Do not parse --max-fps float in the client

Many parsing and formatting C functions like strtof() and asprintf() are
locale-dependent. Forcing a C locale just for the conversions in a way
that works on all platforms is a mess.

In practice, this is not a problem, scrcpy always uses the C locale,
because it never calls:

    setlocale(LC_ALL, "");

But the max-fps option should not depend on the locale configuration
anyway.

Since the value is parsed by the client in Java anyway, just forward the
string value as is.

app/src/cli.c

@@ -1447,26 +1447,6 @@ parse_integers_arg(const char *s, const char sep, size_t max_items, long *out,
     return count;
 }
 
-static bool
-parse_float_arg(const char *s, float *out, float min, float max,
-                const char *name) {
-    float value;
-    bool ok = sc_str_parse_float(s, &value);
-    if (!ok) {
-        LOGE("Could not parse %s: %s", name, s);
-        return false;
-    }
-
-    if (value < min || value > max) {
-        LOGE("Could not parse %s: value (%f) out-of-range (%f; %f)",
-             name, value, min, max);
-        return false;
-    }
-
-    *out = value;
-    return true;
-}
-
 static bool
 parse_bit_rate(const char *s, uint32_t *bit_rate) {
     long value;
@@ -1493,18 +1473,6 @@ parse_max_size(const char *s, uint16_t *max_size) {
     return true;
 }
 
-static bool
-parse_max_fps(const char *s, float *max_fps) {
-    float value;
-    bool ok = parse_float_arg(s, &value, 0, (float) (1 << 16), "max fps");
-    if (!ok) {
-        return false;
-    }
-
-    *max_fps = value;
-    return true;
-}
-
 static bool
 parse_buffering_time(const char *s, sc_tick *tick) {
     long value;
@@ -2252,9 +2220,7 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
                      "--keyboard=uhid instead.");
                 return false;
             case OPT_MAX_FPS:
-                if (!parse_max_fps(optarg, &opts->max_fps)) {
-                    return false;
-                }
+                opts->max_fps = optarg;
                 break;
             case 'm':
                 if (!parse_max_size(optarg, &opts->max_size)) {

app/src/options.c

@@ -48,7 +48,7 @@ const struct scrcpy_options scrcpy_options_default = {
     .max_size = 0,
     .video_bit_rate = 0,
     .audio_bit_rate = 0,
-    .max_fps = 0,
+    .max_fps = NULL,
     .lock_video_orientation = SC_LOCK_VIDEO_ORIENTATION_UNLOCKED,
     .display_orientation = SC_ORIENTATION_0,
     .record_orientation = SC_ORIENTATION_0,

app/src/options.h

@@ -240,7 +240,7 @@ struct scrcpy_options {
     uint16_t max_size;
     uint32_t video_bit_rate;
     uint32_t audio_bit_rate;
-    float max_fps;
+    const char *max_fps; // float to be parsed by the server
     enum sc_lock_video_orientation lock_video_orientation;
     enum sc_orientation display_orientation;
     enum sc_orientation record_orientation;

app/src/server.c

@@ -321,7 +321,8 @@ execute_server(struct sc_server *server,
         ADD_PARAM("max_size=%" PRIu16, params->max_size);
     }
     if (params->max_fps) {
-        ADD_PARAM("max_fps=%f" , params->max_fps);
+        VALIDATE_STRING(params->max_fps);
+        ADD_PARAM("max_fps=%s", params->max_fps);
     }
     if (params->lock_video_orientation != SC_LOCK_VIDEO_ORIENTATION_UNLOCKED) {
         ADD_PARAM("lock_video_orientation=%" PRIi8,

app/src/server.h

@@ -44,7 +44,7 @@ struct sc_server_params {
     uint16_t max_size;
     uint32_t video_bit_rate;
     uint32_t audio_bit_rate;
-    float max_fps;
+    const char *max_fps; // float to be parsed by the server
     int8_t lock_video_orientation;
     bool control;
     uint32_t display_id;

app/src/util/str.c

@@ -147,25 +147,6 @@ sc_str_parse_integer_with_suffix(const char *s, long *out) {
     return true;
 }
 
-bool
-sc_str_parse_float(const char *s, float *out) {
-    char *endptr;
-    if (*s == '\0') {
-        return false;
-    }
-    errno = 0;
-    float value = strtof(s, &endptr);
-    if (errno == ERANGE) {
-        return false;
-    }
-    if (*endptr != '\0') {
-        return false;
-    }
-
-    *out = value;
-    return true;
-}
-
 bool
 sc_str_list_contains(const char *list, char sep, const char *s) {
     char *p;

app/src/util/str.h

@@ -66,14 +66,6 @@ sc_str_parse_integers(const char *s, const char sep, size_t max_items,
 bool
 sc_str_parse_integer_with_suffix(const char *s, long *out);
 
-/**
- * `Parse `s` as a float into `out`
- *
- * Return true if the conversion succeeded, false otherwise.
- */
-bool
-sc_str_parse_float(const char *s, float *out);
-
 /**
  * Search `s` in the list separated by `sep`
  *

app/tests/test_cli.c

@@ -78,7 +78,7 @@ static void test_options(void) {
     assert(opts->video_bit_rate == 5000000);
     assert(!strcmp(opts->crop, "100:200:300:400"));
     assert(opts->fullscreen);
-    assert(opts->max_fps == 30);
+    assert(!strcmp(opts->max_fps, "30"));
     assert(opts->max_size == 1024);
     assert(opts->lock_video_orientation == 2);
     assert(opts->port_range.first == 1234);