0045116606
AAPT Container Format (.apc) is a simple container that enumerates the various intermediate files that AAPT2 generates during the compile phase. The format is defined in formats.md. For now, continue using the .flat extension for the container file, and keep making use of the .flata zip for storing multiple files. This will allow easier integration with existing build systems and allow the evolution of the APC format to better handle arbitrarily large files. Test: make aapt2_tests Change-Id: Id7216e5b76316bdd683f0fa4eaf2d2da273ba815
3.2 KiB
AAPT2 On-Disk Formats
- AAPT2 Container Format (extension
.apc) - AAPT2 Static Library Format (extension
.sapk)
AAPT2 Container Format (extension .apc)
The APC format (AAPT2 Container Format) is generated by AAPT2 during the compile phase and consumed by the AAPT2 link phase. It is a simple container format for storing compiled PNGs, binary and protobuf XML, and intermediate protobuf resource tables. It also stores all associated meta-data from the compile phase.
Format
The file starts with a simple header. All multi-byte fields are little-endian.
| Size (in bytes) | Field | Description |
|---|---|---|
4 |
magic |
The magic bytes must equal 'AAPT' or 0x54504141. |
4 |
version |
The version of the container format. |
4 |
entry_count |
The number of entries in this container. |
This is followed by entry_count of the following data structure. It must be aligned on a 32-bit
boundary, so if a previous entry ends unaligned, padding must be inserted.
| Size (in bytes) | Field | Description |
|---|---|---|
4 |
entry_type |
The type of the entry. This can be one of two types: RES_TABLE (0x00000000) or RES_FILE (0x00000001). |
8 |
entry_length |
The length of the data that follows. |
entry_length |
data |
The payload. The contents of this varies based on the entry_type. |
If the entry_type is equal to RES_TABLE (0x00000000), the data field contains a serialized
aapt.pb.ResourceTable.
If the entry_type is equal to RES_FILE (0x00000001), the data field contains the following:
| Size (in bytes) | Field | Description |
|---|---|---|
4 |
header_size |
The size of the header field. |
8 |
data_size |
The size of the data field. |
header_size |
header |
The serialized Protobuf message aapt.pb.internal.CompiledFile. |
x |
padding |
Up to 4 bytes of zeros, if padding is necessary to align the data field on a 32-bit boundary. |
data_size |
data |
The payload, which is determined by the type field in the aapt.pb.internal.CompiledFile. This can be a PNG file, binary XML, or aapt.pb.XmlNode. |