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Diffstat (limited to 'lib/system/strmantle.nim')
| -rw-r--r-- | lib/system/strmantle.nim | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/lib/system/strmantle.nim b/lib/system/strmantle.nim new file mode 100644 index 000000000..89046253b --- /dev/null +++ b/lib/system/strmantle.nim @@ -0,0 +1,263 @@ +# +# +# Nim's Runtime Library +# (c) Copyright 2018 Andreas Rumpf +# +# See the file "copying.txt", included in this +# distribution, for details about the copyright. +# + +# Compilerprocs for strings that do not depend on the string implementation. + +import std/private/digitsutils + + +proc cmpStrings(a, b: string): int {.inline, compilerproc.} = + let alen = a.len + let blen = b.len + let minlen = min(alen, blen) + if minlen > 0: + result = c_memcmp(unsafeAddr a[0], unsafeAddr b[0], cast[csize_t](minlen)).int + if result == 0: + result = alen - blen + else: + result = alen - blen + +proc leStrings(a, b: string): bool {.inline, compilerproc.} = + # required by upcoming backends (NIR). + cmpStrings(a, b) <= 0 + +proc ltStrings(a, b: string): bool {.inline, compilerproc.} = + # required by upcoming backends (NIR). + cmpStrings(a, b) < 0 + +proc eqStrings(a, b: string): bool {.inline, compilerproc.} = + let alen = a.len + let blen = b.len + if alen == blen: + if alen == 0: return true + return equalMem(unsafeAddr(a[0]), unsafeAddr(b[0]), alen) + +proc hashString(s: string): int {.compilerproc.} = + # the compiler needs exactly the same hash function! + # this used to be used for efficient generation of string case statements + var h = 0'u + for i in 0..len(s)-1: + h = h + uint(s[i]) + h = h + h shl 10 + h = h xor (h shr 6) + h = h + h shl 3 + h = h xor (h shr 11) + h = h + h shl 15 + result = cast[int](h) + +proc eqCstrings(a, b: cstring): bool {.inline, compilerproc.} = + if pointer(a) == pointer(b): result = true + elif a.isNil or b.isNil: result = false + else: result = c_strcmp(a, b) == 0 + +proc hashCstring(s: cstring): int {.compilerproc.} = + # the compiler needs exactly the same hash function! + # this used to be used for efficient generation of cstring case statements + if s.isNil: return 0 + var h : uint = 0 + var i = 0 + while true: + let c = s[i] + if c == '\0': break + h = h + uint(c) + h = h + h shl 10 + h = h xor (h shr 6) + inc i + h = h + h shl 3 + h = h xor (h shr 11) + h = h + h shl 15 + result = cast[int](h) + +proc c_strtod(buf: cstring, endptr: ptr cstring): float64 {. + importc: "strtod", header: "<stdlib.h>", noSideEffect.} + +const + IdentChars = {'a'..'z', 'A'..'Z', '0'..'9', '_'} + powtens = [1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, + 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, + 1e20, 1e21, 1e22] + + +{.push staticBoundChecks: off.} + +proc nimParseBiggestFloat(s: openArray[char], number: var BiggestFloat, + ): int {.compilerproc.} = + # This routine attempt to parse float that can parsed quickly. + # i.e. whose integer part can fit inside a 53bits integer. + # their real exponent must also be <= 22. If the float doesn't follow + # these restrictions, transform the float into this form: + # INTEGER * 10 ^ exponent and leave the work to standard `strtod()`. + # This avoid the problems of decimal character portability. + # see: http://www.exploringbinary.com/fast-path-decimal-to-floating-point-conversion/ + var + i = 0 + sign = 1.0 + kdigits, fdigits = 0 + exponent = 0 + integer = uint64(0) + fracExponent = 0 + expSign = 1 + firstDigit = -1 + hasSign = false + + # Sign? + if i < s.len and (s[i] == '+' or s[i] == '-'): + hasSign = true + if s[i] == '-': + sign = -1.0 + inc(i) + + # NaN? + if i+2 < s.len and (s[i] == 'N' or s[i] == 'n'): + if s[i+1] == 'A' or s[i+1] == 'a': + if s[i+2] == 'N' or s[i+2] == 'n': + if i+3 >= s.len or s[i+3] notin IdentChars: + number = NaN + return i+3 + return 0 + + # Inf? + if i+2 < s.len and (s[i] == 'I' or s[i] == 'i'): + if s[i+1] == 'N' or s[i+1] == 'n': + if s[i+2] == 'F' or