xmlstring.c

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/*
 * string.c : an XML string utilities module
 *
 * This module provides various utility functions for manipulating
 * the xmlChar* type. All functions named xmlStr* have been moved here
 * from the parser.c file (their original home).
 *
 * See Copyright for the status of this software.
 *
 * UTF8 string routines from:
 * William Brack <wbrack@mmm.com.hk>
 *
 * daniel@veillard.com
 */
 
#define IN_LIBXML
#include "libxml.h"
 
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <libxml/xmlmemory.h>
#include <libxml/parserInternals.h>
#include <libxml/xmlstring.h>
 
#include "private/parser.h"
#include "private/string.h"
 
/************************************************************************
 *                                                                      *
 *                Commodity functions to handle xmlChars                *
 *                                                                      *
 ************************************************************************/
 
xmlChar *
xmlStrndup(const xmlChar *cur, int len) {
    xmlChar *ret;
 
    if ((cur == NULL) || (len < 0)) return(NULL);
    ret = (xmlChar *) xmlMallocAtomic((size_t) len + 1);
    if (ret == NULL) {
        return(NULL);
    }
    memcpy(ret, cur, len);
    ret[len] = 0;
    return(ret);
}
 
xmlChar *
xmlStrdup(const xmlChar *cur) {
    const xmlChar *p = cur;
 
    if (cur == NULL) return(NULL);
    while (*p != 0) p++; /* non input consuming */
    return(xmlStrndup(cur, p - cur));
}
 
xmlChar *
xmlCharStrndup(const char *cur, int len) {
    int i;
    xmlChar *ret;
 
    if ((cur == NULL) || (len < 0)) return(NULL);
    ret = (xmlChar *) xmlMallocAtomic((size_t) len + 1);
    if (ret == NULL) {
        return(NULL);
    }
    for (i = 0;i < len;i++) {
        /* Explicit sign change */
        ret[i] = (xmlChar) cur[i];
        if (ret[i] == 0) return(ret);
    }
    ret[len] = 0;
    return(ret);
}
 
xmlChar *
xmlCharStrdup(const char *cur) {
    const char *p = cur;
 
    if (cur == NULL) return(NULL);
    while (*p != '\0') p++; /* non input consuming */
    return(xmlCharStrndup(cur, p - cur));
}
 
int
xmlStrcmp(const xmlChar *str1, const xmlChar *str2) {
    if (str1 == str2) return(0);
    if (str1 == NULL) return(-1);
    if (str2 == NULL) return(1);
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
    return(strcmp((const char *)str1, (const char *)str2));
#else
    do {
        int tmp = *str1++ - *str2;
        if (tmp != 0) return(tmp);
    } while (*str2++ != 0);
    return 0;
#endif
}
 
int
xmlStrEqual(const xmlChar *str1, const xmlChar *str2) {
    if (str1 == str2) return(1);
    if (str1 == NULL) return(0);
    if (str2 == NULL) return(0);
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
    return(strcmp((const char *)str1, (const char *)str2) == 0);
#else
    do {
        if (*str1++ != *str2) return(0);
    } while (*str2++);
    return(1);
#endif
}
 
int
xmlStrQEqual(const xmlChar *pref, const xmlChar *name, const xmlChar *str) {
    if (pref == NULL) return(xmlStrEqual(name, str));
    if (name == NULL) return(0);
    if (str == NULL) return(0);
 
    do {
        if (*pref++ != *str) return(0);
    } while ((*str++) && (*pref));
    if (*str++ != ':') return(0);
    do {
        if (*name++ != *str) return(0);
    } while (*str++);
    return(1);
}
 
int
xmlStrncmp(const xmlChar *str1, const xmlChar *str2, int len) {
    if (len <= 0) return(0);
    if (str1 == str2) return(0);
    if (str1 == NULL) return(-1);
    if (str2 == NULL) return(1);
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
    return(strncmp((const char *)str1, (const char *)str2, len));
#else
    do {
        int tmp = *str1++ - *str2;
        if (tmp != 0 || --len == 0) return(tmp);
    } while (*str2++ != 0);
    return 0;
#endif
}
 
