Updated language and started scanner.

.idea/codeStyles/codeStyleConfig.xml

@@ -0,0 +1,5 @@
+<component name="ProjectCodeStyleConfiguration">
+  <state>
+    <option name="PREFERRED_PROJECT_CODE_STYLE" value="Default" />
+  </state>
+</component>

CMakeLists.txt

@@ -3,4 +3,4 @@ project(SDB C)
 
 set(CMAKE_C_STANDARD 11)
 
-add_executable(SDB src/main.c src/InputBuffer.c src/InputBuffer.h src/SQL.c src/SQL.h)
+add_executable(SDB src/main.c src/InputBuffer.c src/InputBuffer.h src/SQL.c src/SQL.h src/scanner.c src/scanner.h)

Language.txt

@@ -1,11 +1,13 @@
-Select A, B, C From X Where A = '1'
+Select A, B, C From X Where A = '1' AND B <> 2
 Insert Into X Set A = '1', B = 2, C = 'C'
 Update X Set A = '2' Where A = '1'
 Delete From X Where A = '1'
 Create Table X (A String(50) Index, B Int, C String(5))
 Drop Table X
 
+StatementList = StatementList, Statement | Statement ;
 Statement = SelectStmt | InsertStmt | UpdateStmt | DeleteStmt | CreateStmt | DropStmt ';' ;
+
 SelectStmt = 'Select', FieldList, 'From', Identifier, AssignmentList ;
 InsertStmt = 'Insert Into', Identifier, 'Set', AssignmentList ;
 UpdateStmt = 'Update', Identifier, 'Set', AssignmentList, 'Where', AssignmentList ;
@@ -22,5 +24,9 @@ FieldList = Identifier | FieldList, ',', Identifier ;
 AssignmentList = Assignment | AssignmentList, ',', Assignment ;
 Assignment = Identifier, '=', Value ;
 
+ComparisonGroup = Comparison | ComparisonList, 'AND', Comparison
+Comparison = Identifier, Comparator, Value;
+Comparator = '=' | '<>';
+
 Identifier = { letter, '_' } , { letter | digit | '_' } ;
-Value = "'" character ""'" | '"', character, '"' | number ;
+Value = "'", string, "'" | '"', string, '"' | number ;

src/SQL.c

@@ -5,27 +5,66 @@
 #include <malloc.h>
 #include "SQL.h"
 
-T_Value *new_t_value() {
-    T_Value *value = malloc(sizeof(T_Value));
+Value *new_value() {
+    Value *value = malloc(sizeof(Value));
     value->number = 0;
     value->string = NULL;
     return value;
 }
 
-void free_t_value(T_Value *value) {
+void free_value(Value *value) {
     if (value->string != NULL) {
         free(value->string);
     }
     free(value);
 }
 
-T_Assignment *new_t_assignment() {
-    T_Assignment *assignment = malloc(sizeof(T_Assignment));
+Comparison *new_comparison() {
+    Comparison* comparison = malloc(sizeof(Comparison));
+    comparison->identifier = NULL;
+    comparison->value = NULL;
+    comparison->comp = COMP_NONE;
+    return comparison;
+}
+void free_comparison(Comparison *comparison) {
+    if (comparison->value != NULL) {
+        free(comparison->value);
+    }
+    if(comparison->identifier != NULL) {
+        free(comparison->identifier);
+    }
+    free(comparison);
+}
+
+ComparisonGroup *new_comparision_group() {
+    ComparisonGroup *group = malloc(sizeof(ComparisonGroup));
+    group->comparisons = NULL;
+    group->length = 0;
+    return group;
+}
+void free_comparison_group(ComparisonGroup* group) {
+    if (group->length > 0) {
+        for(size_t i=0; i<group->length; i++) {
+            free(group->comparisons[i]);
+        }
+        free(group->comparisons);
+        group->length = 0;
+    }
+    free(group);
+}
+void append_comparison_group(ComparisonGroup *group, Comparison *comparison) {
+    group->length++;
+    group->comparisons = realloc(group->comparisons, sizeof(Assignment) * group->length);
+    group->comparisons[group->length - 1] = comparison;
+}
+
+Assignment *new_assignment() {
+    Assignment *assignment = malloc(sizeof(Assignment));
     assignment->value = NULL;
     assignment->identifier = NULL;
 }
 
