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#include "..\commons.h"
#define CODELEN 65536
#define BASEBITREC 5000
#define UNCOMPRESSED '\002'
#define MAGIC "hz0"
#define MAGIC_ENCRYPT "hz1"
#define MAGICLEN (sizeof(MAGIC) - 1)
int Hunzip::fail(const char * err, const char * par) {
fprintf(stderr, err, par);
return -1;
}
Hunzip::Hunzip(const char * file, const char * key) {
bufsiz = 0;
lastbit = 0;
inc = 0;
outc = 0;
dec = NULL;
fin = NULL;
filename = (char *) malloc(strlen(file) + 1);
if (filename) strcpy(filename, file);
if (getcode(key) == -1) bufsiz = -1;
else bufsiz = getbuf();
}
int Hunzip::getcode(const char * key) {
unsigned char c[2];
int i, j, n, p;
int allocatedbit = BASEBITREC;
const char * enc = key;
if (!filename) return -1;
fin = fopen(filename, "rb");
if (!fin) return -1;
// read magic number
if ((fread(in, 1, 3, fin) < MAGICLEN)
|| !(strncmp(MAGIC, in, MAGICLEN) == 0 ||
strncmp(MAGIC_ENCRYPT, in, MAGICLEN) == 0)) {
return fail(MSG_FORMAT, filename);
}
// check encryption
if (strncmp(MAGIC_ENCRYPT, in, MAGICLEN) == 0) {
unsigned char cs;
if (!key) return fail(MSG_KEY, filename);
if (fread(&c, 1, 1, fin) < 1) return fail(MSG_FORMAT, filename);
for (cs = 0; *enc; enc++) cs ^= *enc;
if (cs != c[0]) return fail(MSG_KEY, filename);
enc = key;
} else key = NULL;
// read record count
if (fread(&c, 1, 2, fin) < 2) return fail(MSG_FORMAT, filename);
if (key) {
c[0] ^= *enc;
if (*(++enc) == '\0') enc = key;
c[1] ^= *enc;
}
n = ((int) c[0] << 8) + c[1];
dec = (struct bit *) malloc(BASEBITREC * sizeof(struct bit));
if (!dec) return fail(MSG_MEMORY, filename);
dec[0].v[0] = 0;
dec[0].v[1] = 0;
// read codes
for (i = 0; i < n; i++) {
unsigned char l;
if (fread(c, 1, 2, fin) < 2) return fail(MSG_FORMAT, filename);
if (key) {
if (*(++enc) == '\0') enc = key;
c[0] ^= *enc;
if (*(++enc) == '\0') enc = key;
c[1] ^= *enc;
}
if (fread(&l, 1, 1, fin) < 1) return fail(MSG_FORMAT, filename);
if (key) {
if (*(++enc) == '\0') enc = key;
l ^= *enc;
}
if (fread(in, 1, l/8+1, fin) < (size_t) l/8+1) return fail(MSG_FORMAT, filename);
if (key) for (j = 0; j <= l/8; j++) {
if (*(++enc) == '\0') enc = key;
in[j] ^= *enc;
}
p = 0;
for (j = 0; j < l; j++) {
int b = (in[j/8] & (1 << (7 - (j % 8)))) ? 1 : 0;
int oldp = p;
p = dec[p].v[b];
if (p == 0) {
lastbit++;
if (lastbit == allocatedbit) {
allocatedbit += BASEBITREC;
dec = (struct bit *) realloc(dec, allocatedbit * sizeof(struct bit));
}
dec[lastbit].v[0] = 0;
dec[lastbit].v[1] = 0;
dec[oldp].v[b] = lastbit;
p = lastbit;
}
}
dec[p].c[0] = c[0];
dec[p].c[1] = c[1];
}
return 0;
}
Hunzip::~Hunzip()
{
if (dec) free(dec);
if (fin) fclose(fin);
if (filename) free(filename);
}
int Hunzip::getbuf() {
int p = 0;
int o = 0;
do {
if (inc == 0) inbits = fread(in, 1, BUFSIZE, fin) * 8;
for (; inc < inbits; inc++) {
int b = (in[inc / 8] & (1 << (7 - (inc % 8)))) ? 1 : 0;
int oldp = p;
p = dec[p].v[b];
if (p == 0) {
if (oldp == lastbit) {
fclose(fin);
fin = NULL;
// add last odd byte
if (dec[lastbit].c[0]) out[o++] = dec[lastbit].c[1];
return o;
}
out[o++] = dec[oldp].c[0];
out[o++] = dec[oldp].c[1];
if (o == BUFSIZE) return o;
p = dec[p].v[b];
}
}
inc = 0;
} while (inbits == BUFSIZE * 8);
return fail(MSG_FORMAT, filename);
}
const char * Hunzip::getline() {
char linebuf[BUFSIZE];
int l = 0, eol = 0, left = 0, right = 0;
if (bufsiz == -1) return NULL;
while (l < bufsiz && !eol) {
linebuf[l++] = out[outc];
switch (out[outc]) {
case '\t': break;
case 31: { // escape
if (++outc == bufsiz) {
bufsiz = getbuf();
outc = 0;
}
linebuf[l - 1] = out[outc];
break;
}
case ' ': break;
default: if (((unsigned char) out[outc]) < 47) {
if (out[outc] > 32) {
right = out[outc] - 31;
if (++outc == bufsiz) {
bufsiz = getbuf();
outc = 0;
}
}
if (out[outc] == 30) left = 9; else left = out[outc];
linebuf[l-1] = '\n';
eol = 1;
}
}
if (++outc == bufsiz) {
outc = 0;
bufsiz = fin ? getbuf(): -1;
}
}
if (right) strcpy(linebuf + l - 1, line + strlen(line) - right - 1);
else linebuf[l] = '\0';
strcpy(line + left, linebuf);
return line;
}
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