Binary I/O library for Ruby that has an interface similar the C# Binary Reader and Writer.

Reader

Loading a file

require 'bin_tools'

f = BinTools::Reader.from_file 'test.bin'

Sets the base (origin) position, which the read pointer considers as 0.

f.set_base 0x8000

Seek to an offset (sets the read pointer).

If a base position was set, the offset in the file will be base + offset.

f.seek 0x4000

Reading values will auto-advance the read pointer by the data size of the value.

Read a byte (advances +1)

x = f.read_byte # unsigned
x = f.read_s8   # signed

Read a 16-bit integer (advances +2)

x = f.read_u16_le # unsigned, little endian
x = f.read_s16_le # signed, little endian
x = f.read_u16_be # unsigned, big endian

Read a 32-bit integer (advances +4)

x = f.read_u32_le # unsigned, little endian
x = f.read_s32_le # signed, little endian
x = f.read_u32_be # unsigned, big endian

Read a 32-bit float (advances +4)

x = f.read_f32_le # little endian

Read byte string of arbitrary length (advances +length)

str = f.read_bin 0x1000
str = f.read_binswap 0x1000 # reads and does a 32-bit byteswap

Read variable length quantity commonly used in MIDI (advances +length)

x = f.read_varlen_le # little endian
x = f.read_varlen_be # big endian (used in MIDI)

Debug print with file offset, read pointer offset

f.msg "GFX section start"
# "C000(4000): GFX section start"

Get current offset

f.seek 0x4000
f.read_byte
f.tell # => 0x4001