# HG changeset patch
# User jbe
# Date 1452789649 -3600
# Node ID 52ebde158c92091b5d376fa50c7bfc957ff7a3cc
# Parent  f0303fca9218d21cd6cb4ca0883ba505bcf53ef8
Fixed minor glitch regarding floating point numbers (e.g. 0.009) in JSON encoder; Distinguish between integers and floats in JSON encoder if Lua version >= 5.3

diff -r f0303fca9218 -r 52ebde158c92 libraries/json/json.c
--- a/libraries/json/json.c	Thu Jan 14 17:13:48 2016 +0100
+++ b/libraries/json/json.c	Thu Jan 14 17:40:49 2016 +0100
@@ -1037,7 +1037,11 @@
   int pretty;           // pretty printing on? (i.e. printing with indentation)
   luaL_Buffer buf;      // Lua buffer containing result string
   lua_Number num;       // number to encode
-  char numstr[21];      // encoded number (sign, zero, point, 17 significant digits, and terminating NULL byte)
+  char numstr[80];      // encoded number
+                        // (21 chars needed for sign, zero, point, 17 significant digits, and NULL byte)
+                        // (21 chars needed for sign, 19 digits INT64, and NULL byte)
+                        // (80 chars needed for sign, 78 digits INT256, and NULL byte)
+                        // (NOTE: we don't know the size of intmax_t and thus use 80)
   const char *str;      // string to encode
   size_t strlen;        // length of string to encode
   size_t strpos ;       // position in string or position of current key
@@ -1101,6 +1105,14 @@
       break;
     // value to encode is of type number:
     case LUA_TNUMBER:
+#if LUA_VERSION_NUM >= 503
+      // handle integers:
+      if (lua_isinteger(L, json_export_value_idx)) {
+        sprintf(numstr, "%ji", (intmax_t)lua_tointeger(L, json_export_value_idx));
+        luaL_addstring(&buf, numstr);
+        break;
+      }
+#endif
       // convert value to double precision number:
       num = lua_tonumber(L, json_export_value_idx);
       // throw error if number is not-a-number:
@@ -1108,10 +1120,21 @@
       // throw error if number is positive or negative infinity:
       if (isinf(num)) return luaL_error(L, "JSON export not possible for infinite numbers");
       // determine necessary precision to represent double precision floating point number:
-      sprintf(numstr, "%.16g", num);
+      sprintf(numstr, "%.15g", num);  // NOTE: e.g. 0.009 should not be 0.008999999999999999
+      if (strtod(numstr, NULL) != num) sprintf(numstr, "%.16g", num);
       if (strtod(numstr, NULL) != num) sprintf(numstr, "%.17g", num);
       // add string encoding of the number to the output buffer:
       luaL_addstring(&buf, numstr);
+#if LUA_VERSION_NUM >= 503
+      // enforce trailing ".0" for floats unless exponential notation was chosen:
+      {
+        char *p;
+        if (numstr[0] == '-' || numstr[0] == '+') p = numstr+1;
+        else p = numstr;
+        for (; *p; p++) if (*p < '0' || *p > '9') break;
+        if (!*p) luaL_addstring(&buf, ".0");
+      }
+#endif
       break;
     // value to encode is of type boolean:
     case LUA_TBOOLEAN: