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string comparisons don't have to know the strings representation

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This commit is contained in:
Andreas Rumpf 2018-07-10 11:37:30 +02:00
commit 8f0c9b2fdd
1 changed files with 8 additions and 21 deletions
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29
lib/system/strmantle.nim
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@ -9,36 +9,23 @@
## Compilerprocs for strings that do not depend on the string implementation. ## Compilerprocs for strings that do not depend on the string implementation.
proc cmpStrings(a, b: NimString): int {.inline, compilerProc.} = proc cmpStrings(a, b: string): int {.inline, compilerProc.} =
if a == b: return 0 let alen = a.len
when defined(nimNoNil): let blen = b.len
let alen = if a == nil: 0 else: a.len
let blen = if b == nil: 0 else: b.len
else:
if a == nil: return -1
if b == nil: return 1
let alen = a.len
let blen = b.len
let minlen = min(alen, blen) let minlen = min(alen, blen)
if minlen > 0: if minlen > 0:
result = c_memcmp(addr a.data, addr b.data, minlen.csize) result = c_memcmp(unsafeAddr a[0], unsafeAddr b[0], minlen.csize)
if result == 0: if result == 0:
result = alen - blen result = alen - blen
else: else:
result = alen - blen result = alen - blen
proc eqStrings(a, b: NimString): bool {.inline, compilerProc.} = proc eqStrings(a, b: string): bool {.inline, compilerProc.} =
if a == b: return true let alen = a.len
when defined(nimNoNil): let blen = b.len
let alen = if a == nil: 0 else: a.len
let blen = if b == nil: 0 else: b.len
else:
if a == nil or b == nil: return false
let alen = a.len
let blen = b.len
if alen == blen: if alen == blen:
if alen == 0: return true if alen == 0: return true
return equalMem(addr(a.data), addr(b.data), alen) return equalMem(unsafeAddr(a[0]), unsafeAddr(b[0]), alen)
proc hashString(s: string): int {.compilerproc.} = proc hashString(s: string): int {.compilerproc.} =
# the compiler needs exactly the same hash function! # the compiler needs exactly the same hash function!