ref: 1f10ca1069d145f9d77575375b1f7a0bbd548c42
parent: 39c1f29555cf6a4607d4d975767d54154fdda7a6
author: rrt <rrt>
date: Sun Dec 17 18:53:12 EST 2006
Make the code a bit more robust, and make the compression arrays local to compress, as only it and its direct callees need them.
--- a/src/hcom.c
+++ b/src/hcom.c
@@ -48,10 +48,7 @@
uint32_t current;
short sample;
/* Dictionary */
- dictent *newdict;
dictent *de;
- long *codes;
- long *codesize;
int32_t new_checksum;
int nbits;
int32_t curword;
@@ -300,27 +297,26 @@
return len;
}
-static void makecodes(ft_t ft, int e, int c, int s, int b)
+static void makecodes(int e, int c, int s, int b, dictent newdict[511], long codes[256], long codesize[256])
{- struct readpriv *p = (struct readpriv *)ft->priv;
- if(p->newdict[e].dict_leftson < 0) {- p->codes[p->newdict[e].dict_rightson] = c;
- p->codesize[p->newdict[e].dict_rightson] = s;
+ assert(b); /* Prevent stack overflow */
+ if (newdict[e].dict_leftson < 0) {+ codes[newdict[e].dict_rightson] = c;
+ codesize[newdict[e].dict_rightson] = s;
} else {- makecodes(ft, p->newdict[e].dict_leftson, c, s + 1, b << 1);
- makecodes(ft, p->newdict[e].dict_rightson, c + b, s + 1, b << 1);
+ makecodes(newdict[e].dict_leftson, c, s + 1, b << 1, newdict, codes, codesize);
+ makecodes(newdict[e].dict_rightson, c + b, s + 1, b << 1, newdict, codes, codesize);
}
}
-
-static void putcode(ft_t ft, unsigned char c, unsigned char **df)
+static void putcode(ft_t ft, long codes[256], long codesize[256], unsigned char c, unsigned char **df)
{struct readpriv *p = (struct readpriv *) ft->priv;
long code, size;
int i;
- code = p->codes[c];
- size = p->codesize[c];
+ code = codes[c];
+ size = codesize[c];
for(i = 0; i < size; i++) {p->curword <<= 1;
if (code & 1)
@@ -344,14 +340,16 @@
unsigned char *ddf, *dfp;
short dictsize;
int frequtable[256];
+ long codes[256], codesize[256];
+ dictent newdict[511];
int i, sample, j, k, d, l, frequcount;
- p->newdict = (dictent *)xmalloc(511 * sizeof(dictent));
- p->codes = (long *)xcalloc(256, sizeof(long));
- p->codesize = (long *)xcalloc(256, sizeof(long));
-
sample = *datafork;
- memset(frequtable, 0, sizeof(int) * 256);
+ memset(frequtable, 0, sizeof(frequtable));
+ memset(codes, 0, sizeof(codes));
+ memset(codesize, 0, sizeof(codesize));
+ memset(newdict, 0, sizeof(newdict));
+
for (i = 1; i < *dl; i++) {d = (datafork[i] - (sample & 0xff)) & 0xff; /* creates absolute entries LMS */
sample = datafork[i];
@@ -359,7 +357,7 @@
assert(d >= 0 && d <= 255); /* check our table is accessed correctly */
frequtable[d]++;
}
- p->de = p->newdict;
+ p->de = newdict;
for (i = 0; i < 256; i++)
if (frequtable[i] != 0) {p->de->frequ = -frequtable[i];
@@ -367,42 +365,42 @@
p->de->dict_rightson = i;
p->de++;
}
- frequcount = p->de - p->newdict;
+ frequcount = p->de - newdict;
for (i = 0; i < frequcount; i++) { for (j = i + 1; j < frequcount; j++) {- if (p->newdict[i].frequ > p->newdict[j].frequ) {- k = p->newdict[i].frequ;
- p->newdict[i].frequ = p->newdict[j].frequ;
- p->newdict[j].frequ = k;
- k = p->newdict[i].dict_leftson;
- p->newdict[i].dict_leftson = p->newdict[j].dict_leftson;
- p->newdict[j].dict_leftson = k;
- k = p->newdict[i].dict_rightson;
- p->newdict[i].dict_rightson = p->newdict[j].dict_rightson;
