Added strings

1 files changed, 90 insertions, 0 deletions

diff --git a/src/strings.c b/src/strings.c
new file mode 100644
index 0000000..a2349bd
--- /dev/null
+++ b/src/strings.c
@@ -0,0 +1,90 @@
+#define _POSIX_C_SOURCE 200809L
+#define _XOPEN_SOURCE 500
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <ctype.h>
+
+static bool valid_char(int c)
+{
+	return isprint(c) || c == ' ' || c == '\t';
+}
+
+static size_t g_min_len = 4;
+static char   g_offset_format = -1;
+static char   *g_buf = NULL;
+
+static void strings(FILE *file)
+{
+	size_t buf_offset = 0;
+	int c;
+	while ((c = fgetc(file)) != EOF)
+	{
+		if (valid_char(c))
+		{
+			if (buf_offset < g_min_len - 1)
+			{
+				g_buf[buf_offset] = c;
+				buf_offset++;
+			}
+			else
+			{
+				switch (g_offset_format)
+				{
+					case 'd': printf("%7ld ", ftell(file) - g_min_len); break;
+					case 'o': printf("%7lo ", ftell(file) - g_min_len); break;
+					case 'x': printf("%7lx ", ftell(file) - g_min_len); break;
+				}
+				fwrite(g_buf, sizeof(char), buf_offset, stdout);
+				buf_offset = 0;
+				fputc(c, stdout);
+				int c2;
+				while ((c2 = fgetc(file)) != EOF && valid_char(c2))
+					fputc(c2, stdout);
+				fputc('\n', stdout);
+			}
+		}
+		else
+			buf_offset = 0;
+	}
+}
+
+int main(int argc, char **argv)
+{
+	int option;
+	while ((option = getopt(argc, argv, "an:t:")) != -1)
+	{
+		switch (option)
+		{
+			case 'a':
+				break;
+			case 'n':
+				sscanf(optarg, "%lu", &g_min_len);
+				break;
+			case 't':
+				g_offset_format = optarg[0];
+				break;
+		}
+	}
+	g_buf = malloc(sizeof(char) * g_min_len);
+	if (g_buf == NULL)
+		exit(1);
+	if (optind == argc)
+	{
+		strings(stdin);
+		free(g_buf);
+		return 0;
+	}
+	for (; optind < argc; optind++)
+	{
+		FILE *file = fopen(argv[optind], "r");
+		if (file == NULL)
+			continue;
+		strings(file);
+		fclose(file);
+	}
+	free(g_buf);
+	return 0;
+}