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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:15:05 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:15:05 +0000
commit46651ce6fe013220ed397add242004d764fc0153 (patch)
tree6e5299f990f88e60174a1d3ae6e48eedd2688b2b /src/port/pgstrcasecmp.c
parentInitial commit. (diff)
downloadpostgresql-14-upstream.tar.xz
postgresql-14-upstream.zip
Adding upstream version 14.5.upstream/14.5upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/port/pgstrcasecmp.c')
-rw-r--r--src/port/pgstrcasecmp.c151
1 files changed, 151 insertions, 0 deletions
diff --git a/src/port/pgstrcasecmp.c b/src/port/pgstrcasecmp.c
new file mode 100644
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+++ b/src/port/pgstrcasecmp.c
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+/*-------------------------------------------------------------------------
+ *
+ * pgstrcasecmp.c
+ * Portable SQL-like case-independent comparisons and conversions.
+ *
+ * SQL99 specifies Unicode-aware case normalization, which we don't yet
+ * have the infrastructure for. Instead we use tolower() to provide a
+ * locale-aware translation. However, there are some locales where this
+ * is not right either (eg, Turkish may do strange things with 'i' and
+ * 'I'). Our current compromise is to use tolower() for characters with
+ * the high bit set, and use an ASCII-only downcasing for 7-bit
+ * characters.
+ *
+ * NB: this code should match downcase_truncate_identifier() in scansup.c.
+ *
+ * We also provide strict ASCII-only case conversion functions, which can
+ * be used to implement C/POSIX case folding semantics no matter what the
+ * C library thinks the locale is.
+ *
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ *
+ * src/port/pgstrcasecmp.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "c.h"
+
+#include <ctype.h>
+
+
+/*
+ * Case-independent comparison of two null-terminated strings.
+ */
+int
+pg_strcasecmp(const char *s1, const char *s2)
+{
+ for (;;)
+ {
+ unsigned char ch1 = (unsigned char) *s1++;
+ unsigned char ch2 = (unsigned char) *s2++;
+
+ if (ch1 != ch2)
+ {
+ if (ch1 >= 'A' && ch1 <= 'Z')
+ ch1 += 'a' - 'A';
+ else if (IS_HIGHBIT_SET(ch1) && isupper(ch1))
+ ch1 = tolower(ch1);
+
+ if (ch2 >= 'A' && ch2 <= 'Z')
+ ch2 += 'a' - 'A';
+ else if (IS_HIGHBIT_SET(ch2) && isupper(ch2))
+ ch2 = tolower(ch2);
+
+ if (ch1 != ch2)
+ return (int) ch1 - (int) ch2;
+ }
+ if (ch1 == 0)
+ break;
+ }
+ return 0;
+}
+
+/*
+ * Case-independent comparison of two not-necessarily-null-terminated strings.
+ * At most n bytes will be examined from each string.
+ */
+int
+pg_strncasecmp(const char *s1, const char *s2, size_t n)
+{
+ while (n-- > 0)
+ {
+ unsigned char ch1 = (unsigned char) *s1++;
+ unsigned char ch2 = (unsigned char) *s2++;
+
+ if (ch1 != ch2)
+ {
+ if (ch1 >= 'A' && ch1 <= 'Z')
+ ch1 += 'a' - 'A';
+ else if (IS_HIGHBIT_SET(ch1) && isupper(ch1))
+ ch1 = tolower(ch1);
+
+ if (ch2 >= 'A' && ch2 <= 'Z')
+ ch2 += 'a' - 'A';
+ else if (IS_HIGHBIT_SET(ch2) && isupper(ch2))
+ ch2 = tolower(ch2);
+
+ if (ch1 != ch2)
+ return (int) ch1 - (int) ch2;
+ }
+ if (ch1 == 0)
+ break;
+ }
+ return 0;
+}
+
+/*
+ * Fold a character to upper case.
+ *
+ * Unlike some versions of toupper(), this is safe to apply to characters
+ * that aren't lower case letters. Note however that the whole thing is
+ * a bit bogus for multibyte character sets.
+ */
+unsigned char
+pg_toupper(unsigned char ch)
+{
+ if (ch >= 'a' && ch <= 'z')
+ ch += 'A' - 'a';
+ else if (IS_HIGHBIT_SET(ch) && islower(ch))
+ ch = toupper(ch);
+ return ch;
+}
+
+/*
+ * Fold a character to lower case.
+ *
+ * Unlike some versions of tolower(), this is safe to apply to characters
+ * that aren't upper case letters. Note however that the whole thing is
+ * a bit bogus for multibyte character sets.
+ */
+unsigned char
+pg_tolower(unsigned char ch)
+{
+ if (ch >= 'A' && ch <= 'Z')
+ ch += 'a' - 'A';
+ else if (IS_HIGHBIT_SET(ch) && isupper(ch))
+ ch = tolower(ch);
+ return ch;
+}
+
+/*
+ * Fold a character to upper case, following C/POSIX locale rules.
+ */
+unsigned char
+pg_ascii_toupper(unsigned char ch)
+{
+ if (ch >= 'a' && ch <= 'z')
+ ch += 'A' - 'a';
+ return ch;
+}
+
+/*
+ * Fold a character to lower case, following C/POSIX locale rules.
+ */
+unsigned char
+pg_ascii_tolower(unsigned char ch)
+{
+ if (ch >= 'A' && ch <= 'Z')
+ ch += 'a' - 'A';
+ return ch;
+}