mirror of https://github.com/zeldaret/oot.git
84 lines
2.1 KiB
Python
84 lines
2.1 KiB
Python
# SPDX-FileCopyrightText: © 2024 ZeldaRET
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# SPDX-License-Identifier: CC0-1.0
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from __future__ import annotations
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import dataclasses
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import struct
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STRUCT_IIII = struct.Struct(">IIII")
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@dataclasses.dataclass
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class DmaEntry:
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"""
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A Python counterpart to the dmadata entry struct:
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```c
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typedef struct {
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/* 0x00 */ uintptr_t vromStart;
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/* 0x04 */ uintptr_t vromEnd;
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/* 0x08 */ uintptr_t romStart;
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/* 0x0C */ uintptr_t romEnd;
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} DmaEntry;
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```
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"""
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vrom_start: int
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vrom_end: int
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rom_start: int
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rom_end: int
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def __repr__(self):
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return (
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"DmaEntry("
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f"vrom_start=0x{self.vrom_start:08X}, "
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f"vrom_end=0x{self.vrom_end:08X}, "
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f"rom_start=0x{self.rom_start:08X}, "
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f"rom_end=0x{self.rom_end:08X}"
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")"
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)
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SIZE_BYTES = STRUCT_IIII.size
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def to_bin(self, data: memoryview):
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STRUCT_IIII.pack_into(
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data,
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0,
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self.vrom_start,
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self.vrom_end,
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self.rom_start,
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self.rom_end,
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)
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@staticmethod
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def from_bin(data: memoryview):
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return DmaEntry(*STRUCT_IIII.unpack_from(data))
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def is_compressed(self) -> bool:
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return self.rom_end != 0
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def is_syms(self) -> bool:
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"""
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"SYMS" DMA entries describe segments that are always filled with 0's in the ROM.
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The DMA entry has both rom_start and rom_end set to 0xFFFFFFFF, where the actual rom start and end is given by vrom_start and vrom_end instead.
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These zeroed segments are used to record the offsets/sizes of subfiles in compressed yaz0 archive files but are not used by the game directly.
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"""
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return self.rom_start == 0xFFFFFFFF and self.rom_end == 0xFFFFFFFF
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DMA_ENTRY_END = DmaEntry(0, 0, 0, 0)
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def read_dmadata(rom_data: memoryview, start_offset: int) -> list[DmaEntry]:
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result = []
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offset = start_offset
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while (
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entry := DmaEntry.from_bin(rom_data[offset : offset + DmaEntry.SIZE_BYTES])
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) != DMA_ENTRY_END:
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result.append(entry)
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offset += DmaEntry.SIZE_BYTES
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return result
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