-void free_t_assignment(T_Assignment *assignment) {
+void free_assignment(Assignment *assignment) {
     if (assignment->identifier != NULL) {
         free(assignment->identifier);
     }
@@ -35,17 +74,17 @@ void free_t_assignment(T_Assignment *assignment) {
     free(assignment);
 }
 
-T_AssignmentList *new_t_assignment_list() {
-    T_AssignmentList *assignmentList = malloc(sizeof(T_AssignmentList));
+AssignmentList *new_assignment_list() {
+    AssignmentList *assignmentList = malloc(sizeof(AssignmentList));
     assignmentList->assignments = NULL;
     assignmentList->length = 0;
     return assignmentList;
 }
 
-void free_t_assignment_list(T_AssignmentList *assignmentList) {
+void free_assignment_list(AssignmentList *assignmentList) {
     if (assignmentList->length > 0) {
         for (size_t i = 0; i < assignmentList->length; i++) {
-            free_t_assignment(assignmentList->assignments[i]);
+            free_assignment(assignmentList->assignments[i]);
         }
         free(assignmentList->assignments);
         assignmentList->length = 0;
@@ -53,20 +92,20 @@ void free_t_assignment_list(T_AssignmentList *assignmentList) {
     free(assignmentList);
 }
 
-void append_t_assignment_list(T_AssignmentList *list, T_Assignment *assignment) {
+void append_assignment_list(AssignmentList *list, Assignment *assignment) {
     list->length++;
-    list->assignments = realloc(list->assignments, sizeof(T_Assignment) * list->length);
+    list->assignments = realloc(list->assignments, sizeof(Assignment) * list->length);
     list->assignments[list->length - 1] = assignment;
 }
 
-T_FieldList *new_t_field_list() {
-    T_FieldList *list = malloc(sizeof(T_FieldList));
+FieldList *new_field_list() {
+    FieldList *list = malloc(sizeof(FieldList));
     list->length = 0;
     list->fields = NULL;
     return list;
 }
 
-void free_t_field_list(T_FieldList *list) {
+void free_field_list(FieldList *list) {
     if (list->length > 0) {
         for (size_t i = 0; i < list->length; i++) {
             free(list->fields[i]);
@@ -78,14 +117,14 @@ void free_t_field_list(T_FieldList *list) {
     free(list);
 }
 
-void append_t_field_list(T_FieldList *list, char *field) {
+void append_field_list(FieldList *list, char *field) {
     list->length++;
     list->fields = realloc(list->fields, sizeof(char *) * list->length);
     list->fields[list->length - 1] = field;
 }
 
-T_ColumnSpec *new_t_column_spec() {
-    T_ColumnSpec *spec = malloc(sizeof(T_ColumnSpec));
+ColumnSpec *new_column_spec() {
+    ColumnSpec *spec = malloc(sizeof(ColumnSpec));
     spec->identifier = NULL;
     spec->option = COLOPT_NONE;
     spec->size = 0;
@@ -93,24 +132,24 @@ T_ColumnSpec *new_t_column_spec() {
     return spec;
 }
 
-void free_t_column_spec(T_ColumnSpec *spec) {
+void free_column_spec(ColumnSpec *spec) {
     if (spec->identifier != NULL) {
         free(spec->identifier);
     }
     free(spec);
 }
 
-T_ColumnSpecList *new_t_column_spec_list() {
-    T_ColumnSpecList *list = malloc(sizeof(T_ColumnSpecList));
+ColumnSpecList *new_column_spec_list() {
+    ColumnSpecList *list = malloc(sizeof(ColumnSpecList));
     list->length = 0;
     list->columns = NULL;
     return list;
 }
 
-void free_t_column_spec_list(T_ColumnSpecList *list) {
+void free_column_spec_list(ColumnSpecList *list) {
     if (list->length > 0) {
         for (size_t i = 0; i < list->length; i++) {
-            free_t_column_spec(list->columns[i]);
+            free_column_spec(list->columns[i]);
         }
         free(list->columns);
         list->columns = NULL;
@@ -119,43 +158,43 @@ void free_t_column_spec_list(T_ColumnSpecList *list) {
     free(list);
 }
 
