[gtksourceview] implregex: copy implementation from gregex

[Christian Hergert <chergert src gnome org>]

commit b0ae9a9fa4245eccd9ef8b074329c1bf57ace8f9
Author: Christian Hergert <chergert redhat com>
Date:   Fri Jul 2 17:16:45 2021 -0700

    implregex: copy implementation from gregex

 gtksourceview/implregex.c | 68 ++++++++++++++++++++---------------------------
 1 file changed, 29 insertions(+), 39 deletions(-)
---
diff --git a/gtksourceview/implregex.c b/gtksourceview/implregex.c
index fbbfd1de..5cf0099c 100644
--- a/gtksourceview/implregex.c
+++ b/gtksourceview/implregex.c
@@ -1025,20 +1025,17 @@ gboolean
 impl_match_info_next (ImplMatchInfo  *match_info,
                       GError        **error)
 {
-       gssize prev_end;
-       gssize prev_begin;
-       int rc;
+       gssize prev_match_start;
+       gssize prev_match_end;
 
        GTK_SOURCE_PROFILER_BEGIN_MARK;
 
-       g_assert (match_info != NULL);
-       g_assert (match_info->regex != NULL);
-       g_assert (match_info->regex->code != NULL);
-       g_assert (match_info->offsets == pcre2_get_ovector_pointer (match_info->match_data));
-       g_assert (match_info->start_pos >= 0);
+       g_return_val_if_fail (match_info != NULL, FALSE);
+       g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+       g_return_val_if_fail (match_info->start_pos >= 0, FALSE);
 
-       prev_begin = match_info->offsets[0];
-       prev_end = match_info->offsets[1];
+       prev_match_start = match_info->offsets[0];
+       prev_match_end = match_info->offsets[1];
 
        if (match_info->start_pos > match_info->string_len)
        {
@@ -1050,13 +1047,13 @@ impl_match_info_next (ImplMatchInfo  *match_info,
 
        if (match_info->regex->has_jit)
        {
-               rc = pcre2_jit_match (match_info->regex->code,
-                                     (PCRE2_SPTR)match_info->string,
-                                     match_info->string_len,
-                                     match_info->start_pos,
-                                     match_info->match_flags,
-                                     match_info->match_data,
-                                     NULL);
+               match_info->matches = pcre2_jit_match (match_info->regex->code,
+                                                      (PCRE2_SPTR)match_info->string,
+                                                      match_info->string_len,
+                                                      match_info->start_pos,
+                                                      match_info->match_flags,
+                                                      match_info->match_data,
+                                                      NULL);
        }
        else
        {
@@ -1065,26 +1062,21 @@ impl_match_info_next (ImplMatchInfo  *match_info,
                if (match_info->regex->compile_flags & PCRE2_UTF)
                        match_flags |= PCRE2_NO_UTF_CHECK;
 
-               rc = pcre2_match (match_info->regex->code,
-                                 (PCRE2_SPTR)match_info->string,
-                                 match_info->string_len,
-                                 match_info->start_pos,
-                                 match_flags,
-                                 match_info->match_data,
-                                 NULL);
+               match_info->matches = pcre2_match (match_info->regex->code,
+                                                  (PCRE2_SPTR)match_info->string,
+                                                  match_info->string_len,
+                                                  match_info->start_pos,
+                                                  match_flags,
+                                                  match_info->match_data,
+                                                  NULL);
        }
 
-       if (set_regex_error (error, rc))
-       {
-               match_info->matches = rc;
-               match_info->start_pos = -1;
+       if (set_regex_error (error, match_info->matches))
                return FALSE;
-       }
 
-       /* Avoid infinite loops if the pattern is an empty string or
-        * something equivalent.
-        */
-       if (prev_end == match_info->offsets[1])
+       /* avoid infinite loops if the pattern is an empty string or something
+        * equivalent */
+       if (match_info->start_pos == match_info->offsets[1])
        {
                if (match_info->start_pos > match_info->string_len)
                {
@@ -1101,6 +1093,8 @@ impl_match_info_next (ImplMatchInfo  *match_info,
                match_info->start_pos = match_info->offsets[1];
        }
 
+       g_assert (match_info->matches <= match_info->n_subpatterns + 1);
+
        /* it's possible to get two identical matches when we are matching
         * empty strings, for instance if the pattern is "(?=[A-Z0-9])" and
         * the string is "RegExTest" we have:
@@ -1113,17 +1107,13 @@ impl_match_info_next (ImplMatchInfo  *match_info,
         * so we have to ignore the duplicates.
         * see bug #515944: http://bugzilla.gnome.org/show_bug.cgi?id=515944 */
        if (match_info->matches >= 0 &&
-           prev_begin == match_info->offsets[0] &&
-           prev_end == match_info->offsets[1])
+           prev_match_start == match_info->offsets[0] &&
+           prev_match_end == match_info->offsets[1])
        {
                /* ignore this match and search the next one */
                return impl_match_info_next (match_info, error);
        }
 
-       match_info->matches = rc;
-
-       g_assert (match_info->offsets == pcre2_get_ovector_pointer (match_info->match_data));
-
        GTK_SOURCE_PROFILER_END_MARK (G_STRFUNC, NULL);
 
        return match_info->matches >= 0;