add bytefallback bpe

Author: chengchingwen

Project.toml

@@ -1,14 +1,16 @@
 name = "BytePairEncoding"
 uuid = "a4280ba5-8788-555a-8ca8-4a8c3d966a71"
 authors = ["chengchingwen <[email protected]>"]
-version = "0.3.1"
+version = "0.3.2"
 
 [deps]
+DoubleArrayTries = "abbaa0e5-f788-499c-92af-c35ff4258c82"
 StructWalk = "31cdf514-beb7-4750-89db-dda9d2eb8d3d"
 TextEncodeBase = "f92c20c0-9f2a-4705-8116-881385faba05"
 Unicode = "4ec0a83e-493e-50e2-b9ac-8f72acf5a8f5"
 
 [compat]
+DoubleArrayTries = "0.1"
 StructWalk = "0.2"
 TextEncodeBase = "0.5.4, 0.6"
 julia = "1.6"

src/BytePairEncoding.jl

@@ -8,6 +8,7 @@ export BPE, BPETokenization
 
 include("mstring.jl")
 include("bpe.jl")
+include("bytefallback.jl")
 include("tokenization.jl")
 include("learn.jl")
 include("gpt2_utils.jl")

src/bpe.jl

@@ -10,7 +10,7 @@ end
 BPE(merging_rank::Dict; sepsym = nothing, endsym = nothing) = BPE(merging_rank, sepsym, endsym)
 BPE(bpefile; sepsym = nothing, endsym = nothing, kws...) = BPE(read_merges(bpefile, endsym; kws...); sepsym, endsym)
 
-(bpe::BPE)(x) = bytepairencode(x, bpe.merging_rank, bpe.sepsym, bpe.endsym)
+(bpe::BPE)(x) = bytepairencode(bpe, x)
 
 function Base.show(io::IO, bpe::BPE)
     print(io, "BPE(")
@@ -101,20 +101,21 @@ function merge!(ms, i)
     return @inbounds @view(ms[1:desidx])
 end
 
-function merges(x::AbstractString, endsym = nothing)
-  buf = map(Merge, graphemes(x))
-  if endsym !== nothing
-    @inbounds buf[end] = Merge(buf[end], true)
-  end
-  return buf
+function merges(x::AbstractString, endsym::Union{Nothing, AbstractString} = nothing)
+    buf = map(Merge, graphemes(x))
+    if endsym !== nothing
+        @inbounds buf[end] = Merge(buf[end], true)
+    end
+    return buf
 end
+merges(bpe::AbstractBPE, x::AbstractString) = merges(x, bpe.endsym)
 
-function bytepairencode(x, merging_rank, sepsym = nothing, endsym = nothing)
-    ms = merges(x, endsym)
+function bytepairencode(bpe::AbstractBPE, x::AbstractString)
+    ms = merges(bpe, x)
     if length(ms) < 2
-        y = [Merge(x, !isnothing(endsym))]
+        y = [Merge(x, !isnothing(bpe.endsym))]
     else
-        y = merge_loop!(merging_rank, ms, x)
+        y = merge_loop!(bpe.merging_rank, ms, x)
     end
-    return as_string.(y, sepsym, endsym)
+    return as_string.(y, bpe.sepsym, bpe.endsym)
 end

