working on the debugger mode

src/debug.c

@@ -0,0 +1,255 @@
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#include <ctype.h>
+#include "debug.h"
+
+#define ANSI_COLOR_RED     "\x1b[31m"
+#define ANSI_COLOR_GREEN   "\x1b[32m"
+#define ANSI_COLOR_YELLOW  "\x1b[33m"
+#define ANSI_COLOR_BLUE    "\x1b[34m"
+#define ANSI_COLOR_MAGENTA "\x1b[35m"
+#define ANSI_COLOR_CYAN    "\x1b[36m"
+#define ANSI_COLOR_RESET   "\x1b[0m"
+
+typedef struct {
+	char *name;
+
+} BreakPoint;
+
+struct xDebug {
+
+};
+
+Debug *Debug_New()
+{
+	Debug *dbg = malloc(sizeof(Debug));
+
+	if(dbg == NULL)
+		return NULL;
+
+	// Do stuff here.
+
+	return dbg;
+}
+
+void Debug_Free(Debug *dbg)
+{
+	if(dbg)
+		free(dbg);
+}
+
+_Bool Debug_Callback(Runtime *runtime, void *userp)
+{
+	assert(runtime != NULL);
+	assert(userp != NULL);
+
+	Debug *dbg = (Debug*) userp;
+
+	char buffer[256];
+	int  length;
+
+	int argc;
+	char *argv[32];
+
+	do {
+		
+		fprintf(stderr, ANSI_COLOR_GREEN "> " ANSI_COLOR_RESET);
+
+		{
+			length = 0;
+
+			char c;
+			while((c = getc(stdin)) != '\n')
+				{
+					if(length < (int) sizeof(buffer)-1)
+						buffer[length] = c;
+				
+					length += 1;
+				}
+
+			if(length > (int) sizeof(buffer)-1)
+				{
+					fprintf(stdout, 
+						"Command is too long. The internal buffer can only contain %ld bytes.\n"
+						"Try inserting another command.\n", 
+						sizeof(buffer)-1);
+					continue;
+				}
+
+			buffer[length] = '\0';
+		}
+
+		// Now split the buffer into words in the (argc, argv) style.
+
+		{
+			argc = 0;
+
+			_Bool again = 0;
+			int curs = 0;
+			while(1)
+				{
+					// Skip whitespace.
+					while(isspace(buffer[curs]))
+						curs += 1;
+
+					if(buffer[curs] == '\0')
+						break;
+
+					int offset = curs;
+
+					while(!isspace(buffer[curs]) && buffer[curs] != '\0')
+						curs += 1;
+
+					int length = curs - offset;
+
+					assert(length > 0);
+
+					{
+						int max_argc = sizeof(argv) / sizeof(argv[0]);
+
+						if(argc == max_argc)
+							{
+								fprintf(stdout, 
+									"Command has too many words. The internal buffer can only contain %d words.\n"
+									"Try inserting another command.\n", 
+									max_argc);
+								again = 1;
+								break;
+							}
+
+						argv[argc++] = buffer + offset;
+					}
+
+					if(buffer[curs] == '\0')
+						break;
+
+					assert(isspace(buffer[curs]));
+
+					buffer[curs] = '\0';
+
+					curs += 1; // Consume the space that ended the word (not overwritten by a zero byte).
+				}
+
+			if(again)
+				continue;
+		}
+
+		if(argc == 0)
+			continue;
+
+		{
+			if(!strcmp(argv[0], "help"))
+				{
+					if(argc == 1)
+						{
+					fprintf(stderr, 
+						"help .............. Show this message\n"
+						"help <command> .... Display additional information for a given command\n"
+						"step .............. Run an instruction\n"
+						"quit .............. Stop execution\n"
+						"continue .......... Run until a breakpoint or the end of the code is reached\n"
+						"breakpoint ........ Add a breakpoint\n");
+						}
+					else if(!strcmp(argv[1], "help"))
+						{
+							fprintf(stderr, 
+								"\n"
+								"     Command | help\n"
+								"             | \n"
+								"       Usage | > help [<command>]\n"
+								"             | \n"
+								" Description | List all available commands or show detailed \n"
+								"             | information about a given command.\n"
+								"\n");
+						}
+					else if(!strcmp(argv[1], "step"))
+						{
+							fprintf(stderr, 
+								"\n"
+								"     Command | step\n"
+								"             | \n"
+								"       Usage | > step\n"
+								"             | \n"
+								" Description | Run a single instruction.\n"
+								"\n");
+						}
+					else if(!strcmp(argv[1], "quit"))
+						{
+							fprintf(stderr, 
+								"\n"
+								"     Command | quit\n"
+								"             | \n"
+								"       Usage | > quit\n"
+								"             | \n"
+								" Description | Stop the execution.\n"
+								"\n");
+						}
+					else if(!strcmp(argv[1], "continue"))
+						{
+							fprintf(stderr, 
+								"\n"
+								"     Command | continue\n"
+								"             | \n"
+								"       Usage | > continue\n"
+								"             | \n"
+								" Description | Run until a breakpoint or the end of the code is\n"
+								"             | reached.\n"
+								"\n");
+						}
+					else if(!strcmp(argv[1], "breakpoint"))
+						{
+							fprintf(stderr, 
+								"\n"
+								"     Command | breakpoint\n"
+								"             | \n"
+								"       Usage | > breakpoint <file> { line | offset | index } <N>\n"
+								"             | \n"
+								" Description | Add a breakpoint. The first argument of the command \n"
+								"             | specifies the source containing the breakpoint, while \n"
+								"             | the second one specifies the way the breakpoint is \n"
+								"             | expressed: \n"
+								"             | \n"
+								"             |       line  | by line number.\n"
+								"             |             | \n"
+								"             |     offset  | by character offset.\n"
+								"             |             | \n"
+								"             |      index  | by instruction index (relative to the \n"
+								"             |             | start of the source executable's body).\n"
+								"             | \n"
+								"             | the third argument is, based on the second one, either\n"
+								"             | a line number, a character offset or an instruction index.\n"
+								"\n");
+						}
+					else
+						{
+							fprintf(stdout, "Unknown command \"%s\".\n", argv[1]);
+						}
+				}
+			else if(!strcmp(argv[0], "breakpoint"))
+				{
+					fprintf(stderr, "Not implemented yet.\n");
+				}
+			else if(!strcmp(argv[0], "continue"))
+				{
+					fprintf(stderr, "Not implemented yet.\n");
+				}
+			else if(!strcmp(argv[0], "step"))
+				{
+					break;
+				}
+			else if(!strcmp(argv[0], "quit"))
+				{
+					return 0;
+				}
+			else
+				{
+					fprintf(stdout, "Unknown command \"%s\". Type \"help\" is you need help.\n", argv[0]);
+				}
+		}
+
+	} while(1);
+
+	return 1;
+}