Basic JSON decode implementation.

module/Library/JSON.cpp

@@ -11,12 +11,242 @@
 namespace SqMod {
 
 // ------------------------------------------------------------------------------------------------
+static SQInteger SqToJSON(HSQUIRRELVM vm) noexcept
+{
+    return sq_throwerror(vm, _SC("Not implemented yet!"));
+}
 
+// ------------------------------------------------------------------------------------------------
+static SQInteger SqFromJson_Push(HSQUIRRELVM vm, const char * str, jsmntok * t, size_t count) noexcept
+{
+    // Are there any elements to process?
+    if (count == 0)
+    {
+        // We still need something on the stack
+        sq_pushnull(vm);
+        // No token consumed
+        return 0;
+    }
+    // Is this a primitive type?
+    else if (t->type & JSMN_PRIMITIVE)
+    {
+        // Primitive length (in characters)
+        const jsmnint l = (t->end - t->start);
+        // Primitive start (character offset)
+        const char * v = (str + t->start);
+        // Is this a floating point?
+        if (memchr(v, '.', l) || memchr(v, 'e', l) || memchr(v, 'E', l))
+        {
+            sq_pushfloat(vm, ConvNum< SQFloat >::FromStr(v));
+        }
+        // Is this an integer?
+        else if (((v[0] >= '0') && (v[0] <= '9')) || (v[0] == '-') || (v[0] == '+'))
+        {
+            sq_pushinteger(vm, ConvNum< SQInteger >::FromStr(v));
+        }
+        // Is this a boolean true?
+        else if (v[0] == 't')
+        {
+            sq_pushbool(vm, SQTrue);
+        }
+        // Is this a boolean false?
+        else if (v[0] == 'f')
+        {
+            sq_pushbool(vm, SQFalse);
+        }
+        // Is this null?
+        else if (v[0] == 'n')
+        {
+            sq_pushnull(vm);
+        }
+        // Should never really get here because it should be sanitized by the JSON parser
+        // But doesn't hurt to have it here in case something out of our scope goes wrong
+        else
+        {
+            return sq_throwerrorf(vm, _SC("Unrecognized JSON primitive: '%.*s'"), l, v);
+        }
+        // One token was consumed
+        return 1;
+    }
+    // Is this a string?
+    else if (t->type & JSMN_STRING)
+    {
+        sq_pushstring(vm, (str + t->start), static_cast< SQInteger >(t->end - t->start));
+        // One token was consumed
+        return 1;
+    }
+    // Is this an object?
+    else if (t->type & JSMN_OBJECT)
+    {
+        // Number of tokens consumed by this object
+        SQInteger c = 0, r = SQ_OK;
+        // Create a new table on the stack
+        sq_newtableex(vm, static_cast< SQInteger >(t->size));
+        // Process object elements
+        for (jsmnint i = 0; i < t->size; i++)
+        {
+            // Locate key token relative to the current token
+            jsmntok * k = (t + 1 + c);
+            // Transform the key into a script object on the stack
+            r = SqFromJson_Push(vm, str, k, count - c);
+            // Did we fail?
+            if (SQ_FAILED(r))
+            {
+                break; // Abort
+            }
+            // Update consumed tokens
+            c += r;
+            // Does the key have an associated value?
+            if (k->size > 0)
+            {
+                // Transform the value into a script object on the stack
+                r = SqFromJson_Push(vm, str, (t + 1 + c), count - c);
+                // Did we fail?
+                if (SQ_FAILED(r))
+                {
+                    // Discard the key
+                    sq_poptop(vm);
+                    // Abort
+                    break;
+                }
+                // Update consumed tokens
+                c += r;
+            }
+            else
+            {
+                sq_pushnull(vm); // Default to null because a value must exist
+            }
+            // At this point we have a key and a value on the stack
+            r = sq_newslot(vm, -3, SQFalse);
+            // Did we fail?
+            if (SQ_FAILED(r))
+            {
+                // Discard the key/value pair
+                sq_pop(vm, 2);
+                // Abort
+                break;
+            }
+        }
+        // Anything bad happened?
+        if (SQ_FAILED(r))
+        {
+            // Discard the table
+            sq_poptop(vm);
+            // Propagate the error
+            return r;
+        }
+        // Return consumed tokens
+        return c + 1;
+    }
+    // Is this an array?
