Revert "tweak: move things around"

This reverts commit ca59138a2aef96960381f986b8c683634e4d8e63.

7 files changed, 192 insertions, 0 deletions

diff --git a/plugins/libre_redirect/README.md b/plugins/libre_redirect/README.md
new file mode 100644
index 0000000..f3f58c9
--- /dev/null
+++ b/plugins/libre_redirect/README.md
@@ -0,0 +1,3 @@
+## About
+
+This code automatically redirects webpage to their open-source frontends. It is based on <https://libredirect.codeberg.page/>
\ No newline at end of file
diff --git a/plugins/libre_redirect/libre_redirect.c b/plugins/libre_redirect/libre_redirect.c
new file mode 100644
index 0000000..3794add
--- /dev/null
+++ b/plugins/libre_redirect/libre_redirect.c
@@ -0,0 +1,84 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "str_replace_start.h"
+
+#define LIBRE_N 19
+
+/* Uncomment for debug */
+/* #define DEBUG */
+
+/* Inspired by https://libredirect.github.io/, but in C. */
+
+void str_init(char* str, int n)
+{
+    for (int i = 0; i < n; i++)
+        str[i] = ' ';
+    str[n] = '\0';
+} // could also use <https://manpages.ubuntu.com/manpages/impish/man3/strinit.3pub.html>
+
+int libre_redirect(const char* uri, char* output)
+{
+    int l1 = strlen(uri);
+    int l2 = strlen(output);
+    int len;
+    char tmp_uri[l2++];
+    char tmp_output[l2++];
+
+    if ((l2 - l1) < LIBRE_N) {
+#ifdef DEBUG
+        printf("Not enough memory\n");
+#endif
+        return 1; // not enough memory.
+    } else {
+        strcpy(tmp_uri, uri); // strcpy also copies the terminating '\0'
+        strcpy(tmp_output, output);
+
+        char* annoying_sites[] = {
+            "https://www.youtube.com",
+            "https://www.reddit.com",
+            "https://medium.com",
+            "https://translate.google.com",
+            // "https://forum.effectivealtruism.org",
+            "https://www.bloomberg.com",
+            "https://twitter.com"
+        };
+
+        char* alternatives[] = {
+            "https://yt.artemislena.eu",
+            "https://teddit.nunosempere.com",
+            "https://scribe.rip",
+            "https://simplytranslate.org/",
+            // "https://ea.greaterwrong.com",
+            "https://archive.is/https://www.bloomberg.com",
+            "https://nitter.net"
+        };
+
+        len = sizeof(annoying_sites) / sizeof(annoying_sites[0]);
+
+        for (int i = 0; i < len; i++) {
+            int replace_check = str_replace_start(tmp_uri, annoying_sites[i],
+                alternatives[i], output);
+            if (replace_check == 2) {
+#ifdef DEBUG
+                printf("tmp_uri: %s\n", tmp_uri);
+                printf("output: %s\n", output);
+#endif
+                return 2;
+            } else if (replace_check == 1) {
+#ifdef DEBUG
+                printf("replace_check failed\n");
+#endif
+                return 1;
+            }
+            strcpy(tmp_uri, output);
+            str_init(output, l2);
+        }
+        strcpy(output, tmp_uri);
+    }
+#ifdef DEBUG
+    printf("No match found\n\n");
+#endif
+    return 0;
+}
diff --git a/plugins/libre_redirect/libre_redirect.h b/plugins/libre_redirect/libre_redirect.h
new file mode 100644
index 0000000..150c95e
--- /dev/null
+++ b/plugins/libre_redirect/libre_redirect.h
@@ -0,0 +1,6 @@
+#pragma once
+
+#define LIBRE_N 19
+
+int libre_redirect(const char* uri, char* uri_filtered);
+void str_init(char* str, int n);
diff --git a/plugins/libre_redirect/str_replace_start.c b/plugins/libre_redirect/str_replace_start.c
new file mode 100644
