Allow crc32c hashing of SubString{String} (#47693)

Author: jakobnissen

base/util.jl

@@ -469,7 +469,9 @@ _crc32c(a::NTuple{<:Any, UInt8}, crc::UInt32=0x00000000) =
 _crc32c(a::Union{Array{UInt8},FastContiguousSubArray{UInt8,N,<:Array{UInt8}} where N}, crc::UInt32=0x00000000) =
     unsafe_crc32c(a, length(a) % Csize_t, crc)
 
-_crc32c(s::String, crc::UInt32=0x00000000) = unsafe_crc32c(s, sizeof(s) % Csize_t, crc)
+function _crc32c(s::Union{String, SubString{String}}, crc::UInt32=0x00000000)
+    unsafe_crc32c(s, sizeof(s) % Csize_t, crc)
+end
 
 function _crc32c(io::IO, nb::Integer, crc::UInt32=0x00000000)
     nb < 0 && throw(ArgumentError("number of bytes to checksum must be ≥ 0, got $nb"))

stdlib/CRC32c/src/CRC32c.jl

@@ -36,7 +36,7 @@ function crc32c end
 
 
 crc32c(a::Union{Array{UInt8},FastContiguousSubArray{UInt8,N,<:Array{UInt8}} where N}, crc::UInt32=0x00000000) = Base._crc32c(a, crc)
-crc32c(s::String, crc::UInt32=0x00000000) = Base._crc32c(s, crc)
+crc32c(s::Union{String, SubString{String}}, crc::UInt32=0x00000000) = Base._crc32c(s, crc)
 
 """
     crc32c(io::IO, [nb::Integer,] crc::UInt32=0x00000000)

stdlib/CRC32c/test/runtests.jl

@@ -6,7 +6,9 @@ using CRC32c
 function test_crc32c(crc32c)
     # CRC32c checksum (test data generated from @andrewcooke's CRC.jl package)
     for (n,crc) in [(0,0x00000000),(1,0xa016d052),(2,0x03f89f52),(3,0xf130f21e),(4,0x29308cf4),(5,0x53518fab),(6,0x4f4dfbab),(7,0xbd3a64dc),(8,0x46891f81),(9,0x5a14b9f9),(10,0xb219db69),(11,0xd232a91f),(12,0x51a15563),(13,0x9f92de41),(14,0x4d8ae017),(15,0xc8b74611),(16,0xa0de6714),(17,0x672c992a),(18,0xe8206eb6),(19,0xc52fd285),(20,0x327b0397),(21,0x318263dd),(22,0x08485ccd),(23,0xea44d29e),(24,0xf6c0cb13),(25,0x3969bba2),(26,0x6a8810ec),(27,0x75b3d0df),(28,0x82d535b1),(29,0xbdf7fc12),(30,0x1f836b7d),(31,0xd29f33af),(32,0x8e4acb3e),(33,0x1cbee2d1),(34,0xb25f7132),(35,0xb0fa484c),(36,0xb9d262b4),(37,0x3207fe27),(38,0xa024d7ac),(39,0x49a2e7c5),(40,0x0e2c157f),(41,0x25f7427f),(42,0x368c6adc),(43,0x75efd4a5),(44,0xa84c5c31),(45,0x0fc817b2),(46,0x8d99a881),(47,0x5cc3c078),(48,0x9983d5e2),(49,0x9267c2db),(50,0xc96d4745),(51,0x058d8df3),(52,0x453f9cf3),(53,0xb714ade1),(54,0x55d3c2bc),(55,0x495710d0),(56,0x3bddf494),(57,0x4f2577d0),(58,0xdae0f604),(59,0x3c57c632),(60,0xfe39bbb0),(61,0x6f5d1d41),(62,0x7d996665),(63,0x68c738dc),(64,0x8dfea7ae)]
-        @test crc32c(UInt8[1:n;]) == crc == crc32c(String(UInt8[1:n;]))
+        s = String(UInt8[1:n;])
+        ss = SubString(String(UInt8[0:(n+1);]), 2:(n+1))
+        @test crc32c(UInt8[1:n;]) == crc == crc32c(s) == crc32c(ss)
     end
 
     # test that crc parameter is equivalent to checksum of concatenated data,
@@ -48,7 +50,11 @@ unsafe_crc32c_sw(a, n, crc) =
     ccall(:jl_crc32c_sw, UInt32, (UInt32, Ptr{UInt8}, Csize_t), crc, a, n)
 crc32c_sw(a::Union{Array{UInt8},Base.FastContiguousSubArray{UInt8,N,<:Array{UInt8}} where N},
           crc::UInt32=0x00000000) = unsafe_crc32c_sw(a, length(a), crc)
-crc32c_sw(s::String, crc::UInt32=0x00000000) = unsafe_crc32c_sw(s, sizeof(s), crc)
+
+function crc32c_sw(s::Union{String, SubString{String}}, crc::UInt32=0x00000000)
+    unsafe_crc32c_sw(s, sizeof(s), crc)
+end
+
 function crc32c_sw(io::IO, nb::Integer, crc::UInt32=0x00000000)
     nb < 0 && throw(ArgumentError("number of bytes to checksum must be ≥ 0"))
     buf = Vector{UInt8}(undef, min(nb, 24576))