src/bytefallback.jl

@@ -0,0 +1,47 @@
+import DoubleArrayTries
+using DoubleArrayTries: DoubleArrayTrie, StringView
+
+struct ByteFallbackBPE <: AbstractBPE
+    vocab::DoubleArrayTrie
+    merging_rank::Dict{NTuple{2, Merge}, Int}
+    sepsym::Union{String, Nothing}
+    endsym::Union{String, Nothing}
+end
+
+ByteFallbackBPE(vocab_list::AbstractVector{String}, merging_rank, sepsym, endsym) =
+    ByteFallbackBPE(DoubleArrayTrie(collect(vocab_list)), merging_rank, sepsym, endsym)
+
+(bpe::ByteFallbackBPE)(x) = bytepairencode(bpe, x)
+
+function Base.show(io::IO, bpe::ByteFallbackBPE)
+    print(io, "ByteFallbackBPE(")
+    print(io, length(bpe.merging_rank))
+    print(io, " merges")
+    !isnothing(bpe.sepsym) && print(io, ", sepsym = ", bpe.sepsym)
+    !isnothing(bpe.endsym) && print(io, ", endsym = ", bpe.endsym)
+    print(io, ')')
+end
+
+function merges(bpe::ByteFallbackBPE, x::AbstractString)
+    vocab = bpe.vocab
+    y = Vector{Merge}()
+    offset = 0
+    for c in split(x, "")
+        i = DoubleArrayTries.lookup(vocab, c)
+        nu = ncodeunits(c)
+        if iszero(i)
+            cu = codeunits(c)
+            for i = 1:nu
+                push!(y, Merge(x, offset, 1, false, true))
+                offset += 1
+            end
+        else
+            push!(y, Merge(x, offset, nu, false))
+            offset += nu
+        end
+    end
+    if bpe.endsym !== nothing
+        @inbounds y[end] = Merge(y[end], true)
+    end
+    return y
+end

src/mstring.jl

@@ -1,13 +1,16 @@
+using DoubleArrayTries: StringView
+
 struct Merge
     string::String
     offset::UInt16
     ncodeunits::UInt16
     extra::Bool
+    byte::Bool
 end
 
-Merge(str, offset::Int, ncodeunits::Int, extra) = Merge(str, UInt16(offset), UInt16(ncodeunits), extra)
-Merge(a::Merge, e::Bool) = Merge(a.string, a.offset, a.ncodeunits, e)
-Merge(s::SubString, e::Bool = false) = Merge(s.string, s.offset, s.ncodeunits, e)
+Merge(str, offset::Int, ncodeunits::Int, extra, byte = false) = Merge(str, UInt16(offset), UInt16(ncodeunits), extra, byte)
+Merge(a::Merge, e::Bool) = Merge(a.string, a.offset, a.ncodeunits, e, a.byte)
+Merge(s::SubString, e::Bool = false) = Merge(s.string, s.offset, s.ncodeunits, e, false)
 Merge(s::String, e::Bool = false) = Merge(SubString(s), e)
 
 function Merge(a::Merge, b::Merge)
@@ -22,7 +25,7 @@ function Merge(a::Merge, b::Merge)
       error("merge two Merge at same offset: partial string?")
     end
     nunits = a.ncodeunits + b.ncodeunits
-    return Merge(a.string, offset, nunits, b.extra)
+    return Merge(a.string, offset, nunits, b.extra, a.byte & b.byte)
   else
     error("merge different Merge")
   end
@@ -92,7 +95,7 @@ function write_merges(io::IO, rank, endsym = nothing; limit = typemax(Int), comm
 end
 
 function Base.hash(m::Merge, h::UInt)
-    h = hash(m.extra, h) + Base.memhash_seed
+    h = hash(m.byte, hash(m.extra, h)) + Base.memhash_seed
     str_size = m.ncodeunits * sizeof(UInt8)
     str = m.string
     ptr = convert(Ptr{UInt8}, pointer(str)) + m.offset
@@ -103,6 +106,7 @@ function Base.:(==)(m1::Merge, m2::Merge)
     m1.extra == m2.extra || return false
     s = m1.ncodeunits
     s == m2.ncodeunits || return false
+    m1.byte == m2.byte || return false
     str1 = m1.string
     str2 = m2.string
     p1 = convert(Ptr{UInt8}, pointer(str1)) + m1.offset
@@ -113,7 +117,13 @@ end
 function as_string(m::Merge, sepsym, endsym)
     str = m.string
     offset = m.offset
-    s = SubString(str, offset+1, prevind(str, offset + m.ncodeunits + 1))
+    cu = codeunits(str)
+    range = offset+1:offset+m.ncodeunits
+    if m.byte
+        s = join(("<0x$(uppercase(string(cu[i]; base=16, pad=2)))>" for i in range))
+    else
+        s = StringView(@view(cu[range]))
+    end
     sym = m.extra ? endsym : sepsym
     return isnothing(sym) ? String(s) : string(s, sym)
 end