From 71ae0e1617218820f405bbf79d5d5dc89d5772ee Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Mon, 13 Apr 2020 19:45:09 -0500
Subject: Add unescape2(), migrate some unescape() users over.

---
 lib/lib.c | 23 +++++++++++++++++++++++
 lib/lib.h |  1 +
 2 files changed, 24 insertions(+)

(limited to 'lib')

diff --git a/lib/lib.c b/lib/lib.c
index 364ce07e..4fa358c0 100644
--- a/lib/lib.c
+++ b/lib/lib.c
@@ -436,6 +436,29 @@ int unescape(char c)
   return (idx == -1) ? 0 : to[idx];
 }
 
+// parse next character advancing pointer. echo requires leading 0 in octal esc
+int unescape2(char **c, int echo)
+{
+  int idx = *((*c)++), i, off;
+
+  if (idx != '\\' || !**c) return idx;
+  if (**c == 'c') return 31&*(++*c);
+  for (i = 0; i<4; i++) {
+    if (sscanf(*c, (char *[]){"0%3o%n"+!echo, "x%2x%n", "u%4x%n", "U%6x%n"}[i],
+        &idx, &off))
+    {
+      *c += off;
+
+      return idx;
+    }
+  }
+
+  if (-1 == (idx = stridx("\\abeEfnrtv'\"?", **c))) return '\\';
+  ++*c;
+
+  return "\\\a\b\033\033\f\n\r\t\v'\"?"[idx];
+}
+
 // If string ends with suffix return pointer to start of suffix in string,
 // else NULL
 char *strend(char *str, char *suffix)
diff --git a/lib/lib.h b/lib/lib.h
index 3200dc32..60c800ca 100644
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -234,6 +234,7 @@ char *strlower(char *s);
 char *strafter(char *haystack, char *needle);
 char *chomp(char *s);
 int unescape(char c);
+int unescape2(char **c, int echo);
 char *strend(char *str, char *suffix);
 int strstart(char **a, char *b);
 int strcasestart(char **a, char *b);
-- 
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