-void append_t_column_spec_list(T_ColumnSpecList *list, T_ColumnSpec *spec) {
+void append_column_spec_list(ColumnSpecList *list, ColumnSpec *spec) {
     list->length++;
-    list->columns = realloc(list->columns, sizeof(T_ColumnSpec) * list->length);
+    list->columns = realloc(list->columns, sizeof(ColumnSpec) * list->length);
     list->columns[list->length - 1] = spec;
 }
 
-T_SelectStmt *new_t_select_stmt() {
-    T_SelectStmt *stmt = malloc(sizeof(T_SelectStmt));
+SelectStmt *new_select_stmt() {
+    SelectStmt *stmt = malloc(sizeof(SelectStmt));
     stmt->fields = NULL;
     stmt->tableName = NULL;
     stmt->where = NULL;
     return stmt;
 }
 
-void free_t_select_stmt(T_SelectStmt *stmt) {
+void free_select_stmt(SelectStmt *stmt) {
     if (stmt->where != NULL) {
-        free_t_assignment_list(stmt->where);
+        free_assignment_list(stmt->where);
     }
     if (stmt->tableName != NULL) {
         free(stmt->tableName);
     }
     if (stmt->fields != NULL) {
-        free_t_field_list(stmt->fields);
+        free_field_list(stmt->fields);
     }
     free(stmt);
 }
 
-T_InsertStmt *new_t_insert_stmt() {
-    T_InsertStmt *stmt = malloc(sizeof(T_InsertStmt));
+InsertStmt *new_insert_stmt() {
+    InsertStmt *stmt = malloc(sizeof(InsertStmt));
     stmt->tableName = NULL;
     stmt->values = NULL;
     return stmt;
 }
 
-void free_t_insert_stmt(T_InsertStmt *stmt) {
+void free_insert_stmt(InsertStmt *stmt) {
     if (stmt->values != NULL) {
-        free_t_assignment_list(stmt->values);
+        free_assignment_list(stmt->values);
     }
     if (stmt->tableName != NULL) {
         free(stmt->tableName);
@@ -163,99 +202,99 @@ void free_t_insert_stmt(T_InsertStmt *stmt) {
     free(stmt);
 }
 
-T_UpdateStmt *new_t_update_stmt() {
-    T_UpdateStmt *stmt = malloc(sizeof(T_UpdateStmt));
+UpdateStmt *new_update_stmt() {
+    UpdateStmt *stmt = malloc(sizeof(UpdateStmt));
     stmt->tableName = NULL;
     stmt->values = NULL;
     stmt->where = NULL;
     return stmt;
 }
 
-void free_t_update_stmt(T_UpdateStmt *stmt) {
+void free_update_stmt(UpdateStmt *stmt) {
     if (stmt->tableName != NULL) {
         free(stmt->tableName);
     }
     if (stmt->where != NULL) {
-        free_t_assignment_list(stmt->where);
+        free_assignment_list(stmt->where);
     }
     if (stmt->values != NULL) {
-        free_t_assignment_list(stmt->values);
+        free_assignment_list(stmt->values);
     }
     free(stmt);
 }
 
-T_DeleteStmt *new_t_delete_stmt() {
-    T_DeleteStmt *stmt = malloc(sizeof(T_DeleteStmt));
+DeleteStmt *new_delete_stmt() {
+    DeleteStmt *stmt = malloc(sizeof(DeleteStmt));
     stmt->tableName = NULL;
     stmt->where = NULL;
 }
 
-void free_t_delete_stmt(T_DeleteStmt *stmt) {
+void free_delete_stmt(DeleteStmt *stmt) {
     if (stmt->tableName != NULL) {
         free(stmt->tableName);
     }
     if (stmt->where != NULL) {
-        free_t_assignment_list(stmt->where);
+        free_assignment_list(stmt->where);
     }
     free(stmt);
 }
 
-T_CreateStmt *new_t_create_stmt() {
-    T_CreateStmt *spec = malloc(sizeof(T_CreateStmt));
+CreateStmt *new_create_stmt() {
+    CreateStmt *spec = malloc(sizeof(CreateStmt));
     spec->tableName = NULL;
     spec->columns = NULL;
     return spec;
 }
 
-void free_t_create_stmt(T_CreateStmt *spec) {
+void free_create_stmt(CreateStmt *spec) {
     if (spec->tableName != NULL) {
         free(spec->tableName);
     }
     if (spec->columns != NULL) {
-        free_t_column_spec_list(spec->columns);
+        free_column_spec_list(spec->columns);
     }
     free(spec);
 }
 
