From cd9a595ff6a84501a8760e5032b5552f9c6ca8fd Mon Sep 17 00:00:00 2001
From: Alan Liu <alansliu@gmail.com>
Date: Mon, 18 Mar 2002 21:25:01 +0000
Subject: [PATCH] ICU-1779 avoid malloc(0)

X-SVN-Rev: 8091
---
 icu4c/source/common/unistr.cpp  | 3 +++
 icu4c/source/common/uvector.cpp | 4 ++++
 icu4c/source/i18n/rbt_set.cpp   | 3 ++-
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/icu4c/source/common/unistr.cpp b/icu4c/source/common/unistr.cpp
index d81a55ab662..e6818828825 100644
--- a/icu4c/source/common/unistr.cpp
+++ b/icu4c/source/common/unistr.cpp
@@ -1364,6 +1364,9 @@ UnicodeString::handleReplaceBetween(int32_t start,
  */
 void 
 UnicodeString::copy(int32_t start, int32_t limit, int32_t dest) {
+    if (limit <= start) {
+        return; // Nothing to do; avoid bogus malloc call
+    }
     UChar* text = (UChar*) uprv_malloc( sizeof(UChar) * (limit - start) );
     extractBetween(start, limit, text, 0);
     insert(dest, text, 0, limit - start);    
diff --git a/icu4c/source/common/uvector.cpp b/icu4c/source/common/uvector.cpp
index 68f248dced2..bd09e2c1ab7 100644
--- a/icu4c/source/common/uvector.cpp
+++ b/icu4c/source/common/uvector.cpp
@@ -32,6 +32,10 @@ UVector::UVector(int32_t initialCapacity, UErrorCode &status) :
     deleter(0),
     comparer(0)
 {
+    // Fix bogus initialCapacity values; avoid malloc(0)
+    if (initialCapacity < 1) {
+        initialCapacity = 1;
+    }
     _init(initialCapacity, status);
 }
 
diff --git a/icu4c/source/i18n/rbt_set.cpp b/icu4c/source/i18n/rbt_set.cpp
index 99cfadd5640..ecdd04fada4 100644
--- a/icu4c/source/i18n/rbt_set.cpp
+++ b/icu4c/source/i18n/rbt_set.cpp
@@ -276,8 +276,9 @@ void TransliterationRuleSet::freeze(UParseError& parseError,UErrorCode& status)
     }
 
     /* Precompute the index values.  This saves a LOT of time.
+     * Be careful not to call malloc(0).
      */
-    int16_t* indexValue = (int16_t*) uprv_malloc( sizeof(int16_t) * n );
+    int16_t* indexValue = (int16_t*) uprv_malloc( sizeof(int16_t) * (n > 0 ? n : 1) );
     for (j=0; j<n; ++j) {
         TransliterationRule* r = (TransliterationRule*) ruleVector->elementAt(j);
         indexValue[j] = r->getIndexValue();