stream_memory: add hex:// protocol

Completely useless, expect for some special purposes.

DOCS/man/mpv.rst

@@ -715,6 +715,9 @@ PROTOCOLS
 ``memory://data``
     Use the ``data`` part as source data.
 
+``hex://data``
+    Like ``memory://``, but the string is interpreted as hexdump.
+
 PSEUDO GUI MODE
 ===============
 

stream/stream_memory.c

@@ -55,6 +55,32 @@ static int control(stream_t *s, int cmd, void *arg)
     return STREAM_UNSUPPORTED;
 }
 
+static int h_to_i(unsigned char c)
+{
+    if (c >= '0' && c <= '9')
+        return c - '0';
+    if (c >= 'a' && c <= 'f')
+        return c - 'a' + 10;
+    if (c >= 'A' && c <= 'F')
+        return c - 'A' + 10;
+    return -1;
+}
+
+static bool bstr_to_hex_inplace(bstr *h)
+{
+    if (h->len % 2)
+        return false;
+    for (int n = 0; n < h->len / 2; n++) {
+        int hi = h_to_i(h->start[n * 2 + 0]);
+        int lo = h_to_i(h->start[n * 2 + 1]);
+        if (hi < 0 || lo < 0)
+            return false;
+        h->start[n] = (hi << 4) | lo;
+    }
+    h->len /= 2;
+    return true;
+}
+
 static int open_f(stream_t *stream)
 {
     stream->fill_buffer = fill_buffer;
@@ -68,14 +94,21 @@ static int open_f(stream_t *stream)
 
     // Initial data
     bstr data = bstr0(stream->url);
+    bool use_hex = bstr_eatstart0(&data, "hex://");
+    if (!use_hex)
         bstr_eatstart0(&data, "memory://");
     stream_control(stream, STREAM_CTRL_SET_CONTENTS, &data);
 
+    if (use_hex && !bstr_to_hex_inplace(&p->data)) {
+        MP_FATAL(stream, "Invalid data.\n");
+        return STREAM_ERROR;
+    }
+
     return STREAM_OK;
 }
 
 const stream_info_t stream_info_memory = {
     .name = "memory",
     .open = open_f,
-    .protocols = (const char*const[]){ "memory", NULL },
+    .protocols = (const char*const[]){ "memory", "hex", NULL },
 };