Allow special floating-point value names in JSON: "inf", "-inf", "infinity",

"-infinity", "nan", "qnan", and "snan".  All are converted into valid JSON
values: 9e999, -9e999, or null.  Requires the SQLITE_ENABLE_JSON_NAN_INF
compile-time option to operate.

FossilOrigin-Name: fc8793e5acac7351749e360c6bace5d5a8b3de3aa600ae23e260557db650c461

manifest

@@ -1,5 +1,5 @@
-C Fix\sharmless\scompiler\swarnings.
+C Allow\sspecial\sfloating-point\svalue\snames\sin\sJSON:\s\s"inf",\s"-inf",\s"infinity",\n"-infinity",\s"nan",\s"qnan",\sand\s"snan".\s\sAll\sare\sconverted\sinto\svalid\sJSON\nvalues:\s9e999,\s-9e999,\sor\snull.\s\sRequires\sthe\sSQLITE_ENABLE_JSON_NAN_INF\ncompile-time\soption\sto\soperate.
-D 2023-04-01T15:51:21.968
+D 2023-04-01T23:29:59.248
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -585,7 +585,7 @@ F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
 F src/hwtime.h b638809e083b601b618df877b2e89cb87c2a47a01f4def10be4c4ebb54664ac7
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
 F src/insert.c a8de1db43335fc4946370a7a7e47d89975ad678ddb15078a150e993ba2fb37d4
-F src/json.c 9e3a6acf9e4fa8bb6c84a38538ed9c2f9ad09f106910ef0e9cc68e19c8dc4fc8
+F src/json.c 5ac77e419921a0e63dafe07b560e9ce5e9823055e814308559e4d54cc885a967
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c be5af440f3192c58681b5d43167dbca3ccbfce394d89faa22378a14264781136
 F src/main.c 09bc5191f75dc48fc4dfddda143cb864c0c3dbc3297eb9a9c8e01fea58ff847d
@@ -2052,8 +2052,11 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P a1cb152e69c7c6cdd99300c91a8104716089de459d9d19e33ef38432aad70908
+P a4fb2864fe01cce9694242a0750623ca47fcecd68f74c4239d3eb5fbf978770a
-R 1d46d8321fd0682be5d0a8790e197dc3
+R d4fc5e6b6e165fd35d3ba84e2f999b35
+T *branch * json-nan-inf
+T *sym-json-nan-inf *
+T -sym-trunk *
 U drh
-Z 9ba80d4da1e49f126926ac3e65e84ef8
+Z 2575536ea35edbedba9ae17b565e4eb0
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-a4fb2864fe01cce9694242a0750623ca47fcecd68f74c4239d3eb5fbf978770a
+fc8793e5acac7351749e360c6bace5d5a8b3de3aa600ae23e260557db650c461

src/json.c

@@ -757,6 +757,27 @@ static int jsonIs4Hex(const char *z){
   return 1;
 }
 
+#ifdef SQLITE_ENABLE_JSON_NAN_INF
+/*
+** Extra floating-point literals to allow in JSON.
+*/
+static const struct NanInfName {
+  char c1;
+  char c2;
+  char n;
+  char eType;
+  char nRepl;
+  char *zMatch;
+  char *zRepl;
+} aNanInfName[] = {
+  { 'i', 'I', 3, JSON_REAL, 7, "inf", "9.0e999" },
+  { 'i', 'I', 8, JSON_REAL, 7, "infinity", "9.0e999" },
+  { 'n', 'N', 3, JSON_NULL, 4, "NaN", "null" },
+  { 'q', 'Q', 4, JSON_NULL, 4, "QNaN", "null" },
+  { 's', 'S', 4, JSON_NULL, 4, "SNaN", "null" },
+}; 
+#endif /* SQLITE_ENABLE_JSON_NAN_INF */
+
 /*
 ** Parse a single JSON value which begins at pParse->zJson[i].  Return the
 ** index of the first character past the end of the value parsed.
@@ -902,6 +923,24 @@ static int jsonParseValue(JsonParse *pParse, u32 i){
         if( c<'0' || c>'9' ) return -1;
         continue;
       }
+#ifdef SQLITE_ENABLE_JSON_NAN_INF
+      /* Non-standard JSON:  Allow "-Inf" (in any case)
+      ** to be understood as floating point literals. */
+      if( (c=='i' || c=='I')
+       && j==i+1
+       && z[i]=='-'
+       && sqlite3StrNICmp(&z[j], "inf",3)==0
+      ){
+        if( !sqlite3Isalnum(z[j+4]) ){
+          jsonParseAddNode(pParse, JSON_REAL, 8, "-9.0e999");
+          return i+4;
+        }else if( (sqlite3StrNICmp(&z[j],"infinity",8)==0 &&
+                  !sqlite3Isalnum(z[j+5])) ){
+          jsonParseAddNode(pParse, JSON_REAL, 8, "-9.0e999");
+          return i+9;
+        }
+      }
+#endif
       break;
     }
     if( z[j-1]<'0' ) return -1;
@@ -915,6 +954,20 @@ static int jsonParseValue(JsonParse *pParse, u32 i){
   }else if( c==0 ){
     return 0;   /* End of file */
   }else{
+#ifdef SQLITE_ENABLE_JSON_NAN_INF
+    int k, nn;
+    for(k=0; k<sizeof(aNanInfName)/sizeof(aNanInfName[0]); k++){
+      if( c!=aNanInfName[k].c1 && c!=aNanInfName[k].c2 ) continue;
+      nn = aNanInfName[k].n;
+      if( sqlite3StrNICmp(&z[i], aNanInfName[k].zMatch, nn)!=0 ){
+        continue;
+      }
+      if( sqlite3Isalnum(z[i+nn]) ) continue;
+      jsonParseAddNode(pParse, aNanInfName[k].eType,
+          aNanInfName[k].nRepl, aNanInfName[k].zRepl);
+      return i + nn;
+    }
+#endif
     return -1;  /* Syntax error */
   }
 }