std/streams (original) (raw)

Source Edit

This module provides a stream interface and two implementations thereof: the FileStream and the StringStream which implement the stream interface for Nim file objects (File) and strings.

Other modules may provide other implementations for this standard stream interface.

**Warning:**Due to the use of

pointer

, the

readData

,

peekData

and

writeData interfaces are not available on the compile-time VM, and must be cast from a ptr string on the JS backend. However, readDataStr is available generally in place of readData.

Basic usage

The basic flow of using this module is:

  1. Open input stream
  2. Read or write stream
  3. Close stream

StringStream example

import std/streams

var strm = newStringStream("""The first line the second line the third line""")

var line = ""

while strm.readLine(line): echo line

strm.close()

FileStream example

Write file stream example:

import std/streams

var strm = newFileStream("somefile.txt", fmWrite) var line = ""

if not isNil(strm): strm.writeLine("The first line") strm.writeLine("the second line") strm.writeLine("the third line") strm.close()

Read file stream example:

import std/streams

var strm = newFileStream("somefile.txt", fmRead) var line = ""

if not isNil(strm): while strm.readLine(line): echo line strm.close()

See also

Types

StreamObj = object of RootObj closeImpl*: proc (s: Stream) {.nimcall, ...raises: [IOError, OSError], tags: [WriteIOEffect], gcsafe.} atEndImpl*: proc (s: Stream): bool {.nimcall, ...raises: [Defect, IOError, OSError], tags: [], gcsafe.} setPositionImpl*: proc (s: Stream; pos: int) {.nimcall, ...raises: [Defect, IOError, OSError], tags: [], gcsafe.} getPositionImpl*: proc (s: Stream): int {.nimcall, ...raises: [Defect, IOError, OSError], tags: [], gcsafe.} readDataStrImpl*: proc (s: Stream; buffer: var string; slice: Slice[int]): int {. nimcall, ...raises: [Defect, IOError, OSError], tags: [ReadIOEffect], gcsafe.} readLineImpl*: proc (s: Stream; line: var string): bool {.nimcall, ...raises: [Defect, IOError, OSError], tags: [ReadIOEffect], gcsafe.} readDataImpl*: proc (s: Stream; buffer: pointer; bufLen: int): int {.nimcall, ...raises: [Defect, IOError, OSError], tags: [ReadIOEffect], gcsafe.} peekDataImpl*: proc (s: Stream; buffer: pointer; bufLen: int): int {.nimcall, ...raises: [Defect, IOError, OSError], tags: [ReadIOEffect], gcsafe.} writeDataImpl*: proc (s: Stream; buffer: pointer; bufLen: int) {.nimcall, ...raises: [Defect, IOError, OSError], tags: [WriteIOEffect], gcsafe.} flushImpl*: proc (s: Stream) {.nimcall, ...raises: [Defect, IOError, OSError], tags: [WriteIOEffect], gcsafe.}

Stream interface that supports writing or reading.

Note:

Procs

proc atEnd(s: Stream): bool {....raises: [IOError, OSError], tags: [], forbids: [].}

Checks if more data can be read from s. Returns true if all data has been read.

Example:

var strm = newStringStream("The first line\nthe second line\nthe third line") var line = "" doAssert strm.atEnd() == false while strm.readLine(line): discard doAssert strm.atEnd() == true strm.close()

Source Edit

proc close(s: Stream) {....raises: [IOError, OSError], tags: [WriteIOEffect], forbids: [].}

Closes the stream s.

See also:

Example:

block: let strm = newStringStream("The first line\nthe second line\nthe third line")

strm.close()

block: let strm = newFileStream("amissingfile.txt")

defer: strm.close() if not isNil(strm):

Source Edit

proc flush(s: Stream) {....raises: [IOError, OSError], tags: [WriteIOEffect], forbids: [].}

Flushes the buffers that the stream s might use.

This procedure causes any unwritten data for that stream to be delivered to the host environment to be written to the file.

See also:

Example:

from std/os import removeFile

var strm = newFileStream("somefile.txt", fmWrite)

doAssert "Before write:" & readFile("somefile.txt") == "Before write:" strm.write("hello") doAssert "After write:" & readFile("somefile.txt") == "After write:"

strm.flush() doAssert "After flush:" & readFile("somefile.txt") == "After flush:hello" strm.write("HELLO") strm.flush() doAssert "After flush:" & readFile("somefile.txt") == "After flush:helloHELLO"

strm.close() doAssert "After close:" & readFile("somefile.txt") == "After close:helloHELLO" removeFile("somefile.txt")

Source Edit

proc getPosition(s: Stream): int {....raises: [IOError, OSError], tags: [], forbids: [].}

Retrieves the current position in the stream s.

Example:

var strm = newStringStream("The first line\nthe second line\nthe third line") doAssert strm.getPosition() == 0 discard strm.readLine() doAssert strm.getPosition() == 15 strm.close()

Source Edit

proc newFileStream(f: File): owned FileStream {....raises: [], tags: [], forbids: [].}

Creates a new stream from the file f.

Note: Not available for JS backend.

See also:

Example:

var f: File if open(f, "somefile.txt", fmRead, -1): var strm = newFileStream(f) var line = "" while strm.readLine(line): echo line

strm.close()

Source Edit

proc newFileStream(filename: string; mode: FileMode = fmRead; bufSize: int = -1): owned FileStream {....raises: [], tags: [], forbids: [].}

Creates a new stream from the file named filename with the mode mode.

If the file cannot be opened, nil is returned. See the io module for a list of available FileMode enums.

Note:

See also:

Example:

from std/os import removeFile var strm = newFileStream("somefile.txt", fmWrite) if not isNil(strm): strm.writeLine("The first line") strm.writeLine("the second line") strm.writeLine("the third line") strm.close()

removeFile("somefile.txt")

Source Edit

proc newStringStream(s: sink string = ""): owned StringStream {....raises: [], tags: [], forbids: [].}

Creates a new stream from the string s.

See also:

Example:

var strm = newStringStream("The first line\nthe second line\nthe third line") doAssert strm.readLine() == "The first line" doAssert strm.readLine() == "the second line" doAssert strm.readLine() == "the third line" strm.close()

Source Edit

proc openFileStream(filename: string; mode: FileMode = fmRead; bufSize: int = -1): owned FileStream {....raises: [IOError], tags: [], forbids: [].}

Creates a new stream from the file named filename with the mode mode. If the file cannot be opened, an IO exception is raised.

Note: Not available for JS backend.

See also:

Example:

try:

var strm = openFileStream("somefile.txt") echo strm.readLine()

strm.close() except: stderr.write getCurrentExceptionMsg()

Source Edit

proc peek[T](s: Stream; result: var T)

Generic peek procedure. Peeks result from the stream s.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream("012")

var i: int8 strm.peek(i) doAssert i == 48

var buffer: array[2, char] strm.peek(buffer) doAssert buffer == ['0', '1'] strm.close()

Source Edit

proc peekBool(s: Stream): bool {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks a bool from the stream s.

A bool is one byte long and it is true for every non-zero (0000_0000) value. Raises IOError if an error occurred.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream()

strm.write(true) strm.write(false) strm.flush() strm.setPosition(0)

doAssert strm.peekBool() == true

doAssert strm.peekBool() == true doAssert strm.readBool() == true doAssert strm.peekBool() == false strm.close()

Source Edit

proc peekChar(s: Stream): char {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks a char from the stream s. Raises IOError if an error occurred. Returns '\0' as an EOF marker.

Example:

var strm = newStringStream("12\n3") doAssert strm.peekChar() == '1' doAssert strm.peekChar() == '1' discard strm.readAll() doAssert strm.peekChar() == '\x00' strm.close()

Source Edit

proc peekData(s: Stream; buffer: pointer; bufLen: int): int {. ...raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Low level proc that reads data into an untyped buffer of bufLen size without moving stream position.

JS note: buffer is treated as a ptr string and written to between 0..<bufLen.