static const xmlChar casemap[256] = {
    0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,
    0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F,
    0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,
    0x18,0x19,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,
    0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,
    0x28,0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,
    0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,
    0x38,0x39,0x3A,0x3B,0x3C,0x3D,0x3E,0x3F,
    0x40,0x61,0x62,0x63,0x64,0x65,0x66,0x67,
    0x68,0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,
    0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,
    0x78,0x79,0x7A,0x7B,0x5C,0x5D,0x5E,0x5F,
    0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67,
    0x68,0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,
    0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,
    0x78,0x79,0x7A,0x7B,0x7C,0x7D,0x7E,0x7F,
    0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87,
    0x88,0x89,0x8A,0x8B,0x8C,0x8D,0x8E,0x8F,
    0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97,
    0x98,0x99,0x9A,0x9B,0x9C,0x9D,0x9E,0x9F,
    0xA0,0xA1,0xA2,0xA3,0xA4,0xA5,0xA6,0xA7,
    0xA8,0xA9,0xAA,0xAB,0xAC,0xAD,0xAE,0xAF,
    0xB0,0xB1,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,
    0xB8,0xB9,0xBA,0xBB,0xBC,0xBD,0xBE,0xBF,
    0xC0,0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,
    0xC8,0xC9,0xCA,0xCB,0xCC,0xCD,0xCE,0xCF,
    0xD0,0xD1,0xD2,0xD3,0xD4,0xD5,0xD6,0xD7,
    0xD8,0xD9,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,
    0xE0,0xE1,0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,
    0xE8,0xE9,0xEA,0xEB,0xEC,0xED,0xEE,0xEF,
    0xF0,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,
    0xF8,0xF9,0xFA,0xFB,0xFC,0xFD,0xFE,0xFF
};
 
int
xmlStrcasecmp(const xmlChar *str1, const xmlChar *str2) {
    register int tmp;
 
    if (str1 == str2) return(0);
    if (str1 == NULL) return(-1);
    if (str2 == NULL) return(1);
    do {
        tmp = casemap[*str1++] - casemap[*str2];
        if (tmp != 0) return(tmp);
    } while (*str2++ != 0);
    return 0;
}
 
int
xmlStrncasecmp(const xmlChar *str1, const xmlChar *str2, int len) {
    register int tmp;
 
    if (len <= 0) return(0);
    if (str1 == str2) return(0);
    if (str1 == NULL) return(-1);
    if (str2 == NULL) return(1);
    do {
        tmp = casemap[*str1++] - casemap[*str2];
        if (tmp != 0 || --len == 0) return(tmp);
    } while (*str2++ != 0);
    return 0;
}
 
const xmlChar *
xmlStrchr(const xmlChar *str, xmlChar val) {
    if (str == NULL) return(NULL);
    while (*str != 0) { /* non input consuming */
        if (*str == val) return((xmlChar *) str);
        str++;
    }
    return(NULL);
}
 
const xmlChar *
xmlStrstr(const xmlChar *str, const xmlChar *val) {
    int n;
 
    if (str == NULL) return(NULL);
    if (val == NULL) return(NULL);
    n = xmlStrlen(val);
 
    if (n == 0) return(str);
    while (*str != 0) { /* non input consuming */
        if (*str == *val) {
            if (!xmlStrncmp(str, val, n)) return((const xmlChar *) str);
        }
        str++;
    }
    return(NULL);
}
 
const xmlChar *
xmlStrcasestr(const xmlChar *str, const xmlChar *val) {
    int n;
 
    if (str == NULL) return(NULL);
    if (val == NULL) return(NULL);
    n = xmlStrlen(val);
 
    if (n == 0) return(str);
    while (*str != 0) { /* non input consuming */
        if (casemap[*str] == casemap[*val])
            if (!xmlStrncasecmp(str, val, n)) return(str);
        str++;
    }
    return(NULL);
}
 
xmlChar *
xmlStrsub(const xmlChar *str, int start, int len) {
    int i;
 
    if (str == NULL) return(NULL);
    if (start < 0) return(NULL);
    if (len < 0) return(NULL);
 
    for (i = 0;i < start;i++) {
        if (*str == 0) return(NULL);
        str++;
    }
    if (*str == 0) return(NULL);
    return(xmlStrndup(str, len));
}
 
int
xmlStrlen(const xmlChar *str) {
    size_t len = str ? strlen((const char *)str) : 0;
    return(len > INT_MAX ? 0 : len);
}
 
xmlChar *
xmlStrncat(xmlChar *cur, const xmlChar *add, int len) {
    int size;
    xmlChar *ret;
 
