1 files changed, 105 insertions, 0 deletions
diff --git a/ascii_strcasecmp.c b/ascii_strcasecmp.c
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+++ b/ascii_strcasecmp.c
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+/*
+ * Copyright (c) 1987 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of California at Berkeley. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific written prior permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+
+#include "ascii_strcasecmp.h"
+
+/*
+ * This array maps upper-case ASCII letters to their lower-case
+ * equivalents; all other byte values are mapped to themselves,
+ * so this is locale-independent and intended to be locale-independent,
+ * to avoid issues with, for example, "i" and "I" not being lower-case
+ * and upper-case versions of the same letter in Turkish, where
+ * there are separate "i with dot" and "i without dot" letters.
+ */
+static const unsigned char charmap[] = {
+	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
+	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
+	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
+	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
+	0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
+	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
+	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
+	0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
+	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
+	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
+	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
+	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
+	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
+	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
+	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
+	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
+	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
+	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
+	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
+	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
+	0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
+	0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
+	0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
+	0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
+	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
+	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
+	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
+	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff,
+};
+
+int
+ascii_strcasecmp(const char *s1, const char *s2)
+{
+	const unsigned char *cm = charmap,
+			*us1 = (const unsigned char *)s1,
+			*us2 = (const unsigned char *)s2;
+
+	while (cm[*us1] == cm[*us2++])
+		if (*us1++ == '\0')
+			return(0);
+	return(cm[*us1] - cm[*--us2]);
+}
+
+int
+ascii_strncasecmp(const char *s1, const char *s2, size_t n)
+{
+	const unsigned char *cm = charmap,
+			*us1 = (const unsigned char *)s1,
+			*us2 = (const unsigned char *)s2;
+
+	for (;;) {
+		if (n == 0) {
+			/*
+			 * We've run out of characters that we should
+			 * compare, and they've all been equal; return
+			 * 0, to indicate that the prefixes are the
+			 * same.
+			 */
+			return(0);
+		}
+		if (cm[*us1] != cm[*us2++]) {
+			/*
+			 * We've found a mismatch.
+			 */
+			break;
+		}
+		if (*us1++ == '\0') {
+			/*
+			 * We've run out of characters *to* compare,
+			 * and they've all been equal; return 0, to
+			 * indicate that the strings are the same.
+			 */
+			return(0);
+		}
+		n--;
+	}
+	return(cm[*us1] - cm[*--us2]);
+}