348 lines
8.4 KiB
C
348 lines
8.4 KiB
C
/****************************************************
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* PCRE maintainers' helper program: UTF-8 converter *
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****************************************************/
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/* This is a test program for converting character code points to UTF-8 and
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vice versa. Note that this program conforms to the original definition of
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UTF-8, which allows codepoints up to 7fffffff. The more recent definition
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limits the validity of Unicode UTF-8 codepoints to a maximum of 10ffffff, and
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forbids the "surrogate" code points. This program now gives warnings for these
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invalid code points.
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The arguments are either single code point values written as U+hh.. or 0xhh..
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for conversion to UTF-8, or sequences of hex values, written without 0x and
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optionally including spaces (but such arguments must be quoted), for conversion
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from UTF-8 to codepoints. For example:
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./utf8 0x1234
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U+00001234 => e1 88 b4
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./utf8 "e1 88 b4"
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U+00001234 <= e1 88 b4
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In the second case, a number of UTF-8 characters can be present in one
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argument. In other words, each such argument is interpreted (after ignoring
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spaces) as a string of UTF-8 bytes representing a string of characters:
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./utf8 "65 e188b4 77"
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0x00000065 <= 65
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0x00001234 <= e1 88 b4
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0x00000077 <= 77
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If the option -s is given, the sequence of UTF-bytes is written out between
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angle brackets at the end of the line. On a UTF-8 terminal, this will show the
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appropriate graphic for the code point.
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Errors provoke error messages, but the program carries on with the next
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argument. The return code is always zero.
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Philip Hazel
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Original creation data: unknown
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Code extended and tidied to avoid compiler warnings: 26 March 2020
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <string.h>
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/* The valid ranges for UTF-8 characters are:
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0000 0000 to 0000 007f 1 byte (ascii)
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0000 0080 to 0000 07ff 2 bytes
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0000 0800 to 0000 ffff 3 bytes
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0001 0000 to 001f ffff 4 bytes
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0020 0000 to 03ff ffff 5 bytes
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0400 0000 to 7fff ffff 6 bytes
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*/
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static const unsigned int utf8_table1[] = {
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0x0000007f, 0x000007ff, 0x0000ffff, 0x001fffff, 0x03ffffff, 0x7fffffff};
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static const int utf8_table2[] = {
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0, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc};
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static const int utf8_table3[] = {
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0xff, 0x1f, 0x0f, 0x07, 0x03, 0x01};
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/*************************************************
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* Convert character value to UTF-8 *
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*************************************************/
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/* This function takes an unsigned long integer value in the range 0 -
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0x7fffffff and encodes it as a UTF-8 character in 1 to 6 bytes.
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Arguments:
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cvalue the character value
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buffer pointer to buffer for result - at least 6 bytes long
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Returns: number of bytes placed in the buffer
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0 if input code point is too big
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*/
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static size_t
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ord2utf8(unsigned long int cvalue, unsigned char *buffer)
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{
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size_t i, j;
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for (i = 0; i < sizeof(utf8_table1)/sizeof(int); i++)
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if (cvalue <= utf8_table1[i]) break;
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if (i >= sizeof(utf8_table1)/sizeof(int)) return 0;
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buffer += i;
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for (j = i; j > 0; j--)
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{
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*buffer-- = 0x80 | (cvalue & 0x3f);
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cvalue >>= 6;
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}
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*buffer = utf8_table2[i] | cvalue;
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return i + 1;
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}
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/*************************************************
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* Convert UTF-8 string to value *
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*************************************************/
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/* This function takes one or more bytes that represent a UTF-8 character from
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the start of a string of bytes. It returns the value of the character, or the
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offset of a malformation. For an overlong encoding that works but is not the
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correct (shortest) one, the error offset is just after the last byte.
