audio: add channel map API

Unused, will be used in the following commits.

Let chmap.h define the number of maximum channels, because that is most
convenient.

2 files changed, 46 insertions, 0 deletions

diff --git a/core/m_option.c b/core/m_option.c
index 6e7b20a688..b1e0f50dd9 100644
--- a/core/m_option.c
+++ b/core/m_option.c
@@ -1555,6 +1555,48 @@ const m_option_type_t m_option_type_afmt = {
     .copy  = copy_opt,
 };
 
+#include "audio/chmap.h"
+
+static int parse_chmap(const m_option_t *opt, struct bstr name,
+                       struct bstr param, void *dst)
+{
+    // min>0: at least min channels, min=0: empty ok, min=-1: invalid ok
+    int min_ch = (opt->flags & M_OPT_MIN) ? opt->min : 1;
+
+    if (bstr_equals0(param, "help")) {
+        mp_chmap_print_help(MSGT_CFGPARSER, MSGL_INFO);
+        return M_OPT_EXIT - 1;
+    }
+
+    if (param.len == 0 && min_ch >= 1)
+        return M_OPT_MISSING_PARAM;
+
+    struct mp_chmap res = {0};
+    if (!mp_chmap_from_str(&res, param)) {
+        mp_msg(MSGT_CFGPARSER, MSGL_ERR,
+               "Error parsing channel layout: %.*s\n", BSTR_P(param));
+        return M_OPT_INVALID;
+    }
+
+    if ((min_ch > 0 && !mp_chmap_is_valid(&res)) ||
+        (min_ch >= 0 && mp_chmap_is_empty(&res)))
+    {
+        mp_msg(MSGT_CFGPARSER, MSGL_ERR,
+               "Invalid channel layout: %.*s\n", BSTR_P(param));
+        return M_OPT_INVALID;
+    }
+
+    *(struct mp_chmap *)dst = res;
+
+    return 1;
+}
+
+const m_option_type_t m_option_type_chmap = {
+    .name  = "Audio channels or channel map",
+    .size  = sizeof(struct mp_chmap *),
+    .parse = parse_chmap,
+    .copy  = copy_opt,
+};
 
 static int parse_timestring(struct bstr str, double *time, char endchar)
 {
diff --git a/core/m_option.h b/core/m_option.h
index fd0ebbd44c..66e7208801 100644
--- a/core/m_option.h
+++ b/core/m_option.h
@@ -60,6 +60,7 @@ extern const m_option_type_t m_option_type_afmt;
 extern const m_option_type_t m_option_type_color;
 extern const m_option_type_t m_option_type_geometry;
 extern const m_option_type_t m_option_type_size_box;
+extern const m_option_type_t m_option_type_chmap;
 
 // Callback used by m_option_type_print_func options.
 typedef int (*m_opt_func_full_t)(const m_option_t *, const char *, const char *);
@@ -581,6 +582,9 @@ static inline void m_option_free(const m_option_t *opt, void *dst)
 #define OPT_AUDIOFORMAT(...) \
     OPT_GENERAL(int, __VA_ARGS__, .type = &m_option_type_afmt)
 
+#define OPT_CHMAP(...) \
+    OPT_GENERAL(struct mp_chmap, __VA_ARGS__, .type = &m_option_type_chmap)
+
 
 #define M_CHOICES(choices)                                              \
     .priv = (void *)&(const struct m_opt_choice_alternatives[]){        \