utils: add a method to substitute string using PCRE

2 files changed, 61 insertions, 1 deletions

diff --git a/src/utils/utils.c b/src/utils/utils.c
index f3ebbb4..ea0b424 100644
--- a/src/utils/utils.c
+++ b/src/utils/utils.c
@@ -7,6 +7,13 @@
 #include "../logger.h"
 #include "utils.h"
 
+static void print_error(int code) {
+  PCRE2_UCHAR message[256];
+  if (pcre2_get_error_message(code, message,
+                              sizeof(message) / sizeof(PCRE2_UCHAR)))
+    LOG("PCRE2", "Error: %s\n", (const char *)message);
+}
+
 int regex_match(const char *subject, str_array_t patterns,
                 str_array_t *results) {
   pcre2_code *re;
@@ -75,7 +82,7 @@ int regex_match(const char *subject, str_array_t patterns,
             "ovector was not big enough for all the captured substrings\n");
         break;
       default:
-        LOG("PCRE2", "Matching error %d\n", rc);
+        print_error(rc);
         return 1;
       }
     }
@@ -83,6 +90,56 @@ int regex_match(const char *subject, str_array_t patterns,
   return 0;
 }
 
+int substitute_str(const char *subject, const char *pattern,
+                   const char *replacement, char **presult) {
+  pcre2_code *re;
+  pcre2_match_context *match_context;
+  int rc, error;
+  PCRE2_SIZE erroffset, outlength;
+  PCRE2_UCHAR *outbuf;
+
+  re = pcre2_compile((PCRE2_SPTR)pattern, PCRE2_ZERO_TERMINATED,
+                     PCRE2_MULTILINE, &error, &erroffset, 0);
+  if (!re) {
+    print_error(error);
+    return 1;
+  }
+
+  match_context = pcre2_match_context_create(0);
+
+  outlength = 0;
+  rc = pcre2_substitute(re, (PCRE2_SPTR)subject, PCRE2_ZERO_TERMINATED, 0,
+                            PCRE2_SUBSTITUTE_GLOBAL |
+                                PCRE2_SUBSTITUTE_OVERFLOW_LENGTH |
+                                PCRE2_SUBSTITUTE_EXTENDED,
+                            0, match_context, (PCRE2_SPTR)replacement,
+                            PCRE2_ZERO_TERMINATED, 0, &outlength);
+
+  if (rc != PCRE2_ERROR_NOMEMORY) {
+    print_error(rc);
+    return 1;
+  }
+
+  outbuf = malloc(outlength * sizeof(PCRE2_UCHAR));
+
+  rc = pcre2_substitute(re, (PCRE2_SPTR)subject, PCRE2_ZERO_TERMINATED, 0,
+                            PCRE2_SUBSTITUTE_GLOBAL | PCRE2_SUBSTITUTE_EXTENDED,
+                            0, match_context, (PCRE2_SPTR)replacement,
+                            PCRE2_ZERO_TERMINATED, outbuf, &outlength);
+
+  if (rc < 0) {
+    print_error(rc);
+    return 1;
+  }
+
+  *presult = (char *)outbuf;
+
+  pcre2_match_context_free(match_context);
+  pcre2_code_free(re);
+
+  return 0;
+}
+
 int repchr(char *str, char t, char r) {
   int c = 0;
   for (size_t i = 0; str[i] != '\0'; i++) {
diff --git a/src/utils/utils.h b/src/utils/utils.h
index d7e45dc..f5bf8fc 100644
--- a/src/utils/utils.h
+++ b/src/utils/utils.h
@@ -6,6 +6,9 @@
 
 int regex_match(const char *, str_array_t, str_array_t *);
 
+int substitute_str(const char *subject, const char *pattern,
+                   const char *replacement, char **presult);
+
 int repchr(char *str, char t, char r);
 
 void free_and_nullify(void *p);