+    else if (t->type & JSMN_ARRAY)
+    {
+        // Number of tokens consumed by this array
+        SQInteger c = 0, r = SQ_OK;
+        // Create a new array on the stack
+        sq_newarrayex(vm, static_cast< SQInteger >(t->size));
+        // Process array elements
+        for (jsmnint i = 0; i < t->size; i++)
+        {
+            // Transform the value into a script object on the stack
+            r = SqFromJson_Push(vm, str, (t + 1 + c), count - c);
+            // Did we fail?
+            if (SQ_FAILED(r))
+            {
+                break; // Abort
+            }
+            // Update consumed tokens
+            c += r;
+            // At this point we have a value on the stack
+            r = sq_arrayappend(vm, -2);
+            // Did we fail?
+            if (SQ_FAILED(r))
+            {
+                // Discard the value
+                sq_poptop(vm);
+                // Abort
+                break;
+            }
+        }
+        // Anything bad happened?
+        if (SQ_FAILED(r))
+        {
+            // Discard the array
+            sq_poptop(vm);
+            // Propagate the error
+            return r;
+        }
+        // Return consumed tokens
+        return c + 1;
+    }
+    // Should never really get here because it should be sanitized by the JSON parser
+    // But doesn't hurt to have it here in case something out of our scope goes wrong
+    return sq_throwerror(vm, _SC("Unrecognized JSON type"));
+}
+
+// ------------------------------------------------------------------------------------------------
+static SQInteger SqFromJSON(HSQUIRRELVM vm) noexcept
+{
+    // Remember the current stack size
+    const SQInteger top = sq_gettop(vm);
+    // Was the JSON string specified?
+    if (top < 2)
+    {
+        return sq_throwerror(vm, _SC("Please specify the JSON string to parse"));
+    }
+    // JSON string storage
+    StackStrF s(vm, 2);
+    // Attempt to retrieve the specified JSON string
+    if (SQ_FAILED(s.Proc(true)))
+    {
+        return s.mRes; // Propagate the error
+    }
+    // Parser context
+    jsmnparser p;
+    // Initialize parser
+    jsmn_init(&p);
+    // Estimate the number of tokens necessary to parse the specified JSON string
+    jsmnint r = jsmn_parse(&p, s.mPtr, static_cast< size_t >(s.mLen), nullptr, 0);
+    // Is there anything to parse?
+    if (r == 0)
+    {
+        // Default to null
+        sq_pushnull(vm);
+        // A value was returned
+        return 1;
+    }
+    // See if there was an error
+    switch (r)
+    {
+        case jsmnint(JSMN_ERROR_NOMEM):
+            return sq_throwerror(vm, _SC("Not enough token memory was provided"));
+        case jsmnint(JSMN_ERROR_LEN):
+            return sq_throwerror(vm, _SC("Input data too long"));
+        case jsmnint(JSMN_ERROR_INVAL):
+            return sq_throwerror(vm, _SC("Invalid character inside JSON string"));
+        case jsmnint(JSMN_ERROR_PART):
+            return sq_throwerror(vm, _SC("The string is not a full JSON packet, more bytes expected"));
+        case jsmnint(JSMN_ERROR_UNMATCHED_BRACKETS):
+            return sq_throwerror(vm, _SC("The JSON string has unmatched brackets"));
+        default: break; // Nothing bad happened
+    }
+    // Initialize the token array
+    std::vector< jsmntok > tks(static_cast< size_t >(r) + 16);
+    // Initialize parser
+    jsmn_init(&p);
+    // Attempt to parse the specified JSON string
+    r = jsmn_parse(&p, s.mPtr, static_cast< size_t >(s.mLen), tks.data(), tks.size());
+    // Process the tokens that were parsed from the string
+    SQInteger res = SqFromJson_Push(vm, s.mPtr, tks.data(), p.toknext);
+    // We either have a value to return or we propagate some error
+    return SQ_SUCCEEDED(res) ? 1 : res;
+}
 
 // ================================================================================================
 void Register_JSON(HSQUIRRELVM vm)
 {
-
+    RootTable(vm).SquirrelFunc(_SC("SqToJSON"), SqToJSON);
+    RootTable(vm).SquirrelFunc(_SC("SqFromJSON"), SqFromJSON);
 }
 
 } // Namespace:: SqMod

module/Library/JSON.hpp

@@ -5,8 +5,9 @@
 #include "Library/IO/Buffer.hpp"
 
 // ------------------------------------------------------------------------------------------------
-#define JSMN_HEADER
+extern "C" {
-#include <jsmn.h>
+	#include <jsmn.h>
+}
 
 // ------------------------------------------------------------------------------------------------
 namespace SqMod {