asciisearch

commit ba9d46cf86de6e89d1e66b6c69d98705205ee1fc
Author: Stephanos Pavlou <steph@stephanospavlou.info>
Date:   Fri, 22 Mar 2024 12:41:58 -0600

intial commit

Diffstat:
A
asciisearch.c
 | 
123
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 123 insertions(+), 0 deletions(-)
diff --git a/asciisearch.c b/asciisearch.c
@@ -0,0 +1,123 @@
+/*
+**    asciisearch.c
+**    Author: Stephanos Pavlou
+**    Small utility for ascii string search (including control characters). 
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define VERSION "0.1.0"
+#define ESC_CHAR '+'
+
+unsigned char *encode_pattern(char *pattern, int *len);
+int search_for_pattern(unsigned char *pattern, int len, char *file_name);
+
+char *usage_msg =
+"asciisearch-"VERSION"\n"
+"Usage: asciisearch [pattern] [file]\n";
+
+char *ctrl_char_code[] = {
+    "^A", "^B", "^C", "^D", "^E", "^F",
+    "^G", "^H", "^I", "^J", "^K", "^L",
+    "^M", "^N", "^O", "^P", "^Q", "^R",
+    "^S", "^T", "^U", "^V", "^W", "^X",
+    "^Y", "^Z", "^@", "^[", "^\\", "^]",
+    "^^", "^_", "^?"
+};
+
+unsigned char ctrl_char[] = {
+    0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
+    0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c,
+    0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12,
+    0x13, 0x14, 0x15, 0x16, 0x17, 0x18,
+    0x19, 0x1a, 0x00, 0x1b, 0x1c, 0x1d,
+    0x1e, 0x1f, 0x7f
+};
+
+int
+main(int argc, char **argv) {
+    if (argc != 3) {
+        printf("%s", usage_msg);
+        return 0;
+    }
+    
+    int *len= malloc(sizeof(int));
+    unsigned char *pattern = encode_pattern(argv[1], len);
+    printf("encoded pattern: ");
+    for (int i = 0; i < *len; i++) {
+        fputc(pattern[i], stdout);
+    }
+    printf("\n");
+    return search_for_pattern(pattern, *len, argv[2]);
+}
+
+unsigned char *
+encode_pattern(char *pattern, int *len) {
+    *len = 0;
+    unsigned char *result = NULL;
+    for (int i = 0; i < strlen(pattern); i++) {
+        if (pattern[i] == '^') {
+            for (int j = 0; j < 33; j++) {
+                if (strstr(pattern + i, ctrl_char_code[j])
+                        == pattern + i) {
+                    result = realloc(result,
+                        sizeof(unsigned char) * ++(*len));
+                    result[*len - 1] = ctrl_char[j];
+                    i++;
+                    break;
+                }
+            } 
+        } else if (i + 1 < strlen(pattern) && 
+            (pattern[i] == ESC_CHAR && pattern[i + 1] == '^')) {
+            for (int j = 0; j < 33; j++) {
+                if (i + 1 < strlen(pattern) && 
+                    (strstr(pattern + i, ctrl_char_code[j])
+                        == pattern + (i + 1))) {
+                    result = realloc(result,
+                        sizeof(unsigned char) * ++(*len));
+                    result[*len - 1] = pattern[i + 1];
+                    i++;
+                    break;
+                }
+            }
+        } else {
+            result = realloc(result,
+                sizeof(unsigned char) * ++(*len));
+            result[*len - 1] = pattern[i];
+        }
+    }
+
+    return result;
+}
+
+int
+search_for_pattern(unsigned char *pattern, int len, 
+        char *file_name) {
+    int ret = 1;
+    FILE *fp = fopen(file_name, "r");
+    if (fp == NULL) {
+        return ret;
+    }
+
+    int c;
+    while ((c = fgetc(fp)) != EOF) {
+        if (c == (int)pattern[0]) {
+            int found = 1;
+            for (int i = 1; i < len && (c = fgetc(fp)) != EOF; i++) {
+                if ((int)pattern[i] != c) {
+                    found = 0;
+                    break;
+                } 
+            }
+            if (c != EOF && found == 1) {
+                ret = 0;
+                break;
+            }
+        }
+    }
+    
+    fclose(fp);
+    return ret;
+}