add snprintf and restrcuture all helper to writte on a buffer

This commit is contained in:
King Kévin 2017-03-08 09:48:52 +01:00
parent 2d7ad6dd86
commit 66c9bdbaab
2 changed files with 99 additions and 96 deletions

View File

@ -19,7 +19,8 @@
*/
/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdbool.h> // boolean type
#include <stdlib.h> // standard definitions
#include <stdbool.h> // boolean types
#include <stdarg.h> // variadic utilities
/* own libraries */
@ -31,35 +32,29 @@
#define CRLF true /**< if CR+LN new line should be enforced */
/** @} */
uint8_t putc(char c)
static size_t print_char(char** str, size_t* size, char c)
{
uint8_t length = 0; // number of characters printed
static char newline = 0; // to remember on which character we sent the newline
if (0==c) {
length = 0; // don't print string termination character
} else if (!CRLF) {
_putc(c); // print character
length++; // remember we printed 1 character
} else if ('\r' == c || '\n' == c) { // send CR+LF newline for most carriage return and line feed combination
if (0==newline || c==newline) { // send newline only if not already send (and only once on \r\n or \n\r)
_putc('\r'); // send CR
_putc('\n'); // send LF
length += 2; // remember we printed 2 characters
newline = c; // remember on which character we sent the newline
}
} else {
_putc(c); // print character
newline = 0; // clear new line
length++; // remember we printed 1 character
size_t length = 1; // remember how many characters have been printed or should have been added on string (normally just one)
if (0==c) { // don't print string termination character
length = 0; // remember we didn't print anything
} else if (NULL==str || NULL==*str || NULL==size) { // character should not be saved on string
length = putc(c); // print on user define output
} else if (*size>1) { // // there is enough space in the string to store the character
**str = c; // add provided character to string
*str += 1; // go to next character on string
*size -= 1; // remember we used one character on string
} else if (1==*size) { // string is reaching it's end
**str = '\0'; // add termination character to string (don't go to next character)
*size -= 1; // remember we used one character on string
}
return length; // return number of characters printed
return length;
}
uint32_t puts(const char* s)
static size_t print_string(char** str, size_t* size, const char* s)
{
uint32_t length = 0; // number of characters printed
size_t length = 0; // number of characters printed
while (*s) { // stop at end of string
length += putc(*(s++)); // send character
length += print_char(str, size, *(s++)); // print character
}
return length;
}
@ -70,10 +65,10 @@ uint32_t puts(const char* s)
* @param[in] sign if sign should be printed
* @return number of characters printed
**/
static uint8_t print_unsigned(uint64_t u, uint8_t padding, bool sign) {
static size_t print_unsigned(char** str, size_t* size, uint64_t u, uint8_t padding, bool sign) {
char number[20] = {0}; // construct the number in reverse order (20 chars are required to store UINT64_MAX)
uint8_t digits = 0; // to count the number of digits
uint8_t length = 0; // number of characters printed
size_t length = 0; // number of characters printed
do {
number[digits++] = '0'+(u%10); // store digit
u /= 10; // go to next digit
@ -82,13 +77,13 @@ static uint8_t print_unsigned(uint64_t u, uint8_t padding, bool sign) {
return 0;
}
if (sign) { // print sign
length += putc('+'); // we only have positive numbers
length += print_char(str, size, '+'); // we only have positive numbers
}
for (uint8_t zeros = digits; zeros<padding; zeros++) { // print padding 0's
length += putc('0'); // print 0
length += print_char(str, size, '0'); // print 0
}
for (uint8_t digit = 0; digit < digits; digit++) { // go through all digits
length += putc(number[digits-digit-1]); // print digit (in reverse order)
length += print_char(str, size, number[digits-digit-1]); // print digit (in reverse order)
}
return length; // return number of characters printed
}
@ -99,13 +94,13 @@ static uint8_t print_unsigned(uint64_t u, uint8_t padding, bool sign) {
* @param[in] sign if sign should be printed
* @return number of characters printed
**/
static uint8_t print_signed(int64_t d, uint8_t padding, bool sign) {
uint8_t length = 0; // number of characters printed
static size_t print_signed(char** str, size_t* size, int64_t d, uint8_t padding, bool sign) {
size_t length = 0; // number of characters printed
if (d<0) {
length += putc('-'); // print sign
length += print_unsigned((uint64_t)-d, padding, false); // print number (casting because there is one more negative value then positive value)
