# This file is a part of Julia. License is MIT: https://julialang.org/license

## SubString and Cstring tests ##

## SubString tests ##
u8str = "∀ ε > 0, ∃ δ > 0: |x-y| < δ ⇒ |f(x)-f(y)| < ε"
u8str2 = u8str^2
len_u8str = length(u8str)
slen_u8str = length(u8str)
len_u8str2 = length(u8str2)
slen_u8str2 = length(u8str2)

@test len_u8str2 == 2 * len_u8str
@test slen_u8str2 == 2 * slen_u8str

u8str2plain = String(u8str2)

for i1 = 1:length(u8str2)
    if !isvalid(u8str2, i1); continue; end
    for i2 = i1:length(u8str2)
        if !isvalid(u8str2, i2); continue; end
        @test length(u8str2[i1:i2]) == length(u8str2plain[i1:i2])
        @test length(u8str2[i1:i2]) == length(u8str2plain[i1:i2])
        @test u8str2[i1:i2] == u8str2plain[i1:i2]
    end
end

# tests that SubString of a single multibyte `Char` string, like "∀" which takes 3 bytes
# gives the same result as `getindex` (except that it is a veiw not a copy)
for idx in 0:1
    @test SubString("∀", 1, idx) == "∀"[1:idx]
end

# Substring provided with invalid end index throws BoundsError
@test_throws StringIndexError SubString("∀", 1, 2)
@test_throws StringIndexError SubString("∀", 1, 3)
@test_throws BoundsError SubString("∀", 1, 4)

# Substring provided with invalid start index throws BoundsError
@test SubString("∀∀", 1:1) == "∀"
@test SubString("∀∀", 1:4) == "∀∀"
@test SubString("∀∀", 4:4) == "∀"
@test_throws StringIndexError SubString("∀∀", 1:2)
@test_throws StringIndexError SubString("∀∀", 1:5)
@test_throws StringIndexError SubString("∀∀", 2:4)
@test_throws BoundsError SubString("∀∀", 0:1)
@test_throws BoundsError SubString("∀∀", 0:4)
@test_throws BoundsError SubString("∀∀", 1:7)
@test_throws BoundsError SubString("∀∀", 4:7)

# tests for SubString of more than one multibyte `Char` string
# we are consistent with `getindex` for `String`
for idx in [0, 1, 4]
    @test SubString("∀∀", 1, idx) == "∀∀"[1:idx]
    @test SubString("∀∀", 4, idx) == "∀∀"[4:idx]
end

# index beyond lastindex("∀∀")
for idx in [2:3; 5:6]
    @test_throws StringIndexError SubString("∀∀", 1, idx)
end
for idx in 7:8
    @test_throws BoundsError SubString("∀∀", 1, idx)
end

let str="tempus fugit"              #length(str)==12
    ss=SubString(str,1,lastindex(str)) #match source string
    @test length(ss)==length(str)

    ss=SubString(str,1:lastindex(str))
    @test length(ss)==length(str)

    ss=SubString(str,1,0)    #empty SubString
    @test length(ss)==0

    ss=SubString(str,1:0)
    @test length(ss)==0

    @test_throws BoundsError SubString(str, 14, 20)  #start indexing beyond source string length
    @test_throws BoundsError SubString(str, 10, 16)  #end indexing beyond source string length

    @test_throws BoundsError SubString("", 1, 4)  #empty source string
    @test_throws BoundsError SubString("", 1, 1)  #empty source string, identical start and end index
    @test_throws BoundsError SubString("", 10, 12)
    @test SubString("", 12, 10) == ""
end

@test SubString("foobar", big(1), big(3)) == "foo"

let str = "aa\u2200\u2222bb"
    u = SubString(str, 3, 6)
    @test length(u) == 2
    b = IOBuffer()
    write(b, u)
    @test String(take!(b)) == "\u2200\u2222"

    @test_throws StringIndexError SubString(str, 4, 5)
    @test_throws BoundsError iterate(u, 0)
    @test_throws BoundsError iterate(u, 8)
    @test_throws BoundsError getindex(u, 0)
    @test_throws BoundsError getindex(u, 7)
    @test_throws BoundsError getindex(u, 0:1)
    @test_throws BoundsError getindex(u, 7:7)
    @test reverseind(u, 1) == 4
    @test typeof(Base.cconvert(Ptr{Int8}, u)) == SubString{String}
    @test Base.cconvert(Ptr{Int8}, u) == u
end

let str = "føøbar"
    @test_throws BoundsError SubString(str, 10, 10)
    u = SubString(str, 4, 3)
    @test length(u) == 0
    b = IOBuffer()
    write(b, u)
    @test String(take!(b)) == ""
end

