planning

node_modules/micromark/lib/preprocess.js

@@ -0,0 +1,96 @@
+'use strict'
+
+var codes = require('./character/codes.js')
+var constants = require('./constant/constants.js')
+
+var search = /[\0\t\n\r]/g
+
+function preprocess() {
+  var start = true
+  var column = 1
+  var buffer = ''
+  var atCarriageReturn
+
+  return preprocessor
+
+  function preprocessor(value, encoding, end) {
+    var chunks = []
+    var match
+    var next
+    var startPosition
+    var endPosition
+    var code
+
+    value = buffer + value.toString(encoding)
+    startPosition = 0
+    buffer = ''
+
+    if (start) {
+      if (value.charCodeAt(0) === codes.byteOrderMarker) {
+        startPosition++
+      }
+
+      start = undefined
+    }
+
+    while (startPosition < value.length) {
+      search.lastIndex = startPosition
+      match = search.exec(value)
+      endPosition = match ? match.index : value.length
+      code = value.charCodeAt(endPosition)
+
+      if (!match) {
+        buffer = value.slice(startPosition)
+        break
+      }
+
+      if (
+        code === codes.lf &&
+        startPosition === endPosition &&
+        atCarriageReturn
+      ) {
+        chunks.push(codes.carriageReturnLineFeed)
+        atCarriageReturn = undefined
+      } else {
+        if (atCarriageReturn) {
+          chunks.push(codes.carriageReturn)
+          atCarriageReturn = undefined
+        }
+
+        if (startPosition < endPosition) {
+          chunks.push(value.slice(startPosition, endPosition))
+          column += endPosition - startPosition
+        }
+
+        if (code === codes.nul) {
+          chunks.push(codes.replacementCharacter)
+          column++
+        } else if (code === codes.ht) {
+          next = Math.ceil(column / constants.tabSize) * constants.tabSize
+          chunks.push(codes.horizontalTab)
+          while (column++ < next) chunks.push(codes.virtualSpace)
+        } else if (code === codes.lf) {
+          chunks.push(codes.lineFeed)
+          column = 1
+        }
+        // Must be carriage return.
+        else {
+          atCarriageReturn = true
+          column = 1
+        }
+      }
+
+      startPosition = endPosition + 1
+    }
+
+    if (end) {
+      if (atCarriageReturn) chunks.push(codes.carriageReturn)
+      if (buffer) chunks.push(buffer)
+      chunks.push(codes.eof)
+    }
+
+    return chunks
+  }
+}
+
+module.exports = preprocess