index 0000000..d1fe083
--- /dev/null
+++ b/plugins/libre_redirect/str_replace_start.c
@@ -0,0 +1,65 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+#define DEBUG false
+
+/*
+See also:
+* <https://web.archive.org/web/20160201212501/coding.debuntu.org/c-implementing-str_replace-replace-all-occurrences-substring>
+* https://github.com/irl/la-cucina/blob/master/str_replace.c
+*/
+
+int str_replace_start(const char* string, const char* target, const char* replacement, char* output)
+{
+    int l1 = strlen(string);
+    int l2 = strlen(target);
+    int l3 = strlen(replacement);
+    int l4 = strlen(output);
+    if (DEBUG)
+        printf("%d,%d,%d,%d\n", l1, l2, l3, l4);
+    // if(DEBUG) printf("%s,%s,%s,%s\n", string, target, replacement, output);
+
+    if ((l4 < (l1 - l2 + l3)) || l4 < l1) {
+        // Not enough memory in output string.
+        if (DEBUG)
+            printf("String not long enough.\n");
+        return 1;
+    }
+    /* else if(l1 < l2){
+    // Not even possible that there is a match.
+    if(DEBUG) printf("Target larger than string.\n");
+    strcpy(output, string);
+  } */
+    else {
+        if (DEBUG)
+            printf("Looking for a match for %s in %s.\n", target, string);
+        int match = true;
+        for (int i = 0; i < l2; i++) {
+            if (string[i] != target[i]) {
+                match = false;
+                break;
+            }
+        }
+        if (match) {
+            if (DEBUG)
+                printf("Found match.\n");
+            for (int i = 0; i < l3; i++) {
+                output[i] = replacement[i];
+            }
+            int counter = l3;
+            for (int i = l2; i < l1; i++) {
+                output[counter] = string[i];
+                counter++;
+            }
+            output[counter] = '\0';
+            return 2; // success
+        } else {
+            if (DEBUG)
+                printf("Did not find match.\n");
+            strcpy(output, string);
+        }
+    }
+
+    return 0;
+}
diff --git a/plugins/libre_redirect/str_replace_start.h b/plugins/libre_redirect/str_replace_start.h
new file mode 100644
index 0000000..78c79b5
--- /dev/null
+++ b/plugins/libre_redirect/str_replace_start.h
@@ -0,0 +1,4 @@
+#pragma once
+
+int str_replace_start(const char* string, const char* target,
+		      const char* replacement, char* output);
diff --git a/plugins/libre_redirect/str_replace_test/build-example.sh b/plugins/libre_redirect/str_replace_test/build-example.sh
new file mode 100644
index 0000000..a9f8022
--- /dev/null
+++ b/plugins/libre_redirect/str_replace_test/build-example.sh
@@ -0,0 +1,11 @@
+#!/bin/bash
+CC=gcc
+
+FLAGS="-std=c99 -Wall -lm"
+
+SRC=example.c
+REQS="../str_replace_start.c ../libre_redirect.c"
+
+echo -e "\n\n\n"
+$CC $FLAGS $SRC $REQS -o example
+
diff --git a/plugins/libre_redirect/str_replace_test/example.c b/plugins/libre_redirect/str_replace_test/example.c
new file mode 100644
index 0000000..b93634a
--- /dev/null
+++ b/plugins/libre_redirect/str_replace_test/example.c
@@ -0,0 +1,19 @@
+#include "../libre_redirect.h"
+#include <stdio.h>
+#include <string.h>
+
+int main()
+{
+    char uri[] = "https://reddit.com/r/blah";
+
+    int l = LIBRE_N + strlen(uri) + 1;
+    char uri_filtered[l];
+    str_init(uri_filtered, l);
+
+    if (!libre_redirect(uri, uri_filtered)) {
+        printf("Filtered uri: %s\n", uri_filtered);
+    } else {
+        printf("Uri: %s\n", uri);
+        // failure; do something with the original uri.
+    }
+}