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/*
* Copyright (c) 2009-2016 Petri Lehtinen <petri@digip.org>
*
* Jansson is free software; you can redistribute it and/or modify
* it under the terms of the MIT license. See LICENSE for details.
*/
#include "utf.h"
#include <string.h>
int utf8_encode(int32_t codepoint, char *buffer, size_t *size) {
if (codepoint < 0)
return -1;
else if (codepoint < 0x80) {
buffer[0] = (char)codepoint;
*size = 1;
} else if (codepoint < 0x800) {
buffer[0] = 0xC0 + ((codepoint & 0x7C0) >> 6);
buffer[1] = 0x80 + ((codepoint & 0x03F));
*size = 2;
} else if (codepoint < 0x10000) {
buffer[0] = 0xE0 + ((codepoint & 0xF000) >> 12);
buffer[1] = 0x80 + ((codepoint & 0x0FC0) >> 6);
buffer[2] = 0x80 + ((codepoint & 0x003F));
*size = 3;
} else if (codepoint <= 0x10FFFF) {
buffer[0] = 0xF0 + ((codepoint & 0x1C0000) >> 18);
buffer[1] = 0x80 + ((codepoint & 0x03F000) >> 12);
buffer[2] = 0x80 + ((codepoint & 0x000FC0) >> 6);
buffer[3] = 0x80 + ((codepoint & 0x00003F));
*size = 4;
} else
return -1;
return 0;
}
size_t utf8_check_first(char byte) {
unsigned char u = (unsigned char)byte;
if (u < 0x80)
return 1;
if (0x80 <= u && u <= 0xBF) {
/* second, third or fourth byte of a multi-byte
sequence, i.e. a "continuation byte" */
return 0;
} else if (u == 0xC0 || u == 0xC1) {
/* overlong encoding of an ASCII byte */
return 0;
} else if (0xC2 <= u && u <= 0xDF) {
/* 2-byte sequence */
return 2;
}
else if (0xE0 <= u && u <= 0xEF) {
/* 3-byte sequence */
return 3;
} else if (0xF0 <= u && u <= 0xF4) {
/* 4-byte sequence */
return 4;
} else { /* u >= 0xF5 */
/* Restricted (start of 4-, 5- or 6-byte sequence) or invalid
UTF-8 */
return 0;
}
}
size_t utf8_check_full(const char *buffer, size_t size, int32_t *codepoint) {
size_t i;
int32_t value = 0;
unsigned char u = (unsigned char)buffer[0];
if (size == 2) {
value = u & 0x1F;
} else if (size == 3) {
value = u & 0xF;
} else if (size == 4) {
value = u & 0x7;
} else
return 0;
for (i = 1; i < size; i++) {
u = (unsigned char)buffer[i];
if (u < 0x80 || u > 0xBF) {
/* not a continuation byte */
return 0;
}
value = (value << 6) + (u & 0x3F);
}
if (value > 0x10FFFF) {
/* not in Unicode range */
return 0;
}
else if (0xD800 <= value && value <= 0xDFFF) {
/* invalid code point (UTF-16 surrogate halves) */
return 0;
}
else if ((size == 2 && value < 0x80) || (size == 3 && value < 0x800) ||
(size == 4 && value < 0x10000)) {
/* overlong encoding */
return 0;
}
if (codepoint)
*codepoint = value;
return 1;
}
const char *utf8_iterate(const char *buffer, size_t bufsize, int32_t *codepoint) {
size_t count;
int32_t value;
if (!bufsize)
return buffer;
count = utf8_check_first(buffer[0]);
if (count <= 0)
return NULL;
if (count == 1)
value = (unsigned char)buffer[0];
else {
if (count > bufsize || !utf8_check_full(buffer, count, &value))
return NULL;
}
if (codepoint)
*codepoint = value;
return buffer + count;
}
int utf8_check_string(const char *string, size_t length) {
size_t i;
for (i = 0; i < length; i++) {
size_t count = utf8_check_first(string[i]);
if (count == 0)
return 0;
else if (count > 1) {
if (count > length - i)
return 0;
if (!utf8_check_full(&string[i], count, NULL))
return 0;
i += count - 1;
}
}
return 1;
}
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