[core:hash] Add CCITT CRC-16

core/hash/crc.odin

@@ -1,10 +1,27 @@
 package hash
 
+/*
+	Compute CRC-16 in the manner of CCITT (ITU-T V.41), using the 0x1021 polynomial.
+	Generator polynomial: x^16 + x^12 + x^5 + 1
+
+	Used in the UDF (DVD *.iso) disk format's Volume Descriptor Tag,
+	and was more historically the ITU-T V.41 CRC-16 used in the XModem protocol,
+	which uses 0xffff as the initial value.
+*/
+@(optimization_mode="favor_size")
+crc16_ccitt_0x1021 :: proc "contextless" (data: []u8, seed := u16(0)) -> (result: u16) #no_bounds_check {
+	result = seed
+	#no_bounds_check for b in data {
+		result = result << 8 ~ _ccitt_0x1021_table[(result >> 8) ~ u16(b)]
+	}
+	return result
+}
+
 @(optimization_mode="favor_size")
 crc64_ecma_182 :: proc "contextless" (data: []byte, seed := u64(0)) -> (result: u64) #no_bounds_check {
 	result = seed
 	#no_bounds_check for b in data {
-		result = result<<8 ~ _crc64_table_ecma_182[((result>>56) ~ u64(b)) & 0xff]
+		result = result << 8 ~ _crc64_table_ecma_182[((result>>56) ~ u64(b)) & 0xff]
 	}
 	return result
 }
@@ -49,9 +66,7 @@ crc64_xz :: proc "contextless" (data: []byte, seed := u64(0)) -> u64 #no_bounds_
 	return u64(~result)
 }
 
-/*
-	Generator polynomial: x^64 + x^4 + x^3 + x + 1
-*/
+// Generator polynomial: x^64 + x^4 + x^3 + x + 1
 @(optimization_mode="favor_size")
 crc64_iso_3306 :: proc "contextless" (data: []byte, seed := u64(0)) -> u64 #no_bounds_check {
 
@@ -75,7 +90,8 @@ crc64_iso_3306_inverse :: proc "contextless" (data: []byte, seed := u64(0)) -> u
 	return ~result
 }
 
-@private _crc64_table_ecma_182 := [256]u64{
+@(private, rodata)
+_crc64_table_ecma_182 := [256]u64{
 	0x0000000000000000, 0x42f0e1eba9ea3693, 0x85e1c3d753d46d26, 0xc711223cfa3e5bb5,
 	0x493366450e42ecdf, 0x0bc387aea7a8da4c, 0xccd2a5925d9681f9, 0x8e224479f47cb76a,
 	0x9266cc8a1c85d9be, 0xd0962d61b56fef2d, 0x17870f5d4f51b498, 0x5577eeb6e6bb820b,
@@ -142,7 +158,8 @@ crc64_iso_3306_inverse :: proc "contextless" (data: []byte, seed := u64(0)) -> u
 	0x5dedc41a34bbeeb2, 0x1f1d25f19d51d821, 0xd80c07cd676f8394, 0x9afce626ce85b507,
 }
 
-@private _crc64_table_xz := [8][256]u64le{
+@(private, rodata)
+_crc64_table_xz := [8][256]u64le{
 	{	
 		0x0000000000000000, 0xb32e4cbe03a75f6f, 0xf4843657a840a05b, 0x47aa7ae9abe7ff34, 
 		0x7bd0c384ff8f5e33, 0xc8fe8f3afc28015c, 0x8f54f5d357cffe68, 0x3c7ab96d5468a107, 
@@ -673,7 +690,8 @@ crc64_iso_3306_inverse :: proc "contextless" (data: []byte, seed := u64(0)) -> u
 	},
 }
 
-@private _crc64_table_iso_3306 := [256]u16{
+@(private, rodata)
+_crc64_table_iso_3306 := [256]u16{
 	0x0000, 0x01b0, 0x0360, 0x02d0, 
 	0x06c0, 0x0770, 0x05a0, 0x0410, 
 	0x0d80, 0x0c30, 0x0ee0, 0x0f50, 
@@ -739,3 +757,39 @@ crc64_iso_3306_inverse :: proc "contextless" (data: []byte, seed := u64(0)) -> u
 	0x9480, 0x9530, 0x97e0, 0x9650, 
 	0x9240, 0x93f0, 0x9120, 0x9090,
 }
+
+@(private, rodata)
+_ccitt_0x1021_table := [256]u16{
+	0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
+	0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
+	0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
+	0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
+	0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
+	0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
+	0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
+	0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
+	0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
+	0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
+	0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
+	0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
+	0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
+	0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
+	0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
+	0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
+	0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
+	0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
+	0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
+	0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
+	0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
+	0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
+	0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
+	0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
+	0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
+	0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
+	0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
+	0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
+	0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
+	0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
+	0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
+	0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0,
+}

tests/core/hash/test_core_hash.odin

@@ -12,6 +12,7 @@ import "base:intrinsics"
 	};
 */
 
+V16 :: struct{s: string, h: u16}
 V32 :: struct{s: string, h: u32}
 V64 :: struct{s: string, h: u64}
 
@@ -263,4 +264,22 @@ test_murmur64_vectors :: proc(t: ^testing.T) {
 	testing.expect_value(t, i128(#hash(vectors[3].s, "murmur64")), i128(vectors[3].h))
 	testing.expect_value(t, i128(#hash(vectors[4].s, "murmur64")), i128(vectors[4].h))
 	testing.expect_value(t, i128(#hash(vectors[5].s, "murmur64")), i128(vectors[5].h))
+}
+
+@test
+test_crc16_ccitt_0x1021_vectors :: proc(t: ^testing.T) {
+	vectors :: []V16{
+		{""             , 0x0000},
+		{"abc"          , 0x9dd6},
+		{"Hello"        , 0xcbd6},
+		{"world"        , 0x2363},
+		{"Hello, world!", 0x7ade},
+		{"\x70\x6a\x77" , 0x3299}, // ECMA-167, 7.2.6 Descriptor CRC
+	}
+
+	for vector in vectors {
+		b := transmute([]u8)vector.s
+		crc16 := hash.crc16_ccitt_0x1021(b)
+		testing.expectf(t, crc16 == vector.h, "\n\t[CCITT CRC-16({0:q})] Expected: 0x{1:4x}, got: 0x{2:4x}", vector.s, vector.h, crc16)
+	}
 }