# search and SubString (issue #5679)
let str = "Hello, world!"
    u = SubString(str, 1, 5)
    @test findlast("World", u) == nothing
    @test findlast(isequal('z'), u) == nothing
    @test findlast("ll", u) == 3:4
end

# SubString created from SubString
let str = "Hello, world!"
    u = SubString(str, 2, 5)
    for idx in 1:4
        @test SubString(u, 2, idx) == u[2:idx]
        @test SubString(u, 2:idx) == u[2:idx]
    end
    @test_throws BoundsError SubString(u, 1, 10)
    @test_throws BoundsError SubString(u, 1:10)
    @test_throws BoundsError SubString(u, 20:30)
    @test SubString(u, 20:15) == ""
    @test_throws BoundsError SubString(u, -1:10)
    @test SubString(u, -1, -10) == ""
    @test SubString(SubString("123", 1, 2), -10, -20) == ""
end

# sizeof
@test sizeof(SubString("abc\u2222def",4,4)) == 3

# issue #3710
@test prevind(SubString("{var}",2,4),4) == 3

# issue #4183
@test split(SubString("x", 2, 0), "y") == [""]

# issue #6772
@test parse(Float64, SubString("10",1,1)) === 1.0
@test parse(Float64, SubString("1 0",1,1)) === 1.0
@test parse(Float32, SubString("10",1,1)) === 1.0f0

# issue #5870
@test !occursin(Regex("aa"), SubString("",1,0))
@test occursin(Regex(""), SubString("",1,0))

# isvalid, length, prevind, nextind for SubString{String}
let s = "lorem ipsum", sdict = Dict(
    SubString(s, 1, 11)  => "lorem ipsum",
    SubString(s, 1, 6)   => "lorem ",
    SubString(s, 1, 0)   => "",
    SubString(s, 2, 4)   => "ore",
    SubString(s, 2, 11)  => "orem ipsum",
    SubString(s, 15, 14) => "",
)
    for (ss, s) in sdict
        @test ncodeunits(ss) == ncodeunits(s)
        for i in -2:13
            @test isvalid(ss, i) == isvalid(s, i)
        end
        for i in 1:ncodeunits(ss), j = i-1:ncodeunits(ss)
            @test length(ss, i, j) == length(s, i, j)
        end
    end
    for (ss, s) in sdict
        @test length(ss) == length(s)
        for i in 0:ncodeunits(ss), j = 0:length(ss)+1
            @test prevind(ss, i+1, j) == prevind(s, i+1, j)
            @test nextind(ss, i, j) == nextind(s, i, j)
        end
        @test_throws BoundsError prevind(s, 0)
        @test_throws BoundsError prevind(ss, 0)
        @test_throws BoundsError nextind(s, ncodeunits(ss)+1)
        @test_throws BoundsError nextind(ss, ncodeunits(ss)+1)
    end
end

# proper nextind/prevind/thisind for SubString{String}
let rng = MersenneTwister(1), strs = ["∀∃∀"*String(rand(rng, UInt8, 40))*"∀∃∀",
                                      String(rand(rng, UInt8, 50))]
    for s in strs
        a = 0
        while a <= ncodeunits(s)
            a = nextind(s, a)
            b = a - 1
            while b <= ncodeunits(s)
                ss = SubString(s, a:b)
                s2 = s[a:b]
                @test ncodeunits(ss) == ncodeunits(s2)
                for i in 0:ncodeunits(ss)+1
                    @test thisind(ss, i) == thisind(s2, i)
                end
                for i in 0:ncodeunits(ss)
                    @test nextind(ss, i) == nextind(s2, i)
                    for j in 0:ncodeunits(ss)+5
                        if j > 0 || isvalid(ss, i)
                            @test nextind(ss, i, j) == nextind(s2, i, j)
                        end
                    end
                end
                for i in 1:ncodeunits(ss)+1
                    @test prevind(ss, i) == prevind(s2, i)
                    for j in 0:ncodeunits(ss)+5
                        if j > 0 || isvalid(ss, i)
                            @test prevind(ss, i, j) == prevind(s2, i, j)
                        end
                    end
                end
                b = nextind(s, b)
            end
        end
    end
end

