jsond_dtoa.c

/*
  +----------------------------------------------------------------------+
  | Copyright (c) The PHP Group                                          |
  +----------------------------------------------------------------------+
  | This source file is subject to version 3.01 of the PHP license,      |
  | that is bundled with this package in the file LICENSE, and is        |
  | available through the world-wide-web at the following url:           |
  | http://www.php.net/license/3_01.txt                                  |
  | If you did not receive a copy of the PHP license and are unable to   |
  | obtain it through the world-wide-web, please send a note to          |
  | license@php.net so we can mail you a copy immediately.               |
  +----------------------------------------------------------------------+
  | Author: Jakub Zelenka <bukka@php.net>                                |
  +----------------------------------------------------------------------+
*/

#include "php.h"
#include "php_jsond_compat.h"
#include "php_jsond_dtoa.h"
#include <zend_strtod.h>

char *php_jsond_gcvt(double value, int ndigit, char dec_point, char exponent, char *buf)
{
	char *digits, *dst, *src;
	int i, decpt;
	php_jsond_dtoa_sign_t sign;
	int mode = ndigit >= 0 ? 2 : 0;

	if (mode == 0) {
		ndigit = 17;
	}
	digits = zend_dtoa(value, mode, ndigit, &decpt, &sign, NULL);
	if (decpt == 9999) {
		/*
		 * Infinity or NaN, convert to inf or nan with sign.
		 * We assume the buffer is at least ndigit long.
		 */
		snprintf(buf, ndigit + 1, "%s%s", (sign && *digits == 'I') ? "-" : "", *digits == 'I' ? "INF" : "NAN");
		zend_freedtoa(digits);
		return (buf);
	}

	dst = buf;
	if (sign) {
		*dst++ = '-';
	}

	if ((decpt >= 0 && decpt > ndigit) || decpt < -3) { /* use E-style */
		/* exponential format (e.g. 1.2345e+13) */
		if (--decpt < 0) {
			sign = 1;
			decpt = -decpt;
		} else {
			sign = 0;
		}
		src = digits;
		*dst++ = *src++;
		*dst++ = dec_point;
		if (*src == '\0') {
			*dst++ = '0';
		} else {
			do {
				*dst++ = *src++;
			} while (*src != '\0');
		}
		*dst++ = exponent;
		if (sign) {
			*dst++ = '-';
		} else {
			*dst++ = '+';
		}
		if (decpt < 10) {
			*dst++ = '0' + decpt;
			*dst = '\0';
		} else {
			/* XXX - optimize */
			int n;
			for (n = decpt, i = 0; (n /= 10) != 0; i++);
			dst[i + 1] = '\0';
			while (decpt != 0) {
				dst[i--] = '0' + decpt % 10;
				decpt /= 10;
			}
		}
	} else if (decpt < 0) {
		/* standard format 0. */
		*dst++ = '0';   /* zero before decimal point */
		*dst++ = dec_point;
		do {
			*dst++ = '0';
		} while (++decpt < 0);
		src = digits;
		while (*src != '\0') {
			*dst++ = *src++;
		}
		*dst = '\0';
	} else {
		/* standard format */
		for (i = 0, src = digits; i < decpt; i++) {
			if (*src != '\0') {
				*dst++ = *src++;
			} else {
				*dst++ = '0';
			}
		}
		if (*src != '\0') {
			if (src == digits) {
				*dst++ = '0';   /* zero before decimal point */
			}
			*dst++ = dec_point;
			for (i = decpt; digits[i] != '\0'; i++) {
				*dst++ = digits[i];
			}
		}
		*dst = '\0';
	}
	zend_freedtoa(digits);
	return (buf);
}