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[bytom/vapor.git] / vendor / golang.org / x / text / internal / export / idna / trieval.go

diff --git a/vendor/golang.org/x/text/internal/export/idna/trieval.go b/vendor/golang.org/x/text/internal/export/idna/trieval.go
new file mode 100644 (file)
index 0000000..63cb03b
--- /dev/null
+++ b/vendor/golang.org/x/text/internal/export/idna/trieval.go
@@ -0,0 +1,114 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+package idna
+
+// This file contains definitions for interpreting the trie value of the idna
+// trie generated by "go run gen*.go". It is shared by both the generator
+// program and the resultant package. Sharing is achieved by the generator
+// copying gen_trieval.go to trieval.go and changing what's above this comment.
+
+// info holds information from the IDNA mapping table for a single rune. It is
+// the value returned by a trie lookup. In most cases, all information fits in
+// a 16-bit value. For mappings, this value may contain an index into a slice
+// with the mapped string. Such mappings can consist of the actual mapped value
+// or an XOR pattern to be applied to the bytes of the UTF8 encoding of the
+// input rune. This technique is used by the cases packages and reduces the
+// table size significantly.
+//
+// The per-rune values have the following format:
+//
+//   if mapped {
+//     if inlinedXOR {
+//       15..13 inline XOR marker
+//       12..11 unused
+//       10..3  inline XOR mask
+//     } else {
+//       15..3  index into xor or mapping table
+//     }
+//   } else {
+//       15..13 unused
+//           12 modifier (including virama)
+//           11 virama modifier
+//       10..8  joining type
+//        7..3  category type
+//   }
+//      2  use xor pattern
+//   1..0  mapped category
+//
+// See the definitions below for a more detailed description of the various
+// bits.
+type info uint16
+
+const (
+       catSmallMask = 0x3
+       catBigMask   = 0xF8
+       indexShift   = 3
+       xorBit       = 0x4    // interpret the index as an xor pattern
+       inlineXOR    = 0xE000 // These bits are set if the XOR pattern is inlined.
+
+       joinShift = 8
+       joinMask  = 0x07
+
+       viramaModifier = 0x0800
+       modifier       = 0x1000
+)
+
+// A category corresponds to a category defined in the IDNA mapping table.
+type category uint16
+
+const (
+       unknown              category = 0 // not defined currently in unicode.
+       mapped               category = 1
+       disallowedSTD3Mapped category = 2
+       deviation            category = 3
+)
+
+const (
+       valid               category = 0x08
+       validNV8            category = 0x18
+       validXV8            category = 0x28
+       disallowed          category = 0x40
+       disallowedSTD3Valid category = 0x80
+       ignored             category = 0xC0
+)
+
+// join types and additional rune information
+const (
+       joiningL = (iota + 1)
+       joiningD
+       joiningT
+       joiningR
+
+       //the following types are derived during processing
+       joinZWJ
+       joinZWNJ
+       joinVirama
+       numJoinTypes
+)
+
+func (c info) isMapped() bool {
+       return c&0x3 != 0
+}
+
+func (c info) category() category {
+       small := c & catSmallMask
+       if small != 0 {
+               return category(small)
+       }
+       return category(c & catBigMask)
+}
+
+func (c info) joinType() info {
+       if c.isMapped() {
+               return 0
+       }
+       return (c >> joinShift) & joinMask
+}
+
+func (c info) isModifier() bool {
+       return c&(modifier|catSmallMask) == modifier
+}
+
+func (c info) isViramaModifier() bool {
+       return c&(viramaModifier|catSmallMask) == viramaModifier
+}