[PATCH 24.03 2/4] 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, parsing the coremask string, filling its values into the cores array.

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     | 58 +++++++++++++++++++++++++++++++++
 lib/arg_parser/rte_arg_parser.h | 33 +++++++++++++++++++
 lib/arg_parser/version.map      |  1 +
 3 files changed, 92 insertions(+)

diff --git a/lib/arg_parser/arg_parser.c b/lib/arg_parser/arg_parser.c
index 45acaf5631..58be94b67d 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)
 	}
 }
 
+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_parse_corelist(const char *corelist, uint16_t *cores, uint32_t cores_len)
@@ -111,3 +123,49 @@ rte_parse_corelist(const char *corelist, uint16_t *cores, uint32_t cores_len)
 
 	return total_count;
 }
+
+int
+rte_parse_coremask(const char *coremask, uint16_t *cores, uint32_t cores_len)
+{
+	struct core_bits *mask = malloc(sizeof(struct core_bits));
+	memset(mask, 0, sizeof(struct core_bits));
+
+	/* 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 -1;
+
+	uint32_t idx = 0;
+	uint8_t j;
+	int val;
+
+	for (i = i - 1; i >= 0; i--) {
+		char c = coremask[i];
+
+		if (isxdigit(c) == 0)
+			return -1;
+
+		val = xdigit2val(c);
+
+		for (j = 0; j < BITS_PER_HEX; j++, idx++) {
+			if ((1 << j) & val)
+				set_core_bit(mask, idx);
+		}
+	}
+
+	corebits_to_array(mask, cores, cores_len);
+	uint32_t total_count = mask->total_bits_set;
+	free(mask);
+
+	return total_count;
+}
diff --git a/lib/arg_parser/rte_arg_parser.h b/lib/arg_parser/rte_arg_parser.h
index 1b12bf451f..b149b37755 100644
--- a/lib/arg_parser/rte_arg_parser.h
+++ b/lib/arg_parser/rte_arg_parser.h
@@ -58,6 +58,39 @@ __rte_experimental
 int
 rte_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 elements added into the array is returned.
+ * For example, passing a 0xA "coremask" results in an array of [1, 3]
+ * and would return 2.
+ * 
+ * Like the snprintf function for strings, if the length of the input array is
+ * insufficient to hold the number of cores in the "coresmask", the input array is
+ * filled to capacity and the return value is the number of elements which would
+ * be returned if the array had been big enough.
+ * Function can also be called with a NULL array and 0 "cores_len" to find out
+ * the "cores_len" required.
+ *
+ * @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".
+ *   -1 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_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 f11699a306..f334f1aaed 100644
--- a/lib/arg_parser/version.map
+++ b/lib/arg_parser/version.map
@@ -7,4 +7,5 @@ EXPERIMENTAL {
 
     # added in 24.03
     rte_parse_corelist;
+    rte_parse_coremask;
 };
-- 
2.34.1