Moved capture retrieval logic into print.c

1 files changed, 59 insertions, 0 deletions

diff --git a/print.c b/print.c
index cb2ea34..a006a5e 100644
--- a/print.c
+++ b/print.c
@@ -2,6 +2,7 @@
 // print.c - Code for printing and visualizing matches.
 //
 
+#include <ctype.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -114,6 +115,64 @@ static const char *context_after(printer_t *pr, const char *pos)
 }
 
 //
+// Get a specific numbered pattern capture.
+//
+__attribute__((nonnull))
+static match_t *get_capture_by_num(match_t *m, int *n)
+{
+    if (*n == 0) return m;
+    if (m->pat->type == BP_CAPTURE && *n == 1) return m;
+    if (m->pat->type == BP_CAPTURE) --(*n);
+    if (m->children) {
+        for (int i = 0; m->children[i]; i++) {
+            match_t *cap = get_capture_by_num(m->children[i], n);
+            if (cap) return cap;
+        }
+    }
+    return NULL;
+}
+
+//
+// Get a capture with a specific name.
+//
+__attribute__((nonnull, pure))
+static match_t *get_capture_by_name(match_t *m, const char *name)
+{
+    if (m->pat->type == BP_CAPTURE && m->pat->args.capture.name
+        && strncmp(m->pat->args.capture.name, name, m->pat->args.capture.namelen) == 0)
+        return m;
+    if (m->children) {
+        for (int i = 0; m->children[i]; i++) {
+            match_t *cap = get_capture_by_name(m->children[i], name);
+            if (cap) return cap;
+        }
+    }
+    return NULL;
+}
+
+//
+// Get a capture by identifier (name or number).
+// Update *id to point to after the identifier (if found).
+//
+__attribute__((nonnull))
+static match_t *get_capture(match_t *m, const char **id)
+{
+    if (isdigit(**id)) {
+        int n = (int)strtol(*id, (char**)id, 10);
+        return get_capture_by_num(m, &n);
+    } else {
+        const char *end = after_name(*id);
+        if (end == *id) return NULL;
+        char *name = strndup(*id, (size_t)(end-*id));
+        match_t *cap = get_capture_by_name(m, name);
+        delete(&name);
+        *id = end;
+        if (**id == ';') ++(*id);
+        return cap;
+    }
+}
+
+//
 // Print the text of a match (no context).
 //
 static void _print_match(FILE *out, printer_t *pr, match_t *m)