diff --git a/Makefile b/Makefile
index 848cdc2..1927a53 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,7 @@ test_object_dirs = $(sort $(foreach fn,$(test_objects),$(dir $(fn))))
 CC = clang
 LD = clang
 
-CFLAGS 	+= -Wall -g -MMD -std=c99 -I.
+CFLAGS 	+= -Wall -Wextra -pedantic -ansi -g -MMD -std=c99 -I.
 TEST_CFLAGS := $(CFLAGS) -O0
 #LDFLAGS +=
 ifneq ($(DEBUG),)
diff --git a/example1.c b/example1.c
index c36559c..97a8c13 100644
--- a/example1.c
+++ b/example1.c
@@ -8,7 +8,7 @@
 
 static const char* _tok_name(jsont_tok_t tok);
 
-int main(int argc, const char** argv) {
+int main(void) {
   // Create a new reusable tokenizer
   jsont_ctx_t* S = jsont_create(0);
 
@@ -37,7 +37,7 @@ int main(int argc, const char** argv) {
     } else if (tok == JSONT_NUMBER_FLOAT) {
       printf(" %f", jsont_float_value(S));
     }
-    
+
     printf("\n");
   }
 
diff --git a/example2.c b/example2.c
index 5077f85..e25bd35 100644
--- a/example2.c
+++ b/example2.c
@@ -58,7 +58,7 @@ typedef struct my_response {
 bool my_user_build(jsont_ctx_t* S, my_user_t* obj) {
   jsont_tok_t tok = jsont_current(S);
   if (tok != JSONT_OBJECT_START) return false;
-  
+
   // for each field
   while ((tok = jsont_next(S)) == JSONT_FIELD_NAME) {
     const uint8_t* fieldname = 0;
@@ -67,7 +67,7 @@ bool my_user_build(jsont_ctx_t* S, my_user_t* obj) {
     if (memcmp("id", fieldname, len) == 0) {
       MY_NEXT_EXPECT(S, JSONT_STRING);
       obj->id = jsont_strcpy_value(S);
-    
+
     } else if (memcmp("name", fieldname, len) == 0) {
       MY_NEXT_EXPECT(S, JSONT_STRING);
       obj->name = jsont_strcpy_value(S);
@@ -119,7 +119,7 @@ bool my_response_build(jsont_ctx_t* S, my_response_t* obj) {
       return false;
     }
   }
-  
+
   return true;
 }
 
@@ -137,7 +137,7 @@ if (jsont_next(S) != JSONT_OBJECT_START) {
   return rsp;
 }
 
-int main(int argc, const char** argv) {
+int main(void) {
   // Create a new reusable tokenizer
   jsont_ctx_t* S = jsont_create(0);
 
diff --git a/jsont.c b/jsont.c
index 5863c7a..ea825c6 100644
--- a/jsont.c
+++ b/jsont.c
@@ -21,6 +21,8 @@ DEF_EM(UNEXPECTED_OBJECT_END,
 DEF_EM(UNEXPECTED_ARRAY_END, "Unexpected end of array while not in an array");
 DEF_EM(UNEXPECTED_COMMA, "Unexpected \",\"");
 DEF_EM(UNEXPECTED_COLON, "Unexpected \":\"");
+DEF_EM(EXTRA_DOT_IN_FLOAT, "Extra \".\" found while parsing float");
+DEF_EM(BAD_EXPONENT, "Bad format while parsing exponent");
 DEF_EM(UNEXPECTED, "Unexpected input");
 DEF_EM(UNEXPECTED_UNICODE_SEQ, "Malformed unicode encoded sequence in string");
 #undef DEF_EM
@@ -45,6 +47,7 @@ typedef uint8_t jsont_tok_t;
 
 typedef struct jsont_ctx {
   void* user_data;
+  void * (*lrealloc)(void * user_data, void * p, size_t size);
   const uint8_t* input_buf;
   const uint8_t* input_buf_ptr;
   size_t input_len;
@@ -74,7 +77,7 @@ unsigned long _hex_str_to_ul(const uint8_t* bytes, size_t len) {
   for (size_t i = 0; i != len; ++i) {
     uint8_t b = bytes[i];
     int digit = (b > '0'-1 && b < 'f'+1) ? kHexValueTable[b-'0'] : -1;
-    if (b == -1 || // bad digit
+    if (digit == -1 || // bad digit
         (value > cutoff) || // overflow
         ((value == cutoff) && (digit > cutoff_digit)) ) {
       return ULONG_MAX;
@@ -86,18 +89,43 @@ unsigned long _hex_str_to_ul(const uint8_t* bytes, size_t len) {
   return value;
 }
 