s[i+2] == 'f': + if i+3 >= s.len or s[i+3] notin IdentChars: + number = Inf*sign + return i+3 + return 0 + + if i < s.len and s[i] in {'0'..'9'}: + firstDigit = (s[i].ord - '0'.ord) + # Integer part? + while i < s.len and s[i] in {'0'..'9'}: + inc(kdigits) + integer = integer * 10'u64 + (s[i].ord - '0'.ord).uint64 + inc(i) + while i < s.len and s[i] == '_': inc(i) + + # Fractional part? + if i < s.len and s[i] == '.': + inc(i) + # if no integer part, Skip leading zeros + if kdigits <= 0: + while i < s.len and s[i] == '0': + inc(fracExponent) + inc(i) + while i < s.len and s[i] == '_': inc(i) + + if firstDigit == -1 and i < s.len and s[i] in {'0'..'9'}: + firstDigit = (s[i].ord - '0'.ord) + # get fractional part + while i < s.len and s[i] in {'0'..'9'}: + inc(fdigits) + inc(fracExponent) + integer = integer * 10'u64 + (s[i].ord - '0'.ord).uint64 + inc(i) + while i < s.len and s[i] == '_': inc(i) + + # if has no digits: return error + if kdigits + fdigits <= 0 and + (i == 0 or # no char consumed (empty string). + (i == 1 and hasSign)): # or only '+' or '- + return 0 + + if i+1 < s.len and s[i] in {'e', 'E'}: + inc(i) + if s[i] == '+' or s[i] == '-': + if s[i] == '-': + expSign = -1 + + inc(i) + if s[i] notin {'0'..'9'}: + return 0 + while i < s.len and s[i] in {'0'..'9'}: + exponent = exponent * 10 + (ord(s[i]) - ord('0')) + inc(i) + while i < s.len and s[i] == '_': inc(i) # underscores are allowed and ignored + + var realExponent = expSign*exponent - fracExponent + let expNegative = realExponent < 0 + var absExponent = abs(realExponent) + + # if exponent greater than can be represented: +/- zero or infinity + if absExponent > 999: + if integer == 0: + number = 0.0 + elif expNegative: + number = 0.0*sign + else: + number = Inf*sign + return i + + # if integer is representable in 53 bits: fast path + # max fast path integer is 1<<53 - 1 or 8999999999999999 (16 digits) + let digits = kdigits + fdigits + if digits <= 15 or (digits <= 16 and firstDigit <= 8): + # max float power of ten with set bits above the 53th bit is 10^22 + if absExponent <= 22: + if expNegative: + number = sign * integer.float / powtens[absExponent] + else: + number = sign * integer.float * powtens[absExponent] + return i + + # if exponent is greater try to fit extra exponent above 22 by multiplying + # integer part is there is space left. + let slop = 15 - kdigits - fdigits + if absExponent <= 22 + slop and not expNegative: + number = sign * integer.float * powtens[slop] * powtens[absExponent-slop] + return i + + # if failed: slow path with strtod. + var t: array[500, char] # flaviu says: 325 is the longest reasonable literal + var ti = 0 + let maxlen = t.high - "e+000".len # reserve enough space for exponent + + let endPos = i + result = endPos + i = 0 + # re-parse without error checking, any error should be handled by the code above. + if i < endPos and s[i] == '.': i.inc + while i < endPos and s[i] in {'0'..'9','+','-'}: + if ti < maxlen: + t[ti] = s[i]; inc(ti) + inc(i) + while i < endPos and s[i] in {'.', '_'}: # skip underscore and decimal point + inc(i) + + # insert exponent + t[ti] = 'E' + inc(ti) + t[ti] = if expNegative: '-' else: '+' + inc(ti, 4) + + # insert adjusted exponent + t[ti-1] = ('0'.ord + absExponent mod 10).char + absExponent = absExponent div 10 + t[ti-2] = ('0'.ord + absExponent mod 10).char + absExponent = absExponent div 10 + t[ti-3] = ('0'.ord + absExponent mod 10).char + number = c_strtod(cast[cstring](addr t), nil) + +{.pop.} # staticBoundChecks + +proc nimBoolToStr(x: bool): string {.compilerRtl.} = + return if x: "true" else: "false" + +proc nimCharToStr(x: char): string {.compilerRtl.} = + result = newString(1) + result[0] = x + +when defined(gcDestructors): + proc GC_getStatistics*(): string = + result = "[GC] total memory: " + result.addInt getTotalMem() + result.add "\n[GC] occupied memory: " + result.addInt getOccupiedMem() + result.add '\n' + #"[GC] cycle collections: " & $gch.stat.cycleCollections & "\n" & |