length += print_char(str, size, '-'); // print sign
length += print_unsigned(str, size, (uint64_t)-d, padding, false); // print number (casting because there is one more negative value then positive value)
} else {
length += print_unsigned(d, padding, sign); // print number
length += print_unsigned(str, size, d, padding, sign); // print number
}
return length; // return number of characters printed
}
@ -115,15 +110,15 @@ static uint8_t print_signed(int64_t d, uint8_t padding, bool sign) {
* @param[in] upcase use upcase digits (A-F)
* @return number of characters printed
**/
static uint8_t print_nibble(uint8_t nibble, bool upcase) {
uint8_t length = 0; // number of characters printed
static size_t print_nibble(char** str, size_t* size, uint8_t nibble, bool upcase) {
size_t length = 0; // number of characters printed
nibble &= 0x0f; // ensure we only have a nibble
if (nibble<10) {
length += putc('0'+nibble);
length += print_char(str, size, '0'+nibble);
} else if (upcase) {
length += putc('A'+nibble-10);
length += print_char(str, size, 'A'+nibble-10);
} else {
length += putc('a'+nibble-10);
length += print_char(str, size, 'a'+nibble-10);
}
return length; // return number of characters printed
}
@ -135,11 +130,11 @@ static uint8_t print_nibble(uint8_t nibble, bool upcase) {
* @param[in] upcase use upcase digits (A-F)
* @return number of characters printed
**/
static uint8_t print_hex(uint32_t hex, uint8_t padding, bool prefix, bool upcase) {
uint8_t length = 0; // number of characters printed
static size_t print_hex(char** str, size_t* size, uint32_t hex, uint8_t padding, bool prefix, bool upcase) {
size_t length = 0; // number of characters printed
if (prefix) { // print 0x prefix
length += putc('0');
length += putc('x');
length += print_char(str, size, '0');
length += print_char(str, size, 'x');
}
uint8_t digits = 0; // number of digits to print
// figure out number of digits to print
@ -153,10 +148,10 @@ static uint8_t print_hex(uint32_t hex, uint8_t padding, bool prefix, bool upcase
digits = 2;
}
for (uint8_t zeros = digits; zeros<padding; zeros++) { // print padding 0's
length += putc('0'); // print 0
length += print_char(str, size, '0'); // print 0
}
for (uint8_t digit = 0; digit < digits; digit++) { // go through all digits
length += print_nibble(hex>>((digits-digit-1)*4), upcase); // print nibble (in reverse order)
length += print_nibble(str, size, hex>>((digits-digit-1)*4), upcase); // print nibble (in reverse order)
}
return length; // return number of characters printed
}
@ -167,10 +162,10 @@ static uint8_t print_hex(uint32_t hex, uint8_t padding, bool prefix, bool upcase
* @param[in] prefix if 0b prefix should be printed
* @return number of characters printed
**/
static uint8_t print_bits(uint32_t u, uint8_t padding, bool prefix) {
static size_t print_bits(char** str, size_t* size, uint32_t u, uint8_t padding, bool prefix) {
char bits[32] = {0}; // construct the bit string in reverse order
uint8_t digits = 0; // to count the number of digits
uint8_t length = 0; // number of characters printed
size_t length = 0; // number of characters printed
do {
bits[digits++] = '0'+(u&0x1); // store bit
u >>= 1; // go to next bit
@ -179,93 +174,110 @@ static uint8_t print_bits(uint32_t u, uint8_t padding, bool prefix) {
return 0;
}
if (prefix) { // print prefix
length += putc('0');
length += putc('b');
length += print_char(str, size, '0');
length += print_char(str, size, 'b');
}
for (uint8_t zeros = digits; zeros<padding; zeros++) { // print padding 0's
length += putc('0'); // print 0
length += print_char(str, size, '0'); // print 0
}
for (uint8_t digit = 0; digit < digits; digit++) { // go through all bits
length += putc(bits[digits-digit-1]); // print bit (in reverse order)
length += print_char(str, size, bits[digits-digit-1]); // print bit (in reverse order)
}
return length; // return number of characters printed
}
uint32_t printf(const char *fmt, ...)
static size_t vsnprintf(char** str, size_t* size, const char *format, va_list va)
{
uint32_t length = 0; // number of characters printed
size_t length = 0; // number of characters printed
uint8_t padding = 0; // number of padding 0's
bool sign = false; // if sign needs to be printed
va_list va; // variable argument list
va_start(va, fmt); // initialise variable argument list
while (*fmt) { // go through format string
while (*format) { // go through format string
padding = 0; // reset padding
sign = false; // reset sign
if ('%'!=*fmt) { // check for format specifier prefix
length += putc(*fmt++); // print character (no interpretation needed)
if ('%'!=*format) { // check for format specifier prefix
length += putc(*format++); // print character (no interpretation needed)
