[PATCH v4 2/8] arg_parser: add new coremask parsing API

[Euan Bourke <euan.bourke@intel.com>]

Add new coremask parsing API. This API behaves similarly
to the corelist parsing API, taking a coremask string, a cores
array and a cores_len int. Parsing the coremask string, filling
its values into the cores array up to cores_len.

The API also returns a 'count' which corresponds to the total number
of cores in the coremask string.

Signed-off-by: Euan Bourke <euan.bourke@intel.com>
---
 lib/arg_parser/arg_parser.c     | 51 +++++++++++++++++++++++++++++++++
 lib/arg_parser/rte_arg_parser.h | 34 ++++++++++++++++++++++
 lib/arg_parser/version.map      |  1 +
 3 files changed, 86 insertions(+)

diff --git a/lib/arg_parser/arg_parser.c b/lib/arg_parser/arg_parser.c
index d8324a27b1..8d86a7b618 100644
--- a/lib/arg_parser/arg_parser.c
+++ b/lib/arg_parser/arg_parser.c
@@ -11,6 +11,9 @@
 #include <rte_arg_parser.h>
 #include <rte_common.h>
 
+#define BITS_PER_HEX 4
+#define MAX_COREMASK_SIZE ((UINT16_MAX + 1) / BITS_PER_HEX)
+
 
 struct core_bits {
 	uint8_t bits[(UINT16_MAX + 1) / CHAR_BIT];
@@ -57,6 +60,15 @@ corebits_to_array(struct core_bits *mask, uint16_t *cores, size_t max_cores)
 	return mask->total_bits_set;
 }
 
+static int xdigit2val(unsigned char c)
+{
+	if (isdigit(c))
+		return c - '0';
+	else if (isupper(c))
+		return c - 'A' + 10;
+	else
+		return c - 'a' + 10;
+}
 
 int
 rte_arg_parse_corelist(const char *corelist, uint16_t *cores, uint32_t cores_len)
@@ -106,3 +118,42 @@ rte_arg_parse_corelist(const char *corelist, uint16_t *cores, uint32_t cores_len
 
 	return corebits_to_array(&mask, cores, cores_len);
 }
+
+int
+rte_arg_parse_coremask(const char *coremask, uint16_t *cores, uint32_t cores_len)
+{
+	struct core_bits mask = {0};
+
+	/* Remove all blank characters ahead and after .
+	 * Remove 0x/0X if exists.
+	 */
+	while (isblank(*coremask))
+		coremask++;
+	if (coremask[0] == '0' && ((coremask[1] == 'x') || (coremask[1] == 'X')))
+		coremask += 2;
+
+	int32_t i = strlen(coremask);
+	while ((i > 0) && isblank(coremask[i - 1]))
+		i--;
+	if (i == 0 || i > MAX_COREMASK_SIZE)
+		return -EINVAL;
+
+	uint32_t idx = 0;
+
+	for (i = i - 1; i >= 0; i--) {
+		int val;
+		char c = coremask[i];
+
+		if (isxdigit(c) == 0)
+			return -EINVAL;
+
+		val = xdigit2val(c);
+
+		for (uint8_t j = 0; j < BITS_PER_HEX; j++, idx++) {
+			if ((1 << j) & val)
+				set_core_bit(&mask, idx);
+		}
+	}
+
+	return corebits_to_array(&mask, cores, cores_len);
+}
diff --git a/lib/arg_parser/rte_arg_parser.h b/lib/arg_parser/rte_arg_parser.h
index a1ef428b95..49d7daa204 100644
--- a/lib/arg_parser/rte_arg_parser.h
+++ b/lib/arg_parser/rte_arg_parser.h
@@ -58,6 +58,40 @@ __rte_experimental
 int
 rte_arg_parse_corelist(const char *corelist, uint16_t *cores, uint32_t cores_len);
 
+/**
+ * Convert a string describing a bitmask of core ids into an array of core ids.
+ *
+ * On success, the passed array is filled with the core ids present in the
+ * bitmask up to the "cores_len", and the number of unique cores present in the
+ * "coremask" is returned.
+ * For example, passing a 0xA "coremask" results in an array of [1, 3]
+ * and would return 2.
+ *
+ * NOTE: if the length of the input array is insufficient to hold the number of core ids
+ * in "coremask" the input array is filled to capacity but the return value is the
+ * number of elements which would have been written to the array, had enough space been
+ * available. [This is similar to the behaviour of the snprintf function]. Because of
+ * this, the number of core values in the "coremask" may be determined by calling the
+ * function with a NULL array pointer and array length given as 0.
+ *
+ * @param coremask
+ *   A string containing a bitmask of core ids.
+ * @param cores
+ *   An array where to store the core ids.
+ *   Array can be NULL if "cores_len" is 0.
+ * @param cores_len
+ *   The length of the "cores" array.
+ *   If the size is smaller than that needed to hold all cores from "coremask",
+ *   only "cores_len" elements will be written to the array.
+ * @return
+ *   n: the number of unique cores present in "coremask".
+ *   -EINVAL if the string was invalid.
+ *   NOTE: if n > "cores_len", then only "cores_len" elements in the "cores" array are valid.
+ */
+__rte_experimental
+int
+rte_arg_parse_coremask(const char *coremask, uint16_t *cores, uint32_t cores_len);
+
 
 #ifdef __cplusplus
 }
diff --git a/lib/arg_parser/version.map b/lib/arg_parser/version.map
index b0caaac569..b44d4b02b7 100644
--- a/lib/arg_parser/version.map
+++ b/lib/arg_parser/version.map
@@ -7,4 +7,5 @@ EXPERIMENTAL {
 
 	# added in 24.03
 	rte_arg_parse_corelist;
+	rte_arg_parse_coremask;
 };
-- 
2.34.1