diff options
| -rw-r--r-- | lib/pure/strutils.nim | 76 |
1 files changed, 49 insertions, 27 deletions
diff --git a/lib/pure/strutils.nim b/lib/pure/strutils.nim index 1f56704f7..9400e5c02 100644 --- a/lib/pure/strutils.nim +++ b/lib/pure/strutils.nim @@ -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 findAux(s, sub: string, start, last: int, a: SkipTable): int = - # Fast "quick search" algorithm: - var +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 + + 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 |