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Argument:
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buffer a pointer to the byte vector
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buffend a pointer to the end of the buffer
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vptr a pointer to a variable to receive the value
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lenptr a pointer to a variable to receive the offset when error detected
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Returns: > 0 => the number of bytes consumed
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0 => invalid UTF-8: first byte missing 0x40 bit
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-1 => invalid UTF-8: first byte has too many high-order 1-bits
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-2 => incomplete sequence at end of string
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-3 => incomplete sequence within string
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-4 => overlong code sequence
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*/
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static int
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utf82ord(unsigned char *buffer, unsigned char *buffend,
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long unsigned int *vptr, int *lenptr)
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{
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unsigned int c = *buffer++;
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unsigned int d = c;
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int i, j, s;
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/* Check for an ASCII character, or find the number of additional bytes in a
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multibyte character. */
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for (i = -1; i < 6; i++)
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{
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if ((d & 0x80) == 0) break;
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d <<= 1;
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}
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switch (i)
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{
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case -1: /* ASCII character; first byte does not have 0x80 bit */
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*vptr = c;
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return 1;
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case 0: /* First byte has 0x80 but is missing 0x40 bit */
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*lenptr = 0;
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return 0;
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case 6:
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*lenptr = 0; /* Too many high bits */
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return -1;
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default:
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break;
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}
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/* i now has a value in the range 1-5 */
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s = 6*i;
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d = (c & utf8_table3[i]) << s;
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for (j = 0; j < i; j++)
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{
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if (buffer >= buffend)
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{
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*lenptr = j + 1;
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return -2;
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}
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c = *buffer++;
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if ((c & 0xc0) != 0x80)
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{
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*lenptr = j + 1;
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return -3;
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}
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s -= 6;
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d |= (c & 0x3f) << s;
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}
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/* Valid UTF-8 syntax */
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*vptr = d;
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/* Check that encoding was the correct one, not overlong */
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for (j = 0; j < (int)(sizeof(utf8_table1)/sizeof(int)); j++)
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if (d <= utf8_table1[j]) break;
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if (j != i)
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{
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*lenptr = i + 1;
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return -4;
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}
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/* Valid value */
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return i + 1;
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}
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/*************************************************
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* Main Program *
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*************************************************/
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int
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main(int argc, char **argv)
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{
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int i = 1;
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int show = 0;
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unsigned char buffer[64];
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if (argc > 1 && strcmp(argv[1], "-s") == 0)
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{
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show = 1;
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i = 2;
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}
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for (; i < argc; i++)
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{
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char *x = argv[i];
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char *endptr;
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if (strncmp(x, "0x", 2) == 0 || strncmp(x, "U+", 2) == 0)
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{
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size_t rc, j;
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unsigned long int d = strtoul(x+2, &endptr, 16);
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if (*endptr != 0)
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{
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printf("** Invalid hex number %s\n", x);
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continue; /* With next argument */
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}
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rc = ord2utf8(d, buffer);
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printf("U+%08lx => ", d);
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if (rc == 0)
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printf("** Code point greater than 0x7fffffff cannot be encoded");
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else
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{
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for (j = 0; j < rc; j++) printf("%02x ", buffer[j]);
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if (show)
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{
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printf(">");
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for (j = 0; j < rc; j++) printf("%c", buffer[j]);
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printf("< ");
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}
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if (d >= 0xd800 && d <= 0xdfff)
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printf("** Invalid Unicode (surrogate)");
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else if (d > 0x10ffff)
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printf("** Invalid Unicode (greater than U+10ffff)");
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}
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printf("\n");
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}
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else
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{
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unsigned char *bptr;
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unsigned char *buffend;
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int len = 0;
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int y = 0;
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int z = 0;
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for (;;)
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{
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while (*x == ' ') x++;
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if (*x == 0 && !z) break;
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if (!isxdigit(*x))
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{
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printf("** Malformed hex string: %s\n", argv[i]);
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len = -1;
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break;
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}
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y = y * 16 + tolower(*x) - ((isdigit(*x))? '0' : 'W');
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x++;
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if (z)
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{
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buffer[len++] = y;
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y = 0;
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}
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z ^= 1;
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}
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if (len < 0) continue; /* With next argument after malformation */
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bptr = buffer;
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buffend = buffer + len;
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while (bptr < buffend)
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{
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unsigned long int d;
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int j;
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int offset;
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int rc = utf82ord(bptr, buffend, &d, &offset);
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if (rc > 0)
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{
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printf("U+%08lx <= ", d);
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for (j = 0; j < rc; j++) printf("%02x ", bptr[j]);
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if (show)
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{
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printf(">");
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for (j = 0; j < rc; j++) printf("%c", bptr[j]);
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printf("<");
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}
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printf("\n");
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bptr += rc;
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}
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else if (rc == -4)
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{
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printf("U+%08lx <= ", d);
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for (j = 0; j < offset; j++) printf("%02x ", bptr[j]);
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printf("** Overlong UTF-8 sequence\n");
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bptr += offset;
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}
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else
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{
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switch (rc)
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{
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case 0: printf("** First byte missing 0x40 bit");
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break;
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case -1: printf("** First byte has too many high-order bits");
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break;
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case -2: printf("** Incomplete UTF-8 sequence at end of string");
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break;
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case -3: printf("** Incomplete UTF-8 sequence");
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break;
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default: printf("** Unexpected return %d from utf82ord()", rc);
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break;
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}
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printf(" at offset %d in string ", offset);
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while (bptr < buffend) printf("%02x ", *bptr++);
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printf("\n");
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break;
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}
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}
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}
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}
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return 0;
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}
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/* End */
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