EncodeSOS(cinfo, scan_index);
 }
 
 void WriteBlock(const int32_t* JXL_RESTRICT symbols,
                 const int32_t* JXL_RESTRICT extra_bits, const int num_nonzeros,
                 const bool emit_eob,
                 const HuffmanCodeTable* JXL_RESTRICT dc_code,
                 const HuffmanCodeTable* JXL_RESTRICT ac_code,
                 JpegBitWriter* JXL_RESTRICT bw) {
   int symbol = symbols[0];
   WriteBits(bw, dc_code->depth[symbol], dc_code->code[symbol] | extra_bits[0]);
   for (int i = 1; i < num_nonzeros; ++i) {
     symbol = symbols[i];
     if (symbol > 255) {
       WriteBits(bw, ac_code->depth[0xf0], ac_code->code[0xf0]);
       symbol -= 256;
       if (symbol > 255) {
         WriteBits(bw, ac_code->depth[0xf0], ac_code->code[0xf0]);
         symbol -= 256;
         if (symbol > 255) {
           WriteBits(bw, ac_code->depth[0xf0], ac_code->code[0xf0]);
           symbol -= 256;
         }
       }
     }
     WriteBits(bw, ac_code->depth[symbol],
               ac_code->code[symbol] | extra_bits[i]);
   }
   if (emit_eob) {
     WriteBits(bw, ac_code->depth[0], ac_code->code[0]);
   }
 }
 
 namespace {
 
 JXL_INLINE void EmitMarker(JpegBitWriter* bw, int marker) {
   bw->data[bw->pos++] = 0xFF;
   bw->data[bw->pos++] = marker;
 }
 
 void WriteTokens(j_compress_ptr cinfo, int scan_index, JpegBitWriter* bw) {
   jpeg_comp_master* m = cinfo->master;
   HuffmanCodeTable* coding_tables = &m->coding_tables[0];
   int next_restart_marker = 0;
   const ScanTokenInfo& sti = m->scan_token_info[scan_index];
   size_t num_token_arrays = m->cur_token_array + 1;
   size_t total_tokens = 0;
   size_t restart_idx = 0;
   size_t next_restart = sti.restarts[restart_idx];
   uint8_t* context_map = m->context_map;
   for (size_t i = 0; i < num_token_arrays; ++i) {
     Token* tokens = m->token_arrays[i].tokens;
     size_t num_tokens = m->token_arrays[i].num_tokens;
     if (sti.token_offset < total_tokens + num_tokens &&
         total_tokens < sti.token_offset + sti.num_tokens) {
       size_t start_ix =
           total_tokens < sti.token_offset ? sti.token_offset - total_tokens : 0;
       size_t end_ix = std::min(sti.token_offset + sti.num_tokens - total_tokens,
                                num_tokens);
       size_t cycle_len = bw->len / 8;
       size_t next_cycle = cycle_len;
       for (size_t i = start_ix; i < end_ix; ++i) {
         if (total_tokens + i == next_restart) {
           JumpToByteBoundary(bw);
           EmitMarker(bw, 0xD0 + next_restart_marker);
           next_restart_marker += 1;
           next_restart_marker &= 0x7;
           next_restart = sti.restarts[++restart_idx];
         }
         Token t = tokens[i];
         const HuffmanCodeTable* code = &coding_tables[context_map[t.context]];
         WriteBits(bw, code->depth[t.symbol], code->code[t.symbol] | t.bits);
         if (--next_cycle == 0) {
           if (!EmptyBitWriterBuffer(bw)) {
             JPEGLI_ERROR(
                 "Output suspension is not supported in "
                 "finish_compress");
           }
           next_cycle = cycle_len;
         }
       }
     }
     total_tokens += num_tokens;
   }
 }
 
 void WriteACRefinementTokens(j_compress_ptr cinfo, int scan_index,
                              JpegBitWriter* bw) {
   jpeg_comp_master* m = cinfo->master;
   const ScanTokenInfo& sti = m->scan_token_info[scan_index];
   const uint8_t context = m->ac_ctx_offset[scan_index];
   const HuffmanCodeTable* code = &m->coding_tables[m->context_map[context]];
   size_t cycle_len = bw->len / 64;
   size_t next_cycle = cycle_len;
   size_t refbit_idx = 0;
   size_t eobrun_idx = 0;
   size_t restart_idx = 0;
   size_t next_restart = sti.restarts[restart_idx];
   int next_restart_marker = 0;
   for (size_t i = 0; i < sti.num_tokens; ++i) {
     if (i == next_restart) {
       JumpToByteBoundary(bw);
       EmitMarker(bw, 0xD0 + next_restart_marker);
       next_restart_marker += 1;
       next_restart_marker &= 0x7;
       next_restart = sti.restarts[++restart_idx];
     }
     RefToken t = sti.tokens[i];
     int symbol = t.symbol & 253;
     uint16_t bits = 0;
     if ((symbol & 1) == 0) {
       int r = symbol >> 4;
       if (r > 0 && r < 15) {
         bits = sti.eobruns[eobrun_idx++];
       }
     } else {
       bits = (t.symbol >> 1) & 1;
     }
     WriteBits(bw, code->depth[symbol], code->code[symbol] | bits);
     for (int j = 0; j < t.refbits; ++j) {
       WriteBits(bw, 1, sti.refbits[refbit_idx++]);
     }
     if (--next_cycle == 0) {
       if (!EmptyBitWriterBuffer(bw)) {
         JPEGLI_ERROR("Output suspension is not supported in finish_compress");
       }
       next_cycle = cycle_len;
     }
   }
 }
 
 void WriteDCRefinementBits(j_compress_ptr cinfo, int scan_index,
                            JpegBitWriter* bw) {
   jpeg_comp_master* m = cinfo->master;
   const ScanTokenInfo& sti = m->scan_token_info[scan_index];
   size_t restart_idx = 0;
   size_t next_restart = sti.restarts[restart_idx];
   int next_restart_marker = 0;
   size_t cycle_len = bw->len * 4;
   size_t next_cycle = cycle_len;
   size_t refbit_idx = 0;
   for (size_t i = 0; i < sti.num_tokens; ++i) {
     if (i == next_restart) {
       JumpToByteBoundary(bw);
       EmitMarker(bw, 0xD0 + next_restart_marker);
       next_restart_marker += 1;
       next_restart_marker &= 0x7;
       next_restart = sti.restarts[++restart_idx];
     }
     WriteBits(bw, 1, sti.refbits[refbit_idx++]);
     if (--next_cycle == 0) {
       if (!EmptyBitWriterBuffer(bw)) {
         JPEGLI_ERROR(
             "Output suspension is not supported in "
             "finish_compress");
       }
       next_cycle = cycle_len;
     }
   }
 }
 
 }  // namespace
 
 void WriteScanData(j_compress_ptr cinfo, int scan_index) {
   const jpeg_scan_info* scan_info = &cinfo->scan_info[scan_index];
   JpegBitWriter* bw = &cinfo->master->bw;
   if (scan_info->Ah == 0) {
     WriteTokens(cinfo, scan_index, bw);
   } else if (scan_info->Ss > 0) {
     WriteACRefinementTokens(cinfo, scan_index, bw);
   } else {
     WriteDCRefinementBits(cinfo, scan_index, bw);
   }
   if (!bw->healthy) {
     JPEGLI_ERROR("Unknown Huffman coded symbol found in scan %d", scan_index);
   }
   JumpToByteBoundary(bw);
   if (!EmptyBitWriterBuffer(bw)) {
     JPEGLI_ERROR("Output suspension is not supported in finish_compress");
   }
 }
 
 }  // namespace jpegli