diff options
author | Mark Pulford <mark@kyne.com.au> | 2012-01-01 08:54:30 +0400 |
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committer | Mark Pulford <mark@kyne.com.au> | 2012-01-01 08:54:30 +0400 |
commit | 929c814b12e3575859fa0d5a8ea9950ae2187c56 (patch) | |
tree | c953eadc2fe8415ca85bf15175b6c3114fbc0622 | |
parent | 4ce40cdccf28551f4b091cb8f9a735c2cc9f5513 (diff) |
Sanitise locale code, comments and documentation
-rw-r--r-- | fpconv.c | 70 | ||||
-rw-r--r-- | fpconv.h | 7 | ||||
-rw-r--r-- | lua_cjson.c | 7 | ||||
-rw-r--r-- | manual.txt | 28 |
4 files changed, 71 insertions, 41 deletions
@@ -1,3 +1,9 @@ +/* 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> @@ -5,15 +11,21 @@ #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, and nl_langinfo() is not - * supported on some platforms. Use sprintf() instead. */ -void fpconv_update_locale() + * 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]; @@ -29,11 +41,14 @@ void fpconv_update_locale() locale_decimal_point = buf[1]; } -/* Check for a valid number character: [-+0-9a-fA-FpPxX.] - * It doesn't matter if actual 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 int valid_number_character(char ch) +/* 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; @@ -42,9 +57,7 @@ static int valid_number_character(char ch) if (ch == '-' || ch == '+' || ch == '.') return 1; - /* Hex digits, exponent (e), base (p), "infinity",.. - * The main purpose is to not include a "comma". If any other invalid - * characters are included, the will only generate a parse error later. */ + /* Hex digits, exponent (e), base (p), "infinity",.. */ lower_ch = ch | 0x20; if ('a' <= lower_ch && lower_ch <= 'y') return 1; @@ -52,8 +65,8 @@ static int valid_number_character(char ch) return 0; } -/* Calculate the size of the buffer required for a locale - * conversion. Returns 0 if conversion is not required */ +/* Calculate the size of the buffer required for a strtod locale + * conversion. */ static int strtod_buffer_size(const char *s) { const char *p = s; @@ -68,38 +81,38 @@ static int strtod_buffer_size(const char *s) * character. Guaranteed to be called at the start of any valid number in a string */ double fpconv_strtod(const char *nptr, char **endptr) { - char *num, *endnum, *dp; - int numlen; + char *buf, *endbuf, *dp; + int buflen; double value; /* System strtod() is fine when decimal point is '.' */ if (locale_decimal_point == '.') return strtod(nptr, endptr); - numlen = strtod_buffer_size(nptr); - if (!numlen) { + buflen = strtod_buffer_size(nptr); + if (!buflen) { /* No valid characters found, standard strtod() return */ *endptr = (char *)nptr; return 0; } /* Duplicate number into buffer */ - num = malloc(numlen + 1); - if (!num) { + buf = malloc(buflen + 1); + if (!buf) { fprintf(stderr, "Out of memory"); abort(); } - memcpy(num, nptr, numlen); - num[numlen] = 0; + memcpy(buf, nptr, buflen); + buf[buflen] = 0; /* Update decimal point character if found */ - dp = strchr(num, '.'); + dp = strchr(buf, '.'); if (dp) *dp = locale_decimal_point; - value = strtod(num, &endnum); - *endptr = (char *)&nptr[endnum - num]; - free(num); + value = strtod(buf, &endbuf); + *endptr = (char *)&nptr[endbuf - buf]; + free(buf); return value; } @@ -142,7 +155,7 @@ int fpconv_g_fmt(char *str, double num, int precision) /* snprintf() to a buffer then translate for other decimal point characters */ len = snprintf(buf, FPCONV_G_FMT_BUFSIZE, fmt, num); - /* Returned 'len' includes the null terminator */ + /* Copy into target location. Translate decimal point if required */ b = buf; do { *str++ = (*b == locale_decimal_point ? '.' : *b); @@ -151,5 +164,10 @@ int fpconv_g_fmt(char *str, double num, int precision) return len; } +void fpconv_init() +{ + fpconv_update_locale(); +} + /* vi:ai et sw=4 ts=4: */ @@ -1,9 +1,12 @@ /* Lua CJSON floating point conversion routines */ -/* Buffer larger than required to store the largest %.14g number */ +/* Buffer required to store the largest string representation of a double. + * + * Longest double printed with %.14g is 21 characters long: + * -1.7976931348623e+308 */ # define FPCONV_G_FMT_BUFSIZE 32 -extern void fpconv_update_locale(); +extern void fpconv_init(); extern int fpconv_g_fmt(char*, double, int); extern double fpconv_strtod(const char*, char**); diff --git a/lua_cjson.c b/lua_cjson.c index fe6d41a..175433a 100644 --- a/lua_cjson.c +++ b/lua_cjson.c @@ -571,8 +571,6 @@ static void json_append_number(lua_State *l, json_config_t *cfg, /* Some platforms may print -nan, just hard code it */ strbuf_append_mem(json, "nan", 3); } else { - /* Longest double printed with %.14g is 21 characters long: - * -1.7976931348623e+308 */ strbuf_ensure_empty_length(json, FPCONV_G_FMT_BUFSIZE); len = fpconv_g_fmt(strbuf_empty_ptr(json), num, cfg->encode_number_precision); strbuf_extend_length(json, len); @@ -1283,9 +1281,8 @@ static int lua_cjson_new(lua_State *l) { NULL, NULL } }; - /* Update the current locale for g_fmt/strtod. - * Using different locales per-thread is not supported. */ - fpconv_update_locale(); + /* Initialise number conversions */ + fpconv_init(); /* cjson module table */ lua_newtable(l); @@ -48,7 +48,7 @@ Build Options (#define) [horizontal] USE_INTERNAL_ISINF:: Workaround for Solaris platforms missing isinf(). DISABLE_CJSON_GLOBAL:: Do not store module table in global "cjson" - variable. + variable. Redundant from Lua 5.2 onwards. Make @@ -150,10 +150,10 @@ local cjson = require "cjson" local cjson2 = cjson.new() ------------ -Lua CJSON can be loaded via +require+. A global +cjson+ table is -registered under Lua 5.1 to maintain backward compatibility. Lua CJSON -does not register a global table under Lua 5.2 since this practice is -discouraged. +Lua CJSON can be loaded via the Lua +require+ function. A global ++cjson+ module table is registered under Lua 5.1 to maintain backward +compatibility. Lua CJSON does not register a global table under Lua +5.2 since this practice is discouraged. +cjson.new+ can be used to instantiate an independent copy of the Lua CJSON module. The new module has a separate persistent encoding @@ -164,9 +164,21 @@ threads within a single Lua state provided the persistent encoding buffer is not shared. This can be achieved by one of the following methods: -- Disabling the persistent encoding buffer with +encode_keep_buffer+. -- Ensuring only a single thread calls +encode+ at a time. -- Using a separate +cjson+ instantiation per pre-emptive thread. +- Disabling the persistent encoding buffer with + +cjson.encode_keep_buffer+. +- Ensuring each thread calls +cjson.encode+ at a time. +- Using a separate +cjson+ module table per pre-emptive thread + (+cjson.new+). + +[NOTE] +Lua CJSON uses ++strtod++(3) and ++snprintf++(3) to perform numeric +conversion as they are usually well supported, fast and bug free. +However, these functions require a workaround for JSON +encoding/parsing under locales using a comma decimal separator. Lua +CJSON detects the current locale during instantiation to determine +whether a workaround is required. CJSON should be reinitialised via ++cjson.new+ if the locale of the current process changes. Different +locales per thread are not supported. decode |