diff options
| -rw-r--r-- | doc/tut1.rst | 7 | ||||
| -rw-r--r-- | lib/pure/strutils.nim | 29 |
2 files changed, 32 insertions, 4 deletions
diff --git a/doc/tut1.rst b/doc/tut1.rst index d2d6f8fe7..cca4e8c0e 100644 --- a/doc/tut1.rst +++ b/doc/tut1.rst @@ -67,6 +67,11 @@ aiming for your debugging pleasure. With `-d:release` some checks are `turned off and optimizations are turned on <nimc.html#compiler-usage-compileminustime-symbols>`_. +For benchmarking or production code, use the `-d:release` switch. +For comparing the performance with unsafe languages like C, use the `-d:danger` switch +in order to get meaningful, comparable results. Otherwise Nim might be handicapped +by checks that are **not even available** for C. + Though it should be pretty obvious what the program does, I will explain the syntax: statements which are not indented are executed when the program starts. Indentation is Nim's way of grouping statements. Indentation is @@ -626,7 +631,7 @@ Some terminology: in the example `question` is called a (formal) *parameter*, Result variable --------------- A procedure that returns a value has an implicit `result` variable declared -that represents the return value. A `return` statement with no expression is +that represents the return value. A `return` statement with no expression is shorthand for `return result`. The `result` value is always returned automatically at the end of a procedure if there is no `return` statement at the exit. diff --git a/lib/pure/strutils.nim b/lib/pure/strutils.nim index 3680b11de..bfd53a3a0 100644 --- a/lib/pure/strutils.nim +++ b/lib/pure/strutils.nim @@ -1826,6 +1826,9 @@ func find*(a: SkipTable, s, sub: string, start: Natural = 0, last = 0): int {. when not (defined(js) or defined(nimdoc) or defined(nimscript)): func c_memchr(cstr: pointer, c: char, n: csize_t): pointer {. importc: "memchr", header: "<string.h>".} + func c_strstr(haystack, needle: cstring): cstring {. + importc: "strstr", header: "<string.h>".} + const hasCStringBuiltin = true else: const hasCStringBuiltin = false @@ -1889,9 +1892,29 @@ func find*(s, sub: string, start: Natural = 0, last = 0): int {.rtl, ## * `replace func<#replace,string,string,string>`_ 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) + + template useSkipTable {.dirty.} = + var a {.noinit.}: SkipTable + initSkipTable(a, sub) + result = find(a, s, sub, start, last) + + when not hasCStringBuiltin: + useSkipTable() + else: + when nimvm: + useSkipTable() + else: + when hasCStringBuiltin: + if last == 0 and s.len > start: + let found = c_strstr(s[start].unsafeAddr, sub) + if not found.isNil: + result = cast[ByteAddress](found) -% cast[ByteAddress](s.cstring) + else: + result = -1 + else: + useSkipTable() + else: + useSkipTable() func rfind*(s: string, sub: char, start: Natural = 0, last = -1): int {.rtl, extern: "nsuRFindChar".} = |