# for isvalid(SubString{String})
let s = "Σx + βz - 2"
    for i in -1:ncodeunits(s)+2
        if checkbounds(Bool, s, i)
            if isvalid(s, i)
                ss = SubString(s, 1, i)
                for j = 1:ncodeunits(ss)
                    @test isvalid(ss, j) == isvalid(s, j)
                end
            else
                @test_throws StringIndexError SubString(s, 1, i)
            end
        elseif i > 0
            @test_throws BoundsError SubString(s, 1, i)
        else
            @test SubString(s, 1, i) == ""
        end
    end
end

let ss = SubString("hello", 1, 5)
    @test length(ss, 1, 0) == 0
    @test_throws BoundsError length(ss, 1, -1)
    @test_throws BoundsError length(ss, 1, 6)
    @test_throws BoundsError length(ss, 1, 10)
    @test_throws BoundsError prevind(ss, 0, 1)
    @test prevind(ss, 1, 1) == 0
    @test prevind(ss, 6, 1) == 5
    @test_throws BoundsError prevind(ss, 7, 1)
    @test_throws BoundsError nextind(ss, -1, 1)
    @test nextind(ss, 0, 1) == 1
    @test nextind(ss, 5, 1) == 6
    @test_throws BoundsError nextind(ss, 6, 1)
end

# length(SubString{String}) performance specialization
let s = "|η(α)-ϕ(κ)| < ε"
    @test length(SubString(s, 1, 0)) == length(s[1:0])
    @test length(SubString(s, 4, 4)) == length(s[4:4])
    @test length(SubString(s, 1, 7)) == length(s[1:7])
    @test length(SubString(s, 4, 11)) == length(s[4:11])
end

@testset "reverseind" for T in (String, SubString, GenericString)
    for prefix in ("", "abcd", "\U0001d6a4\U0001d4c1", "\U0001d6a4\U0001d4c1c", " \U0001d6a4\U0001d4c1")
        for suffix in ("", "abcde", "\U0001d4c1β\U0001d6a4", "\U0001d4c1β\U0001d6a4c", " \U0001d4c1β\U0001d6a4")
            for c in ('X', 'δ', '\U0001d6a5')
                s = convert(T, string(prefix, c, suffix))
                r = reverse(s)
                ri = findfirst(isequal(c), r)
                @test c == s[reverseind(s, ri)] == r[ri]
                s = convert(T, string(prefix, prefix, c, suffix, suffix))
                pre = convert(T, prefix)
                sb = SubString(s, nextind(pre, lastindex(pre)),
                               lastindex(convert(T, string(prefix, prefix, c, suffix))))
                r = reverse(sb)
                ri = findfirst(isequal(c), r)
                @test c == sb[reverseind(sb, ri)] == r[ri]
            end
        end
    end
end

@testset "reverseind of empty strings" begin
    for s in ("",
              SubString("", 1, 0),
              SubString("ab", 1, 0),
              SubString("ab", 2, 1),
              SubString("ab", 3, 2),
              GenericString(""))
        @test reverseind(s, 0) == 1
        @test reverseind(s, 1) == 0
    end
end

## Cstring tests ##

# issue #13974: comparison against pointers
let
    str = String("foobar")
    ptr = pointer(str)
    cstring = Cstring(ptr)
    @test ptr == cstring
    @test cstring == ptr

    # convenient NULL string creation from Ptr{Cvoid}
    nullstr = Cstring(C_NULL)

    # Comparisons against NULL strings
    @test ptr != nullstr
    @test nullstr != ptr

    # Short-hand comparison against C_NULL
    @test nullstr == C_NULL
    @test C_NULL == nullstr
    @test cstring != C_NULL
    @test C_NULL != cstring
end

# issue #31381: eltype(Cstring) != Cchar
let
    s = Cstring(C_NULL)
    @test eltype(Cstring) == Cchar
    @test eltype(s) == Cchar
    @test pointer(s) isa Ptr{Cchar}
end
