expose findfirst findnext for UInt8 vector (#37283)

* expose findfirst findnext for UInt8 vector * Update base/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * Update base/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * Update base/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * Update base/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * Update base/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * Update test/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * Update base/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * address comments * address comments add OffsetArray test * add findlast findprev * implement comments * let _(r)searchindex handle exception * fix _rsearchindex special behavior * style fix * restirct to 1-indexed array * Update test/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * Update base/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * Update base/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * Update base/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * Update base/strings/search.jl Co-authored-by: Milan Bouchet-Valat <[email protected]> * address comments * change sentinel value to firstindex - 1 * NEWS for find* on Vector of U/Int8 * Update NEWS.md shorten NEWS Co-authored-by: Milan Bouchet-Valat <[email protected]> Co-authored-by: Steven G. Johnson <[email protected]>
JuliaLang · Oct 26, 2020 · 5d8225a · 5d8225a · nanosoldier · Oct 27, 2020
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diff --git a/NEWS.md b/NEWS.md
@@ -13,6 +13,7 @@ New language features
 * The library name passed to `ccall` or `@ccall` can now be an expression involving
  global variables and function calls. The expression will be evaluated the first
  time the `ccall` executes ([#36458]).
+* `findfirst`, `findnext`, `findlast`, and `findall` now support `AbstractVector{<:Union{Int8,UInt8}}` (pattern, array) arguments ([#37283]).
 * `ꜛ` (U+A71B), `ꜜ` (U+A71C) and `ꜝ` (U+A71D) can now also be used as operator
  suffixes. They can be tab-completed from `\^uparrow`, `\^downarrow` and `\^!` in the REPL
  ([#37542]).

diff --git a/base/strings/search.jl b/base/strings/search.jl
@@ -123,6 +123,25 @@ true
 """
 findfirst(ch::AbstractChar, string::AbstractString) = findfirst(==(ch), string)
 
+"""
+ findfirst(pattern::AbstractVector{<:Union{Int8,UInt8}},
+ A::AbstractVector{<:Union{Int8,UInt8}})
+
+Find the first occurrence of sequence `pattern` in vector `A`.
+
+!!! compat "Julia 1.6"
+ This method requires at least Julia 1.6.
+
+# Examples
+```jldoctest
+julia> findfirst([0x52, 0x62], [0x40, 0x52, 0x62, 0x63])
+2:3
+```
+"""
+findfirst(pattern::AbstractVector{<:Union{Int8,UInt8}},
+ A::AbstractVector{<:Union{Int8,UInt8}}) =
+ _search(A, pattern, firstindex(A))
+
 # AbstractString implementation of the generic findnext interface
 function findnext(testf::Function, s::AbstractString, i::Integer)
  i = Int(i)
@@ -166,29 +185,34 @@ function _search_bloom_mask(c)
 end
 
 _nthbyte(s::String, i) = codeunit(s, i)
-_nthbyte(a::Union{AbstractVector{UInt8},AbstractVector{Int8}}, i) = a[i]
+_nthbyte(t::AbstractVector, index) = t[index + (firstindex(t)-1)]
 
 function _searchindex(s::String, t::String, i::Integer)
  # Check for fast case of a single byte
  lastindex(t) == 1 && return something(findnext(isequal(t[1]), s, i), 0)
  _searchindex(unsafe_wrap(Vector{UInt8},s), unsafe_wrap(Vector{UInt8},t), i)
 end
 
-function _searchindex(s::ByteArray, t::ByteArray, i::Integer)
- n = sizeof(t)
- m = sizeof(s)
+function _searchindex(s::AbstractVector{<:Union{Int8,UInt8}},
+ t::AbstractVector{<:Union{Int8,UInt8}},
+ _i::Integer)
+ sentinel = firstindex(s) - 1
+ n = length(t)
+ m = length(s)
+ i = Int(_i) - sentinel
+ (i < 1 || i > m+1) && throw(BoundsError(s, _i))
 
  if n == 0
- return 1 <= i <= m+1 ? max(1, i) : 0
+ return 1 <= i <= m+1 ? max(1, i) : sentinel
  elseif m == 0
- return 0
+ return sentinel
  elseif n == 1
- return something(findnext(isequal(_nthbyte(t,1)), s, i), 0)
+ return something(findnext(isequal(_nthbyte(t,1)), s, i), sentinel)
  end
 
  w = m - n
  if w < 0 || i - 1 > w
- return 0
+ return sentinel
  end
 
  bloom_mask = UInt64(0)
@@ -215,7 +239,8 @@ function _searchindex(s::ByteArray, t::ByteArray, i::Integer)
 
