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/**
* Accepts any node Stream instance and hijacks its "write()" function,
* so that it can count any newlines that get written to the output.
*
* When a '\n' byte is encountered, then a "newline" event will be emitted
* on the stream, with no arguments. It is up to the listeners to determine
* any necessary deltas required for their use-case.
*
* Ex:
*
* var cursor = ansi(process.stdout)
* , ln = 0
* process.stdout.on('newline', function () {
* ln++
* })
*/
/**
* Module dependencies.
*/
var assert = require('assert')
var NEWLINE = '\n'.charCodeAt(0)
function emitNewlineEvents (stream) {
if (stream._emittingNewlines) {
// already emitting newline events
return
}
var write = stream.write
stream.write = function (data) {
// first write the data
var rtn = write.apply(stream, arguments)
if (stream.listeners('newline').length > 0) {
var len = data.length
, i = 0
// now try to calculate any deltas
if (typeof data == 'string') {
for (; i<len; i++) {
processByte(stream, data.charCodeAt(i))
}
} else {
// buffer
for (; i<len; i++) {
processByte(stream, data[i])
}
}
}
return rtn
}
stream._emittingNewlines = true
}
module.exports = emitNewlineEvents
/**
* Processes an individual byte being written to a stream
*/
function processByte (stream, b) {
assert.equal(typeof b, 'number')
if (b === NEWLINE) {
stream.emit('newline')
}
}