Provide consistent behaviour for memchr(_,_,0)

third_party/android_crazy_linker/src/src/crazy_linker_proc_maps.cpp

Index: third_party/android_crazy_linker/src/src/crazy_linker_proc_maps.cpp
diff --git a/third_party/android_crazy_linker/src/src/crazy_linker_proc_maps.cpp b/third_party/android_crazy_linker/src/src/crazy_linker_proc_maps.cpp
index 104f609df48aac2c99608af67086ece4ed058007..713870bea6ccbe32af090136c51c8e14534f4f89 100644
--- a/third_party/android_crazy_linker/src/src/crazy_linker_proc_maps.cpp
+++ b/third_party/android_crazy_linker/src/src/crazy_linker_proc_maps.cpp
@@ -56,10 +56,15 @@ bool ParseProcMapsLine(const char* line,
       p++;
 
     // find start and end of current token, and compute start of
-    // next search.
+    // next search. The result of memchr(_,_,0) is undefined, treated as
+    // not-found.
     const char* tok_start = p;
-    const char* tok_end =
-        static_cast<const char*>(memchr(p, separator, line_end - p));
+    const size_t range = line_end - p;
+    const char* tok_end;
+    if (range > 0)
+      tok_end = static_cast<const char*>(memchr(p, separator, range));
+    else
+      tok_end = NULL;

[rmcilroy, 2014/07/22 09:16:36]

Optional suggestion - I'm not sure if the crazy linker has a useful utility
class, but could we factor this out to a separate helper function (e.g.,
safe_memchr) which also automatically does the const char* static_cast?  

     if (!tok_end) {
       tok_end = line_end;
       p = line_end;