  # match found
  if j == n - 1
- return i+1
+ # restore in case `s` is an OffSetArray
+ return i+firstindex(s)
  end
 
  # no match, try to rule out the next character
@@ -232,16 +257,16 @@ function _searchindex(s::ByteArray, t::ByteArray, i::Integer)
  i += 1
  end
 
- 0
+ sentinel
 end
 
-function _search(s::Union{AbstractString,ByteArray},
- t::Union{AbstractString,AbstractChar,Int8,UInt8},
+function _search(s::Union{AbstractString,AbstractVector{<:Union{Int8,UInt8}}},
+ t::Union{AbstractString,AbstractChar,AbstractVector{<:Union{Int8,UInt8}}},
  i::Integer)
  idx = _searchindex(s,t,i)
  if isempty(t)
  idx:idx-1
- elseif idx > 0
+ elseif idx >= firstindex(s)
  idx:(idx + lastindex(t) - 1)
  else
  nothing
@@ -274,7 +299,7 @@ julia> findnext("Lang", "JuliaLang", 2)
 6:9
 ```
 """
-findnext(t::AbstractString, s::AbstractString, i::Integer) = _search(s, t, Int(i))
+findnext(t::AbstractString, s::AbstractString, start::Integer) = _search(s, t, Int(start))
 
 """
  findnext(ch::AbstractChar, string::AbstractString, start::Integer)
@@ -293,8 +318,32 @@ julia> findnext('o', "Hello to the world", 6)
 8
 ```
 """
-findnext(ch::AbstractChar, string::AbstractString, ind::Integer) =
- findnext(==(ch), string, ind)
+findnext(ch::AbstractChar, string::AbstractString, start::Integer) =
+ findnext(==(ch), string, start)
+
+"""
+ findnext(pattern::AbstractVector{<:Union{Int8,UInt8}},
+ A::AbstractVector{<:Union{Int8,UInt8}},
+ start::Integer)
+
+Find the next occurrence of the sequence `pattern` in vector `A` starting at position `start`.
+
+!!! compat "Julia 1.6"
+ This method requires at least Julia 1.6.
+
+# Examples
+```jldoctest
+julia> findnext([0x52, 0x62], [0x52, 0x62, 0x72], 3) === nothing
+true
+
+julia> findnext([0x52, 0x62], [0x40, 0x52, 0x62, 0x52, 0x62], 3)
+4:5
+```
+"""
+findnext(pattern::AbstractVector{<:Union{Int8,UInt8}},
+ A::AbstractVector{<:Union{Int8,UInt8}},
+ start::Integer) =
+ _search(A, pattern, start)
 
 """
  findlast(pattern::AbstractString, string::AbstractString)
@@ -314,6 +363,23 @@ julia> findfirst("Julia", "JuliaLang")
 findlast(pattern::AbstractString, string::AbstractString) =
  findprev(pattern, string, lastindex(string))
 
+"""
+ findlast(pattern::AbstractVector{<:Union{Int8,UInt8}},
+ A::AbstractVector{<:Union{Int8,UInt8}})
+
+Find the last occurrence of `pattern` in array `A`. Equivalent to
+[`findprev(pattern, A, lastindex(A))`](@ref).
+
+# Examples
+```jldoctest
+julia> findlast([0x52, 0x62], [0x52, 0x62, 0x52, 0x62])
+3:4
+```
+"""
+findlast(pattern::AbstractVector{<:Union{Int8,UInt8}},
+ A::AbstractVector{<:Union{Int8,UInt8}}) =
+ findprev(pattern, A, lastindex(A))
+
 """
  findlast(ch::AbstractChar, string::AbstractString)
 
@@ -387,21 +453,24 @@ function _rsearchindex(s::String, t::String, i::Integer)
  end
 end
 
-function _rsearchindex(s::ByteArray, t::ByteArray, k::Integer)
- n = sizeof(t)
- m = sizeof(s)
+function _rsearchindex(s::AbstractVector{<:Union{Int8,UInt8}}, t::AbstractVector{<:Union{Int8,UInt8}}, _k::Integer)
+ sentinel = firstindex(s) - 1
+ n = length(t)
+ m = length(s)
+ k = Int(_k) - sentinel
+ k < 1 && throw(BoundsError(s, _k))
 
  if n == 0
- return 0 <= k <= m ? max(k, 1) : 0
+ return 0 <= k <= m ? max(k, 1) : sentinel
  elseif m == 0
- return 0
+ return sentinel
  elseif n == 1
- return something(findprev(isequal(_nthbyte(t,1)), s, k), 0)
+ return something(findprev(isequal(_nthbyte(t,1)), s, k), sentinel)
  end
 
  w = m - n
  if w < 0 || k <= 0
- return 0
+ return sentinel
  end
 
  bloom_mask = UInt64(0)
@@ -426,9 +495,9 @@ function _rsearchindex(s::ByteArray, t::ByteArray, k::Integer)
  j += 1
  end
 
