Move mg_*printf* decls in fmt.h

src/fmt.c

@@ -1,5 +1,5 @@
+#include "fmt.h"
 #include "iobuf.h"
-#include "str.h"
 
 size_t mg_vasprintf(char **buf, size_t size, const char *fmt, va_list ap) {
   va_list ap_copy;
@@ -32,6 +32,15 @@ size_t mg_asprintf(char **buf, size_t size, const char *fmt, ...) {
   return ret;
 }
 
+size_t mg_snprintf(char *buf, size_t len, const char *fmt, ...) {
+  va_list ap;
+  size_t n;
+  va_start(ap, fmt);
+  n = mg_vsnprintf(buf, len, fmt, &ap);
+  va_end(ap);
+  return n;
+}
+
 char *mg_vmprintf(const char *fmt, va_list ap) {
   char *s = NULL;
   mg_vasprintf(&s, 0, fmt, ap);
@@ -98,6 +107,140 @@ static bool is_digit(int c) {
   return c >= '0' && c <= '9';
 }
 
+double mg_atod(const char *p, int len, int *numlen) {
+  double d = 0.0;
+  int i = 0, sign = 1;
+
+  // Sign
+  if (i < len && *p == '-') {
+    sign = -1, i++;
+  } else if (i < len && *p == '+') {
+    i++;
+  }
+
+  // Decimal
+  for (; i < len && p[i] >= '0' && p[i] <= '9'; i++) {
+    d *= 10.0;
+    d += p[i] - '0';
+  }
+  d *= sign;
+
+  // Fractional
+  if (i < len && p[i] == '.') {
+    double frac = 0.0, base = 0.1;
+    i++;
+    for (; i < len && p[i] >= '0' && p[i] <= '9'; i++) {
+      frac += base * (p[i] - '0');
+      base /= 10.0;
+    }
+    d += frac * sign;
+  }
+
+  // Exponential
+  if (i < len && (p[i] == 'e' || p[i] == 'E')) {
+    int j, exp = 0, minus = 0;
+    i++;
+    if (i < len && p[i] == '-') minus = 1, i++;
+    if (i < len && p[i] == '+') i++;
+    while (i < len && p[i] >= '0' && p[i] <= '9' && exp < 308)
+      exp = exp * 10 + (p[i++] - '0');
+    if (minus) exp = -exp;
+    for (j = 0; j < exp; j++) d *= 10.0;
+    for (j = 0; j < -exp; j++) d /= 10.0;
+  }
+
+  if (numlen != NULL) *numlen = i;
+  return d;
+}
+
+static int addexp(char *buf, int e, int sign) {
+  int n = 0;
+  buf[n++] = 'e';
+  buf[n++] = (char) sign;
+  if (e > 400) return 0;
+  if (e < 10) buf[n++] = '0';
+  if (e >= 100) buf[n++] = (char) (e / 100 + '0'), e -= 100 * (e / 100);
+  if (e >= 10) buf[n++] = (char) (e / 10 + '0'), e -= 10 * (e / 10);
+  buf[n++] = (char) (e + '0');
+  return n;
+}
+
+static int xisinf(double x) {
+  union {
+    double f;
+    uint64_t u;
+  } ieee754 = {x};
+  return ((unsigned) (ieee754.u >> 32) & 0x7fffffff) == 0x7ff00000 &&
+         ((unsigned) ieee754.u == 0);
+}
+
+static int xisnan(double x) {
+  union {
+    double f;
+    uint64_t u;
+  } ieee754 = {x};
+  return ((unsigned) (ieee754.u >> 32) & 0x7fffffff) +
+             ((unsigned) ieee754.u != 0) >
+         0x7ff00000;
+}
+
+size_t mg_dtoa(char *dst, size_t dstlen, double d, int width) {
+  char buf[40];
+  int i, s = 0, n = 0, e = 0;
+  double t, mul, saved;
+  if (d == 0.0) return mg_snprintf(dst, dstlen, "%s", "0");
+  if (xisinf(d)) return mg_snprintf(dst, dstlen, "%s", d > 0 ? "inf" : "-inf");
+  if (xisnan(d)) return mg_snprintf(dst, dstlen, "%s", "nan");
+  if (d < 0.0) d = -d, buf[s++] = '-';
+
+  // Round
+  saved = d;
+  mul = 1.0;
+  while (d >= 10.0 && d / mul >= 10.0) mul *= 10.0;
+  while (d <= 1.0 && d / mul <= 1.0) mul /= 10.0;
+  for (i = 0, t = mul * 5; i < width; i++) t /= 10.0;
+  d += t;
+  // Calculate exponent, and 'mul' for scientific representation
+  mul = 1.0;
+  while (d >= 10.0 && d / mul >= 10.0) mul *= 10.0, e++;
+  while (d < 1.0 && d / mul < 1.0) mul /= 10.0, e--;
+  // printf(" --> %g %d %g %g\n", saved, e, t, mul);
+
+  if (e >= width) {
+    n = (int) mg_dtoa(buf, sizeof(buf), saved / mul, width);
+    // printf(" --> %.*g %d [%.*s]\n", 10, d / t, e, n, buf);
+    n += addexp(buf + s + n, e, '+');
+    return mg_snprintf(dst, dstlen, "%.*s", n, buf);
+  } else if (e <= -width) {
+    n = (int) mg_dtoa(buf, sizeof(buf), saved / mul, width);
+    // printf(" --> %.*g %d [%.*s]\n", 10, d / mul, e, n, buf);
+    n += addexp(buf + s + n, -e, '-');
+    return mg_snprintf(dst, dstlen, "%.*s", n, buf);
+  } else {
+    for (i = 0, t = mul; t >= 1.0 && s + n < (int) sizeof(buf); i++) {
+      int ch = (int) (d / t);
+      if (n > 0 || ch > 0) buf[s + n++] = (char) (ch + '0');
+      d -= ch * t;
+      t /= 10.0;
+    }
+    // printf(" --> [%g] -> %g %g (%d) [%.*s]\n", saved, d, t, n, s + n, buf);
+    if (n == 0) buf[s++] = '0';
+    while (t >= 1.0 && n + s < (int) sizeof(buf)) buf[n++] = '0', t /= 10.0;
+    if (s + n < (int) sizeof(buf)) buf[n + s++] = '.';
+    // printf(" 1--> [%g] -> [%.*s]\n", saved, s + n, buf);
+    for (i = 0, t = 0.1; s + n < (int) sizeof(buf) && n < width; i++) {
+      int ch = (int) (d / t);
+      buf[s + n++] = (char) (ch + '0');
+      d -= ch * t;
+      t /= 10.0;
+    }
+  }
+  while (n > 0 && buf[s + n - 1] == '0') n--;  // Trim trailing zeros
+  if (n > 0 && buf[s + n - 1] == '.') n--;     // Trim trailing dot
+  buf[s + n] = '\0';
+  return mg_snprintf(dst, dstlen, "%s", buf);
+}
+
 size_t mg_lld(char *buf, int64_t val, bool is_signed, bool is_hex) {
   const char *letters = "0123456789abcdef";
   uint64_t v = (uint64_t) val;