Update frozen readme

CL: Update frozen readme

PUBLISHED_FROM=2fd2e5222cbab46748a986e26259a66dfffbbc56

README.md

@@ -42,13 +42,22 @@ Scans the JSON string `str`, performing scanf-like conversions according to `fmt
       json_scanf(str, strlen(str), "{c: %B}", &value);
       ```
 3. Several extra format specifiers are supported:
-   - `%B`: consumes `int *`, expects boolean `true` or `false`.
-   - `%Q`: consumes `char **`, expects quoted, JSON-encoded string. A scanned
-      string is malloc-ed, caller must free() the string. The scanned string
-      is a JSON decoded, unescaped UTF-8 string.
-   - `%M`: consumes custom scanning function pointer and
+   - %B: consumes `int *` (or `char *`, if `sizeof(bool) == sizeof(char)`),
+      expects boolean `true` or `false`.
+   - %Q: consumes `char **`, expects quoted, JSON-encoded string. Scanned
+      string is malloc-ed, caller must free() the string.
+   - %V: consumes `char **`, `int *`. Expects base64-encoded string.
+      Result string is base64-decoded, malloced and NUL-terminated.
+      The length of result string is stored in `int *` placeholder.
+      Caller must free() the result.
+   - %H: consumes `int *`, `char **`.
+      Expects a hex-encoded string, e.g. "fa014f".
+      Result string is hex-decoded, malloced and NUL-terminated.
+      The length of the result string is stored in `int *` placeholder.
+      Caller must free() the result.
+   - %M: consumes custom scanning function pointer and
       `void *user_data` parameter - see json_scanner_t definition.
-   - `%T`: consumes `struct json_token *`, fills it out with matched token.
+   - %T: consumes `struct json_token *`, fills it out with matched token.
 
 Returns the number of elements successfully scanned & converted.
 Negative number means scan error.
@@ -148,20 +157,17 @@ int json_printf(struct json_out *, const char *fmt, ...);
 int json_vprintf(struct json_out *, const char *fmt, va_list ap);
 ```
 
-Generates formatted output into a given sting buffer.
-String values escape when printed (see `%M` specifier).
-This is a superset of the printf() function, with extra format specifiers:
-- `%B` prints JSON boolean, `true` or `false`. Accepts an `int`.
-- `%Q` prints quoted escaped string or `null`. Accepts a `const char *`.
-- `%.*Q` like `%Q` but accepts the length of the string explicitly, pretty much like `%.*s`.
-Embedded NUL bytes are supported and will be properly encoded as `\u0000`.
-Accepts an `int` length and a `const char *`.
-- `%M` invokes a json_printf_callback_t function. That callback function
-can consume more parameters.
-
-`json_printf()` also auto-escapes keys.
-
-Returns the number of bytes printed. If the return value is bigger then the
+Generate formatted output into a given sting buffer, auto-escaping keys.
+This is a superset of printf() function, with extra format specifiers:
+ - `%B` print json boolean, `true` or `false`. Accepts an `int`.
+ - `%Q` print quoted escaped string or `null`. Accepts a `const char *`.
+ - `%.*Q` same as `%Q`, but with length. Accepts `int`, `const char *`
+ - `%V` print quoted base64-encoded string. Accepts a `const char *`, `int`.
+ - `%H` print quoted hex-encoded string. Accepts a `int`, `const char *`.
+ - `%M` invokes a json_printf_callback_t function. That callback function
+ can consume more parameters.
+
+Return number of bytes printed. If the return value is bigger than the
 supplied buffer, that is an indicator of overflow. In the overflow case,
 overflown bytes are not printed.
 

frozen.h

@@ -151,7 +151,7 @@ typedef int (*json_printf_callback_t)(struct json_out *, va_list *ap);
  *  - `%M` invokes a json_printf_callback_t function. That callback function
  *  can consume more parameters.
  *
- * Return number of bytes printed. If the return value is bigger then the
+ * Return number of bytes printed. If the return value is bigger than the
  * supplied buffer, that is an indicator of overflow. In the overflow case,
  * overflown bytes are not printed.
  */