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#
#
# The Nim Compiler
# (c) Copyright 2012 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## Low-level streams for high performance.
import
strutils
# support '-d:useGnuReadline' for backwards compatibility:
when not defined(windows) and (defined(useGnuReadline) or defined(useLinenoise)):
import rdstdin
type
TLLStreamKind* = enum # enum of different stream implementations
llsNone, # null stream: reading and writing has no effect
llsString, # stream encapsulates a string
llsFile, # stream encapsulates a file
llsStdIn # stream encapsulates stdin
TLLStream* = object of RootObj
kind*: TLLStreamKind # accessible for low-level access (lexbase uses this)
f*: File
s*: string
rd*, wr*: int # for string streams
lineOffset*: int # for fake stdin line numbers
PLLStream* = ref TLLStream
proc llStreamOpen*(data: string): PLLStream =
new(result)
result.s = data
result.kind = llsString
proc llStreamOpen*(f: File): PLLStream =
new(result)
result.f = f
result.kind = llsFile
proc llStreamOpen*(filename: string, mode: FileMode): PLLStream =
new(result)
result.kind = llsFile
if not open(result.f, filename, mode): result = nil
proc llStreamOpen*(): PLLStream =
new(result)
result.kind = llsNone
proc llStreamOpenStdIn*(): PLLStream =
new(result)
result.kind = llsStdIn
result.s = ""
result.lineOffset = -1
proc llStreamClose*(s: PLLStream) =
case s.kind
of llsNone, llsString, llsStdIn:
discard
of llsFile:
close(s.f)
when not declared(readLineFromStdin):
# fallback implementation:
proc readLineFromStdin(prompt: string, line: var string): bool =
stdout.write(prompt)
result = readLine(stdin, line)
if not result:
stdout.write("\n")
quit(0)
proc endsWith*(x: string, s: set[char]): bool =
var i = x.len-1
while i >= 0 and x[i] == ' ': dec(i)
if i >= 0 and x[i] in s:
result = true
const
LineContinuationOprs = {'+', '-', '*', '/', '\\', '<', '>', '!', '?', '^',
'|', '%', '&', '$', '@', '~', ','}
AdditionalLineContinuationOprs = {'#', ':', '='}
proc endsWithOpr*(x: string): bool =
# also used by the standard template filter:
result = x.endsWith(LineContinuationOprs)
proc continueLine(line: string, inTripleString: bool): bool {.inline.} =
result = inTripleString or
line[0] == ' ' or
line.endsWith(LineContinuationOprs+AdditionalLineContinuationOprs)
proc countTriples(s: string): int =
var i = 0
while i < s.len:
if s[i] == '"' and s[i+1] == '"' and s[i+2] == '"':
inc result
inc i, 2
inc i
proc llReadFromStdin(s: PLLStream, buf: pointer, bufLen: int): int =
s.s = ""
s.rd = 0
var line = newStringOfCap(120)
var triples = 0
while readLineFromStdin(if s.s.len == 0: ">>> " else: "... ", line):
add(s.s, line)
add(s.s, "\n")
inc triples, countTriples(line)
if not continueLine(line, (triples and 1) == 1): break
inc(s.lineOffset)
result = min(bufLen, len(s.s) - s.rd)
if result > 0:
copyMem(buf, addr(s.s[s.rd]), result)
inc(s.rd, result)
proc llStreamRead*(s: PLLStream, buf: pointer, bufLen: int): int =
case s.kind
of llsNone:
result = 0
of llsString:
result = min(bufLen, len(s.s) - s.rd)
if result > 0:
copyMem(buf, addr(s.s[0 + s.rd]), result)
inc(s.rd, result)
of llsFile:
result = readBuffer(s.f, buf, bufLen)
of llsStdIn:
result = llReadFromStdin(s, buf, bufLen)
proc llStreamReadLine*(s: PLLStream, line: var string): bool =
setLen(line, 0)
case s.kind
of llsNone:
result = true
of llsString:
while s.rd < len(s.s):
case s.s[s.rd]
of '\x0D':
inc(s.rd)
if s.s[s.rd] == '\x0A': inc(s.rd)
break
of '\x0A':
inc(s.rd)
break
else:
add(line, s.s[s.rd])
inc(s.rd)
result = line.len > 0 or s.rd < len(s.s)
of llsFile:
result = readLine(s.f, line)
of llsStdIn:
result = readLine(stdin, line)
proc llStreamWrite*(s: PLLStream, data: string) =
case s.kind
of llsNone, llsStdIn:
discard
of llsString:
add(s.s, data)
inc(s.wr, len(data))
of llsFile:
write(s.f, data)
proc llStreamWriteln*(s: PLLStream, data: string) =
llStreamWrite(s, data)
llStreamWrite(s, "\n")
proc llStreamWrite*(s: PLLStream, data: char) =
var c: char
case s.kind
of llsNone, llsStdIn:
discard
of llsString:
add(s.s, data)
inc(s.wr)
of llsFile:
c = data
discard writeBuffer(s.f, addr(c), sizeof(c))
proc llStreamWrite*(s: PLLStream, buf: pointer, buflen: int) =
case s.kind
of llsNone, llsStdIn:
discard
of llsString:
if buflen > 0:
setLen(s.s, len(s.s) + buflen)
copyMem(addr(s.s[0 + s.wr]), buf, buflen)
inc(s.wr, buflen)
of llsFile:
discard writeBuffer(s.f, buf, buflen)
proc llStreamReadAll*(s: PLLStream): string =
const
bufSize = 2048
case s.kind
of llsNone, llsStdIn:
result = ""
of llsString:
if s.rd == 0: result = s.s
else: result = substr(s.s, s.rd)
s.rd = len(s.s)
of llsFile:
result = newString(bufSize)
var bytes = readBuffer(s.f, addr(result[0]), bufSize)
var i = bytes
while bytes == bufSize:
setLen(result, i + bufSize)
bytes = readBuffer(s.f, addr(result[i + 0]), bufSize)
inc(i, bytes)
setLen(result, i)
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