various: don't check if endptr is null for strto[udll]

These functions always set endptr to non-null so there is no need to
check.

common/av_common.c

@@ -340,7 +340,7 @@ static void resolve_positional_arg(void *avobj, char **name)
 
     char *end = NULL;
     int pos = strtol(*name + 1, &end, 10);
-    if (!end || *end || pos < 0)
+    if (*end || pos < 0)
         return;
 
     const AVOption *opt = NULL;

demux/demux.c

@@ -2869,7 +2869,7 @@ static int decode_float(char *str, float *out)
     float dec_val;
 
     dec_val = strtod(str, &rest);
-    if (!rest || (rest == str) || !isfinite(dec_val))
+    if (rest == str || !isfinite(dec_val))
         return -1;
 
     *out = dec_val;

demux/demux_lavf.c

@@ -660,7 +660,7 @@ static int dict_get_decimal(AVDictionary *dict, const char *entry, int def)
     if (e && e->value) {
         char *end = NULL;
         long int r = strtol(e->value, &end, 10);
-        if (end && !end[0] && r >= INT_MIN && r <= INT_MAX)
+        if (!end[0] && r >= INT_MIN && r <= INT_MAX)
             return r;
     }
     return def;

demux/demux_mkv.c

@@ -1839,7 +1839,7 @@ static void parse_vorbis_chmap(struct mp_chmap *channels, unsigned char *data,
             snprintf(smask, sizeof(smask), "%.*s", (int)(len - 34), data + 34);
             char *end = NULL;
             uint32_t mask = strtol(smask, &end, 0);
-            if (!end || end[0])
+            if (end[0])
                 mask = 0;
             struct mp_chmap chmask = {0};
             mp_chmap_from_waveext(&chmask, mask);

options/m_option.c

@@ -786,7 +786,7 @@ static int choice_get(const m_option_t *opt, void *ta_parent,
     if (alt) {
         char *end = NULL;
         ival = strtol(alt->name, &end, 10);
-        if (end && !end[0])
+        if (!end[0])
             alt = NULL;
     }
     if (alt) {

stream/stream_file.c

@@ -300,7 +300,7 @@ static int open_f(stream_t *stream, const struct stream_open_args *args)
         stream->is_local_fs = false;
         char *begin = strstr(stream->url, "://") + 3, *end = NULL;
         p->fd = strtol(begin, &end, 0);
-        if (!end || end == begin || end[0] || p->fd < 0) {
+        if (end == begin || end[0] || p->fd < 0) {
             MP_ERR(stream, "Invalid FD number: %s\n", stream->url);
             return STREAM_ERROR;
         }