Example:

var strm = newStringStream("abcde") var buffer: array[6, char] doAssert strm.peekData(addr(buffer), 1024) == 5 doAssert buffer == ['a', 'b', 'c', 'd', 'e', '\x00'] doAssert strm.atEnd() == false strm.close()

Source Edit

proc peekFloat32(s: Stream): float32 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks a float32 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream()

strm.write(1'f32) strm.write(2'f32) strm.flush() strm.setPosition(0)

doAssert strm.peekFloat32() == 1'f32

doAssert strm.peekFloat32() == 1'f32 doAssert strm.readFloat32() == 1'f32 doAssert strm.peekFloat32() == 2'f32 strm.close()

Source Edit

proc peekFloat64(s: Stream): float64 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks a float64 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream()

strm.write(1'f64) strm.write(2'f64) strm.flush() strm.setPosition(0)

doAssert strm.peekFloat64() == 1'f64

doAssert strm.peekFloat64() == 1'f64 doAssert strm.readFloat64() == 1'f64 doAssert strm.peekFloat64() == 2'f64 strm.close()

Source Edit

proc peekInt8(s: Stream): int8 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks an int8 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream()

strm.write(1'i8) strm.write(2'i8) strm.flush() strm.setPosition(0)

doAssert strm.peekInt8() == 1'i8

doAssert strm.peekInt8() == 1'i8 doAssert strm.readInt8() == 1'i8 doAssert strm.peekInt8() == 2'i8 strm.close()

Source Edit

proc peekInt16(s: Stream): int16 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks an int16 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream()

strm.write(1'i16) strm.write(2'i16) strm.flush() strm.setPosition(0)

doAssert strm.peekInt16() == 1'i16

doAssert strm.peekInt16() == 1'i16 doAssert strm.readInt16() == 1'i16 doAssert strm.peekInt16() == 2'i16 strm.close()

Source Edit

proc peekInt32(s: Stream): int32 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks an int32 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream()

strm.write(1'i32) strm.write(2'i32) strm.flush() strm.setPosition(0)

doAssert strm.peekInt32() == 1'i32

doAssert strm.peekInt32() == 1'i32 doAssert strm.readInt32() == 1'i32 doAssert strm.peekInt32() == 2'i32 strm.close()

Source Edit

proc peekInt64(s: Stream): int64 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks an int64 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream()

strm.write(1'i64) strm.write(2'i64) strm.flush() strm.setPosition(0)

doAssert strm.peekInt64() == 1'i64

doAssert strm.peekInt64() == 1'i64 doAssert strm.readInt64() == 1'i64 doAssert strm.peekInt64() == 2'i64 strm.close()

Source Edit

proc peekLine(s: Stream): string {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks a line from a stream s. Raises IOError if an error occurred.

Note: This is not very efficient.

See also:

Example:

var strm = newStringStream("The first line\nthe second line\nthe third line") doAssert strm.peekLine() == "The first line"

doAssert strm.peekLine() == "The first line" doAssert strm.readLine() == "The first line" doAssert strm.peekLine() == "the second line" strm.close()

Source Edit

proc peekLine(s: Stream; line: var string): bool {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks a line of text from the stream s into line. line must not be nil! May throw an IO exception.

A line of text may be delimited by CR, LF or CRLF. The newline character(s) are not part of the returned string. Returns false if the end of the file has been reached, true otherwise. If false is returned line contains no new data.

See also:

Example:

var strm = newStringStream("The first line\nthe second line\nthe third line") var line = "" doAssert strm.peekLine(line) == true doAssert line == "The first line" doAssert strm.peekLine(line) == true

doAssert line == "The first line" doAssert strm.readLine(line) == true doAssert line == "The first line" doAssert strm.peekLine(line) == true doAssert line == "the second line" strm.close()

Source Edit

proc peekStr(s: Stream; length: int): string {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks a string of length length from the stream s. Raises IOError if an error occurred.

