/jansson/src/utf.c
http://github.com/nicolasff/webdis · C · 190 lines · 143 code · 29 blank · 18 comment · 66 complexity · ea60c1c08659281709509bbaee02fd38 MD5 · raw file
- /*
- * Copyright (c) 2009, 2010 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 <string.h>
- #include "utf.h"
- int utf8_encode(int32_t codepoint, char *buffer, int *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;
- }
- int 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;
- }
- }
- int utf8_check_full(const char *buffer, int size, int32_t *codepoint)
- {
- int 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, int32_t *codepoint)
- {
- int count;
- int32_t value;
- if(!*buffer)
- return buffer;
- count = utf8_check_first(buffer[0]);
- if(count <= 0)
- return NULL;
- if(count == 1)
- value = (unsigned char)buffer[0];
- else
- {
- if(!utf8_check_full(buffer, count, &value))
- return NULL;
- }
- if(codepoint)
- *codepoint = value;
- return buffer + count;
- }
- int utf8_check_string(const char *string, int length)
- {
- int i;
- if(length == -1)
- length = strlen(string);
- for(i = 0; i < length; i++)
- {
- int count = utf8_check_first(string[i]);
- if(count == 0)
- return 0;
- else if(count > 1)
- {
- if(i + count > length)
- return 0;
- if(!utf8_check_full(&string[i], count, NULL))
- return 0;
- i += count - 1;
- }
- }
- return 1;
- }