| // Copyright 2023 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef MEDIA_VIDEO_BIT_READER_MACROS_H_ |
| #define MEDIA_VIDEO_BIT_READER_MACROS_H_ |
| |
| // Warning! Should only be included in .cc files. |
| // Common bit reader macros shared by H.26x parsers. |
| #define READ_BITS_OR_RETURN(num_bits, out) \ |
| do { \ |
| int _out; \ |
| if (!br_.ReadBits(num_bits, &_out)) { \ |
| DVLOG(1) \ |
| << "Error in stream: unexpected EOS while trying to read " #out; \ |
| return kInvalidStream; \ |
| } \ |
| *out = _out; \ |
| } while (0) |
| |
| #define READ_BITS_AND_MINUS_BITS_READ_OR_RETURN(num_bits, out, \ |
| num_bits_remain) \ |
| do { \ |
| int _out; \ |
| if (!br_.ReadBits(num_bits, &_out)) { \ |
| DVLOG(1) \ |
| << "Error in stream: unexpected EOS while trying to read " #out; \ |
| return kInvalidStream; \ |
| } \ |
| *num_bits_remain -= num_bits; \ |
| *out = _out; \ |
| } while (0) |
| |
| #define SKIP_BITS_OR_RETURN(num_bits) \ |
| do { \ |
| int bits_left = num_bits; \ |
| int discard; \ |
| while (bits_left > 0) { \ |
| if (!br_.ReadBits(bits_left > 16 ? 16 : bits_left, &discard)) { \ |
| DVLOG(1) << "Error in stream: unexpected EOS while trying to skip"; \ |
| return kInvalidStream; \ |
| } \ |
| bits_left -= 16; \ |
| } \ |
| } while (0) |
| |
| #define READ_BOOL_OR_RETURN(out) \ |
| do { \ |
| int _out; \ |
| if (!br_.ReadBits(1, &_out)) { \ |
| DVLOG(1) \ |
| << "Error in stream: unexpected EOS while trying to read " #out; \ |
| return kInvalidStream; \ |
| } \ |
| *out = _out != 0; \ |
| } while (0) |
| |
| #define READ_BOOL_AND_MINUS_BITS_READ_OR_RETURN(out, num_bits_remain) \ |
| do { \ |
| int _out; \ |
| if (!br_.ReadBits(1, &_out)) { \ |
| DVLOG(1) \ |
| << "Error in stream: unexpected EOS while trying to read " #out; \ |
| return kInvalidStream; \ |
| } \ |
| *num_bits_remain -= 1; \ |
| *out = _out != 0; \ |
| } while (0) |
| |
| // Exp-Golomb code parsing as specified in H.26x specifications. |
| // Read one unsigned exp-Golomb code from the stream and return in |*out| |
| // with total bits read return in |*bits_read|. |
| #define READ_UE_WITH_BITS_READ_OR_RETURN(out, bits_read) \ |
| do { \ |
| int _bit = 0; \ |
| int _num_bits_processed = -1; \ |
| do { \ |
| READ_BITS_OR_RETURN(1, &_bit); \ |
| _num_bits_processed++; \ |
| } while (_bit == 0); \ |
| if (_num_bits_processed > 31) { \ |
| return kInvalidStream; \ |
| } \ |
| *out = (1u << _num_bits_processed) - 1u; \ |
| *bits_read = 1 + _num_bits_processed * 2; \ |
| int _rest; \ |
| if (_num_bits_processed == 31) { \ |
| READ_BITS_OR_RETURN(_num_bits_processed, &_rest); \ |
| if (_rest == 0) { \ |
| break; \ |
| } else { \ |
| DVLOG(1) \ |
| << "Error in stream: invalid value while trying to read " #out; \ |
| return kInvalidStream; \ |
| } \ |
| } \ |
| if (_num_bits_processed > 0) { \ |
| READ_BITS_OR_RETURN(_num_bits_processed, &_rest); \ |
| *out += _rest; \ |
| } \ |
| } while (0) |
| |
| #define READ_UE_OR_RETURN(out) \ |
| do { \ |
| int _bits_read = -1; \ |
| READ_UE_WITH_BITS_READ_OR_RETURN(out, &_bits_read); \ |
| } while (0) |
| |
| #define READ_UE_AND_MINUS_BITS_READ_OR_RETURN(out, num_bits_remain) \ |
| do { \ |
| int num_bits_read = -1; \ |
| READ_UE_WITH_BITS_READ_OR_RETURN(out, &num_bits_read); \ |
| *num_bits_remain -= num_bits_read; \ |
| } while (0) |
| |
| // Read one signed exp-Golomb code from the stream and return in |*out|. |
| #define READ_SE_OR_RETURN(out) \ |
| do { \ |
| int _bits_read = -1; \ |
| int ue = 0; \ |
| READ_UE_WITH_BITS_READ_OR_RETURN(&ue, &_bits_read); \ |
| if (ue % 2 == 0) { \ |
| *out = -(ue / 2); \ |
| } else { \ |
| *out = ue / 2 + 1; \ |
| } \ |
| } while (0) |
| |
| #define IN_RANGE_OR_RETURN(val, min, max) \ |
| do { \ |
| if ((val) < (min) || (val) > (max)) { \ |
| DVLOG(1) << "Error in stream: invalid value, expected " #val " to be" \ |
| << " in range [" << (min) << ":" << (max) << "]" \ |
| << " found " << (val) << " instead"; \ |
| return kInvalidStream; \ |
| } \ |
| } while (0) |
| |
| #define TRUE_OR_RETURN(a) \ |
| do { \ |
| if (!(a)) { \ |
| DVLOG(1) << "Error in stream: invalid value, expected " << #a; \ |
| return kInvalidStream; \ |
| } \ |
| } while (0) |
| |
| #define EQ_OR_RETURN(shdr1, shdr2, field) \ |
| do { \ |
| if ((shdr1->field) != (shdr2->field)) { \ |
| DVLOG(1) << "Error in stream, slice header fields must match for: " \ |
| << #field; \ |
| return kInvalidStream; \ |
| } \ |
| } while (0) |
| |
| #define GT_OR_RETURN(val1, val2) \ |
| do { \ |
| if ((val1) <= (val2)) { \ |
| DVLOG(1) << "Error in stream, " #val1 " is smaller than " #val2; \ |
| return kInvalidStream; \ |
| } \ |
| } while (0) |
| |
| #define LE_OR_RETURN(val1, val2) \ |
| do { \ |
| if ((val1) > (val2)) { \ |
| DVLOG(1) << "Error in stream, " #val1 " is larger than " #val2; \ |
| return kInvalidStream; \ |
| } \ |
| } while (0) |
| |
| #define GE_OR_RETURN(val1, val2) \ |
| do { \ |
| if ((val1) < (val2)) { \ |
| DVLOG(1) << "Error in stream, " #val1 " is larger than " #val2; \ |
| return kInvalidStream; \ |
| } \ |
| } while (0) |
| |
| #define BYTE_ALIGNMENT() \ |
| do { \ |
| int bits_left_to_align = br_.NumBitsLeft() % 8; \ |
| if (bits_left_to_align) { \ |
| SKIP_BITS_OR_RETURN(bits_left_to_align); \ |
| } \ |
| } while (0) |
| |
| #endif // MEDIA_VIDEO_BIT_READER_MACROS_H_ |
