implemented strings

src/strings/Makefile

@@ -0,0 +1,5 @@
+OUT := strings
+
+SRC := strings.c
+
+include ../shared.mk

src/strings/strings.1

@@ -0,0 +1 @@
+\" TODO

src/strings/strings.c

@@ -0,0 +1,147 @@
+#include <ctype.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define NAME "strings (canoutils)"
+#define VERSION "0.0.1"
+#define AUTHOR "cospplredman"
+
+#include "cgetopt.h"
+#include "version_info.h"
+
+static const char usage[] = {
+    "Usage: strings [Option]... [File]...\n"
+    "  --version   version information\n"
+    "  --help      display this help and exit\n"
+    "  -a          scan files in their entirety\n"
+    "  -n NUMBER   specify minimum string length\n"
+    "  -t FORMAT   write each string with its byte offset\n"
+    "                o  offset is in octal\n"
+    "                x  offset is in hex\n"
+    "                d  offset is in decimal\n"};
+
+// flags
+static int long_output = 0;
+static int output_format = 't';
+static size_t string_length = 4;
+
+static struct option long_options[] = {
+    {"version", no_argument, NULL, 'v'},
+    {"help", no_argument, NULL, 'h'},
+};
+
+static void strings(FILE *file) {
+  size_t offset = 0;
+  size_t ngraph = 0;
+  int cur_char;
+  char *buf = malloc(string_length + 1);
+  buf[string_length] = 0;
+
+  while ((cur_char = getc(file)) != EOF) {
+    if ((isgraph(cur_char) || isspace(cur_char)) && cur_char != '\n') {
+      buf[ngraph] = cur_char;
+      ngraph++;
+    }
+
+    if (ngraph > string_length) {
+      if (long_output) {
+        switch (output_format) {
+        case 'o':
+          printf("%lo ", offset);
+          break;
+        case 'x':
+          printf("%lx ", offset);
+          break;
+        case 'd':
+          printf("%lu ", offset);
+          break;
+        }
+      }
+
+      printf("%s", buf);
+      while ((isgraph(cur_char = getc(file)) || isspace(cur_char)) &&
+             cur_char != '\n') {
+        putchar(cur_char);
+        offset++;
+      }
+      putchar('\n');
+      ngraph = 0;
+    }
+
+    offset++;
+  }
+
+  free(buf);
+}
+
+int main(int argc, char **argv) {
+  int opt, option_index;
+  while ((opt = getopt_long(argc, argv, "an:t:", long_options,
+                            &option_index)) != -1) {
+    switch (opt) {
+    case 0:
+      break;
+    case 'v':
+      print_version();
+      return EXIT_SUCCESS;
+      break;
+    case 'h':
+      printf("%s\n", usage);
+      return EXIT_SUCCESS;
+    case 'a': // default
+      break;
+    case 'n':
+      if (sscanf(optarg, "%lu", &string_length) != 1) {
+        fprintf(stderr, "strings: -n: expected positive decimal number\n");
+        return EXIT_FAILURE;
+      }
+      break;
+    case 't':
+      if (optarg[1] != '\0') {
+        fprintf(stderr,
+                "strings: -t: expected one of 'o', 'x', 'd'. got `%s`\n",
+                optarg);
+        return EXIT_FAILURE;
+      }
+      switch (optarg[0]) {
+      case 'o':
+      case 'x':
+      case 'd':
+        output_format = optarg[0];
+        break;
+      default:
+        fprintf(stderr,
+                "strings: -t: expected one of 'o', 'x', 'd'. got `%s`\n",
+                optarg);
+        return EXIT_FAILURE;
+      }
+      long_output = 1;
+      break;
+    }
+  }
+
+  argc -= optind;
+  argv += optind;
+
+  int index = 0;
+
+  if (argc < 1) {
+    strings(stdin);
+    return EXIT_SUCCESS;
+  }
+
+  for (; index < argc; index++) {
+    FILE *file = fopen(argv[index], "r+");
+
+    if (file == NULL) {
+      fprintf(stderr, "strings: %s: %s\n", argv[index], strerror(errno));
+      continue;
+    }
+
+    strings(file);
+    fclose(file);
+  }
+}