    if ((add == NULL) || (len == 0))
        return(cur);
    if (len < 0)
    return(NULL);
    if (cur == NULL)
        return(xmlStrndup(add, len));
 
    size = xmlStrlen(cur);
    if ((size < 0) || (size > INT_MAX - len))
        return(NULL);
    ret = (xmlChar *) xmlRealloc(cur, (size_t) size + len + 1);
    if (ret == NULL) {
        return(cur);
    }
    memcpy(&ret[size], add, len);
    ret[size + len] = 0;
    return(ret);
}
 
xmlChar *
xmlStrncatNew(const xmlChar *str1, const xmlChar *str2, int len) {
    int size;
    xmlChar *ret;
 
    if (len < 0) {
        len = xmlStrlen(str2);
        if (len < 0)
            return(NULL);
    }
    if ((str2 == NULL) || (len == 0))
        return(xmlStrdup(str1));
    if (str1 == NULL)
        return(xmlStrndup(str2, len));
 
    size = xmlStrlen(str1);
    if ((size < 0) || (size > INT_MAX - len))
        return(NULL);
    ret = (xmlChar *) xmlMalloc((size_t) size + len + 1);
    if (ret == NULL) {
        return(xmlStrndup(str1, size));
    }
    memcpy(ret, str1, size);
    memcpy(&ret[size], str2, len);
    ret[size + len] = 0;
    return(ret);
}
 
xmlChar *
xmlStrcat(xmlChar *cur, const xmlChar *add) {
    const xmlChar *p = add;
 
    if (add == NULL) return(cur);
    if (cur == NULL)
        return(xmlStrdup(add));
 
    while (*p != 0) p++; /* non input consuming */
    return(xmlStrncat(cur, add, p - add));
}
 
int
xmlStrPrintf(xmlChar *buf, int len, const char *msg, ...) {
    va_list args;
    int ret;
 
    if((buf == NULL) || (msg == NULL)) {
        return(-1);
    }
 
    va_start(args, msg);
    ret = vsnprintf((char *) buf, len, (const char *) msg, args);
    va_end(args);
    buf[len - 1] = 0; /* be safe ! */
 
    return(ret);
}
 
int
xmlStrVPrintf(xmlChar *buf, int len, const char *msg, va_list ap) {
    int ret;
 
    if((buf == NULL) || (msg == NULL)) {
        return(-1);
    }
 
    ret = vsnprintf((char *) buf, len, (const char *) msg, ap);
    buf[len - 1] = 0; /* be safe ! */
 
    return(ret);
}
 
/************************************************************************
 *                                                                      *
 *              Generic UTF8 handling routines                          *
 *                                                                      *
 * From rfc2044: encoding of the Unicode values on UTF-8:               *
 *                                                                      *
 * UCS-4 range (hex.)           UTF-8 octet sequence (binary)           *
 * 0000 0000-0000 007F   0xxxxxxx                                       *
 * 0000 0080-0000 07FF   110xxxxx 10xxxxxx                              *
 * 0000 0800-0000 FFFF   1110xxxx 10xxxxxx 10xxxxxx                     *
 *                                                                      *
 * I hope we won't use values > 0xFFFF anytime soon !                   *
 *                                                                      *
 ************************************************************************/
 
 
int
xmlUTF8Size(const xmlChar *utf) {
    xmlChar mask;
    int len;
 
    if (utf == NULL)
        return -1;
    if (*utf < 0x80)
        return 1;
    /* check valid UTF8 character */
    if (!(*utf & 0x40))
        return -1;
    /* determine number of bytes in char */
    len = 2;
    for (mask=0x20; mask != 0; mask>>=1) {
        if (!(*utf & mask))
            return len;
        len++;
    }
    return -1;
}
 
int
xmlUTF8Charcmp(const xmlChar *utf1, const xmlChar *utf2) {
 
    if (utf1 == NULL ) {
        if (utf2 == NULL)
            return 0;
        return -1;
    }
    return xmlStrncmp(utf1, utf2, xmlUTF8Size(utf1));
}
 
int
xmlUTF8Strlen(const xmlChar *utf) {
    size_t ret = 0;
 
    if (utf == NULL)
        return(-1);
 
