implemented %f/e/g in ksprintf_fast(); unfinished

diff --git a/kstring.c b/kstring.c
index 3262aef0b3bdc9317580463bafe97b237d2d7f53..dbd6f2386ff622174bb5ba82e5461cdf51429db3 100644 (file)
--- a/kstring.c
+++ b/kstring.c
@@ -172,7 +172,7 @@ char *kstrnstr(const char *str, const char *pat, int n, int **_prep)
  ****************/
 
 typedef struct {
-       int base, width, fill, left_aln, n_ell, n_Ell;
+       int base, w, f, left_aln, n_ell, n_Ell;
 } printf_conv_t;
 
 static inline void enlarge(kstring_t *s, int l)
@@ -184,6 +184,30 @@ static inline void enlarge(kstring_t *s, int l)
        }
 }
 
+double frexp10(double x, int *e)
+{
+       const double M_LOG_10_2 = M_LN2 / M_LN10;
+       double z;
+       int tmp;
+       if (x == 0.) {
+               *e = 0;
+               return 0.;
+       }
+       frexp(x, e);
+       if (*e >= 0) {
+               *e = (int)(*e * M_LOG_10_2);
+               for (z = .1, tmp = *e; tmp; z *= z, tmp >>= 1)
+                       if (tmp & 1) x *= z;
+       } else {
+               *e = (int)((*e - 1) * M_LOG_10_2);
+               for (z = 10., tmp = -*e; tmp; z *= z, tmp >>= 1)
+                       if (tmp & 1) x *= z;
+       }
+       if (x >= 10. || x <= -10.) ++(*e), x *= .1;
+       else if (x > -1. && x < 1.) --(*e), x *= 10.;
+       return x;
+}
+
 int ksprintf_fast(kstring_t *s, const char *fmt, ...)
 {
 
@@ -195,8 +219,8 @@ int ksprintf_fast(kstring_t *s, const char *fmt, ...)
                        for (x = _c < 0? -_c : _c; x > 0; x /= _z.base) buf[l++] = _conv[x%_z.base]; \
                        if (_c < 0) buf[l++] = '-'; \
                } else buf[l++] = '0'; \
-               f = l > _z.fill? l : _z.fill; \
-               w = f > _z.width? f : _z.width; \
+               f = l > _z.f? l : _z.f; \
+               w = f > _z.w? f : _z.w; \
                enlarge(_s, w); \
                if (w > f && !_z.left_aln) \
                        for (k = f; k < w; ++k) _s->s[_s->l++] = ' '; \
@@ -212,12 +236,31 @@ int ksprintf_fast(kstring_t *s, const char *fmt, ...)
                write_integer0(c, _s, _type, _z, _conv); \
        } while (0)
 