- p->newdict[j].dict_rightson = k;
+ if (newdict[i].frequ > newdict[j].frequ) {+ k = newdict[i].frequ;
+ newdict[i].frequ = newdict[j].frequ;
+ newdict[j].frequ = k;
+ k = newdict[i].dict_leftson;
+ newdict[i].dict_leftson = newdict[j].dict_leftson;
+ newdict[j].dict_leftson = k;
+ k = newdict[i].dict_rightson;
+ newdict[i].dict_rightson = newdict[j].dict_rightson;
+ newdict[j].dict_rightson = k;
}
}
}
while (frequcount > 1) {j = frequcount - 1;
- p->de->frequ = p->newdict[j - 1].frequ;
- p->de->dict_leftson = p->newdict[j - 1].dict_leftson;
- p->de->dict_rightson = p->newdict[j - 1].dict_rightson;
- l = p->newdict[j - 1].frequ + p->newdict[j].frequ;
- for (i = j - 2; i >= 0 && l < p->newdict[i].frequ; i--)
- p->newdict[i + 1] = p->newdict[i];
+ p->de->frequ = newdict[j - 1].frequ;
+ p->de->dict_leftson = newdict[j - 1].dict_leftson;
+ p->de->dict_rightson = newdict[j - 1].dict_rightson;
+ l = newdict[j - 1].frequ + newdict[j].frequ;
+ for (i = j - 2; i >= 0 && l < newdict[i].frequ; i--)
+ newdict[i + 1] = newdict[i];
i = i + 1;
- p->newdict[i].frequ = l;
- p->newdict[i].dict_leftson = j;
- p->newdict[i].dict_rightson = p->de - p->newdict;
+ newdict[i].frequ = l;
+ newdict[i].dict_leftson = j;
+ newdict[i].dict_rightson = p->de - newdict;
p->de++;
frequcount--;
}
- dictsize = p->de - p->newdict;
- makecodes(ft, 0, 0, 0, 1);
+ dictsize = p->de - newdict;
+ makecodes(0, 0, 0, 1, newdict, codes, codesize);
l = 0;
for (i = 0; i < 256; i++)
- l += frequtable[i] * p->codesize[i];
+ l += frequtable[i] * codesize[i];
l = (((l + 31) >> 5) << 2) + 24 + dictsize * 4;
st_debug(" Original size: %6d bytes", *dl); st_debug("Compressed size: %6d bytes", l);@@ -409,8 +407,8 @@
datafork = (unsigned char *)xmalloc((unsigned)l);
ddf = datafork + 22;
for(i = 0; i < dictsize; i++) {- put16_be(&ddf, p->newdict[i].dict_leftson);
- put16_be(&ddf, p->newdict[i].dict_rightson);
+ put16_be(&ddf, newdict[i].dict_leftson);
+ put16_be(&ddf, newdict[i].dict_rightson);
}
*ddf++ = 0;
*ddf++ = *(*df)++;
@@ -418,11 +416,11 @@
p->nbits = 0;
p->curword = 0;
for (i = 1; i < *dl; i++)
- putcode(ft, *(*df)++, &ddf);
+ putcode(ft, codes, codesize, *(*df)++, &ddf);
if (p->nbits != 0) {- p->codes[0] = 0;
- p->codesize[0] = 32 - p->nbits;
- putcode(ft, 0, &ddf);
+ codes[0] = 0;
+ codesize[0] = 32 - p->nbits;
+ putcode(ft, codes, codesize, 0, &ddf);
}
strncpy((char *)datafork, "HCOM", 4);
dfp = datafork + 4;
@@ -434,10 +432,6 @@
put16_be(&dfp, dictsize);
*df = datafork; /* reassign passed pointer to new datafork */
*dl = l; /* and its compressed length */
-
- free(p->newdict);
- free(p->codes);
- free(p->codesize);
}
/* End of hcom utility routines */
@@ -450,8 +444,9 @@
int rc = ST_SUCCESS;
/* Compress it all at once */
- compress(ft, &compressed_data, (int32_t *)&compressed_len, (double) ft->info.rate);
- free((char *) p->data);
+ if (compressed_len)
+ compress(ft, &compressed_data, (int32_t *)&compressed_len, (double) ft->info.rate);
+ free((char *)p->data);
/* Write the header */
st_writebuf(ft, (void *)"\000\001A", 1, 3); /* Dummy file name "A" */
@@ -473,7 +468,7 @@
if (rc == ST_SUCCESS)
/* Pad the compressed_data fork to a multiple of 128 bytes */
- st_padbytes(ft, 128 - (int) (compressed_len%128));
+ st_padbytes(ft, 128 - (int) (compressed_len % 128));
return rc;
}