mirrors/Nim
1
0
Fork 0
mirror of https://github.com/nim-lang/Nim.git synced 2026-01-07 13:33:22 +00:00
Code Issues Packages Projects Releases Wiki Activity

strutils.find enhancements (#6582)

Browse Source
This commit is contained in:
Dmitry Atamanov
2017-10-28 10:30:19 +03:00
committed by Andreas Rumpf
parent d2c7d391c8
commit 93fd0b0cb5
1 changed files with 48 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
lib/pure/strutils.nim
View File

@@ -1330,18 +1330,36 @@ proc join*[T: not string](a: openArray[T], sep: string = ""): string {.
add(result, $x)
type
SkipTable = array[char, int]
SkipTable* = array[char, int]
{.push profiler: off.}
proc preprocessSub(sub: string, a: var SkipTable) =
var m = len(sub)
for i in 0..0xff: a[chr(i)] = m+1
for i in 0..m-1: a[sub[i]] = m-i
{.pop.}
proc initSkipTable*(a: var SkipTable, sub: string)
{.noSideEffect, rtl, extern: "nsuInitSkipTable".} =
## Preprocess table `a` for `sub`.
let m = len(sub)
let m1 = m + 1
var i = 0
while i <= 0xff-7:
a[chr(i + 0)] = m1
a[chr(i + 1)] = m1
a[chr(i + 2)] = m1
a[chr(i + 3)] = m1
a[chr(i + 4)] = m1
a[chr(i + 5)] = m1
a[chr(i + 6)] = m1
a[chr(i + 7)] = m1
i += 8
proc findAux(s, sub: string, start, last: int, a: SkipTable): int =
# Fast "quick search" algorithm:
var
for i in 0..m-1:
a[sub[i]] = m-i
proc find*(a: SkipTable, s, sub: string, start: Natural = 0, last: Natural = 0): int
{.noSideEffect, rtl, extern: "nsuFindStrA".} =
## Searches for `sub` in `s` inside range `start`..`last` using preprocessed table `a`.
## If `last` is unspecified, it defaults to `s.high`.
##
## Searching is case-sensitive. If `sub` is not in `s`, -1 is returned.
let
last = if last==0: s.high else: last
m = len(sub)
n = last + 1
# search:
@@ -1361,17 +1379,6 @@ when not (defined(js) or defined(nimdoc) or defined(nimscript)):
else:
const hasCStringBuiltin = false
proc find*(s, sub: string, start: Natural = 0, last: Natural = 0): int {.noSideEffect,
rtl, extern: "nsuFindStr".} =
## Searches for `sub` in `s` inside range `start`..`last`.
## If `last` is unspecified, it defaults to `s.high`.
##
## Searching is case-sensitive. If `sub` is not in `s`, -1 is returned.
var a {.noinit.}: SkipTable
let last = if last==0: s.high else: last
preprocessSub(sub, a)
result = findAux(s, sub, start, last, a)
proc find*(s: string, sub: char, start: Natural = 0, last: Natural = 0): int {.noSideEffect,
rtl, extern: "nsuFindChar".} =
## Searches for `sub` in `s` inside range `start`..`last`.
@@ -1390,9 +1397,24 @@ proc find*(s: string, sub: char, start: Natural = 0, last: Natural = 0): int {.n
else:
for i in start..last:
if sub == s[i]: return i
return -1
proc find*(s, sub: string, start: Natural = 0, last: Natural = 0): int {.noSideEffect,
rtl, extern: "nsuFindStr".} =
## Searches for `sub` in `s` inside range `start`..`last`.
## If `last` is unspecified, it defaults to `s.high`.
##
## Searching is case-sensitive. If `sub` is not in `s`, -1 is returned.
if sub.len > s.len:
return -1
if sub.len == 1:
return find(s, sub[0], start, last)
var a {.noinit.}: SkipTable
initSkipTable(a, sub)
result = find(a, s, sub, start, last)
proc find*(s: string, chars: set[char], start: Natural = 0, last: Natural = 0): int {.noSideEffect,
rtl, extern: "nsuFindCharSet".} =
## Searches for `chars` in `s` inside range `start`..`last`.
@@ -1524,11 +1546,11 @@ proc replace*(s, sub: string, by = ""): string {.noSideEffect,
## Replaces `sub` in `s` by the string `by`.
var a {.noinit.}: SkipTable
result = ""
preprocessSub(sub, a)
initSkipTable(a, sub)
let last = s.high
var i = 0
while true:
var j = findAux(s, sub, i, last, a)
var j = find(a, s, sub, i, last)
if j < 0: break
add result, substr(s, i, j - 1)
add result, by
@@ -1558,11 +1580,11 @@ proc replaceWord*(s, sub: string, by = ""): string {.noSideEffect,
const wordChars = {'a'..'z', 'A'..'Z', '0'..'9', '_', '\128'..'\255'}
var a {.noinit.}: SkipTable
result = ""
preprocessSub(sub, a)
initSkipTable(a, sub)
var i = 0
let last = s.high
while true:
var j = findAux(s, sub, i, last, a)
var j = find(a, s, sub, i, last)
if j < 0: break
# word boundary?
if (j == 0 or s[j-1] notin wordChars) and