From 83cd2267b309fa7411acaed356f88101196bb2ad Mon Sep 17 00:00:00 2001
From: Aleksey Veresov <aleksey@veresov.pro>
Date: Thu, 6 Feb 2020 19:43:57 +0300
Subject: [magi] Broken to become better.

---
 src/urlencoded.c | 144 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 144 insertions(+)
 create mode 100644 src/urlencoded.c

(limited to 'src/urlencoded.c')

diff --git a/src/urlencoded.c b/src/urlencoded.c
new file mode 100644
index 0000000..e3ea56a
--- /dev/null
+++ b/src/urlencoded.c
@@ -0,0 +1,144 @@
+#include "inner_urlencoded.h"
+
+#include "inner_tools.h"
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Local Shortcuts
+ */
+/* Call only if is_hex(c). */
+static int from_hex(char c)
+{
+    if (isdigit(c)) {
+        return c - '0';
+    } else {
+        return toupper(c) - 'A' + 10;
+    }
+}
+
+static int is_hex(char c)
+{
+    return isdigit(c) || strchr("ABCDEF", toupper(c));
+}
+
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * URL Decoding
+ */
+static int deurl(char ** data)
+{
+    char * val = *data;
+    int    ti;
+    int    ci;
+    if (!val) {
+        *data  = malloc(1);
+        **data = 0;
+        return 1;
+    }
+    for (ti = 0, ci = 0; val[ci]; ++ti, ++ci) {
+        if (val[ci] == '%') {
+            if (is_hex(val[ci + 1]) && is_hex(val[ci + 2])) {
+                /* Since chars can be signed, arithmetics are not safe. */
+                val[ti] = from_hex(val[ci + 2]);       /* 0000xxxx */
+                val[ti] |= from_hex(val[ci + 1]) << 4; /* XXXXxxxx */
+                ci += 2; /* Two extra characters are readed from code. */
+            } else {
+                return 0;
+            }
+        } else if (val[ci] == '+') {
+            val[ti] = ' ';
+        } else {
+            val[ti] = val[ci];
+        }
+    }
+    val[ti] = 0;
+    return 1;
+}
+
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Urlencoded Automata
+ */
+enum st { st_error = 0, st_name, st_data };
+
+struct automata {
+    struct magi_param_list ** list;
+    struct magi_param         param;
+    int                       size;
+    int                       len;
+};
+
+
+static enum st parse_name(struct automata * a, char c)
+{
+    if (c == '&' || c == ';') { /* Impossible character means error. */
+        return st_error;
+    }
+    if (c == '=') { /* Separator ends name. */
+        a->size = 1;
+        a->len  = 0;
+        return st_data;
+    }
+
+    if (!magi_str_add(&a->param.name, &a->len, &a->size, c)) {
+        return st_error;
+    }
+    return st_name;
+}
+
+static enum st end_data(struct automata * a)
+{
+    if (deurl(&a->param.name) && deurl(&a->param.data)) {
+        if (magi_param_list_add(a->list, &a->param)) {
+            a->size       = 1;
+            a->len        = 0;
+            a->param.name = 0;
+            a->param.data = 0;
+            return st_name;
+        }
+    }
+    return st_error;
+}
+
+static enum st parse_data(struct automata * a, char c)
+{
+    if (c == '=') { /* Impossible character means error. */
+        return st_error;
+    }
+    if (c == '&' || c == ';') { /* Separator ends data. */
+        return end_data(a);
+    }
+
+    if (!magi_str_add(&a->param.data, &a->len, &a->size, c)) {
+        return st_error;
+    }
+    return st_data;
+}
+
+void magi_urlencoded(struct magi_param_list ** list,
+                     struct magi_request *     request,
+                     const char *              encoded)
+{
+    enum st         state;
+    struct automata a = { 0, { 0, 0 }, 1, 0 };
+    a.list            = list;
+    *list             = 0;
+    if (!encoded || !*encoded) {
+        return;
+    }
+    for (state = st_name; state && *encoded; ++encoded) {
+        if (state == st_name) {
+            state = parse_name(&a, *encoded);
+        } else {
+            state = parse_data(&a, *encoded);
+        }
+    }
+    if (state == st_name || !state || !end_data(&a)) {
+        free(a.param.name);
+        free(a.param.data);
+        request->error = magi_error_urlenc;
+    }
+}
-- 
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