[libvirt] [PATCH v3 02/14] util: Implement virStringFilterLines()

[Stefan Berger]

Implement virStringFilterLines() that takes as an input a buffer with text
and extracts each line that contains a given needle. The size of each re-
turned line can be restricted and if it is restricted '...' will automa-
tically be appended.

Signed-off-by: Stefan Berger <stefanb at linux.vnet.ibm.com>
---
 src/util/virstring.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/util/virstring.h |  3 +++
 2 files changed, 65 insertions(+)

diff --git a/src/util/virstring.c b/src/util/virstring.c
index 15f367a..f1d91c7 100644
--- a/src/util/virstring.c
+++ b/src/util/virstring.c
@@ -1499,3 +1499,65 @@ virStringParsePort(const char *str,
 
     return 0;
 }
+
+/**
+ * virStringFilterLines:
+ * @input: input buffer with text
+ * @needle: the needle to search in each line
+ * @maxlinelen: maximum line length of each line in output buffer;
+ *              0 to not restrict
+ *
+ * Search for a given needle in each line of the input buffer and create
+ * an output buffer that contains only these line.
+ */
+char *
+virStringFilterLines(char *input, const char *needle, size_t maxlinelen)
+{
+    char *sol = input;
+    char *eol;
+    char *buf = NULL;
+    size_t buflen = 1, llen;
+    const char *dots = "...";
+
+    while (*sol) {
+        eol = strchr(sol, '\n');
+        if (eol)
+            *eol = 0;
+
+        if (strstr(sol, needle)) {
+            size_t additional = 0;
+
+            llen = strlen(sol);
+            if (maxlinelen && llen > maxlinelen) {
+                llen = maxlinelen;
+                additional = strlen(dots);
+            }
+
+            if (VIR_REALLOC_N(buf, buflen + llen + additional + 1) < 0) {
+                VIR_FREE(buf);
+                if (*eol)
+                    *eol = '\n';
+                return NULL;
+            }
+            strncpy(&buf[buflen - 1], sol, llen);
+            buflen += llen;
+
+            if (additional) {
+                strncpy(&buf[buflen - 1], dots, additional);
+                buflen += additional;
+            }
+
+            strcpy(&buf[buflen - 1], "\n");
+            buflen += 1;
+        }
+
+        if (eol)
+            *eol = '\n';
+        else
+            break;
+
+        sol = eol + 1;
+    }
+
+    return buf;
+}
diff --git a/src/util/virstring.h b/src/util/virstring.h
index fa2ec1d..1fb9851 100644
--- a/src/util/virstring.h
+++ b/src/util/virstring.h
@@ -309,4 +309,7 @@ int virStringParsePort(const char *str,
                        unsigned int *port)
     ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
 
+char *virStringFilterLines(char *input, const char *needle, size_t maxlinelen)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
+
 #endif /* __VIR_STRING_H__ */
-- 
2.5.5