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| /* |
| * Tiny BASIC |
| * Error Handling Module |
| * |
| * Released as Public Domain by Damian Gareth Walker 2019 |
| * Created: 18-Aug-2019 |
| */ |
| |
| |
| /* included headers */ |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include "errors.h" |
| |
| |
| /* |
| * Internal Data Structures |
| */ |
| |
| |
| /* Private data */ |
| typedef struct { |
| ErrorCode error; /* the last error encountered */ |
| int line; /* the source line on which the error occurred */ |
| int label; /* the label for the source line */ |
| } Private; |
| |
| |
| /* |
| * Internal Data |
| */ |
| |
| |
| /* convenience variables */ |
| ErrorHandler *this; /* object being worked on */ |
| Private *data; /* private data of object being worked on */ |
| |
| /* global variables */ |
| static char *messages[E_LAST] = { /* the error messages */ |
| "Successful", |
| "Invalid line number", |
| "Unrecognised command", |
| "Invalid variable", |
| "Invalid assignment", |
| "Invalid expression", |
| "Missing )", |
| "Invalid PRINT output", |
| "Bad command line", |
| "File not found", |
| "Invalid operator", |
| "THEN expected", |
| "Unexpected parameter", |
| "RETURN without GOSUB", |
| "Divide by zero", |
| "Overflow", |
| "Out of memory", |
| "Too many gosubs" |
| }; |
| |
| |
| /* |
| * Public Methods |
| */ |
| |
| |
| /* |
| * Record an error encountered |
| * globals: |
| * ErrorCode error the last error encountered |
| * int line the source line |
| * int label the line's label |
| * params: |
| * ErrorCode new_error the error code to set |
| * int new_line the source line to set |
| * int new_label the label to set |
| */ |
| static void set_code (ErrorHandler *errors, ErrorCode new_error, int new_line, |
| int new_label) { |
| |
| /* initialise */ |
| this = errors; |
| data = this->data; |
| |
| /* set the properties */ |
| data->error = new_error; |
| data->line = new_line; |
| data->label = new_label; |
| } |
| |
| /* |
| * Return the last error code encountered |
| * params: |
| * ErrorHandler* errors the error handler |
| * returns: |
| * ErrorCode the last error encountered |
| */ |
| static ErrorCode get_code (ErrorHandler *errors) { |
| this = errors; |
| data = this->data; |
| return data->error; |
| } |
| |
| /* |
| * Return the last error line encountered |
| * params: |
| * ErrorHandler* errors the error handler |
| * returns: |
| * int the source line of the last error |
| */ |
| static int get_line (ErrorHandler *errors) { |
| this = errors; |
| data = this->data; |
| return data->line; |
| } |
| |
| /* |
| * Return the last error label encountered |
| * params: |
| * ErrorHandler* errors the error handler |
| * returns: |
| * int the line label of the last error |
| */ |
| static int get_label (ErrorHandler *errors) { |
| this = errors; |
| data = this->data; |
| return data->label; |
| } |
| |
| /* |
| * Generate an error message |
| * params: |
| * ErrorHandler* errors the error handler |
| * globals: |
| * char* messages a list of error messages |
| * returns: |
| * char* the full error message |
| */ |
| static char *get_text (ErrorHandler *errors) { |
| |
| /* local variables */ |
| char |
| *message, /* the complete message */ |
| *line_text, /* source line N */ |
| *label_text; /* label N */ |
| |
| /* initialise the error object */ |
| this = errors; |
| data = this->data; |
| |
| /* get the source line, if there is one */ |
| line_text = malloc (20); |
| if (data->line) |
| sprintf (line_text, ", source line %d", data->line); |
| else |
| strcpy (line_text, ""); |
| |
| /* get the source label, if there is one */ |
| label_text = malloc (19); |
| if (data->label) |
| sprintf (label_text, ", line label %d", data->label); |
| else |
| strcpy (label_text, ""); |
| |
| /* put the error message together */ |
| message = malloc (strlen (messages[data->error]) + strlen (line_text) |
| + strlen (label_text) + 1); |
| strcpy (message, messages[data->error]); |
| strcat (message, line_text); |
| strcat (message, label_text); |
| free (line_text); |
| free (label_text); |
| |
| /* return the assembled error message */ |
| return message; |
| } |
| |
| /* |
| * ErrorHandler destructor |
| * params: |
| * ErrorHandler* errors the doomed error handler |
| */ |
| static void destroy (ErrorHandler *errors) { |
| if ((this = errors)) { |
| data = this->data; |
| free (data); |
| free (this); |
| } |
| } |
| |
| |
| /* |
| * Constructors |
| */ |
| |
| |
| /* |
| * Principal constructor |
| * returns: |
| * ErrorHandler* the new error handler object |
| */ |
| ErrorHandler *new_ErrorHandler (void) { |
| |
| /* allocate memory */ |
| this = malloc (sizeof (ErrorHandler)); |
| this->data = data = malloc (sizeof (Private)); |
| |
| /* initialise the methods */ |
| this->set_code = set_code; |
| this->get_code = get_code; |
| this->get_line = get_line; |
| this->get_label = get_label; |
| this->get_text = get_text; |
| this->destroy = destroy; |
| |
| /* initialise the properties */ |
| data->error = E_NONE; |
| data->line = 0; |
| data->label = 0; |
| |
| /* return the new object */ |
| return this; |
| } |