+#define write_fraction(_s, _f, _z, _trim0) do { \
+               int j, last; \
+               for (j = 0; j < _z.f - 1; ++j) { \
+                       _f = (_f - (int)_f) * 10.; \
+                       _s->s[_s->l++] = (int)_f + '0'; \
+               } \
+               _f = (_f - (int)_f) * 10.; \
+               last = (int)(_f + .499999999999999999); \
+               if (last >= 10) { \
+                       _s->s[_s->l++] = '0'; \
+                       for (j = _s->l - 2; _s->s[j] == '9'; --j) _s->s[j] = '0'; \
+                       if (_s->s[j] != '.') ++_s->s[j]; \
+               } else _s->s[_s->l++] = last + '0'; \
+               if (_trim0) { \
+                       while (_s->s[_s->l - 1] == '0') --_s->l; \
+                       if (_s->s[_s->l - 1] == '.') --_s->l; \
+               } \
+       } while (0)
+
        va_list ap;
        const char *p = fmt, *q;
        int state = 0;
        printf_conv_t z, ztmp;
-       memset(&z, 0, sizeof(printf_conv_t)); z.fill = -1;
-       ztmp = z;
+       memset(&z, 0, sizeof(printf_conv_t)); z.f = -1;
+       ztmp = z; ztmp.base = 10;
        va_start(ap, fmt);
        while (*p) {
                if (state == 1) {
@@ -226,13 +269,13 @@ int ksprintf_fast(kstring_t *s, const char *fmt, ...)
                                enlarge(s, 1);
                                s->s[s->l++] = '%';
                                finished = 1;
-                       } else if (*p >= '0' && *p <= '9') { // width
+                       } else if (*p >= '0' && *p <= '9') { // w
                                char *r;
-                               z.width = strtol(p, &r, 10);
+                               z.w = strtol(p, &r, 10);
                                p = r - 1;
-                       } else if (*p == '.') { // fill
+                       } else if (*p == '.') { // f
                                char *r;
-                               z.fill = strtol(p + 1, &r, 10);
+                               z.f = strtol(p + 1, &r, 10);
                                p = r - 1;
                        } else if (*p == 'l') { // %l
                                ++z.n_ell;
@@ -266,7 +309,7 @@ int ksprintf_fast(kstring_t *s, const char *fmt, ...)
                                else if (z.n_ell == 1) write_integer(ap, s, unsigned long, z, conv);
                                else write_integer(ap, s, unsigned long long, z, conv);
                                finished = 1;
-                       } else if (*p == 'f' || *p == 'e') {
+                       } else if (*p == 'f' || *p == 'e' || *p == 'g') {
                                const char *t, *r = 0;
                                double x = va_arg(ap, double);
                                uint64_t *y = (uint64_t*)&x;
@@ -278,7 +321,52 @@ int ksprintf_fast(kstring_t *s, const char *fmt, ...)
                                        l = strlen(r);
                                        enlarge(s, l);
                                        for (t = r; *t; ++t) s->s[s->l++] = *t;
-                               } else if (*p == 'f') {
+                               } else {
+                                       double f;
+                                       int type = *p, e, w, trim0 = (*p == 'g')? 1 : 0;
+                                       if (z.f < 0) z.f = 6;
+                                       f = frexp10(x, &e);
+                                       if (*p == 'g') type = (e < -4 || e >= z.f)? 'e' : 'f'; // see the printf() manual page
+                                       if (type == 'e') {
+                                               int j, w = 8 + z.f > z.w? 8 + z.f : z.w;
+                                               enlarge(s, w);
+                                               if (f < 0) s->s[s->l++] = '-', f = -f;
+                                               s->s[s->l++] = (int)f + '0';
+                                               if (z.f > 0) {
+                                                       s->s[s->l++] = '.';
+                                                       write_fraction(s, f, z, trim0);
+                                               }
+                                               s->s[s->l++] = 'e';
+                                               if (e >= 0) s->s[s->l++] = '+';
+                                               ztmp.f = 2;
+                                               write_integer0(e, s, int, ztmp, "0123456789");
+                                       } else {
+                                               int j, w = abs(e) + 2 + z.f > z.w? abs(e) + 2 + z.f : z.w;
+                                               enlarge(s, w);
+                                               if (f < 0) s->s[s->l++] = '-', f = -f;
+                                               if (e >= 0) {
+                                                       for (j = 0; j < e; ++j) {
+                                                               s->s[s->l++] = (int)f + '0';
+                                                               f = (f - (int)f) * 10.;
+                                                       }
+                                                       if (z.f != 0) {
+                                                               s->s[s->l++] = (int)f + '0';
+                                                               s->s[s->l++] = '.';
+                                                               write_fraction(s, f, z, trim0);
+                                                       } else s->s[s->l++] = (int)(f + .49999999999999999) + '0';
+                                               } else {
+                                                       s->s[s->l++] = '0';
+                                                       if (z.f != 0) {
+                                                               s->s[s->l++] = '.';
+                                                               for (j = 1; j < -e && j <= z.f; ++j) s->s[s->l++] = '0';
+                                                               if (j - 1 < z.f) {
+                                                                       f *= .1;
+                                                                       z.f -= j - 1;
+                                                                       write_fraction(s, f, z, trim0);
+                                                               }
+                                                       }
+                                               }
+                                       }
                                }
                                finished = 1;
                        }
@@ -295,7 +383,7 @@ int ksprintf_fast(kstring_t *s, const char *fmt, ...)
                        if (*p == '%') {
                                state = 1;
                                ++p;
-                               memset(&z, 0, sizeof(printf_conv_t)); z.fill = -1;
+                               memset(&z, 0, sizeof(printf_conv_t)); z.f = -1;
                        }
                }
        }
@@ -319,8 +407,10 @@ int main()
        s = (kstring_t*)calloc(1, sizeof(kstring_t));
        { // test ksprintf_fast()
                long xx = -10;
-               ksprintf_fast(s, " pooiu %% %s %ld %c%-5.4X %f", "+++", xx, '*', 110, 2.45); printf("'%s'\n", s->s); s->l = 0;
-               printf("%4.3x, %.1f\n", 100, 1e30);
+               int e;
+               ksprintf_fast(s, " pooiu %% %s %ld %c%-5.4X %g", "+++", xx, '*', 110, 0.246); printf("'%s'\n", s->s); s->l = 0;
+               frexp10(-1.2e10, &e);
+               printf("%g, %.1f\n", 1e100, 1e30);
        }
        // test ksprintf()
        ksprintf(s, " abcdefg:    %d ", 100);