Initial import

libc/escape/escapec.c

@@ -0,0 +1,68 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/escape/escape.h"
+#include "libc/limits.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Escapes memory for inclusion in C string literals (or Python, etc.)
+ *
+ * The outer quotation marks are *not* added.
+ *
+ * @param buf is the output area, which can't overlap and, no matter
+ *     what, a NUL-terminator will always be placed in the buffer at
+ *     an appropriate place, provided buf!=NULL && size!=0
+ * @param size is the byte-length of the output area
+ * @param s is the data, which may have NUL characters
+ * @param l is the byte-length of s or -1 if s is NUL-terminated
+ * @return number of characters written, excluding NUL terminator; or,
+ *     if the output buffer wasn't passed, or was too short, then the
+ *     number of characters that *would* have been written is returned;
+ *     since that's how the snprintf() API works; or -1 on overflow
+ * @see xaescapec() for an easier api
+ */
+int escapec(char *buf, unsigned size, const char *s, unsigned l) {
+  if (l >= INT_MAX) return eoverflow();
+  unsigned i, j = 0;
+  for (i = 0; i < l; ++i) {
+    unsigned t = cescapec(s[i]);
+    if (t) {
+      while (t) {
+        if (j < size) {
+          buf[j] = (unsigned char)t;
+          t >>= 8;
+        }
+        j++;
+      }
+    } else {
+      if (l == -1) {
+        break;
+      }
+    }
+  }
+  if (buf && size) {
+    if (j < size) {
+      buf[j] = '\0';
+    } else {
+      buf[size - 1] = '\0';
+    }
+  }
+  return j;
+}