[gtksourceview] implregex: rename start_pos to pos

[Christian Hergert <chergert src gnome org>]

commit 658f248304255fa761f7bda6c5d2cc0562fa6080
Author: Christian Hergert <chergert redhat com>
Date:   Mon Jul 5 14:48:22 2021 -0700

    implregex: rename start_pos to pos
    
    This more closely matches gregex.c, in hopes to make things easier to
    triage differences.

 gtksourceview/implregex.c | 46 +++++++++++++++++++++++++---------------------
 1 file changed, 25 insertions(+), 21 deletions(-)
---
diff --git a/gtksourceview/implregex.c b/gtksourceview/implregex.c
index 3e3e839f..05e763de 100644
--- a/gtksourceview/implregex.c
+++ b/gtksourceview/implregex.c
@@ -76,9 +76,12 @@ struct _ImplMatchInfo
        PCRE2_SIZE       *offsets;
        int               matches;
        int               n_subpatterns;
-       gssize            start_pos;
+       gssize            pos;
 };
 
+/* if the string is in UTF-8 use g_utf8_ functions, else use use just +/- 1. */
+#define NEXT_CHAR(re, s) ((!((re)->compile_flags & PCRE2_UTF)) ? ((s) + 1) : g_utf8_next_char (s))
+
 #define TAKE(f,gbit,pbit)            \
        G_STMT_START {               \
                if (f & gbit)        \
@@ -285,7 +288,8 @@ static ImplMatchInfo *
 impl_match_info_new (ImplRegex        *regex,
                      GRegexMatchFlags  match_options,
                      const char       *string,
-                     gssize            string_len)
+                     gssize            string_len,
+                     gssize            position)
 {
        ImplMatchInfo *match_info;
 
@@ -301,18 +305,16 @@ impl_match_info_new (ImplRegex        *regex,
        match_info = g_slice_new0 (ImplMatchInfo);
        match_info->regex = impl_regex_ref (regex);
        match_info->match_flags = regex->match_flags | translate_match_flags (match_options);
-       match_info->start_pos = 0;
-       match_info->matches = -1;
+       match_info->pos = MAX (0, position);
+       match_info->matches = PCRE2_ERROR_NOMATCH;
        match_info->string = string;
        match_info->string_len = string_len;
        match_info->match_data = pcre2_match_data_create_from_pattern (regex->code, NULL);
 
-       pcre2_pattern_info (regex->code, PCRE2_INFO_CAPTURECOUNT, &match_info->n_subpatterns);
-
        if (match_info->match_data == NULL)
-       {
                g_error ("Failed to allocate match data");
-       }
+
+       pcre2_pattern_info (regex->code, PCRE2_INFO_CAPTURECOUNT, &match_info->n_subpatterns);
 
        match_info->offsets = pcre2_get_ovector_pointer (match_info->match_data);
        match_info->offsets[0] = -1;
@@ -333,7 +335,7 @@ impl_match_info_free (ImplMatchInfo *match_info)
                match_info->compile_flags = 0;
                match_info->match_flags = 0;
                match_info->matches = 0;
-               match_info->start_pos = 0;
+               match_info->pos = 0;
                match_info->offsets = NULL;
                g_slice_free (ImplMatchInfo, match_info);
        }
@@ -486,8 +488,7 @@ impl_regex_match_full (const ImplRegex   *regex,
                string_len = strlen (string);
        }
 
-       local_match_info = impl_match_info_new ((ImplRegex *)regex, match_options, string, string_len);
-       local_match_info->start_pos = start_position;
+       local_match_info = impl_match_info_new ((ImplRegex *)regex, match_options, string, string_len, 
start_position);
 
        ret = impl_match_info_next (local_match_info, error);
 
@@ -1041,15 +1042,15 @@ impl_match_info_next (ImplMatchInfo  *match_info,
 
        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);
+       g_return_val_if_fail (match_info->pos >= 0, FALSE);
 
        prev_match_start = match_info->offsets[0];
        prev_match_end = match_info->offsets[1];
 
-       if (match_info->start_pos > match_info->string_len)
+       if (match_info->pos > match_info->string_len)
        {
                /* we have reached the end of the string */
-               match_info->start_pos = -1;
+               match_info->pos = -1;
                match_info->matches = PCRE2_ERROR_NOMATCH;
                return FALSE;
        }
@@ -1059,7 +1060,7 @@ impl_match_info_next (ImplMatchInfo  *match_info,
                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->pos,
                                                       match_info->match_flags,
                                                       match_info->match_data,
                                                       NULL);
@@ -1074,7 +1075,7 @@ impl_match_info_next (ImplMatchInfo  *match_info,
                match_info->matches = pcre2_match (match_info->regex->code,
                                                   (PCRE2_SPTR)match_info->string,
                                                   match_info->string_len,
-                                                  match_info->start_pos,
+                                                  match_info->pos,
                                                   match_flags,
                                                   match_info->match_data,
                                                   NULL);
@@ -1085,21 +1086,24 @@ impl_match_info_next (ImplMatchInfo  *match_info,
 
        /* 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->pos == match_info->offsets[1])
        {
-               if (match_info->start_pos > match_info->string_len)
+               if (match_info->pos > match_info->string_len)
                {
                        /* we have reached the end of the string */
-                       match_info->start_pos = -1;
+                       match_info->pos = -1;
                        match_info->matches = PCRE2_ERROR_NOMATCH;
                        return FALSE;
                }
 
-               match_info->start_pos = g_utf8_next_char (&match_info->string[match_info->start_pos]) - 
match_info->string;
+               match_info->pos = NEXT_CHAR (match_info->regex, &match_info->string[match_info->pos]) -
+                                 match_info->string;
+
+
        }
        else
        {
-               match_info->start_pos = match_info->offsets[1];
+               match_info->pos = match_info->offsets[1];
        }
 
        g_assert (match_info->matches <= match_info->n_subpatterns + 1);