Example:

var strm = newStringStream("abcde") doAssert strm.peekStr(2) == "ab"

doAssert strm.peekStr(2) == "ab" doAssert strm.readStr(2) == "ab" doAssert strm.peekStr(2) == "cd" strm.close()

Source Edit

proc peekStr(s: Stream; length: int; str: var string) {. ...raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks a string of length length from the stream s. Raises IOError if an error occurred.Source Edit

proc peekUint8(s: Stream): uint8 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks an uint8 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream()

strm.write(1'u8) strm.write(2'u8) strm.flush() strm.setPosition(0)

doAssert strm.peekUint8() == 1'u8

doAssert strm.peekUint8() == 1'u8 doAssert strm.readUint8() == 1'u8 doAssert strm.peekUint8() == 2'u8 strm.close()

Source Edit

proc peekUint16(s: Stream): uint16 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks an uint16 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream()

strm.write(1'u16) strm.write(2'u16) strm.flush() strm.setPosition(0)

doAssert strm.peekUint16() == 1'u16

doAssert strm.peekUint16() == 1'u16 doAssert strm.readUint16() == 1'u16 doAssert strm.peekUint16() == 2'u16 strm.close()

Source Edit

proc peekUint32(s: Stream): uint32 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks an uint32 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream()

strm.write(1'u32) strm.write(2'u32) strm.flush() strm.setPosition(0)

doAssert strm.peekUint32() == 1'u32

doAssert strm.peekUint32() == 1'u32 doAssert strm.readUint32() == 1'u32 doAssert strm.peekUint32() == 2'u32 strm.close()

Source Edit

proc peekUint64(s: Stream): uint64 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Peeks an uint64 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use peekStr for now.

Example:

var strm = newStringStream()

strm.write(1'u64) strm.write(2'u64) strm.flush() strm.setPosition(0)

doAssert strm.peekUint64() == 1'u64

doAssert strm.peekUint64() == 1'u64 doAssert strm.readUint64() == 1'u64 doAssert strm.peekUint64() == 2'u64 strm.close()

Source Edit

proc read[T](s: Stream; result: var T)

Generic read procedure. Reads result from the stream s.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream("012")

var i: int8 strm.read(i) doAssert i == 48

var buffer: array[2, char] strm.read(buffer) doAssert buffer == ['1', '2'] strm.close()

Source Edit

proc readAll(s: Stream): string {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads all available data.

Example:

var strm = newStringStream("The first line\nthe second line\nthe third line") doAssert strm.readAll() == "The first line\nthe second line\nthe third line" doAssert strm.atEnd() == true strm.close()

Source Edit

proc readBool(s: Stream): bool {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads a bool from the stream s.

A bool is one byte long and it is true for every non-zero (0000_0000) value. Raises IOError if an error occurred.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream()

strm.write(true) strm.write(false) strm.flush() strm.setPosition(0)

doAssert strm.readBool() == true doAssert strm.readBool() == false doAssertRaises(IOError): discard strm.readBool() strm.close()

Source Edit

proc readChar(s: Stream): char {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads a char from the stream s.

Raises IOError if an error occurred. Returns '\0' as an EOF marker.

Example:

var strm = newStringStream("12\n3") doAssert strm.readChar() == '1' doAssert strm.readChar() == '2' doAssert strm.readChar() == '\n' doAssert strm.readChar() == '3' doAssert strm.readChar() == '\x00' strm.close()

Source Edit

proc readData(s: Stream; buffer: pointer; bufLen: int): int {. ...raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Low level proc that reads data into an untyped buffer of bufLen size.

JS note: buffer is treated as a ptr string and written to between 0..<bufLen.

Example:

var strm = newStringStream("abcde") var buffer: array[6, char] doAssert strm.readData(addr(buffer), 1024) == 5 doAssert buffer == ['a', 'b', 'c', 'd', 'e', '\x00'] doAssert strm.atEnd() == true strm.close()

Source Edit

proc readDataStr(s: Stream; buffer: var string; slice: Slice[int]): int {. ...raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Low level proc that reads data into a string buffer at slice.

