- %k added

- %f rounding fixed

embformat.c

@@ -6,6 +6,7 @@
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
+#include <sys/_types.h>
 
 #define MAX(x, y) (((x) > (y)) ? (x) : (y))
 #define MIN(x, y) (((x) < (y)) ? (x) : (y))
@@ -14,17 +15,31 @@
 
 // format length ((nothing),l)
 typedef enum {
-    LEN_NORMAL, LEN_LONG
+    LEN_NORMAL,
+    LEN_LONG
 } FmtLength;
 
 // format flags ((nothing),0)
 typedef enum {
-    FLAG_NO = 0, FLAG_LEADING_ZEROS = 1, FLAG_LEADING_SPACES = 2, FLAG_PREPEND_PLUS_SIGN = 4
+    FLAG_NO = 0,
+    FLAG_LEADING_ZEROS = 1,
+    FLAG_LEADING_SPACES = 2,
+    FLAG_PREPEND_PLUS_SIGN = 4
 } FmtFlags;
 
 // format type
 typedef enum {
-    UNKNOWN = -1, LITERAL_PERCENT, SIGNED_INTEGER, UNSIGNED_INTEGER, DOUBLE, DOUBLE_EXPONENTIAL, UNSIGNED_HEXADECIMAL_INT, UNSIGNED_HEXADECIMAL_INT_UPPERCASE, STRING, CHARACTER
+    UNKNOWN = -1,
+    LITERAL_PERCENT,
+    SIGNED_INTEGER,
+    UNSIGNED_INTEGER,
+    DOUBLE,
+    DOUBLE_EXPONENTIAL,
+    DOUBLE_TRUNCATE,
+    UNSIGNED_HEXADECIMAL_INT,
+    UNSIGNED_HEXADECIMAL_INT_UPPERCASE,
+    STRING,
+    CHARACTER
 } FmtType;
 
 struct _FmtWord;
@@ -84,6 +99,21 @@ static uint64_t power(uint64_t a, unsigned long int n) {
     return a;
 }
 
+static double powerf(double d, long int n) {
+    if (n == 0) {
+        return 1.0;
+    }
+
+    d = (n < 0) ? (1 / d) : d;
+    n = (n < 0) ? -n : n;
+
+    double d_orig = d;
+    for (unsigned long int i = 0; i < n - 1; i++) {
+        d *= d_orig;
+    }
+    return d;
+}
+
 // round to closest base^1 value
 static uint64_t round_to_base(uint64_t a, uint64_t base) {
     uint64_t mod = a % base;
@@ -249,6 +279,12 @@ static int pfn_double(va_list *va, FmtWord *fmt, char *outbuf, size_t free_space
         d *= -1;
     }
 
+    // round to requested precision if trucation is not instructed
+    if (fmt->type != DOUBLE_TRUNCATE) {
+        double r = 0.5 * powerf(10, -fmt->precision);
+        d += r;
+    }
+
     // normalize if exponential form is required
     int exponent = 0;
     if (fmt->type == DOUBLE_EXPONENTIAL) {
@@ -264,7 +300,7 @@ static int pfn_double(va_list *va, FmtWord *fmt, char *outbuf, size_t free_space
     FmtWord int_fmt = {.flags = fmt->flags, .type = UNSIGNED_INTEGER, .width = fmt->width};
 
     // separate into integer and fractional part
-    uint64_t int_part = (uint64_t) d; // integer part
+    uint64_t int_part = (uint64_t)d; // integer part
     int copy_len = print_number(int_part, negative, &int_fmt, outbuf, free_space);
     free_space -= copy_len;
     outbuf += copy_len;
@@ -285,7 +321,7 @@ static int pfn_double(va_list *va, FmtWord *fmt, char *outbuf, size_t free_space
         FmtWord frac_fmt = {.flags = FLAG_NO, .width = -1, .type = UNSIGNED_INTEGER};
 
         // get "leading zeros" in fractional part
-        double d_frac = d - (double) int_part;
+        double d_frac = d - (double)int_part;
 
         // print leading zeros
         int leading_zeros_printed = 0;
@@ -300,9 +336,8 @@ static int pfn_double(va_list *va, FmtWord *fmt, char *outbuf, size_t free_space
         }
 
         // extract fractional part as integer
-        d_frac *= (double) power(10, fmt->precision - leading_zeros_printed + 1); // get one more digit
+        d_frac *= (double)power(10, fmt->precision - leading_zeros_printed);
-        uint64_t frac_part = (uint64_t) d_frac;
+        uint64_t frac_part = (uint64_t)d_frac;
-        frac_part = round_to_base(frac_part, 10) / 10; // remove last zero digit (result of rounding)
 
         // print fractional part
         copy_len = print_number(frac_part, false, &frac_fmt, outbuf, free_space);
@@ -348,17 +383,19 @@ static int pfn_char(va_list *va, FmtWord *fmt, char *outbuf, size_t free_space)
 
 // print string
 static int pfn_string(va_list *va, FmtWord *fmt, char *outbuf, size_t free_space) {
-    char *str = va_arg((*va), char*);
+    char *str = va_arg((*va), char *);
     return string_copy(outbuf, str, free_space);
 }
 
 // format swting assignment table
-static FmtTypeDesignatorPair sTypeDesAssignment[] = {{'%',  LITERAL_PERCENT,                    pfn_literal_percent},
+static FmtTypeDesignatorPair sTypeDesAssignment[] = {
+    {'%', LITERAL_PERCENT, pfn_literal_percent},
     {'d', SIGNED_INTEGER, pfn_integer},
     {'i', SIGNED_INTEGER, pfn_integer},
     {'u', UNSIGNED_INTEGER, pfn_integer},
     {'f', DOUBLE, pfn_double},
     {'e', DOUBLE_EXPONENTIAL, pfn_double},
+    {'k', DOUBLE_TRUNCATE, pfn_double},
     {'x', UNSIGNED_HEXADECIMAL_INT, pfn_integer},
     {'X', UNSIGNED_HEXADECIMAL_INT_UPPERCASE, pfn_integer},
     {'p', UNSIGNED_HEXADECIMAL_INT, pfn_integer},
@@ -575,7 +612,7 @@ unsigned long int vembfmt(char *str, unsigned long int len, const char *format,
         sum_copy_len += copy_len;
 
         // print data
-        FmtWord word = { 0 };
+        FmtWord word = {0};
         int rewind;
         process_format_word(word_str, &word, &rewind);
         if (word.type != UNKNOWN) {