    while (*utf != 0) {
        if (utf[0] & 0x80) {
            if ((utf[1] & 0xc0) != 0x80)
                return(-1);
            if ((utf[0] & 0xe0) == 0xe0) {
                if ((utf[2] & 0xc0) != 0x80)
                    return(-1);
                if ((utf[0] & 0xf0) == 0xf0) {
                    if ((utf[0] & 0xf8) != 0xf0 || (utf[3] & 0xc0) != 0x80)
                        return(-1);
                    utf += 4;
                } else {
                    utf += 3;
                }
            } else {
                utf += 2;
            }
        } else {
            utf++;
        }
        ret++;
    }
    return(ret > INT_MAX ? 0 : ret);
}
 
int
xmlGetUTF8Char(const unsigned char *utf, int *len) {
    unsigned int c;
 
    if (utf == NULL)
        goto error;
    if (len == NULL)
        goto error;
 
    c = utf[0];
    if (c < 0x80) {
        if (*len < 1)
            goto error;
        /* 1-byte code */
        *len = 1;
    } else {
        if ((*len < 2) || ((utf[1] & 0xc0) != 0x80))
            goto error;
        if (c < 0xe0) {
            if (c < 0xc2)
                goto error;
            /* 2-byte code */
            *len = 2;
            c = (c & 0x1f) << 6;
            c |= utf[1] & 0x3f;
        } else {
            if ((*len < 3) || ((utf[2] & 0xc0) != 0x80))
                goto error;
            if (c < 0xf0) {
                /* 3-byte code */
                *len = 3;
                c = (c & 0xf) << 12;
                c |= (utf[1] & 0x3f) << 6;
                c |= utf[2] & 0x3f;
                if ((c < 0x800) || ((c >= 0xd800) && (c < 0xe000)))
                    goto error;
            } else {
                if ((*len < 4) || ((utf[3] & 0xc0) != 0x80))
                    goto error;
                *len = 4;
                /* 4-byte code */
                c = (c & 0x7) << 18;
                c |= (utf[1] & 0x3f) << 12;
                c |= (utf[2] & 0x3f) << 6;
                c |= utf[3] & 0x3f;
                if ((c < 0x10000) || (c >= 0x110000))
                    goto error;
            }
        }
    }
    return(c);
 
error:
    if (len != NULL)
    *len = 0;
    return(-1);
}
 
int
xmlCheckUTF8(const unsigned char *utf)
{
    int ix;
    unsigned char c;
 
    if (utf == NULL)
        return(0);
    /*
     * utf is a string of 1, 2, 3 or 4 bytes.  The valid strings
     * are as follows (in "bit format"):
     *    0xxxxxxx                                      valid 1-byte
     *    110xxxxx 10xxxxxx                             valid 2-byte
     *    1110xxxx 10xxxxxx 10xxxxxx                    valid 3-byte
     *    11110xxx 10xxxxxx 10xxxxxx 10xxxxxx           valid 4-byte
     */
    while ((c = utf[0])) {      /* string is 0-terminated */
        ix = 0;
        if ((c & 0x80) == 0x00) {   /* 1-byte code, starts with 10 */
            ix = 1;
    } else if ((c & 0xe0) == 0xc0) {/* 2-byte code, starts with 110 */
        if ((utf[1] & 0xc0 ) != 0x80)
            return 0;
        ix = 2;
    } else if ((c & 0xf0) == 0xe0) {/* 3-byte code, starts with 1110 */
        if (((utf[1] & 0xc0) != 0x80) ||
            ((utf[2] & 0xc0) != 0x80))
            return 0;
        ix = 3;
    } else if ((c & 0xf8) == 0xf0) {/* 4-byte code, starts with 11110 */
        if (((utf[1] & 0xc0) != 0x80) ||
            ((utf[2] & 0xc0) != 0x80) ||
        ((utf[3] & 0xc0) != 0x80))
            return 0;
        ix = 4;
    } else              /* unknown encoding */
        return 0;
        utf += ix;
      }
      return(1);
}
 
int
xmlUTF8Strsize(const xmlChar *utf, int len) {
    const xmlChar *ptr=utf;
    int ch;
    size_t ret;
 
    if (utf == NULL)
        return(0);
 
    if (len <= 0)
        return(0);
 
    while ( len-- > 0) {
        if ( !*ptr )
            break;
        if ( (ch = *ptr++) & 0x80)
            while ((ch<<=1) & 0x80 ) {
        if (*ptr == 0) break;
                ptr++;
        }
    }
    ret = ptr - utf;
    return (ret > INT_MAX ? 0 : ret);
}
 
