[libvirt] [PATCHv5 2/5] virstring.h/c: Util method for making some find and replace in strings

[Manuel VIVES]

---
 src/libvirt_private.syms |    1 +
 src/util/virstring.c     |   66 +++++++++++++++++++++++++++++++++++++++++++++-
 src/util/virstring.h     |    1 +
 3 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 14ad8f4..17aadfe 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1766,6 +1766,7 @@ virStringSortRevCompare;
 virStringSplit;
 virStrncpy;
 virStrndup;
+virStrReplace;
 virStrToDouble;
 virStrToLong_i;
 virStrToLong_l;
diff --git a/src/util/virstring.c b/src/util/virstring.c
index 3c93450..b6f6192 100644
--- a/src/util/virstring.c
+++ b/src/util/virstring.c
@@ -618,7 +618,6 @@ size_t virStringListLength(char **strings)
     return i;
 }
 
-
 /**
  * virStringSortCompare:
  *
@@ -742,3 +741,68 @@ cleanup:
     VIR_FREE(pmatch);
     return ret;
 }
+
+/*
+ virStrReplace(haystack, oldneedle, newneedle) --
+  Search haystack and replace all occurences of oldneedle with newneedle.
+  Return a string with all the replacements in case of success, NULL in case
+  of failure
+*/
+char *
+virStrReplace(char *haystack,
+              const char *oldneedle, const char *newneedle)
+{
+    char *ret = NULL;
+    size_t i = strlen(haystack);
+    size_t count = 0;
+    size_t newneedle_len = strlen(newneedle);
+    size_t oldneedle_len = strlen(oldneedle);
+    int diff_len = newneedle_len - oldneedle_len;
+    size_t totalLength = 0;
+    size_t numberOfElementsToAllocate = 0;
+    if (!haystack || !oldneedle || !newneedle) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("null value for haystack, oldneedle or newneedle"));
+        goto cleanup;
+    }
+    if (oldneedle_len == 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("oldneedle cannot be empty"));
+        goto cleanup;
+    }
+    if (diff_len == 0 && memcmp(oldneedle, newneedle, newneedle_len) == 0) {
+        ignore_value(VIR_STRDUP(ret, haystack));
+        goto cleanup;
+    }
+
+    for (i = 0; haystack[i] != '\0'; i++) {
+        if (memcmp(&haystack[i], oldneedle, oldneedle_len) == 0) {
+            count ++;
+            i += oldneedle_len - 1;
+        }
+    }
+    numberOfElementsToAllocate = (i + count * (newneedle_len - oldneedle_len));
+
+    if (VIR_ALLOC_N(ret, numberOfElementsToAllocate) < 0)
+        goto cleanup;
+
+    totalLength = sizeof(char) * numberOfElementsToAllocate;
+    i = 0;
+    while (*haystack) {
+        if (memcmp(haystack, oldneedle, oldneedle_len) == 0) {
+            if (virStrcpy(&ret[i], newneedle, totalLength) == NULL) {
+                VIR_FREE(ret);
+                goto cleanup;
+            }
+            totalLength -= newneedle_len;
+            i += newneedle_len;
+            haystack += oldneedle_len;
+        } else {
+            ret[i++] = *haystack++;
+            totalLength --;
+        }
+    }
+    ret[i] = '\0';
+cleanup:
+    return ret;
+}
diff --git a/src/util/virstring.h b/src/util/virstring.h
index fe05403..2df0695 100644
--- a/src/util/virstring.h
+++ b/src/util/virstring.h
@@ -227,6 +227,7 @@ int virStringSortCompare(const void *a, const void *b);
 int virStringSortRevCompare(const void *a, const void *b);
 
 int virSearchRegex(const char *sourceString, unsigned int occurrence, const char *regexp, char **result);
+char * virStrReplace(char *haystack, const char *oldneedle, const char *newneedle);
 
 
 #endif /* __VIR_STRING_H__ */
-- 
1.7.10.4