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Contents
module FormatParser::IOUtils
INTEGER_DIRECTIVES = {
1 => 'C',
2 => 'S',
4 => 'L',
8 => 'Q'
}
class InvalidRead < ArgumentError
end
class MalformedFile < ArgumentError
end
def safe_read(io, n)
raise ArgumentError, 'Unbounded reads are not supported' if n.nil?
buf = io.read(n)
raise InvalidRead, "We wanted to read #{n} bytes from the IO, but the IO is at EOF" unless buf
raise InvalidRead, "We wanted to read #{n} bytes from the IO, but we got #{buf.bytesize} instead" if buf.bytesize != n
buf
end
def safe_skip(io, n)
raise ArgumentError, 'Unbounded skips are not supported' if n.nil?
return if n == 0
raise InvalidRead, 'Negative skips are not supported' if n < 0
io.seek(io.pos + n)
nil
end
# Read an integer.
# @param [Integer] n Number of bytes. Defaults to 4 (32-bit).
# @param [Boolean] signed Signed if true, Unsigned if false. Defaults to false. (unsigned)
# @param [Boolean] big_endian Big-endian if true, little-endian if false. Defaults to true (big-endian).
def read_int(n: 4, signed: false, big_endian: true)
directive = INTEGER_DIRECTIVES[n]
directive.downcase! if signed
directive += (big_endian ? ">" : "<") if n > 1
read_bytes(n).unpack(directive).first
end
def read_fixed_point(fractional_digits: 16, **kwargs)
read_int(**kwargs) / 2.0**fractional_digits
end
# 'n' is the number of bytes to read
def read_bytes(n)
safe_read(@buf, n)
end
alias_method :read_string, :read_bytes
def skip_bytes(n)
safe_skip(@buf, n)
yield if block_given?
end
### TODO: Some kind of built-in offset for the read
end
Version data entries
11 entries across 11 versions & 1 rubygems