new file mode 100644
--- /dev/null
+++ b/src/core/ngx_string.c
@@ -0,0 +1,284 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+u_char *ngx_cpystrn(u_char *dst, u_char *src, size_t n)
+{
+    if (n == 0) {
+        return dst;
+    }
+
+    for (/* void */; --n; dst++, src++) {
+        *dst = *src;
+
+        if (*dst == '\0') {
+            return dst;
+        }
+    }
+
+    *dst = '\0';
+
+    return dst;
+}
+
+
+ngx_int_t ngx_rstrncmp(u_char *s1, u_char *s2, size_t n)
+{
+    if (n == 0) {
+        return 0;
+    }
+
+    n--;
+
+    for ( ;; ) {
+        if (s1[n] != s2[n]) {
+            return s1[n] - s2[n];
+        }
+
+        if (n == 0) {
+            return 0;
+        }
+
+        n--;
+    }
+}
+
+
+ngx_int_t ngx_atoi(u_char *line, size_t n)
+{
+    ngx_int_t  value;
+
+    if (n == 0) {
+        return NGX_ERROR;
+    }
+
+    for (value = 0; n--; line++) {
+        if (*line < '0' || *line > '9') {
+            return NGX_ERROR;
+        }
+
+        value = value * 10 + (*line - '0');
+    }
+
+    if (value < 0) {
+        return NGX_ERROR;
+
+    } else {
+        return value;
+    }
+}
+
+
+ngx_int_t ngx_hextoi(u_char *line, size_t n)
+{
+    u_char     ch;
+    ngx_int_t  value;
+
+    if (n == 0) {
+        return NGX_ERROR;
+    }
+
+    for (value = 0; n--; line++) {
+        ch = *line;
+
+        if (ch >= '0' && ch <= '9') {
+            value = value * 16 + (ch - '0');
+            continue;
+        }
+
+        if (ch >= 'A' && ch <= 'F') {
+            value = value * 16 + (ch - 'A' + 10);
+            continue;
+        }
+
+        if (ch >= 'a' && ch <= 'f') {
+            value = value * 16 + (ch - 'a' + 10);
+            continue;
+        }
+
+        return NGX_ERROR;
+    }
+
+    if (value < 0) {
+        return NGX_ERROR;
+
+    } else {
+        return value;
+    }
+}
+
+
+void ngx_md5_text(u_char *text, u_char *md5)
+{
+    int            i;
+    static u_char  hex[] = "0123456789abcdef";
+
+    for (i = 0; i < 16; i++) {
+        *text++ = hex[md5[i] >> 4];
+        *text++ = hex[md5[i] & 0xf];
+    }
+
+    *text = '\0';
+}
+
+
+void ngx_encode_base64(ngx_str_t *src, ngx_str_t *dst)
+{
+    u_char         *d, *s;
+    size_t          len;
+    static u_char   basis64[] =
+            "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+    len = src->len;
+    s = src->data;
+    d = dst->data;
+
+    while (len > 2) {
+        *d++ = basis64[(s[0] >> 2) & 0x3f];
+        *d++ = basis64[((s[0] & 3) << 4) | (s[1] >> 4)];
+        *d++ = basis64[((s[1] & 0x0f) << 2) | (s[2] >> 6)];
+        *d++ = basis64[s[2] & 0x3f];
+
+        s += 3;
+        len -= 3;
+    }
+
+    if (len) {
+        *d++ = basis64[(s[0] >> 2) & 0x3f];
+
+        if (len == 1) {
+            *d++ = basis64[(s[0] & 3) << 4];
+            *d++ = '=';
+
+        } else {
+            *d++ = basis64[((s[0] & 3) << 4) | (s[1] >> 4)];
+            *d++ = basis64[(s[1] & 0x0f) << 2];
+        }
+
+        *d++ = '=';
+    }
+
+    dst->len = d - dst->data;
+}
+
+
+ngx_int_t ngx_decode_base64(ngx_str_t *src, ngx_str_t *dst)
+{
+    size_t          len;
+    u_char         *d, *s;
+    static u_char   basis64[] =
+        { 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+          77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+          77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 62, 77, 77, 77, 63,
+          52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 77, 77, 77, 77, 77, 77,
+          77,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
+          15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 77, 77, 77, 77, 77,
+          77, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+          41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 77, 77, 77, 77, 77,
+
+          77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+          77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+          77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+          77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+          77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+          77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+          77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+          77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77 };
+
+    for (len = 0; len < src->len; len++) {
+        if (src->data[len] == '=') {
+            break;
+        }
+
+        if (basis64[src->data[len]] == 77) {
+            return NGX_ERROR;
+        }
+    }
+
+    if (len % 4 == 1) {
+        return NGX_ERROR;
+    }
+
+    s = src->data;
+    d = dst->data;
+
+    while (len > 3) {
+        *d++ = (u_char) (basis64[s[0]] << 2 | basis64[s[1]] >> 4);
+        *d++ = (u_char) (basis64[s[1]] << 4 | basis64[s[2]] >> 2);
+        *d++ = (u_char) (basis64[s[2]] << 6 | basis64[s[3]]);
+
+        s += 4;
+        len -= 4;
+    }
+
+    if (len > 1) {
+        *d++ = (u_char) (basis64[s[0]] << 2 | basis64[s[1]] >> 4);
+    }
+
+    if (len > 2) {
+        *d++ = (u_char) (basis64[s[1]] << 4 | basis64[s[2]] >> 2);
+    }
+
+    dst->len = d - dst->data;
+
+    return NGX_OK;
+}
+
+
+#if 0
+char *ngx_psprintf(ngx_pool_t *p, const char *fmt, ...)
+{
+    va_list    args;
+
+    va_start(args, fmt);
+
+    while (*fmt) {
+         switch(*fmt++) {
+         case '%':
+             switch(*fmt++) {
+             case 's':
+                 s = va_arg(args, char *);
+                 n += ngx_strlen(s);
+                 break;
+
+             default:
+                 n++;
+         }
+         default:
+             n++;
+         }
+    }
+
+    str = ngx_palloc(p, n);
+
+    va_start(args, fmt);
+
+    for (i = 0; i < n; i++) {
+         switch(*fmt++) {
+         case '%':
+             switch(*fmt++) {
+             case 's':
+                 s = va_arg(args, char *);
+                 while (str[i++] = s);
+                 break;
+
+             default:
+                 n++;
+         }
+         default:
+             str[i] = *fmt;
+         }
+    }
+
+    len += ngx_vsnprintf(errstr + len, sizeof(errstr) - len - 1, fmt, args);
+
+    va_end(args);
+
+}
+#endif