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Improve readLine to work with strings containing \0 again.

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This decreases performance slightly.
This commit is contained in:
def
2015-07-25 20:25:58 +02:00
parent 401189c3fe
commit a9b299b4ed
1 changed files with 15 additions and 5 deletions
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20
lib/system/sysio.nim
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@@ -39,6 +39,10 @@ proc fseek(f: File, offset: clong, whence: int): int {.
proc ftell(f: File): int {.importc: "ftell", header: "<stdio.h>", tags: [].}
proc setvbuf(stream: File, buf: pointer, typ, size: cint): cint {.
importc, header: "<stdio.h>", tags: [].}
proc memchr(s: pointer, c: cint, n: csize): pointer {.
importc: "memchr", header: "<string.h>", tags: [].}
proc memset(s: pointer, c: cint, n: csize) {.
header: "<string.h>", importc: "memset", tags: [].}
{.push stackTrace:off, profiler:off.}
proc write(f: File, c: cstring) = fputs(c, f)
@@ -70,21 +74,27 @@ proc readLine(f: File, line: var TaintedString): bool =
var pos = 0
# Use the currently reserved space for a first try
var space = cast[PGenericSeq](line.string).space
line.string.setLen(space)
while true:
# memset to \l so that we can tell how far fgets wrote, even on EOF, where
# fgets doesn't append an \l
memset(addr line.string[pos], '\l'.ord, space)
if fgets(addr line.string[pos], space, f) == nil:
line.string.setLen(0)
return false
# This will cut the string short when it contains \0
let last = pos + cstring(addr line.string[pos]).len-1
if line.string[last] == '\l':
let m = memchr(addr line.string[pos], '\l'.ord, space)
if m != nil:
# \l found: Could be our own or the one by fgets, in any case, we're done
let last = cast[ByteAddress](m) - cast[ByteAddress](addr line.string[0])
if last > 0 and line.string[last-1] == '\c':
line.string.setLen(last-1)
return true
line.string.setLen(last)
return true
pos = last+1
space = 128 # Read in 128 bytes at a time
# No \l found: Increase buffer and read more
inc pos, space
space = 128 # read in 128 bytes at a time
line.string.setLen(pos+space)
proc readLine(f: File): TaintedString =