} else {
fmt++; // go to format specifier
if (0==*fmt) { // end of string detected
format++; // go to format specifier
if (0==*format) { // end of string detected
goto end;
}
// check if sign need to be printed
if ('+'==*fmt) { // sign required
if ('+'==*format) { // sign required
sign = true; // remember sign is required
fmt++; // go to padding number
if (0==*fmt) { // end of string detected
format++; // go to padding number
if (0==*format) { // end of string detected
goto end;
}
}
// check padding
if ('0'==*fmt) { // padding required
fmt++; // go to padding number
if (0==*fmt) { // end of string detected
if ('0'==*format) { // padding required
format++; // go to padding number
if (0==*format) { // end of string detected
goto end;
}
if (*fmt>='0' && *fmt<='9') {
padding = *fmt-'0';
fmt++; // go to format specifier
if (0==*fmt) { // end of string detected
if (*format>='0' && *format<='9') {
padding = *format-'0';
format++; // go to format specifier
if (0==*format) { // end of string detected
goto end;
}
}
}
// check format specifier
switch (*fmt) {
switch (*format) {
case 'u': // for uint8_t, uint16_t, uint32_t, unsigned int, unsigned long
length += print_unsigned(va_arg(va,uint32_t), padding, sign);
length += print_unsigned(str, size, va_arg(va,uint32_t), padding, sign);
break;
case 'U': // for uint64_t, unsigned long long
length += print_unsigned(va_arg(va,uint64_t), padding, sign);
length += print_unsigned(str, size, va_arg(va,uint64_t), padding, sign);
break;
case 'd': // for int8_t, int16_t, int32_t, int, long
length += print_signed(va_arg(va,int32_t), padding, sign);
length += print_signed(str, size, va_arg(va,int32_t), padding, sign);
break;
case 'D': // for int64_t, long long
length += print_signed(va_arg(va,int64_t), padding, sign);
length += print_signed(str, size, va_arg(va,int64_t), padding, sign);
break;
case 'c': // for char, unsigned char
length += putc((char)(va_arg(va,int))); // needs casting because the returned value is promoted
length += print_char(str, size, (char)(va_arg(va,int))); // needs casting because the returned value is promoted
break;
case 'x': // for downcase hexadecimal
length += print_hex(va_arg(va,uint32_t), padding, sign, false);
length += print_hex(str, size, va_arg(va,uint32_t), padding, sign, false);
break;
case 'X': // for upcase hexadecimal
length += print_hex(va_arg(va,uint32_t), padding, sign, true);
length += print_hex(str, size, va_arg(va,uint32_t), padding, sign, true);
break;
case 'b': // for bits
length += print_bits(va_arg(va,uint32_t), padding, sign);
length += print_bits(str, size, va_arg(va,uint32_t), padding, sign);
break;
case 's': // for strings
length += puts(va_arg(va,char*));
length += print_string(str, size, va_arg(va,char*));
break;
default:
length += putc(*fmt); // print character (unknown format specifier)
length += print_char(str, size, *format); // print character (unknown format specifier)
}
fmt++; // go to next character
format++; // go to next character
}
}
end:
va_end(va);
return length;
}
size_t printf(const char *format, ...)
{
size_t length = 0;
va_list arglist;
va_start(arglist, format);
length = vsnprintf(NULL, NULL, format, arglist);
va_end(arglist);
return length;
}
size_t snprintf(char* str, size_t size, const char* format, ...)
{
size_t length = 0;
va_list arglist;
va_start(arglist, format);
length = vsnprintf(&str, &size, format, arglist);
va_end(arglist);
return length;
}

View File

@ -23,18 +23,7 @@
* @warning this must be implemented by the user (using the desired output interface)
* @param[in] c character to be printed
**/
void _putc(char c);
/** print character
* @note a CR+LF new line can be enforced in the code using @ref print_crlf
* @param[in] c character to be printed
* @return number of characters printed
*/
uint8_t putc(char c);
/** print string
* @param[in] s string to be printed
* @return number of characters printed (excluding null termination)
*/
uint32_t puts(const char* s);
size_t putc(char c);
/** print format string
* use % as format specifier prefix, followed by + to enforce sign of prefix, 0 and 0-9 for padding, and format specifier
* format specifier supported are: c for far, s for string, u for uint32_t, d for int32_t, U for uint64_t, D for int64_t, x for lower case hex up to uint32_t, X for upper case hex up to uint32_t, b for bits up to uint32_t
@ -42,4 +31,6 @@ uint32_t puts(const char* s);
* @param[in] ... arguments to to be formated
* @return number of characters printed (excluding null termination)
*/
uint32_t printf(const char *fmt, ...);
size_t printf(const char* format, ...);
size_t snprintf(char* str, size_t size, const char* format, ...);