-T_DropStmt *new_t_drop_stmt() {
-    T_DropStmt *stmt = malloc(sizeof(T_DropStmt));
+DropStmt *new_drop_stmt() {
+    DropStmt *stmt = malloc(sizeof(DropStmt));
     stmt->tableName = NULL;
     return stmt;
 }
 
-void free_t_drop_stmt(T_DropStmt *stmt) {
+void free_drop_stmt(DropStmt *stmt) {
     if (stmt->tableName != NULL) {
         free(stmt->tableName);
     }
     free(stmt);
 }
 
-T_Statement *new_t_statement() {
-    T_Statement *stmt = malloc(sizeof(T_Statement));
+Statement *new_statement() {
+    Statement *stmt = malloc(sizeof(Statement));
     stmt->type = STMT_NONE;
     stmt->stmt = NULL;
     return stmt;
 }
 
-void free_t_statement(T_Statement *stmt) {
+void free_statement(Statement *stmt) {
     switch (stmt->type) {
         case STMT_SELECT:
-            free_t_select_stmt(stmt->stmt);
+            free_select_stmt(stmt->stmt);
             break;
         case STMT_INSERT:
-            free_t_insert_stmt(stmt->stmt);
+            free_insert_stmt(stmt->stmt);
             break;
         case STMT_UPDATE:
-            free_t_update_stmt(stmt->stmt);
+            free_update_stmt(stmt->stmt);
             break;
         case STMT_DELETE:
-            free_t_delete_stmt(stmt->stmt);
+            free_delete_stmt(stmt->stmt);
             break;
         case STMT_CREATE:
-            free_t_create_stmt(stmt->stmt);
+            free_create_stmt(stmt->stmt);
             break;
         case STMT_DROP:
-            free_t_drop_stmt(stmt->stmt);
+            free_drop_stmt(stmt->stmt);
             break;
         default:
             break;
@@ -265,17 +304,17 @@ void free_t_statement(T_Statement *stmt) {
     free(stmt);
 }
 
-T_StatementList *new_t_statement_list() {
-    T_StatementList *list = malloc(sizeof(T_StatementList));
+StatementList *new_statement_list() {
+    StatementList *list = malloc(sizeof(StatementList));
     list->length = 0;
     list->statements = NULL;
     return list;
 }
 
-void free_t_statement_list(T_StatementList *list) {
+void free_statement_list(StatementList *list) {
     if (list->length > 0) {
         for (size_t i = 0; i < list->length; i++) {
-            free_t_statement(list->statements[i]);
+            free_statement(list->statements[i]);
         }
         free(list->statements);
         list->statements = NULL;
@@ -284,8 +323,8 @@ void free_t_statement_list(T_StatementList *list) {
     free(list);
 }
 
-void append_t_statement_list(T_StatementList *list, T_Statement *statement) {
+void append_statement_list(StatementList *list, Statement *statement) {
     list->length++;
-    list->statements = realloc(list->statements, sizeof(T_Statement) * list->length);
+    list->statements = realloc(list->statements, sizeof(Statement) * list->length);
     list->statements[list->length - 1] = statement;
 }

src/SQL.h

@@ -7,149 +7,176 @@
 
 #include <stddef.h>
 
-union T_Value_t {
+union Value_t {
     char *string;
     int number;
 };
-typedef union T_Value_t T_Value;
+typedef union Value_t Value;
 
-T_Value *new_t_value();
+Value *new_value();
 
-void free_t_value(T_Value *value);
+void free_value(Value *value);
 
-struct T_Assignment_t {
-    char *identifier;
-    T_Value *value;
+enum Comparator_t {
+    COMP_NONE,
+    COMP_EQ,
+    COMP_NEQ
 };
-typedef struct T_Assignment_t T_Assignment;
+typedef enum Comparator_t Comparator;
 
-T_Assignment *new_t_assignment();
+struct Comparison_t {
+    char *identifier;
+    Comparator comp;
+    Value *value;
+};
+typedef struct Comparison_t Comparison;
 
-void free_t_assignment(T_Assignment *assignment);
+Comparison *new_comparison();
+void free_comparison(Comparison *comparison);
 
