<Libc> Add support for scanf to accept formatted

input

modified:   src/lib/libc/include/stdio.h
modified:   src/lib/libc/scanf.c

- Support for int, char, string, float format specifiers added for scanf
- Added gets function to accept string with spaces

Issue: #225

src/lib/libc/include/stdio.h

@@ -35,6 +35,8 @@ int fputc(const FILE *, const char);
 int fgetc(const FILE *, char *);
 char getch();
 char getchar();
+char *gets();
+int scanf(const char * restrict, ...);
 
 #ifdef _STDBOOL_H_
 int fprintf(const FILE *, bool, const char *fmt, ...);

src/lib/libc/scanf.c

@@ -15,6 +15,9 @@
 #include <ccpfs.h>
 #include <stdio.h>
 #include <stddev.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <ctype.h>
 
 int fgetc(const FILE *dev, char *c)
 {
@@ -42,3 +45,156 @@ char getchar()
     } while(temp != '\r');
     return c;
 }
+
+/**
+ * get string with spaces
+ *
+ * @brief This function will take string input with spaces
+ *
+ */
+char *gets()
+{
+	char *s = (char *)malloc(sizeof(char)), temp;
+	int i = 0;
+	do
+	{
+		temp = getch();
+		fputc(stdout, temp);
+		if(temp == '\r')
+		{
+			fputc(stdout, '\n');
+		}
+		else
+		{
+			s[i++] = temp;
+		}
+	} while(temp != '\r');
+	return s;
+}
+
+/**
+ * scanf
+ *
+ * @brief This function will take standard input for default data types.
+ *	  input will break at spaces
+ *
+ */
+
+#define CURRCHAR (temp)
+#define CHARIN() (temp = getch())
+int scanf(const char * restrict fmt, ...)
+{
+	unsigned int count = 0;
+	char c = '0', temp;
+	va_list ap;
+	va_start(ap, fmt);
+	while (*fmt)
+	{
+		if (*fmt == '%')
+		{
+			fmt++;
+			/* char length : %7d */
+			unsigned int cl = 0;
+			while (isDigit(*fmt))
+			{
+				cl *= 10;
+				cl += *fmt++ - '0';
+			}
+			switch (*fmt++)
+			{
+				case 'c':
+				{
+					/* skip leading spaces */
+					while (isSpace(CHARIN()))
+					{
+						if (CURRCHAR == '\r')
+							fputc(stdout, '\n');
+						else
+							fputc(stdout, CURRCHAR);
+					}
+					fputc(stdout, CURRCHAR);
+					c = CURRCHAR;
+					while (CHARIN())
+					{
+						fputc(stdout, CURRCHAR);
+						if (isSpace(CURRCHAR))
+							break;
+					}
+					fputc(stdout, '\n');
+					*(char *)va_arg(ap, char *) = c;
+					count++;
+					break;
+				}
+				case 's':
+				{
+					char *s = va_arg(ap, char *);
+					/* skip leading spaces */
+					while (isSpace(CHARIN()))
+					{
+						if (CURRCHAR == '\r')
+							fputc(stdout, '\n');
+						else
+							fputc(stdout, CURRCHAR);
+					}
+					fputc(stdout, CURRCHAR);
+					*s++ = CURRCHAR;
+					while (CHARIN())
+					{
+						fputc(stdout, CURRCHAR);
+						if (isSpace(CURRCHAR))
+							break;
+						*s++ = CURRCHAR;
+					}
+					fputc(stdout, '\n');
+					*s = '\0';
+					count++;
+					break;
+				}
+				case 'u':
+				case 'd':
+				{
+					int a = 0;
+					/* skip leading spaces */
+					while (isSpace(CHARIN()))
+					{
+						if (CURRCHAR == '\r')
+							fputc(stdout, '\n');
+						else
+							fputc(stdout, CURRCHAR);
+					}
+					fputc(stdout, CURRCHAR);
+					c = CURRCHAR;
+					while (CHARIN())
+					{
+						a *= 10;
+						if (isDigit(c))
+							a += (c - '0');
+						else
+							a += (int)c;
+						if (isSpace(CURRCHAR))
+							break;
+						c = CURRCHAR;
+						fputc(stdout, CURRCHAR);
+					}
+					fputc(stdout, '\n');
+					*(int *)va_arg(ap, int *) = a;
+					count++;
+					break;
+				}
+				case 'f':
+				{
+					char *a = gets();
+					*(float *)va_arg(ap, float *) = (float)atof(a);
+					count++;
+					break;
+				}
+				default:
+					break;
+			}
+			continue;
+		}
+		/* increment pointer if % not found */
+		fmt++;
+	}
+	return count;
+}