 
xmlChar *
xmlUTF8Strndup(const xmlChar *utf, int len) {
    xmlChar *ret;
    int i;
 
    if ((utf == NULL) || (len < 0)) return(NULL);
    i = xmlUTF8Strsize(utf, len);
    ret = (xmlChar *) xmlMallocAtomic((size_t) i + 1);
    if (ret == NULL) {
        return(NULL);
    }
    memcpy(ret, utf, i);
    ret[i] = 0;
    return(ret);
}
 
const xmlChar *
xmlUTF8Strpos(const xmlChar *utf, int pos) {
    int ch;
 
    if (utf == NULL) return(NULL);
    if (pos < 0)
        return(NULL);
    while (pos--) {
        if ((ch=*utf++) == 0) return(NULL);
        if ( ch & 0x80 ) {
            /* if not simple ascii, verify proper format */
            if ( (ch & 0xc0) != 0xc0 )
                return(NULL);
            /* then skip over remaining bytes for this char */
            while ( (ch <<= 1) & 0x80 )
                if ( (*utf++ & 0xc0) != 0x80 )
                    return(NULL);
        }
    }
    return((xmlChar *)utf);
}
 
int
xmlUTF8Strloc(const xmlChar *utf, const xmlChar *utfchar) {
    size_t i;
    int size;
    int ch;
 
    if (utf==NULL || utfchar==NULL) return -1;
    size = xmlUTF8Strsize(utfchar, 1);
        for(i=0; (ch=*utf) != 0; i++) {
            if (xmlStrncmp(utf, utfchar, size)==0)
                return(i > INT_MAX ? 0 : i);
            utf++;
            if ( ch & 0x80 ) {
                /* if not simple ascii, verify proper format */
                if ( (ch & 0xc0) != 0xc0 )
                    return(-1);
                /* then skip over remaining bytes for this char */
                while ( (ch <<= 1) & 0x80 )
                    if ( (*utf++ & 0xc0) != 0x80 )
                        return(-1);
            }
        }
 
    return(-1);
}
xmlChar *
xmlUTF8Strsub(const xmlChar *utf, int start, int len) {
    int i;
    int ch;
 
    if (utf == NULL) return(NULL);
    if (start < 0) return(NULL);
    if (len < 0) return(NULL);
 
    /*
     * Skip over any leading chars
     */
    for (i = 0;i < start;i++) {
        if ((ch=*utf++) == 0) return(NULL);
        if ( ch & 0x80 ) {
            /* if not simple ascii, verify proper format */
            if ( (ch & 0xc0) != 0xc0 )
                return(NULL);
            /* then skip over remaining bytes for this char */
            while ( (ch <<= 1) & 0x80 )
                if ( (*utf++ & 0xc0) != 0x80 )
                    return(NULL);
        }
    }
 
    return(xmlUTF8Strndup(utf, len));
}
 
xmlChar *
xmlEscapeFormatString(xmlChar **msg)
{
    xmlChar *msgPtr = NULL;
    xmlChar *result = NULL;
    xmlChar *resultPtr = NULL;
    size_t count = 0;
    size_t msgLen = 0;
    size_t resultLen = 0;
 
    if (!msg || !*msg)
        return(NULL);
 
    for (msgPtr = *msg; *msgPtr != '\0'; ++msgPtr) {
        ++msgLen;
        if (*msgPtr == '%')
            ++count;
    }
 
    if (count == 0)
        return(*msg);
 
    if ((count > INT_MAX) || (msgLen > INT_MAX - count))
        return(NULL);
    resultLen = msgLen + count + 1;
    result = (xmlChar *) xmlMallocAtomic(resultLen);
    if (result == NULL) {
        /* Clear *msg to prevent format string vulnerabilities in
           out-of-memory situations. */
        xmlFree(*msg);
        *msg = NULL;
        return(NULL);
    }
 
    for (msgPtr = *msg, resultPtr = result; *msgPtr != '\0'; ++msgPtr, ++resultPtr) {
        *resultPtr = *msgPtr;
        if (*msgPtr == '%')
            *(++resultPtr) = '%';
    }
    result[resultLen - 1] = '\0';
 
    xmlFree(*msg);
    *msg = result;
 
    return *msg;
}