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HASUMI Hitoshi
03a426ec8d
This patch extends the following String methods: * String#bit_set(offset, length, lsb_first: true) -> self * String#bit_set(range, lsb_first: true) -> self * String#bit_clear(offset, length, lsb_first: true) -> self * String#bit_clear(range, lsb_first: true) -> self * String#bit_flip(offset, length, lsb_first: true) -> self * String#bit_flip(range, lsb_first: true) -> self * String#bit_count(offset, length, lsb_first: true) -> Integer * String#bit_count(range, lsb_first: true) -> Integer Link: [Feature #22279]
35 lines
1.3 KiB
Plaintext
35 lines
1.3 KiB
Plaintext
Sets the bit at zero-based bit +offset+ to 0; returns +self+:
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s = "\xFF"
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s.bit_clear(1) # => "\xFD"
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s # => "\xFD"
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With +length+, clears the +length+ consecutive bits beginning at +offset+;
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with a Range, clears the bits covered by +range+:
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s = "\xFF\xFF"
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s.bit_clear(4, 8) # => "\x0F\xF0"
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s = "\xFF\xFF"
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s.bit_clear(4..11) # => "\x0F\xF0"
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The entire region must lie within +self+; a region that extends beyond the
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end raises +IndexError+ rather than being clamped. Writing zero bits is a
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no-op, but even an empty region raises +IndexError+ when it begins beyond
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the end of +self+.
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By default, bits within each byte are numbered from least-significant to
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most-significant. If +lsb_first+ is +false+, byte order is unchanged but bits
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within each byte are numbered from most-significant to least-significant:
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s = "\xFF"
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s.bit_clear(1, lsb_first: false) # => "\xBF"
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s = "\xFF\xFF"
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s.bit_clear(4, 8, lsb_first: false) # => "\xF0\x0F"
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Raises +IndexError+ if +offset+ is out of range, or if any part of the
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region lies outside +self+.
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Raises +ArgumentError+ if +length+ is negative.
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Raises +ArgumentError+ if a bit position is too large to be represented.
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Raises +ArgumentError+ if +lsb_first+ is neither +true+ nor +false+.
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Raises +FrozenError+ if +self+ is frozen, even when writing zero bits.
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