- # match found
+ # match found, restore in case `s` is an OffsetArray
  if j == n
- return i
+ return i + sentinel
  end
 
  # no match, try to rule out the next character
@@ -445,16 +514,16 @@ function _rsearchindex(s::ByteArray, t::ByteArray, k::Integer)
  i -= 1
  end
 
- 0
+ sentinel
 end
 
-function _rsearch(s::Union{AbstractString,ByteArray},
- t::Union{AbstractString,AbstractChar,Int8,UInt8},
+function _rsearch(s::Union{AbstractString,AbstractVector{<:Union{Int8,UInt8}}},
+ t::Union{AbstractString,AbstractChar,AbstractVector{<:Union{Int8,UInt8}}},
  i::Integer)
  idx = _rsearchindex(s,t,i)
  if isempty(t)
  idx:idx-1
- elseif idx > 0
+ elseif idx > firstindex(s) - 1
  idx:(idx + lastindex(t) - 1)
  else
  nothing
@@ -503,9 +572,29 @@ julia> findprev('o', "Hello to the world", 18)
 15
 ```
 """
-findprev(ch::AbstractChar, string::AbstractString, ind::Integer) =
- findprev(==(ch), string, ind)
+findprev(ch::AbstractChar, string::AbstractString, start::Integer) =
+ findprev(==(ch), string, start)
+
+"""
+ findprev(pattern::AbstractVector{<:Union{Int8,UInt8}},
+ A::AbstractVector{<:Union{Int8,UInt8}},
+ start::Integer)
+
+Find the previous occurrence of the sequence `pattern` in vector `A` starting at position `start`.
 
+!!! compat "Julia 1.6"
+ This method requires at least Julia 1.6.
+
+# Examples
+```jldoctest
+julia> findprev([0x52, 0x62], [0x40, 0x52, 0x62, 0x52, 0x62], 3)
+2:3
+```
+"""
+findprev(pattern::AbstractVector{<:Union{Int8,UInt8}},
+ A::AbstractVector{<:Union{Int8,UInt8}},
+ start::Integer) =
+ _rsearch(A, pattern, start)
 """
  occursin(needle::Union{AbstractString,AbstractPattern,AbstractChar}, haystack::AbstractString)
 

diff --git a/test/strings/search.jl b/test/strings/search.jl
@@ -390,6 +390,36 @@ s_18109 = "fooα🐨βcd3"
  @test findall("aa", "aaaaaa", overlap=true) == [1:2, 2:3, 3:4, 4:5, 5:6]
 end
 
+# issue 37280
+@testset "UInt8, Int8 vector" begin
+ for T in [Int8, UInt8], VT in [Int8, UInt8]
+ A = T[0x40, 0x52, 0x62, 0x52, 0x62]
+
+ @test findfirst(VT[0x30], A) === nothing
+ @test findfirst(VT[0x52], A) === 2:2
+ @test findlast(VT[0x30], A) === nothing
+ @test findlast(VT[0x52], A) === 4:4
+
+ pattern = VT[0x52, 0x62]
+
+ @test findfirst(pattern, A) === 2:3
+ @test findnext(pattern, A, 2) === 2:3
+ @test findnext(pattern, A, 3) === 4:5
+ # 1 idx too far is allowed
+ @test findnext(pattern, A, length(A)+1) === nothing
+ @test_throws BoundsError findnext(pattern, A, -3)
+ @test_throws BoundsError findnext(pattern, A, length(A)+2)
+
+ @test findlast(pattern, A) === 4:5
+ @test findprev(pattern, A, 3) === 2:3
+ @test findprev(pattern, A, 5) === 4:5
+ @test findprev(pattern, A, 2) === nothing
+ @test findprev(pattern, A, length(A)+1) == findlast(pattern, A)
+ @test findprev(pattern, A, length(A)+2) == findlast(pattern, A)
+ @test_throws BoundsError findprev(pattern, A, -3)
+ end
+end
+
 # issue 32568
 for T = (UInt, BigInt)
  for x = (4, 5)