-jsont_ctx_t* jsont_create(void* user_data) {
-  jsont_ctx_t* ctx = (jsont_ctx_t*)calloc(1, sizeof(jsont_ctx_t));
+/**
+ *  a "multitool" allocator that encapsulates allocate, reallocate 
+ *     and free functionality. 
+ * 
+ *  if p == NULL, then allocate "size" bytes.
+ *  if p != NULL, and size != 0, then reallocate to "size" bytes.
+ *  otherwise, free(p)
+ */
+static void * lrealloc(void * ign, void *p, size_t size) {
+    (void)ign; // unused
+    if (size) return realloc(p, size);
+    free(p);
+    return NULL;
+}
+
+
+jsont_ctx_t* jsont_create_alloc(
+		void* user_data,
+		void * (*lrealloc)(void * user_data, void * p, size_t size)) {
+  jsont_ctx_t* ctx = (jsont_ctx_t*)lrealloc(user_data, NULL, sizeof(jsont_ctx_t));
+  memset(ctx, 0, sizeof(jsont_ctx_t));
   ctx->user_data = user_data;
+  ctx->lrealloc = lrealloc;
   ctx->st_stack_size = _STRUCT_TYPE_STACK_SIZE;
   return ctx;
 }
 
+jsont_ctx_t* jsont_create(void* user_data) {
+	return jsont_create_alloc(user_data, lrealloc);
+}
+
+
 void jsont_destroy(jsont_ctx_t* ctx) {
   if (ctx->value_buf.data != 0) {
-    free(ctx->value_buf.data);
+    ctx->lrealloc(ctx->user_data, ctx->value_buf.data, 0);
   }
-  free(ctx);
+  ctx->lrealloc(ctx->user_data, ctx, 0);
 }
 
 void jsont_reset(jsont_ctx_t* ctx, const uint8_t* bytes, size_t length) {
@@ -172,9 +200,13 @@ bool jsont_data_equals(jsont_ctx_t* ctx, const uint8_t* bytes, size_t length) {
       (memcmp((const void*)ctx->value_buf.data,
         (const void*)bytes, length) == 0);
   } else {
-    return (ctx->input_buf_value_end - ctx->input_buf_value_start == length) &&
-      (memcmp((const void*)ctx->input_buf_value_start,
-        (const void*)bytes, length) == 0);
+    size_t value_length =
+      ctx->input_buf_value_end - ctx->input_buf_value_start;
+    if (value_length != length) {
+      return 0;
+    }
+    return (memcmp((const void*)ctx->input_buf_value_start,
+                   (const void*)bytes, length) == 0);
   }
 }
 
@@ -184,7 +216,7 @@ char* jsont_strcpy_value(jsont_ctx_t* ctx) {
   } else {
     const uint8_t* bytes = 0;
     size_t len = jsont_data_value(ctx, &bytes);
-    char* buf = (char*)malloc(len+1);
+    char* buf = (char*)ctx->lrealloc(ctx->user_data, NULL, len+1);
     if (memcpy((void*)buf, (const void*)bytes, len) != buf) {
       return 0;
     }
@@ -351,14 +383,14 @@ static void _value_buf_append(jsont_ctx_t* ctx, const uint8_t* data, size_t len)
     if (ctx->value_buf.size < _VALUE_BUF_MIN_SIZE) {
       ctx->value_buf.size = _VALUE_BUF_MIN_SIZE;
     }
-    ctx->value_buf.data = (uint8_t*)malloc(ctx->value_buf.size);
+    ctx->value_buf.data = (uint8_t*)ctx->lrealloc(ctx->user_data, NULL, ctx->value_buf.size);
     if (len != 0) {
       memcpy(ctx->value_buf.data, data, len);
     }
   } else {
     if (ctx->value_buf.length + len > ctx->value_buf.size) {
       size_t new_size = ctx->value_buf.size + (len * 2);
-      ctx->value_buf.data = realloc(ctx->value_buf.data, new_size);
+      ctx->value_buf.data = ctx->lrealloc(ctx->user_data, ctx->value_buf.data, new_size);
       assert(ctx->value_buf.data != 0);
       ctx->value_buf.size = new_size;
     }
@@ -543,10 +575,31 @@ jsont_tok_t jsont_next(jsont_ctx_t* ctx) {
           ctx->input_buf_value_start = ctx->input_buf_ptr-1;
           //uint8_t prev_b = 0;
           bool is_float = false;
+          bool is_exp = false;
           while (1) {
             b = _next_byte(ctx);
             if (b == '.') {
+              if (is_float || is_exp) {
+                ctx->error_info = JSONT_ERRINFO_EXTRA_DOT_IN_FLOAT;
+                return _set_tok(ctx, JSONT_ERR);
+              }
+              is_float = true;
+            } else if ( b == 'E' || b == 'e') {
+              if (is_exp) {
+                ctx->error_info = JSONT_ERRINFO_BAD_EXPONENT;
+                return _set_tok(ctx, JSONT_ERR);
+              }
+              is_exp = true;
               is_float = true;
+              // check for +- on exponent
+              b = _next_byte(ctx);
+              if (b == '+' || b == '-') {
+                b = _next_byte(ctx);
+              }
+              if (!isdigit((int)b)) {
+                ctx->error_info = JSONT_ERRINFO_BAD_EXPONENT;
+                return _set_tok(ctx, JSONT_ERR);
+              }
             } else if (!isdigit((int)b)) {
               _rewind_one_byte(ctx);
               ctx->input_buf_value_end = ctx->input_buf_ptr;
@@ -566,4 +619,3 @@ jsont_tok_t jsont_next(jsont_ctx_t* ctx) {
     }
   } // while (1)
 }
-
diff --git a/jsont.h b/jsont.h
index 22cd043..64ecd09 100644
--- a/jsont.h
+++ b/jsont.h
@@ -51,6 +51,17 @@ extern "C" {
 // accessible through `jsont_user_data`.
 jsont_ctx_t* jsont_create(void* user_data);
 
