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Diffstat (limited to 'deps/lua/src/fpconv.c')
| -rw-r--r-- | deps/lua/src/fpconv.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/deps/lua/src/fpconv.c b/deps/lua/src/fpconv.c new file mode 100644 index 0000000..7990831 --- /dev/null +++ b/deps/lua/src/fpconv.c @@ -0,0 +1,205 @@ +/* fpconv - Floating point conversion routines + * + * Copyright (c) 2011-2012 Mark Pulford <mark@kyne.com.au> + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. + * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY + * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, + * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE + * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +/* JSON uses a '.' decimal separator. strtod() / sprintf() under C libraries + * with locale support will break when the decimal separator is a comma. + * + * fpconv_* will around these issues with a translation buffer if required. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <assert.h> +#include <string.h> + +#include "fpconv.h" + +/* Lua CJSON assumes the locale is the same for all threads within a + * process and doesn't change after initialisation. + * + * This avoids the need for per thread storage or expensive checks + * for call. */ +static char locale_decimal_point = '.'; + +/* In theory multibyte decimal_points are possible, but + * Lua CJSON only supports UTF-8 and known locales only have + * single byte decimal points ([.,]). + * + * localconv() may not be thread safe (=>crash), and nl_langinfo() is + * not supported on some platforms. Use sprintf() instead - if the + * locale does change, at least Lua CJSON won't crash. */ +static void fpconv_update_locale() +{ + char buf[8]; + + snprintf(buf, sizeof(buf), "%g", 0.5); + + /* Failing this test might imply the platform has a buggy dtoa + * implementation or wide characters */ + if (buf[0] != '0' || buf[2] != '5' || buf[3] != 0) { + fprintf(stderr, "Error: wide characters found or printf() bug."); + abort(); + } + + locale_decimal_point = buf[1]; +} + +/* Check for a valid number character: [-+0-9a-yA-Y.] + * Eg: -0.6e+5, infinity, 0xF0.F0pF0 + * + * Used to find the probable end of a number. It doesn't matter if + * invalid characters are counted - strtod() will find the valid + * number if it exists. The risk is that slightly more memory might + * be allocated before a parse error occurs. */ +static inline int valid_number_character(char ch) +{ + char lower_ch; + + if ('0' <= ch && ch <= '9') + return 1; + if (ch == '-' || ch == '+' || ch == '.') + return 1; + + /* Hex digits, exponent (e), base (p), "infinity",.. */ + lower_ch = ch | 0x20; + if ('a' <= lower_ch && lower_ch <= 'y') + return 1; + + return 0; +} + +/* Calculate the size of the buffer required for a strtod locale + * conversion. */ +static int strtod_buffer_size(const char *s) +{ + const char *p = s; + + while (valid_number_character(*p)) + p++; + + return p - s; +} + +/* Similar to strtod(), but must be passed the current locale's decimal point + * character. Guaranteed to be called at the start of any valid number in a string */ +double fpconv_strtod(const char *nptr, char **endptr) +{ + char localbuf[FPCONV_G_FMT_BUFSIZE]; + char *buf, *endbuf, *dp; + int buflen; + double value; + + /* System strtod() is fine when decimal point is '.' */ + if (locale_decimal_point == '.') + return strtod(nptr, endptr); + + buflen = strtod_buffer_size(nptr); + if (!buflen) { + /* No valid characters found, standard strtod() return */ + *endptr = (char *)nptr; + return 0; + } + + /* Duplicate number into buffer */ + if (buflen >= FPCONV_G_FMT_BUFSIZE) { + /* Handle unusually large numbers */ + buf = malloc(buflen + 1); + if (!buf) { + fprintf(stderr, "Out of memory"); + abort(); + } + } else { + /* This is the common case.. */ + buf = localbuf; + } + memcpy(buf, nptr, buflen); + buf[buflen] = 0; + + /* Update decimal point character if found */ + dp = strchr(buf, '.'); + if (dp) + *dp = locale_decimal_point; + + value = strtod(buf, &endbuf); + *endptr = (char *)&nptr[endbuf - buf]; + if (buflen >= FPCONV_G_FMT_BUFSIZE) + free(buf); + + return value; +} + +/* "fmt" must point to a buffer of at least 6 characters */ +static void set_number_format(char *fmt, int precision) +{ + int d1, d2, i; + + assert(1 <= precision && precision <= 14); + + /* Create printf format (%.14g) from precision */ + d1 = precision / 10; + d2 = precision % 10; + fmt[0] = '%'; + fmt[1] = '.'; + i = 2; + if (d1) { + fmt[i++] = '0' + d1; + } + fmt[i++] = '0' + d2; + fmt[i++] = 'g'; + fmt[i] = 0; +} + +/* Assumes there is always at least 32 characters available in the target buffer */ +int fpconv_g_fmt(char *str, double num, int precision) +{ + char buf[FPCONV_G_FMT_BUFSIZE]; + char fmt[6]; + int len; + char *b; + + set_number_format(fmt, precision); + + /* Pass through when decimal point character is dot. */ + if (locale_decimal_point == '.') + return snprintf(str, FPCONV_G_FMT_BUFSIZE, fmt, num); + + /* snprintf() to a buffer then translate for other decimal point characters */ + len = snprintf(buf, FPCONV_G_FMT_BUFSIZE, fmt, num); + + /* Copy into target location. Translate decimal point if required */ + b = buf; + do { + *str++ = (*b == locale_decimal_point ? '.' : *b); + } while(*b++); + + return len; +} + +void fpconv_init() +{ + fpconv_update_locale(); +} + +/* vi:ai et sw=4 ts=4: + */ |