Difference between revisions of "BCSV"

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(Clarification on field data)
(Updated information on column names)
 
(One intermediate revision by the same user not shown)
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| 0x04 || 0x4 || Entry size
 
| 0x04 || 0x4 || Entry size
 
|-
 
|-
| 0x08 || 0x2 || Field count
+
| 0x08 || 0x2 || Column count
 
|-
 
|-
 
| 0x0A || 0x2 || Always '''0x0101'''
 
| 0x0A || 0x2 || Always '''0x0101'''
Line 29: Line 29:
 
| 0x12 || 0xA || Padding
 
| 0x12 || 0xA || Padding
 
|-
 
|-
| 0x1C || 0x8*Field count || Fields
+
| 0x1C || 0x8*Column count || Columns
 
|}
 
|}
  
== Fields ==
+
== Column ==
  
The fields are defined in the header as 2 sections; a data identifier and the relative offset in each entry
+
The columns are defined in the header as 2 sections; an identifier and the relative offset in each entry for that entries column value
  
 
{|class="wikitable"
 
{|class="wikitable"
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! Offset !! Size !! Description
 
! Offset !! Size !! Description
 
|-
 
|-
| 0x00 || 0x4 || Data identifier
+
| 0x00 || 0x4 || Identifier
 
|-
 
|-
 
| 0x04 || 0x4 || Offset
 
| 0x04 || 0x4 || Offset
 
|}
 
|}
  
The data identifier determines what type of data the offset is pointing to. The meaning behind each identifier seems to rely on the context of the files content, generally, with only a small number of identifiers being reused in multiple files. In AC:NH there is a total 2048 unique identifiers, with only 191 being reused in multiple files. For a list of all identifiers in AC:NH and the files they are used in, see here https://pastebin.com/KnbnD1r8
+
The `Identifier` is the CRC32 of the "field name + data type", for example `UniqueID u16`. In the case of AC:NH these are entirely in-lined and the game has no knowledge of the pre-hashed strings, so knowing what the fields original names are requires calculating them yourself
 +
 
 +
The data type for each field is only known at compile time and therefore there is no way to 100% know what each data type is. It is possible roughly determine the type by checking the data size, though (IE, data with a size of 2 could be an '''int16''')
  
 
== Entries ==
 
== Entries ==
  
Entries always begin with their offset relative to the file start, and then contain the blocks data. Nearly every file seems to contain a field with type `0x54607054`, which is always a unique int16 for each entry, though the location of this field is not always the same
+
Entries always begin with their offset relative to the file start, and then contain the entries data
  
 
{|class="wikitable"
 
{|class="wikitable"

Latest revision as of 11:35, 20 May 2020

BCSV, known as Binary CSV, stores information relating to general content in a compact CSV format

General

All information in this document is from Animal Crossing: New Horizons

BCSV files contain a header which defines the number of entries, the size of each entry block, and the fields each entry has, followed by a number of entries with context-specific data

Header

The header contains

Offset Size Description
0x00 0x4 Entry count
0x04 0x4 Entry size
0x08 0x2 Column count
0x0A 0x2 Always 0x0101
0x0C 0x4 VSCB Magic
0x10 0x2 Always 0x1027
0x12 0xA Padding
0x1C 0x8*Column count Columns

Column

The columns are defined in the header as 2 sections; an identifier and the relative offset in each entry for that entries column value

Offset Size Description
0x00 0x4 Identifier
0x04 0x4 Offset

The `Identifier` is the CRC32 of the "field name + data type", for example `UniqueID u16`. In the case of AC:NH these are entirely in-lined and the game has no knowledge of the pre-hashed strings, so knowing what the fields original names are requires calculating them yourself

The data type for each field is only known at compile time and therefore there is no way to 100% know what each data type is. It is possible roughly determine the type by checking the data size, though (IE, data with a size of 2 could be an int16)

Entries

Entries always begin with their offset relative to the file start, and then contain the entries data

Offset Size Description
0x00 0x4 Offset relative to file start
0x04 Entry data