+// Create a new JSON tokenizer context with a
+// custom allocation function. 
+//
+// the custom allocation function serves as malloc, realloc and free.
+// * if size == 0, then the operation is a free,
+// * if ptr == NULL, then the operation is a malloc.
+// * otherwise, the operation is a realloc
+jsont_ctx_t* jsont_create_alloc(
+   void* user_data,
+   void * (*lrealloc)(void * user_data, void * p, size_t size));
+
 // Destroy a JSON tokenizer context. This will free any internal data, except
 // from the input buffer.
 void jsont_destroy(jsont_ctx_t* ctx);
diff --git a/test/test_tokenizer.c b/test/test_tokenizer.c
index f994c85..fc17658 100644
--- a/test/test_tokenizer.c
+++ b/test/test_tokenizer.c
@@ -10,7 +10,7 @@
     strlen(fieldName)) == true); \
 } while(0)
 
-int main(int argc, const char** argv) {
+int main(void) {
   // Create a new reusable tokenizer
   jsont_ctx_t* S = jsont_create(0);
 
@@ -37,7 +37,10 @@ int main(int argc, const char** argv) {
       "\"a\\rb\","
       "\"a\\tb\","
       "\"\","
-      "\"   \""
+      "\"   \","
+      "123.4e-2,"
+      "345.6E2,"
+      "789.12e+10"
     "]"
   "}";
 
@@ -81,7 +84,7 @@ int main(int argc, const char** argv) {
   // Expect the string '\u2192' (RIGHTWARDS ARROW, UTF8: E2,86,92)
   assert(jsont_next(S) == JSONT_STRING);
   assert(jsont_str_equals(S, "\xe2\x86\x92") == true);
-  
+
   // Expect a field name 'n'
   jsont_next(S);
   JSONT_ASSERT_FIELD_NAME("n");
@@ -169,6 +172,20 @@ int main(int argc, const char** argv) {
   assert(jsont_str_equals(S, "   ") == true);
   assert(jsont_str_equals(S, "") == false);
 
+  // exponent formatting works 
+  //"123.4e-2"
+  assert(jsont_next(S) == JSONT_NUMBER_FLOAT);
+  assert(fabs(jsont_float_value(S) - 1.234) < 0.001);
+
+  //"345.6E2"
+  assert(jsont_next(S) == JSONT_NUMBER_FLOAT);
+  assert(fabs(jsont_float_value(S) - 34560.0) < 0.001);
+
+
+  //"789.12E+10"
+  assert(jsont_next(S) == JSONT_NUMBER_FLOAT);
+  assert(fabs(jsont_float_value(S) - 7891200000000.0) < 0.1);
+
   // ] }
   assert(jsont_next(S) == JSONT_ARRAY_END);
   assert(jsont_next(S) == JSONT_OBJECT_END);