Add crop marks

Signed-off-by: Mattias Andrée <m@maandree.se>

1 files changed, 59 insertions, 0 deletions

diff --git a/libcharconv_crop_marks.c b/libcharconv_crop_marks.c
new file mode 100644
index 0000000..81d3aa1
--- /dev/null
+++ b/libcharconv_crop_marks.c
@@ -0,0 +1,59 @@
+/* See LICENSE file for copyright and license details. */
+#include "lib-common.h"
+
+
+enum libcharconv_result
+libcharconv_crop_marks(const char *s, size_t slen, size_t *n, uint_least32_t *cp, size_t *ncp)
+{
+	uint_least32_t c;
+	*n = 0;
+	for (; slen--; s++) {
+		if (s[0] == '|') {
+			if (!slen)
+				goto indeterminate;
+			if (s[1] == '-')
+				c = UINT32_C(0x230C);
+			else if (s[1] == '_')
+				c = UINT32_C(0x230E);
+			else
+				goto no_conv;
+			goto conv;
+		} else if (s[0] == '-') {
+			if (!slen)
+				goto indeterminate;
+			if (s[1] != '|')
+				goto no_conv;
+			c = UINT32_C(0x230D);
+			goto conv;
+		} else if (s[0] == '_') {
+			if (!slen)
+				goto indeterminate;
+			if (s[1] != '|')
+				goto no_conv;
+			c = UINT32_C(0x230F);
+			goto conv;
+		} else {
+			*n += 1u;
+		}
+	}
+	return LIBCHARCONV_NO_CONVERT;
+
+no_conv:
+	if (!*n)
+		*n = 1u;
+	return LIBCHARCONV_NO_CONVERT;
+
+indeterminate:
+	if (*n)
+		goto no_conv;
+	return LIBCHARCONV_INDETERMINATE;
+
+conv:
+	if (*n)
+		goto no_conv;
+	if (*ncp)
+		*cp = c;
+	*n += 2u;
+	*ncp = 1u;
+	return LIBCHARCONV_CONVERTED;
+}