Re: [libvirt] [PATCHv6 2/5] virstring.h/c: Util method for making some find and replace in strings
On Thu, Jan 23, 2014 at 10:28:30AM +0100, Manuel VIVES wrote:
---
src/libvirt_private.syms |1 +
src/util/virstring.c | 66
+-
src/util/virstring.h |1 +
3 files changed, 67 insertions(+), 1 deletion(-)
Can you also add a test case to src/virstringtest.c for this one
too. In particular test what happens when matches are exactly at
the start and end of the string so we validate proper boundary
handling.
+
+/*
+ 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)
Can we call this virStringReplace instead.
+{
+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) {
This looks like a out of bounds read. eg consider
haystack = foo
oldneedle = baar
You're going to be making memcmp read beyond the end of the haystack
array I believe.
+count ++;
+i += oldneedle_len - 1;
+}
+}
+numberOfElementsToAllocate = (i + count * (newneedle_len -
oldneedle_len));
+
+if (VIR_ALLOC_N(ret, numberOfElementsToAllocate) 0)
+goto cleanup;
Rather than trying to pre-caculate buffer lengths, I thin it would
probably be simpler if you just used the virBuffer APIs to construct
the new string, since that does grow-on-demand.
+
+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;
+}
Daniel
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[libvirt] [PATCHv6 2/5] virstring.h/c: Util method for making some find and replace in strings
---
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 68ca39d..5103919 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1778,6 +1778,7 @@ 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
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