Example:

var strm = newStringStream("abcde") var buffer = "12345" doAssert strm.readDataStr(buffer, 0..3) == 4 doAssert buffer == "abcd5" strm.close()

Source Edit

proc readFloat32(s: Stream): float32 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads a float32 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream()

strm.write(1'f32) strm.write(2'f32) strm.flush() strm.setPosition(0)

doAssert strm.readFloat32() == 1'f32 doAssert strm.readFloat32() == 2'f32 doAssertRaises(IOError): discard strm.readFloat32() strm.close()

Source Edit

proc readFloat64(s: Stream): float64 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads a float64 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream()

strm.write(1'f64) strm.write(2'f64) strm.flush() strm.setPosition(0)

doAssert strm.readFloat64() == 1'f64 doAssert strm.readFloat64() == 2'f64 doAssertRaises(IOError): discard strm.readFloat64() strm.close()

Source Edit

proc readInt8(s: Stream): int8 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads an int8 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream()

strm.write(1'i8) strm.write(2'i8) strm.flush() strm.setPosition(0)

doAssert strm.readInt8() == 1'i8 doAssert strm.readInt8() == 2'i8 doAssertRaises(IOError): discard strm.readInt8() strm.close()

Source Edit

proc readInt16(s: Stream): int16 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads an int16 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream()

strm.write(1'i16) strm.write(2'i16) strm.flush() strm.setPosition(0)

doAssert strm.readInt16() == 1'i16 doAssert strm.readInt16() == 2'i16 doAssertRaises(IOError): discard strm.readInt16() strm.close()

Source Edit

proc readInt32(s: Stream): int32 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads an int32 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream()

strm.write(1'i32) strm.write(2'i32) strm.flush() strm.setPosition(0)

doAssert strm.readInt32() == 1'i32 doAssert strm.readInt32() == 2'i32 doAssertRaises(IOError): discard strm.readInt32() strm.close()

Source Edit

proc readInt64(s: Stream): int64 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads an int64 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream()

strm.write(1'i64) strm.write(2'i64) strm.flush() strm.setPosition(0)

doAssert strm.readInt64() == 1'i64 doAssert strm.readInt64() == 2'i64 doAssertRaises(IOError): discard strm.readInt64() strm.close()

Source Edit

proc readLine(s: Stream): string {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads a line from a stream s. Raises IOError if an error occurred.

Note: This is not very efficient.

See also:

Example:

var strm = newStringStream("The first line\nthe second line\nthe third line") doAssert strm.readLine() == "The first line" doAssert strm.readLine() == "the second line" doAssert strm.readLine() == "the third line" doAssertRaises(IOError): discard strm.readLine() strm.close()

Source Edit

proc readLine(s: Stream; line: var string): bool {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads a line of text from the stream s into line. line must not be nil! May throw an IO exception.

A line of text may be delimited by LF or CRLF. The newline character(s) are not part of the returned string. Returns false if the end of the file has been reached, true otherwise. If false is returned line contains no new data.

See also:

Example:

var strm = newStringStream("The first line\nthe second line\nthe third line") var line = "" doAssert strm.readLine(line) == true doAssert line == "The first line" doAssert strm.readLine(line) == true doAssert line == "the second line" doAssert strm.readLine(line) == true doAssert line == "the third line" doAssert strm.readLine(line) == false doAssert line == "" strm.close()

Source Edit

proc readStr(s: Stream; length: int): string {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads a string of length length from the stream s. Raises IOError if an error occurred.

Example:

var strm = newStringStream("abcde") doAssert strm.readStr(2) == "ab" doAssert strm.readStr(2) == "cd" doAssert strm.readStr(2) == "e" doAssert strm.readStr(2) == "" strm.close()

Source Edit

proc readStr(s: Stream; length: int; str: var string) {. ...raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads a string of length length from the stream s. Raises IOError if an error occurred.Source Edit

proc readUint8(s: Stream): uint8 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads an uint8 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream()

strm.write(1'u8) strm.write(2'u8) strm.flush() strm.setPosition(0)

doAssert strm.readUint8() == 1'u8 doAssert strm.readUint8() == 2'u8 doAssertRaises(IOError): discard strm.readUint8() strm.close()

Source Edit

proc readUint16(s: Stream): uint16 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads an uint16 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream()

strm.write(1'u16) strm.write(2'u16) strm.flush() strm.setPosition(0)

doAssert strm.readUint16() == 1'u16 doAssert strm.readUint16() == 2'u16 doAssertRaises(IOError): discard strm.readUint16() strm.close()

Source Edit

proc readUint32(s: Stream): uint32 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads an uint32 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream()

strm.write(1'u32) strm.write(2'u32) strm.flush() strm.setPosition(0)

doAssert strm.readUint32() == 1'u32 doAssert strm.readUint32() == 2'u32 doAssertRaises(IOError): discard strm.readUint32() strm.close()

Source Edit

proc readUint64(s: Stream): uint64 {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Reads an uint64 from the stream s. Raises IOError if an error occurred.

