Initial import

libc/escape/escapesh.c

@@ -0,0 +1,73 @@
+/*-*- 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/assert.h"
+#include "libc/bits/bits.h"
+#include "libc/bits/safemacros.h"
+#include "libc/dce.h"
+#include "libc/escape/escape.h"
+#include "libc/limits.h"
+#include "libc/runtime/runtime.h"
+#include "libc/sysv/errfuns.h"
+
+#define SHQUOTE_PUTCHAR(c)             \
+  do {                                 \
+    if (buf != NULL && j < size - 1) { \
+      buf[j] = (c);                    \
+    }                                  \
+    j++;                               \
+  } while (0)
+
+/**
+ * Quotes memory for inclusion in single-quoted SystemV string literals.
+ *
+ * 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
+ * @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; and never < 0
+ * @see xaescapesh() for an easier api
+ */
+int escapesh(char *buf, unsigned size, const char *s, unsigned l) {
+  assert(size <= INT_MAX && l <= INT_MAX);
+  if (!IsTrustworthy() && l >= INT_MAX) abort();
+  unsigned j = 0;
+  for (unsigned i = 0; i < l; ++i) {
+    if (s[i] != '\'') {
+      SHQUOTE_PUTCHAR(s[i]);
+    } else {
+      const char *const s2 = "'\"'\"'";
+      unsigned l2 = 5;
+      for (unsigned k = 0; k < l2; ++k) {
+        SHQUOTE_PUTCHAR(s2[k]);
+      }
+    }
+  }
+  if (buf && size) {
+    buf[min(j, size - 1)] = '\0';
+  }
+  return j;
+}