feat(printf): added support for %h, %hh, %j and %t length modifiers

- Renamed compiler switches
- Minor cleanup
Closes #12

1 files changed, 16 insertions, 6 deletions

diff --git a/README.md b/README.md
index f415329..5d03f03 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ Primarily designed for usage in embedded systems, where printf is not available
 Using the standard libc printf may pull **a lot** of unwanted library stuff and can bloat code size about 20k or is not 100% thread safe. In this cases the following implementation can be used.  

 Absolutely **NO dependencies** are required, *printf.c* brings all necessary routines, even its own fast `ftoa` (float), `ntoa` (decimal) conversion.

 

-If memory footprint is really a critical issue, floating point and 'long long' support and can be turned off via the `PRINTF_FLOAT_SUPPORT` and `PRINTF_LONG_LONG_SUPPORT` compiler switches.

+If memory footprint is really a critical issue, floating point and 'long long' support and can be turned off via the `PRINTF_SUPPORT_FLOAT` and `PRINTF_SUPPORT_LONG_LONG` compiler switches.

 When using printf (instead of sprintf/snprintf) you have to provide your own `_putchar()` low level function as console/serial output.

 

 

@@ -52,7 +52,12 @@ int snprintf(char* buffer, size_t count, const char* format, ...);
 int vsnprintf(char* buffer, size_t count, const char* format, va_list va);

 ```

 

-**Due to genaral security reasons it is highly recommended to use `snprintf` (with the max buffer size as `count` parameter) instead of `sprintf`.**  

+If `buffer` is set to `nullptr` nothing is written and just the formatted length is returned.

+```C

+int length = sprintf(nullptr, "Hello, world"); // length is set to 12

+```

+

+**Due to genaral security reasons it is highly recommended to prefer and use `snprintf` (with the max buffer size as `count` parameter) instead of `sprintf`.**  

 `sprintf` has no buffer limitation, so when needed - use it really with care!

 

 

@@ -113,9 +118,13 @@ The length sub-specifier modifies the length of the data type.
 | Length | d i  | u o x X |

 |--------|------|---------|

 | (none) | int  | unsigned int |

+| hh     | char | unsigned char |

+| h      | short int | unsigned short int |

 | l      | long int | unsigned long int |

-| ll     | long long int | unsigned long long int (if PRINTF_LONG_LONG_SUPPORT is defined) |

-| z      | size_t int | unsigned size_t int |

+| ll     | long long int | unsigned long long int (if PRINTF_SUPPORT_LONG_LONG is defined) |

+| j      | intmax_t | uintmax_t |

+| z      | size_t | size_t |

+| t      | ptrdiff_t | ptrdiff_t (if PRINTF_SUPPORT_PTRDIFF_T is defined) |

 

 

 ### Return value

@@ -134,8 +143,9 @@ If any error is encountered, `-1` is returned.
 |------|---------------|-------------|

 | PRINTF_NTOA_BUFFER_SIZE  | 32        | ntoa (integer) conversion buffer size. This must be big enough to hold one converted numeric number _including_ leading zeros, normally 32 is a sufficient value. Created on the stack |

 | PRINTF_FTOA_BUFFER_SIZE  | 32        | ftoa (float) conversion buffer size. This must be big enough to hold one converted float number _including_ leading zeros, normally 32 is a sufficient value. Created on the stack |

-| PRINTF_FLOAT_SUPPORT     | undefined | Define this to enable floating point (%f) support |

-| PRINTF_LONG_LONG_SUPPORT | undefined | Define this to enable long long (%ll) support |

+| PRINTF_SUPPORT_FLOAT     | defined   | Define this to enable floating point (%f) support |

+| PRINTF_SUPPORT_LONG_LONG | defined   | Define this to enable long long (%ll) support |

+| PRINTF_SUPPORT_PTRDIFF_T | defined   | Define this to enable ptrdiff_t (%t) support |

 

 

 ## Test suite