-struct T_AssignmentList_t {
-    T_Assignment **assignments;
+struct ComparisonGroup_t {
+    Comparison **comparisons;
     size_t length;
 };
-typedef struct T_AssignmentList_t T_AssignmentList;
+typedef struct ComparisonGroup_t ComparisonGroup;
 
-T_AssignmentList *new_t_assignment_list();
+ComparisonGroup *new_comparision_group();
+void free_comparison_group(ComparisonGroup* group);
+void append_comparison_group(ComparisonGroup *group, Comparison *comparison);
 
-void free_t_assignment_list(T_AssignmentList *assignmentList);
+struct Assignment_t {
+    char *identifier;
+    Value *value;
+};
+typedef struct Assignment_t Assignment;
 
-void append_t_assignment_list(T_AssignmentList *list, T_Assignment *assignment);
+Assignment *new_assignment();
 
-struct T_FieldList_t {
+void free_assignment(Assignment *assignment);
+
+struct AssignmentList_t {
+    Assignment **assignments;
+    size_t length;
+};
+typedef struct AssignmentList_t AssignmentList;
+
+AssignmentList *new_assignment_list();
+
+void free_assignment_list(AssignmentList *assignmentList);
+
+void append_assignment_list(AssignmentList *list, Assignment *assignment);
+
+struct FieldList_t {
     char **fields;
     size_t length;
 };
-typedef struct T_FieldList_t T_FieldList;
+typedef struct FieldList_t FieldList;
 
-T_FieldList *new_t_field_list();
+FieldList *new_field_list();
 
-void free_t_field_list(T_FieldList *list);
+void free_field_list(FieldList *list);
 
-void append_t_field_list(T_FieldList *list, char *field);
+void append_field_list(FieldList *list, char *field);
 
-enum T_ColumnOption_t {
+enum ColumnOption_t {
     COLOPT_NONE = 0,
     COLOPT_INDEX = 1
 };
-typedef enum T_ColumnOption_t T_ColumnOption;
+typedef enum ColumnOption_t ColumnOption;
 
-enum T_ColumnType_t {
+enum ColumnType_t {
     COLTYPE_NONE,
     COLTYPE_STRING,
     COLTYPE_INT
 };
-typedef enum T_ColumnType_t T_ColumnType;
+typedef enum ColumnType_t ColumnType;
 
-struct T_ColumnSpec_t {
+struct ColumnSpec_t {
     char *identifier;
-    T_ColumnType type;
+    ColumnType type;
     size_t size;
-    T_ColumnOption option;
+    ColumnOption option;
 };
-typedef struct T_ColumnSpec_t T_ColumnSpec;
+typedef struct ColumnSpec_t ColumnSpec;
 
-T_ColumnSpec *new_t_column_spec();
+ColumnSpec *new_column_spec();
 
-void free_t_column_spec(T_ColumnSpec *spec);
+void free_column_spec(ColumnSpec *spec);
 
-struct T_ColumnSpecList_t {
-    T_ColumnSpec **columns;
+struct ColumnSpecList_t {
+    ColumnSpec **columns;
     size_t length;
 };
-typedef struct T_ColumnSpecList_t T_ColumnSpecList;
+typedef struct ColumnSpecList_t ColumnSpecList;
 
-T_ColumnSpecList *new_t_column_spec_list();
+ColumnSpecList *new_column_spec_list();
 
-void free_t_column_spec_list(T_ColumnSpecList *list);
+void free_column_spec_list(ColumnSpecList *list);
 
-void append_t_column_spec_list(T_ColumnSpecList *list, T_ColumnSpec *spec);
+void append_column_spec_list(ColumnSpecList *list, ColumnSpec *spec);
 
-struct T_SelectStmt_t {
-    T_FieldList *fields;
+struct SelectStmt_t {
+    FieldList *fields;
     char *tableName;
-    T_AssignmentList *where;
+    AssignmentList *where;
 };
-typedef struct T_SelectStmt_t T_SelectStmt;
+typedef struct SelectStmt_t SelectStmt;
 
-T_SelectStmt *new_t_select_stmt();
+SelectStmt *new_select_stmt();
 
-void free_t_select_stmt(T_SelectStmt *stmt);
+void free_select_stmt(SelectStmt *stmt);
 
-struct T_InsertStmt_t {
+struct InsertStmt_t {
     char *tableName;
-    T_AssignmentList *values;
+    AssignmentList *values;
 };
-typedef struct T_InsertStmt_t T_InsertStmt;
+typedef struct InsertStmt_t InsertStmt;
 
