lavu: introduce av_parse_ratio() and use it in ffmpeg and lavfi/aspect

Factorize code and provide ratio parsing consistency.

4 files changed, 54 insertions, 5 deletions

diff --git a/libavutil/avutil.h b/libavutil/avutil.h
index 5d574e8851..c8427fd0bf 100644
--- a/libavutil/avutil.h
+++ b/libavutil/avutil.h
@@ -154,7 +154,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR 51
-#define LIBAVUTIL_VERSION_MINOR 37
+#define LIBAVUTIL_VERSION_MINOR 38
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
diff --git a/libavutil/log.h b/libavutil/log.h
index 02a0e1ac8c..26c806f644 100644
--- a/libavutil/log.h
+++ b/libavutil/log.h
@@ -124,6 +124,8 @@ typedef struct AVClass {
  */
 #define AV_LOG_DEBUG    48
 
+#define AV_LOG_MAX_OFFSET (AV_LOG_DEBUG - AV_LOG_QUIET)
+
 /**
  * Send the specified message to the log if the level is less than or equal
  * to the current av_log_level. By default, all logging messages are sent to
diff --git a/libavutil/parseutils.c b/libavutil/parseutils.c
index 2649e3b2bc..802931dd2e 100644
--- a/libavutil/parseutils.c
+++ b/libavutil/parseutils.c
@@ -31,6 +31,32 @@
 #include "random_seed.h"
 #include "parseutils.h"
 
+int av_parse_ratio(AVRational *q, const char *str, int max,
+                   int log_offset, void *log_ctx)
+{
+    char c;
+    int ret;
+    int64_t gcd;
+
+    if (sscanf(str, "%d:%d%c", &q->num, &q->den, &c) != 2) {
+        double d;
+        ret = av_expr_parse_and_eval(&d, str, NULL, NULL,
+                                     NULL, NULL, NULL, NULL,
+                                     NULL, log_offset, log_ctx);
+        if (ret < 0)
+            return ret;
+        *q = av_d2q(d, max);
+    }
+
+    gcd = av_gcd(FFABS(q->num), FFABS(q->den));
+    if (gcd) {
+        q->num /= gcd;
+        q->den /= gcd;
+    }
+
+    return 0;
+}
+
 typedef struct {
     const char *abbr;
     int width, height;
@@ -124,7 +150,6 @@ int av_parse_video_rate(AVRational *rate, const char *arg)
 {
     int i, ret;
     int n = FF_ARRAY_ELEMS(video_rate_abbrs);
-    double res;
 
     /* First, we check our abbreviation table */
     for (i = 0; i < n; ++i)
@@ -134,10 +159,8 @@ int av_parse_video_rate(AVRational *rate, const char *arg)
         }
 
     /* Then, we try to parse it as fraction */
-    if ((ret = av_expr_parse_and_eval(&res, arg, NULL, NULL, NULL, NULL, NULL, NULL,
-                                      NULL, 0, NULL)) < 0)
+    if ((ret = av_parse_ratio_quiet(rate, arg, 1001000)) < 0)
         return ret;
-    *rate = av_d2q(res, 1001000);
     if (rate->num <= 0 || rate->den <= 0)
         return AVERROR(EINVAL);
     return 0;
diff --git a/libavutil/parseutils.h b/libavutil/parseutils.h
index 2a74a060f2..a545652d9e 100644
--- a/libavutil/parseutils.h
+++ b/libavutil/parseutils.h
@@ -29,6 +29,30 @@
  */
 
 /**
+ * Parse str and store the parsed ratio in q.
+ *
+ * Note that a ratio with infinite (1/0) or negative value is
+ * considered valid, so you should check on the returned value if you
+ * want to exclude those values.
+ *
+ * The undefined value can be expressed using the "0:0" string.
+ *
+ * @param[in,out] q pointer to the AVRational which will contain the ratio
+ * @param[in] str the string to parse: it has to be a string in the format
+ * num:den, a float number or an expression
+ * @param[in] max the maximum allowed numerator and denominator
+ * @param[in] log_offset log level offset which is applied to the log
+ * level of log_ctx
+ * @param[in] log_ctx parent logging context
+ * @return >= 0 on success, a negative error code otherwise
+ */
+int av_parse_ratio(AVRational *q, const char *str, int max,
+                   int log_offset, void *log_ctx);
+
+#define av_parse_ratio_quiet(rate, str, max) \
+    av_parse_ratio(rate, str, max, AV_LOG_MAX_OFFSET, NULL)
+
+/**
  * Parse str and put in width_ptr and height_ptr the detected values.
  *
  * @param[in,out] width_ptr pointer to the variable which will contain the detected