strtod, strtof, strtold

code/stdlib/conv.c

@@ -4,10 +4,10 @@
 #include <stdbool.h>
 #include <limits.h>
 #include <errno.h>
+#include <math.h>
 
-// TODO: strto*: locale-based parsing for integers
-// TODO: i made a function that parses longs and i'm fucken
-// tired. someone make float parsing :kekw:
+// TODO: strto*: locale-based parsing
+// TODO: correctly rounded base 16 floats parsing
 
 // Call me weak if you want but I'm actually too lazy to type
 // them out every time, also they take up a lot of horiz space.
@@ -36,8 +36,20 @@ static bool isbase(int c, int base) {
     return val < base;
 }
 
+static bool
+strprefix_i(char const *restrict str, char const *restrict prefix)
+{
+    while(*prefix != 0) {
+        if(*str == 0) break;
+        if(toupper(*str) != toupper(*prefix)) return false;
+        ++prefix;
+        ++str;
+    }
+    return true;
+}
+
 // Called only when isbase(c, base) for some base in range
-static long todigitl(int c) {
+static long todigit(int c) {
     int val;
     if(isdigit(c)) {
         val = c-'0';
@@ -51,7 +63,7 @@ static long todigitl(int c) {
     return val;
 }
 
-static intull strto_generic(
+static intull strtoi_generic(
     const char *restrict nptr,
     char **restrict endptr,
     int inbase,
@@ -89,7 +101,7 @@ static intull strto_generic(
     }
     // See if we need to parse base in C-like format
     // then set the base accordingly
-    if(*str == '0' && (*(str+1) == 'x' || *(str+1) == 'X')) {
+    if(strprefix_i(str, "0X")) {
         ++str;
         if(base == 16 || base == 0) {
             ++str;
@@ -109,7 +121,7 @@ static intull strto_generic(
     // Parse the string of digits in the given base. If the value
     // exceeds abs(int_min) we exit with range error.
     while(isbase(*str, (int)base)) {
-        intull digit = (intull)todigitl(*str);
+        intull digit = (intull)todigit(*str);
         if(value > (int_abs_max - digit)/base) {
             goto error_out_of_range;
         }
@@ -152,10 +164,126 @@ finish:
     return value;
 }
 
+static double strtod_generic(
+    const char *restrict nptr,
+    char **restrict endptr
+) {
+    const char *restrict str = nptr;
+    bool conv_performed = false;
+    double value = 0.0;
+    double coef = 1.0;
+    // Skip space on the beginning
+    while(isspace(*str)) {
+        ++str;
+    }
+    // Check for inf and nan
+    if(strprefix_i(str, "INF")) {
+        str += sizeof "INF"-1;
+        value = HUGE_VAL;
+        conv_performed = true;
+        goto finish;
+    }
+    if(strprefix_i(str, "INFINITY")) {
+        str += sizeof "INFINITY"-1;
+        value = HUGE_VAL;
+        conv_performed = true;
+        goto finish;
+    }
+    if(strprefix_i(str, "NAN")) {
+        str += sizeof "NAN"-1;
+        value = NAN;
+        conv_performed = true;
+        if(*str == '(') {
+            while(*str != ')') {
+                ++str;
+            }
+            ++str;
+        }
+        goto finish;
+    }
+    // Parse C float
+    if(*str == '+') {
+        ++str;
+    }
+    else if(*str == '-') {
+        coef = -1.;
+        ++str;
+    }
+    int base = 10;
+    if(strprefix_i(str, "0X")) {
+        str += sizeof "0X"-1;
+        base = 16;
+    }
+    // Parse the whole part
+    while(isbase(*str, base)) {
+        long digit = todigit(*str);
+        value = 10.0*value + (double)digit;
+        ++str;
+    }
+    if(*str != '.') {
+        value = 0.0;
+        goto finish;
+    }
+    ++str;
+    // Parse the fractional part
+    long exp = 1;
+    while(isbase(*str, base)) {
+        long digit = todigit(*str);
+        double fract = (double)digit;
+        long cexp = exp;
+        while(cexp-- != 0) {
+            fract /= (double)base;
+        }
+        value += fract;
+        ++exp;
+        ++str;
+    }
+    // Parse the exponent
+    if((base == 10 && strprefix_i(str, "E"))
+    || (base == 16 && strprefix_i(str, "P")))
+    {
+        ++str;
+        long exp = 0;
+        long exp_coef = 1;
+        if(*str == '+') {
+            ++str;
+        }
+        else if(*str == '-') {
+            exp_coef = -1;
+            ++str;
+        }
+        while(isdigit(*str)) {
+            exp = 10*exp + (long)(*str-'0');
+            ++str;
+        }
+        if(exp_coef == 1) {
+            while(exp--!=0) value = value * base;
+        }
+        else if(exp_coef == -1) {
+            while(exp--!=0) value = value / base;
+        }
+    }
+    if(!isfinite(value)) {
+        errno = ERANGE;
+        value = coef*HUGE_VAL;
+    }
+    conv_performed = true;
+finish:
+    if(endptr != NULL) {
+        if(conv_performed) {
+            *endptr = (char *)str;
+        }
+        else {
+            *endptr = (char *)nptr;
+        }
+    }
+    return coef*value;
+}
+
 intl strtol(const char *restrict nptr, char **restrict endptr, int base) {
     intull int_max = (intull)LONG_MAX;
     intl coef;
-    intull modulo = strto_generic(nptr, endptr, base, &coef, int_max);
+    intull modulo = strtoi_generic(nptr, endptr, base, &coef, int_max);
     intl value;
     if(modulo == int_max) {
         value = LONG_MIN;
@@ -169,7 +297,7 @@ intl strtol(const char *restrict nptr, char **restrict endptr, int base) {
 intll strtoll(const char *restrict nptr, char **restrict endptr, int base) {
     intull int_max = (intull)LLONG_MAX;
     intl coef;
-    intull modulo = strto_generic(nptr, endptr, base, &coef, int_max);
+    intull modulo = strtoi_generic(nptr, endptr, base, &coef, int_max);
     intll value;
     if(modulo == int_max) {
         value = LLONG_MIN;
@@ -182,13 +310,13 @@ intll strtoll(const char *restrict nptr, char **restrict endptr, int base) {
 