-T_InsertStmt *new_t_insert_stmt();
+InsertStmt *new_insert_stmt();
 
-void free_t_insert_stmt(T_InsertStmt *stmt);
+void free_insert_stmt(InsertStmt *stmt);
 
-struct T_UpdateStmt_t {
+struct UpdateStmt_t {
     char *tableName;
-    T_AssignmentList *values;
-    T_AssignmentList *where;
+    AssignmentList *values;
+    AssignmentList *where;
 };
-typedef struct T_UpdateStmt_t T_UpdateStmt;
+typedef struct UpdateStmt_t UpdateStmt;
 
-T_UpdateStmt *new_t_update_stmt();
+UpdateStmt *new_update_stmt();
 
-void free_t_update_stmt(T_UpdateStmt *stmt);
+void free_update_stmt(UpdateStmt *stmt);
 
-struct T_DeleteStmt_t {
+struct DeleteStmt_t {
     char *tableName;
-    T_AssignmentList *where;
+    AssignmentList *where;
 };
-typedef struct T_DeleteStmt_t T_DeleteStmt;
+typedef struct DeleteStmt_t DeleteStmt;
 
-T_DeleteStmt *new_t_delete_stmt();
+DeleteStmt *new_delete_stmt();
 
-void free_t_delete_stmt(T_DeleteStmt *stmt);
+void free_delete_stmt(DeleteStmt *stmt);
 
-struct T_CreateStmt_t {
+struct CreateStmt_t {
     char *tableName;
-    T_ColumnSpecList *columns;
+    ColumnSpecList *columns;
 };
-typedef struct T_CreateStmt_t T_CreateStmt;
+typedef struct CreateStmt_t CreateStmt;
 
-T_CreateStmt *new_t_create_stmt();
+CreateStmt *new_create_stmt();
 
-void free_t_create_stmt(T_CreateStmt *spec);
+void free_create_stmt(CreateStmt *spec);
 
-struct T_DropStmt_t {
+struct DropStmt_t {
     char *tableName;
 };
-typedef struct T_DropStmt_t T_DropStmt;
+typedef struct DropStmt_t DropStmt;
 
-T_DropStmt *new_t_drop_stmt();
+DropStmt *new_drop_stmt();
 
-void free_t_drop_stmt(T_DropStmt *stmt);
+void free_drop_stmt(DropStmt *stmt);
 
-enum T_StatementType_t {
+enum StatementType_t {
     STMT_NONE = 0,
     STMT_SELECT,
     STMT_INSERT,
@@ -158,28 +185,28 @@ enum T_StatementType_t {
     STMT_CREATE,
     STMT_DROP
 };
-typedef enum T_StatementType_t T_StatementType;
+typedef enum StatementType_t StatementType;
 
-struct T_Statement_t {
-    T_StatementType type;
+struct Statement_t {
+    StatementType type;
     void *stmt;
 };
-typedef struct T_Statement_t T_Statement;
+typedef struct Statement_t Statement;
 
-T_Statement *new_t_statement();
+Statement *new_statement();
 
-void free_t_statement(T_Statement *stmt);
+void free_statement(Statement *stmt);
 
-struct T_StatementList_t {
-    T_Statement **statements;
+struct StatementList_t {
+    Statement **statements;
     size_t length;
 };
-typedef struct T_StatementList_t T_StatementList;
+typedef struct StatementList_t StatementList;
 
-T_StatementList *new_t_statement_list();
+StatementList *new_statement_list();
 
-void free_t_statement_list(T_StatementList *list);
+void free_statement_list(StatementList *list);
 
-void append_t_statement_list(T_StatementList *list, T_Statement *statement);
+void append_statement_list(StatementList *list, Statement *statement);
 
