From 6b2b7e8803027b7089a853af0f47b53a7d20e950 Mon Sep 17 00:00:00 2001

From: Peter Jones <pjones@redhat.com>

Date: Tue, 18 Jun 2019 13:12:39 -0400

Subject: [PATCH 35/86] ucs2: document things a little better

Signed-off-by: Peter Jones <pjones@redhat.com>

---

 src/ucs2.h | 135 +++++++++++++++++++++++++++++++++++++++--------------

 1 file changed, 100 insertions(+), 35 deletions(-)

diff --git a/src/ucs2.h b/src/ucs2.h

index 478de23b23f..3f8a41d8ccc 100644

--- a/src/ucs2.h

+++ b/src/ucs2.h

@@ -22,11 +22,20 @@

 #define ev_bits(val, mask, shift) \

 	(((val) & ((mask) << (shift))) >> (shift))

+/*

+ * ucs2len(): Count the number of characters in a UCS-2 string.

+ * s: a UCS-2 string

+ * limit: the maximum number of uint16_t bytepairs to examine

+ *

+ * returns the number of characters before NUL is found (i.e., excluding

+ * the NUL character).  If limit is non-negative, no character index above

+ * limit will be accessed, and the maximum return value is limit.

+ */

 static inline size_t UNUSED

-ucs2len(const void *vs, ssize_t limit)

+ucs2len(const void *s, ssize_t limit)

 {

 	ssize_t i;

-	const uint8_t *s8 = vs;

+	const uint8_t *s8 = s;

 	for (i = 0;

 	     i < (limit >= 0 ? limit : i+1) && !(s8[0] == 0 && s8[1] == 0);

@@ -35,6 +44,15 @@ ucs2len(const void *vs, ssize_t limit)

 	return i;

 }

+/*

+ * ucs2size(): count the number of bytes in use by a UCS-2 string.

+ * s: a UCS-2 string

+ * limit: the maximum number of uint16_t bytepairs to examine

+ *

+ * returns the number of bytes, including NUL, in the UCS-2 string s.  If

+ * limit is non-negative, no character index above limit will be accessed,

+ * and the maximum return value is limit.

+ */

 static inline size_t UNUSED

 ucs2size(const void *s, ssize_t limit)

 {

@@ -46,6 +64,18 @@ ucs2size(const void *s, ssize_t limit)

 	return rc;

 }

+/*

+ * utf8len(): Count the number of characters in a UTF-8 string.

+ * s: a UTF-8 string

+ * limit: the maximum number of bytes to examine

+ *

+ * returns the number of UTF-8 charters before NUL is found (i.e.,

+ * excluding the NUL character).  If limit is non-negative, no character

+ * index above limit will be accessed, and the maximum return value is

+ * limit.

+ *

+ * Caveat: only good up to 3-byte sequences.

+ */

 static inline size_t UNUSED NONNULL(1)

 utf8len(const unsigned char *s, ssize_t limit)

 {

@@ -63,6 +93,15 @@ utf8len(const unsigned char *s, ssize_t limit)

 	return j;

 }

+/*

+ * utf8size(): count the number of bytes in use by a UTF-8 string.

+ * s: a UTF-8 string

+ * limit: the maximum number of bytes to examine

+ *

+ * returns the number of bytes, including NUL, in the UTF-8 string s.

+ * If limit is non-negative, no character index above limit will be

+ * accessed, and the maximum return value is limit.

+ */

 static inline size_t UNUSED NONNULL(1)

 utf8size(const unsigned char *s, ssize_t limit)

 {

@@ -72,68 +111,94 @@ utf8size(const unsigned char *s, ssize_t limit)

 	return ret;

 }

+/*

+ * ucs2_to_utf8(): convert UCS-2 to UTF-8

+ * s: the UCS-2 string

+ * limit: the maximum number of characters to copy from s, including the

+ *	  NUL terminator, or -1 for no limit.

+ *

+ * returns an allocated string, into which at most limit - 1 characters of

+ * UTF-8 are translated from UCS-2.  The return value is *always*

+ * NUL-terminated.

+ */

 static inline unsigned char * UNUSED

-ucs2_to_utf8(const void * const voidchars, ssize_t limit)

+ucs2_to_utf8(const void * const s, ssize_t limit)

 {

 	ssize_t i, j;

-	unsigned char *ret;

-	const uint16_t * const chars = voidchars;

+	unsigned char *out, *ret;

+	const uint16_t * const chars = s;

 	if (limit < 0)

 		limit = ucs2len(chars, -1);

-	ret = malloc(limit * 6 + 1);

-	if (!ret)

+	out = malloc(limit * 6 + 1);

+	if (!out)

 		return NULL;

-	memset(ret, 0, limit * 6 +1);

+	memset(out, 0, limit * 6 +1);

 	for (i=0, j=0; chars[i] && i < (limit >= 0 ? limit : i+1); i++,j++) {

 		if (chars[i] <= 0x7f) {

-			ret[j] = chars[i];

+			out[j] = chars[i];

 		} else if (chars[i] > 0x7f && chars[i] <= 0x7ff) {

-			ret[j++] = 0xc0 | ev_bits(chars[i], 0x1f, 6);

-			ret[j]   = 0x80 | ev_bits(chars[i], 0x3f, 0);

+			out[j++] = 0xc0 | ev_bits(chars[i], 0x1f, 6);