Note: Not available for JS backend. Use readStr for now.

Example:

var strm = newStringStream()

strm.write(1'u64) strm.write(2'u64) strm.flush() strm.setPosition(0)

doAssert strm.readUint64() == 1'u64 doAssert strm.readUint64() == 2'u64 doAssertRaises(IOError): discard strm.readUint64() strm.close()

Source Edit

proc setPosition(s: Stream; pos: int) {....raises: [IOError, OSError], tags: [], forbids: [].}

Sets the position pos of the stream s.

Example:

var strm = newStringStream("The first line\nthe second line\nthe third line") strm.setPosition(4) doAssert strm.readLine() == "first line" strm.setPosition(0) doAssert strm.readLine() == "The first line" strm.close()

Source Edit

proc write(s: Stream; args: varargs[string, $]) {....raises: [IOError, OSError], tags: [WriteIOEffect], forbids: [].}

Writes one or more strings to the the stream. No length fields or terminating zeros are written.

Example:

var strm = newStringStream("") strm.write(1, 2, 3, 4) strm.setPosition(0) doAssert strm.readLine() == "1234" strm.close()

Source Edit

proc write(s: Stream; x: string) {....raises: [IOError, OSError], tags: [WriteIOEffect], forbids: [].}

Writes the string x to the stream s. No length field or terminating zero is written.

Example:

var strm = newStringStream("") strm.write("THE FIRST LINE") strm.setPosition(0) doAssert strm.readLine() == "THE FIRST LINE" strm.close()

Source Edit

proc write[T](s: Stream; x: T)

Generic write procedure. Writes x to the stream s. Implementation:

Note: Not available for JS backend. Use write(Stream, string) for now.

s.writeData(s, unsafeAddr(x), sizeof(x))

Example:

var strm = newStringStream("") strm.write("abcde") strm.setPosition(0) doAssert strm.readAll() == "abcde" strm.close()

Source Edit

proc writeData(s: Stream; buffer: pointer; bufLen: int) {. ...raises: [IOError, OSError], tags: [WriteIOEffect], forbids: [].}

Low level proc that writes an untyped buffer of bufLen size to the stream s.

JS note: buffer is treated as a ptr string and read between 0..<bufLen.

Example:

var strm = newStringStream("") var buffer = ['a', 'b', 'c', 'd', 'e'] strm.writeData(addr(buffer), sizeof(buffer)) doAssert strm.atEnd() == true

strm.setPosition(0) var buffer2: array[6, char] doAssert strm.readData(addr(buffer2), sizeof(buffer2)) == 5 doAssert buffer2 == ['a', 'b', 'c', 'd', 'e', '\x00'] strm.close()

Source Edit

proc writeLine(s: Stream; args: varargs[string, $]) {. ...raises: [IOError, OSError], tags: [WriteIOEffect], forbids: [].}

Writes one or more strings to the the stream s followed by a new line. No length field or terminating zero is written.

Example:

var strm = newStringStream("") strm.writeLine(1, 2) strm.writeLine(3, 4) strm.setPosition(0) doAssert strm.readAll() == "12\n34\n" strm.close()

Source Edit

Iterators

iterator lines(s: Stream): string {....raises: [IOError, OSError], tags: [ReadIOEffect], forbids: [].}

Iterates over every line in the stream. The iteration is based on readLine.

See also:

Example:

var strm = newStringStream("The first line\nthe second line\nthe third line") var lines: seq[string] for line in strm.lines(): lines.add line doAssert lines == @["The first line", "the second line", "the third line"] strm.close()

Source Edit