 #endif //SDB_SQL_H

src/scanner.c

@@ -0,0 +1,94 @@
+//
+// Created by Sam on 05/06/2018.
+//
+
+#include <malloc.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdbool.h>
+#include "scanner.h"
+
+Scanner_Result *new_scanner_result() {
+    Scanner_Result *result = malloc(sizeof(Scanner_Result));
+    result->token = T_NONE;
+    result->value_int = 0;
+    result->value_str = NULL;
+    return result;
+}
+
+void free_scanner_result(Scanner_Result *result) {
+    if (result->value_str != NULL) {
+        free(result);
+    }
+    free(result);
+}
+
+Scanner *new_scanner(char *input) {
+    Scanner *scanner = malloc(sizeof(Scanner));
+    scanner->input = input;
+    scanner->pos = 0;
+    scanner->state = SCANSTATE_START;
+    return scanner;
+}
+
+void free_scanner(Scanner *scanner) {
+    if (scanner->input != NULL) {
+        free(scanner->input);
+    }
+    free(scanner);
+}
+
+void reuse_scanner(Scanner *scanner, char *input) {
+    scanner->state = SCANSTATE_START;
+    if (scanner->input != NULL) {
+        free(scanner->input);
+    }
+    scanner->input = input;
+    scanner->pos = 0;
+}
+
+Scanner_Result *scanner_next_token(Scanner *scanner, Scanner_Result *result) {
+    if (scanner->state == SCANSTATE_DONE) {
+        return NULL;
+    }
+    //Consume white space
+    while (scanner_peek_char(scanner) != NULL && isblank(scanner_peek_char(scanner))) {
+        scanner->pos++;
+    }
+    //Check for end of string
+    if (scanner_peek_char(scanner) == NULL) {
+        scanner->state = SCANSTATE_DONE;
+        return NULL;
+    }
+}
+
+char scanner_next_char(Scanner *scanner) {
+    char next = scanner->input[scanner->pos];
+    if (next != NULL) {
+        scanner->pos++;
+    }
+    return next;
+}
+
+char scanner_peek_char(Scanner *scanner) {
+    return scanner->input[scanner->pos];
+}
+
+bool scanner_match(Scanner *scanner, const char *text) {
+    char a = NULL;
+    char b = NULL;
+    size_t ai = scanner->pos;
+    size_t bi = 0;
+
+    do {
+        b = text[bi++];
+        //Match if we reach the end of text
+        if (b == NULL) {
+            scanner->pos = ai; //consume text from scanner input
+            return true;
+        }
+        a = scanner->input[ai++];
+    } while (a != NULL && tolower(a) == tolower(b));
+
+    return false;
+}

src/scanner.h

@@ -0,0 +1,83 @@
+//
+// Created by Sam on 05/06/2018.
+//
+
+#ifndef SDB_SCANNER_H
+#define SDB_SCANNER_H
+
+#include <stdbool.h>
+
+enum Scanner_Token_t {
+    T_NONE,
+
+    //Values
+    T_STRING,
+    T_NUMBER,
+    T_IDENTIFIER,
+
+    //Punctuation
+    T_COMMA,
+    T_SEMICOLON,
+
+    //Comparators
+    T_COMP_EQ,
+    T_COMP_NEQ,
+    T_COMP_AND,
+
+    //Keywords
+    K_SELECT,
+    K_FROM,
+    K_INSERT,
+    K_INTO,
+    K_SET,
+    K_UPDATE,
+    K_WHERE,
+    K_DELETE,
+    K_CREATE,
+    K_TABLE,
+    K_DROP,
+    K_STRING,
+    K_INT,
+    K_INDEX
+};
+typedef enum Scanner_Token_t Scanner_Token;
+
+struct Scanner_Result_t {
+    Scanner_Token token;
+    char *value_str;
+    int value_int;
+};
+typedef struct Scanner_Result_t Scanner_Result;
+
+Scanner_Result *new_scanner_result();
+
+void free_scanner_result(Scanner_Result *result);
+
+enum Scanner_State_t {
+    SCANSTATE_START,
+    SCANSTATE_DONE
+};
+typedef enum Scanner_State_t Scanner_State;
+
+struct Scanner_t {
+    char *input;
+    size_t pos;
+    Scanner_State state;
+};
+typedef struct Scanner_t Scanner;
+
+Scanner *new_scanner(char *input);
+
+void free_scanner(Scanner *scanner);
+
+void reuse_scanner(Scanner *scanner, char *input);
+
+Scanner_Result *scanner_next_token(Scanner *scanner, Scanner_Result *result);
+
+char scanner_next_char(Scanner *scanner);
+
+char scanner_peek_char(Scanner *scanner);
+
+bool scanner_match(Scanner *scanner, const char *text);
+
+#endif //SDB_SCANNER_H