+			out[j]   = 0x80 | ev_bits(chars[i], 0x3f, 0);

 #if 1

 		} else if (chars[i] > 0x7ff) {

-			ret[j++] = 0xe0 | ev_bits(chars[i], 0xf, 12);

-			ret[j++] = 0x80 | ev_bits(chars[i], 0x3f, 6);

-			ret[j]   = 0x80| ev_bits(chars[i], 0x3f, 0);

+			out[j++] = 0xe0 | ev_bits(chars[i], 0xf, 12);

+			out[j++] = 0x80 | ev_bits(chars[i], 0x3f, 6);

+			out[j]   = 0x80| ev_bits(chars[i], 0x3f, 0);

 		}

 #else

 		} else if (chars[i] > 0x7ff && chars[i] < 0x10000) {

-			ret[j++] = 0xe0 | ev_bits(chars[i], 0xf, 12);

-			ret[j++] = 0x80 | ev_bits(chars[i], 0x3f, 6);

-			ret[j]   = 0x80| ev_bits(chars[i], 0x3f, 0);

+			out[j++] = 0xe0 | ev_bits(chars[i], 0xf, 12);

+			out[j++] = 0x80 | ev_bits(chars[i], 0x3f, 6);

+			out[j]   = 0x80| ev_bits(chars[i], 0x3f, 0);

 		} else if (chars[i] > 0xffff && chars[i] < 0x200000) {

-			ret[j++] = 0xf0 | ev_bits(chars[i], 0x7, 18);

-			ret[j++] = 0x80 | ev_bits(chars[i], 0x3f, 12);

-			ret[j++] = 0x80 | ev_bits(chars[i], 0x3f, 6);

-			ret[j]   = 0x80| ev_bits(chars[i], 0x3f, 0);

+			out[j++] = 0xf0 | ev_bits(chars[i], 0x7, 18);

+			out[j++] = 0x80 | ev_bits(chars[i], 0x3f, 12);

+			out[j++] = 0x80 | ev_bits(chars[i], 0x3f, 6);

+			out[j]   = 0x80| ev_bits(chars[i], 0x3f, 0);

 		} else if (chars[i] > 0x1fffff && chars[i] < 0x4000000) {

-			ret[j++] = 0xf8 | ev_bits(chars[i], 0x3, 24);

-			ret[j++] = 0x80 | ev_bits(chars[i], 0x3f, 18);

-			ret[j++] = 0x80 | ev_bits(chars[i], 0x3f, 12);

-			ret[j++] = 0x80 | ev_bits(chars[i], 0x3f, 6);

-			ret[j]   = 0x80 | ev_bits(chars[i], 0x3f, 0);

+			out[j++] = 0xf8 | ev_bits(chars[i], 0x3, 24);

+			out[j++] = 0x80 | ev_bits(chars[i], 0x3f, 18);

+			out[j++] = 0x80 | ev_bits(chars[i], 0x3f, 12);

+			out[j++] = 0x80 | ev_bits(chars[i], 0x3f, 6);

+			out[j]   = 0x80 | ev_bits(chars[i], 0x3f, 0);

 		} else if (chars[i] > 0x3ffffff) {

-			ret[j++] = 0xfc | ev_bits(chars[i], 0x1, 30);

-			ret[j++] = 0x80 | ev_bits(chars[i], 0x3f, 24);

-			ret[j++] = 0x80 | ev_bits(chars[i], 0x3f, 18);

-			ret[j++] = 0x80 | ev_bits(chars[i], 0x3f, 12);

-			ret[j++] = 0x80 | ev_bits(chars[i], 0x3f, 6);

-			ret[j]   = 0x80 | ev_bits(chars[i], 0x3f, 0);

+			out[j++] = 0xfc | ev_bits(chars[i], 0x1, 30);

+			out[j++] = 0x80 | ev_bits(chars[i], 0x3f, 24);

+			out[j++] = 0x80 | ev_bits(chars[i], 0x3f, 18);

+			out[j++] = 0x80 | ev_bits(chars[i], 0x3f, 12);

+			out[j++] = 0x80 | ev_bits(chars[i], 0x3f, 6);

+			out[j]   = 0x80 | ev_bits(chars[i], 0x3f, 0);

 		}

 #endif

 	}

-	ret[j] = '\0';

+	out[j++] = '\0';

+	ret = realloc(out, j);

+	if (!ret) {

+		free(out);

+		return NULL;

+	}

 	return ret;

 }

+/*

+ * utf8_to_ucs2(): convert UTF-8 to UCS-2

+ * s: the destination buffer to write to.

+ * size: the size of the allocation to write to

+ * terminate: whether or not to add a terminator to the string

+ * utf8: the utf8 source

+ *

+ * returns the number of characters written to s, including the NUL

+ * terminator if "terminate" is true, or -1 on error.  In the case of an

+ * error, the buffer will not be modified.

+ */

 static inline ssize_t UNUSED NONNULL(4)

-utf8_to_ucs2(void *ucs2void, ssize_t size, int terminate, const unsigned char *utf8)

+utf8_to_ucs2(void *s, ssize_t size, bool terminate, const unsigned char *utf8)

 {

 	ssize_t req;

 	ssize_t i, j;

-	uint16_t *ucs2 = ucs2void;

+	uint16_t *ucs2 = s;

 	uint16_t val16;

 	if (!ucs2 && size > 0) {

-- 

2.24.1