init

.gitignore

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+*.out

README.md

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+# Caret Notater
+> Header only C library for converting to caret notation
+
+### What is caret notation
+You may recognize it like this: `^H`.
+It is commonly used on the command line, an example would be Bash's Readline input.
+For details consult other sources: [wiki](https://en.wikipedia.org/wiki/Caret_notation).
+
+### API
+```C
+static inline int  is_caretable(const char c);
+static inline char to_caret_char(const char c);
+// NOTE: these functions return their `output` argument
+char * char_to_caret_notation(const char c, char output[3]);
+char * string_to_caret_notation(const char * const input, const unsigned long size, char * const output);
+#if CARET_NOTATER_ALLOC == 1
+static inline char * alloc_char_to_caret_notation(const char c);
+static inline char * alloc_string_to_caret_notation(const char * const input, const unsigned long size);
+```
+
+### NOTES
+`*string_to_caret_notation()` takes a (-n input) size explicitly because
+you may want to convert null characters as `'\0'` is `"^@"` in caret notation.
+If you dont care, you are advised to just pass a `strlen()` call.

caret_notater.h

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+#ifndef CARET_NOTATER_H
+#define CARET_NOTATER_H
+/* caret_notater.h converts strings containing
+ *  unprintable characters to equivalent strings
+ *  in caret notation.
+ */
+
+#if !defined(CARET_NOTATER_ALLOC) && defined(__STDC__) && __STDC__ == 1
+# define CARET_NOTATER_ALLOC 1
+#endif
+
+static inline int  is_caretable(const char c);
+static inline char to_caret_char(const char c);
+// NOTE: these functions return their `output` argument
+char * char_to_caret_notation(const char c, char output[3]);
+char * string_to_caret_notation(const char * const input, const unsigned long size, char * const output);
+#if CARET_NOTATER_ALLOC == 1
+static inline char * alloc_char_to_caret_notation(const char c);
+static inline char * alloc_string_to_caret_notation(const char * const input, const unsigned long size);
+#endif
+
+// --- Implementation
+
+static inline
+int is_caretable(const char c) {
+    return ((0 <= c && c <= 31) || c == 127);
+}
+
+static inline
+char to_caret_char(const char c) {
+    return c ^ 0x40;
+}
+
+char * char_to_caret_notation(const char c, char output[3]) {
+    if (is_caretable(c)) {
+        output[0] = '^';
+        output[1] = to_caret_char(c);
+        output[2] = '\0';
+    } else {
+        output[0] = '\0';
+    }
+    return output;
+}
+
+/* NOTE: the size must be passed because `'\0' -> "^@"` must be a valid transformation
+ */
+char * string_to_caret_notation(const char * const input, const unsigned long size, char * const output) {
+    int output_empty_end = 0;
+    for (unsigned long i = 0; i < size; i++) {
+        if (is_caretable(input[i])) {
+            output[output_empty_end++] = '^';
+            output[output_empty_end++] = to_caret_char(input[i]);
+        } else {
+            output[output_empty_end++] = input[i];
+        }
+    }
+    output[output_empty_end] = '\0';
+
+    return output;
+}
+
+#if CARET_NOTATER_ALLOC == 1
+  #include <stdlib.h>
+
+  static inline
+  char * alloc_char_to_caret_notation(const char c) {
+      char * const r = malloc(3);
+      return char_to_caret_notation(c, r);
+  }
+  
+  static inline
+  char * alloc_string_to_caret_notation(const char * const input, const unsigned long size) {
+      char * const r = malloc(size*2);
+      return string_to_caret_notation(input, size, r);
+  }
+#endif
+
+#endif
+/* --- LICENSE
+ * This software is in the Public Domain;
+ *  and if (You) dare to say this notice is not legally valid,
+ *  I will sue you.
+ */

example.c

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+// @BAKE gcc $@ -o $*.out; ./$*.out
+#include <stdio.h>
+#include "caret_notater.h"
+
+signed main() {
+    char input[] = "null: \00; \\07: \07; esc: \033; del: \x7f";
+    puts(alloc_string_to_caret_notation(input, sizeof(input)-1));
+    return 0;
+}