 intul strtoul(const char *restrict nptr, char **restrict endptr, int base) {
     intull int_max = (intull)ULONG_MAX;
-    intull value = strto_generic(nptr, endptr, base, NULL, int_max);
+    intull value = strtoi_generic(nptr, endptr, base, NULL, int_max);
     return (intul)value;
 }
 
 intull strtoull(const char *restrict nptr, char **restrict endptr, int base) {
     intull int_max = (intull)ULLONG_MAX;
-    return strto_generic(nptr, endptr, base, NULL, int_max);
+    return strtoi_generic(nptr, endptr, base, NULL, int_max);
 }
 
 double atof(const char *nptr) {
@@ -208,13 +336,13 @@ long long int atoll(const char *nptr) {
 }
 
 double strtod(const char *restrict nptr, char **restrict endptr) {
-    return 0;
+    return strtod_generic(nptr, endptr);
 }
 
 float strtof(const char *restrict nptr, char **restrict endptr) {
-    return 0;
+    return (float)strtod_generic(nptr, endptr);
 }
 
 long double strtold(const char *restrict nptr, char **restrict endptr) {
-    return 0;
+    return (long double)strtod_generic(nptr, endptr);
 }

inc/math.h

@@ -21,11 +21,11 @@ typedef double double_t;
 #define FP_INFINITE  1
 #define FP_NAN       2
 
-FP_INFINITE
-FP_NAN
-FP_NORMAL
-FP_SUBNORMAL
-FP_ZERO
+//FP_INFINITE
+//FP_NAN
+//FP_NORMAL
+//FP_SUBNORMAL
+//FP_ZERO
 #define FP_FAST_FMA  1
 #define FP_FAST_FMAF 1
 #define FP_FAST_FMAL 1
@@ -39,8 +39,11 @@ FP_ZERO
 
 // TODO: implement this
 #define fpclassify(x) 0
-#define isfinite(x)   0
-#define isinf(x)      0
+
+// HACK: If its fine just remove the comment
+#define isfinite(x)   ((double)(x) != HUGE_VAL && (double)(x) != -HUGE_VAL)
+#define isinf(x)      (!(isinf(x)))
+
 #define isnan(x)      0
 #define isnormal(x)   0
 #define signbit(x)    0

test/test.c

@@ -1,44 +1,27 @@
-#include <assert.h>
-#include <ctype.h>
-#include <stdlib.h>
-#include <stddef.h>
-#include <stdbool.h>
+#include <stdio.h>
 #include <errno.h>
+#include <stdlib.h>
  
-int main(int argc, char** argv) {
-    const char *p = "10 200000000000000000000000000000 30 -40 junk";
-    // printf("Parsing '%s':\n", p);
+int main(void)
+{
+    double v0 = strtod("0X1.BC70A3D70A3D7P+6", NULL);
 
-    for (;;)
+    // parsing with error handling
+    const char *p = "111.11 -2.22 Nan nan(2) inF 0X1.BC70A3D70A3D7P+6  1.18973e+4932zzz";
+    
+    char *end;
+    for (double f = strtod(p, &end); p != end; f = strtod(p, &end))
     {
-        // errno can be set to any non-zero value by a library function call
-        // regardless of whether there was an error, so it needs to be cleared
-        // in order to check the error set by strtol
-        errno = 0;
-        char *end;
-        const long i = strtol(p, &end, 10);
-        if (p == end)
-            break;
- 
-        const bool range_error = errno == ERANGE;
-        // printf("Extracted '%.*s', strtol returned %ld.", (int)(end-p), p, i);
+        // printf("'%.*s' -> ", (int)(end-p), p);
         p = end;
- 
-        // if (range_error)
-        //     printf(" Range error occurred.");
- 
-        // putchar('\n');
+        if (errno == ERANGE){
+            // printf("range error, got ");
+            errno = 0;
+        }
+        // printf("%f\n", f);
     }
  
-    // printf("Unextracted leftover: '%s'\n\n", p);
- 
     // parsing without error handling
-    long v1 = strtol("1010", NULL, 2);
-    long v2 = strtol("12",   NULL, 8);
-    long v3 = strtol("A",    NULL, 16);
-    long v4 = strtol("junk", NULL, 36);
-    long v5 = strtol("012",  NULL, 0);
-    long v6 = strtol("0xA",  NULL, 0);
-    long v7 = strtol("junk", NULL, 0);
-    return 0;
+    double v1 = strtod("  -0.0000000123junk", NULL);
+    double v2 = strtod("junk", NULL);
 }