From 05121d84b33c1fd765d6998d01ef530592590ea6 Mon Sep 17 00:00:00 2001
From: Araq <rumpf_a@web.de>
Date: Wed, 8 Aug 2018 12:05:29 +0200
Subject: fixes a long standing nil bug in substr

---
 lib/system/sysstr.nim | 1 +
 1 file changed, 1 insertion(+)

(limited to 'lib/system/sysstr.nim')

diff --git a/lib/system/sysstr.nim b/lib/system/sysstr.nim
index 19c2c62ad..77f2ca040 100644
--- a/lib/system/sysstr.nim
+++ b/lib/system/sysstr.nim
@@ -95,6 +95,7 @@ proc mnewString(len: int): NimString {.compilerProc.} =
 
 proc copyStrLast(s: NimString, start, last: int): NimString {.compilerProc.} =
   let start = max(start, 0)
+  if s == nil: return nil
   let len = min(last, s.len-1) - start + 1
   if len > 0:
     result = rawNewStringNoInit(len)
-- 
cgit 1.4.1-2-gfad0


From babd31360a93b1c17d33240c82391761e8419a95 Mon Sep 17 00:00:00 2001
From: Araq <rumpf_a@web.de>
Date: Wed, 8 Aug 2018 18:22:48 +0200
Subject: fixes more nil string bugs

---
 lib/packages/docutils/rstgen.nim |  7 +++----
 lib/pure/strutils.nim            | 10 ++++++----
 lib/system/sysstr.nim            |  1 +
 3 files changed, 10 insertions(+), 8 deletions(-)

(limited to 'lib/system/sysstr.nim')

diff --git a/lib/packages/docutils/rstgen.nim b/lib/packages/docutils/rstgen.nim
index 43a429a17..db9a83755 100644
--- a/lib/packages/docutils/rstgen.nim
+++ b/lib/packages/docutils/rstgen.nim
@@ -312,7 +312,6 @@ proc setIndexTerm*(d: var RstGenerator, id, term: string,
   ## The index won't be written to disk unless you call `writeIndexFile()
   ## <#writeIndexFile>`_. The purpose of the index is documented in the `docgen
   ## tools guide <docgen.html#index-switch>`_.
-  assert(not d.theIndex.isNil)
   var
     entry = term
     isTitle = false
@@ -337,7 +336,7 @@ proc hash(n: PRstNode): int =
     result = hash(n.text)
   elif n.len > 0:
     result = hash(n.sons[0])
-    for i in 1 .. <len(n):
+    for i in 1 ..< len(n):
       result = result !& hash(n.sons[i])
     result = !$result
 
@@ -452,7 +451,7 @@ proc generateSymbolIndex(symbols: seq[IndexEntry]): string =
           title="$3" data-doc-search-tag="$2" href="$1">$2</a></li>
           """, [url, text, desc])
       else:
-        result.addf("""<li><a class="reference external" 
+        result.addf("""<li><a class="reference external"
           data-doc-search-tag="$2" href="$1">$2</a></li>
           """, [url, text])
       inc j
@@ -524,7 +523,7 @@ proc generateDocumentationTOC(entries: seq[IndexEntry]): string =
       titleTag = levels[L].text
     else:
       result.add(level.indentToLevel(levels[L].level))
-      result.addf("""<li><a class="reference" data-doc-search-tag="$1" href="$2"> 
+      result.addf("""<li><a class="reference" data-doc-search-tag="$1" href="$2">
         $3</a></li>
         """, [titleTag & " : " & levels[L].text, link, levels[L].text])
     inc L
diff --git a/lib/pure/strutils.nim b/lib/pure/strutils.nim
index 4aede541a..989a832cf 100644
--- a/lib/pure/strutils.nim
+++ b/lib/pure/strutils.nim
@@ -1366,9 +1366,11 @@ proc find*(s: string, sub: char, start: Natural = 0, last: Natural = 0): int {.n
       if sub == s[i]: return i
   else:
     when hasCStringBuiltin:
-      let found = c_memchr(s[start].unsafeAddr, sub, last-start+1)
-      if not found.isNil:
-        return cast[ByteAddress](found) -% cast[ByteAddress](s.cstring)
+      let L = last-start+1
+      if L > 0:
+        let found = c_memchr(s[start].unsafeAddr, sub, L)
+        if not found.isNil:
+          return cast[ByteAddress](found) -% cast[ByteAddress](s.cstring)
     else:
       for i in start..last:
         if sub == s[i]: return i
@@ -1515,7 +1517,7 @@ proc replace*(s, sub: string, by = ""): string {.noSideEffect,
   elif subLen == 1:
     # when the pattern is a single char, we use a faster
     # char-based search that doesn't need a skip table:
-    var c = sub[0]
+    let c = sub[0]
     let last = s.high
     var i = 0
     while true:
diff --git a/lib/system/sysstr.nim b/lib/system/sysstr.nim
index 77f2ca040..0e690d832 100644
--- a/lib/system/sysstr.nim
+++ b/lib/system/sysstr.nim
@@ -110,6 +110,7 @@ proc nimToCStringConv(s: NimString): cstring {.compilerProc, inline.} =
   else: result = cstring(addr s.data)
 
 proc copyStr(s: NimString, start: int): NimString {.compilerProc.} =
+  if s == nil: return nil
   result = copyStrLast(s, start, s.len-1)
 
 proc toNimStr(str: cstring, len: int): NimString {.compilerProc.} =
-- 
cgit 1.4.1-2-gfad0