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-rw-r--r--libpng/infcodes.c257
1 files changed, 257 insertions, 0 deletions
diff --git a/libpng/infcodes.c b/libpng/infcodes.c
new file mode 100644
index 0000000..d4e5ee9
--- /dev/null
+++ b/libpng/infcodes.c
@@ -0,0 +1,257 @@
+/* infcodes.c -- process literals and length/distance pairs
+ * Copyright (C) 1995-1998 Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+#include "zutil.h"
+#include "inftrees.h"
+#include "infblock.h"
+#include "infcodes.h"
+#include "infutil.h"
+#include "inffast.h"
+
+/* simplify the use of the inflate_huft type with some defines */
+#define exop word.what.Exop
+#define bits word.what.Bits
+
+typedef enum { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
+ START, /* x: set up for LEN */
+ LEN, /* i: get length/literal/eob next */
+ LENEXT, /* i: getting length extra (have base) */
+ DIST, /* i: get distance next */
+ DISTEXT, /* i: getting distance extra */
+ COPY, /* o: copying bytes in window, waiting for space */
+ LIT, /* o: got literal, waiting for output space */
+ WASH, /* o: got eob, possibly still output waiting */
+ END, /* x: got eob and all data flushed */
+ BADCODE} /* x: got error */
+inflate_codes_mode;
+
+/* inflate codes private state */
+struct inflate_codes_state {
+
+ /* mode */
+ inflate_codes_mode mode; /* current inflate_codes mode */
+
+ /* mode dependent information */
+ uInt len;
+ union {
+ struct {
+ inflate_huft *tree; /* pointer into tree */
+ uInt need; /* bits needed */
+ } code; /* if LEN or DIST, where in tree */
+ uInt lit; /* if LIT, literal */
+ struct {
+ uInt get; /* bits to get for extra */
+ uInt dist; /* distance back to copy from */
+ } copy; /* if EXT or COPY, where and how much */
+ } sub; /* submode */
+
+ /* mode independent information */
+ Byte lbits; /* ltree bits decoded per branch */
+ Byte dbits; /* dtree bits decoder per branch */
+ inflate_huft *ltree; /* literal/length/eob tree */
+ inflate_huft *dtree; /* distance tree */
+
+};
+
+
+inflate_codes_statef *inflate_codes_new(bl, bd, tl, td, z)
+uInt bl, bd;
+inflate_huft *tl;
+inflate_huft *td; /* need separate declaration for Borland C++ */
+z_streamp z;
+{
+ inflate_codes_statef *c;
+
+ if ((c = (inflate_codes_statef *)
+ ZALLOC(z,1,sizeof(struct inflate_codes_state))) != Z_NULL)
+ {
+ c->mode = START;
+ c->lbits = (Byte)bl;
+ c->dbits = (Byte)bd;
+ c->ltree = tl;
+ c->dtree = td;
+ Tracev((stderr, "inflate: codes new\n"));
+ }
+ return c;
+}
+
+
+int inflate_codes(s, z, r)
+inflate_blocks_statef *s;
+z_streamp z;
+int r;
+{
+ uInt j; /* temporary storage */
+ inflate_huft *t; /* temporary pointer */
+ uInt e; /* extra bits or operation */
+ uLong b; /* bit buffer */
+ uInt k; /* bits in bit buffer */
+ Bytef *p; /* input data pointer */
+ uInt n; /* bytes available there */
+ Bytef *q; /* output window write pointer */
+ uInt m; /* bytes to end of window or read pointer */
+ Bytef *f; /* pointer to copy strings from */
+ inflate_codes_statef *c = s->sub.decode.codes; /* codes state */
+
+ /* copy input/output information to locals (UPDATE macro restores) */
+ LOAD
+
+ /* process input and output based on current state */
+ while (1) switch (c->mode)
+ { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
+ case START: /* x: set up for LEN */
+#ifndef SLOW
+ if (m >= 258 && n >= 10)
+ {
+ UPDATE
+ r = inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z);
+ LOAD
+ if (r != Z_OK)
+ {
+ c->mode = r == Z_STREAM_END ? WASH : BADCODE;
+ break;
+ }
+ }
+#endif /* !SLOW */
+ c->sub.code.need = c->lbits;
+ c->sub.code.tree = c->ltree;
+ c->mode = LEN;
+ case LEN: /* i: get length/literal/eob next */
+ j = c->sub.code.need;
+ NEEDBITS(j)
+ t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
+ DUMPBITS(t->bits)
+ e = (uInt)(t->exop);
+ if (e == 0) /* literal */
+ {
+ c->sub.lit = t->base;
+ Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
+ "inflate: literal '%c'\n" :
+ "inflate: literal 0x%02x\n", t->base));
+ c->mode = LIT;
+ break;
+ }
+ if (e & 16) /* length */
+ {
+ c->sub.copy.get = e & 15;
+ c->len = t->base;
+ c->mode = LENEXT;
+ break;
+ }
+ if ((e & 64) == 0) /* next table */
+ {
+ c->sub.code.need = e;
+ c->sub.code.tree = t + t->base;
+ break;
+ }
+ if (e & 32) /* end of block */
+ {
+ Tracevv((stderr, "inflate: end of block\n"));
+ c->mode = WASH;
+ break;
+ }
+ c->mode = BADCODE; /* invalid code */
+ z->msg = (char*)"invalid literal/length code";
+ r = Z_DATA_ERROR;
+ LEAVE
+ case LENEXT: /* i: getting length extra (have base) */
+ j = c->sub.copy.get;
+ NEEDBITS(j)
+ c->len += (uInt)b & inflate_mask[j];
+ DUMPBITS(j)
+ c->sub.code.need = c->dbits;
+ c->sub.code.tree = c->dtree;
+ Tracevv((stderr, "inflate: length %u\n", c->len));
+ c->mode = DIST;
+ case DIST: /* i: get distance next */
+ j = c->sub.code.need;
+ NEEDBITS(j)
+ t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
+ DUMPBITS(t->bits)
+ e = (uInt)(t->exop);
+ if (e & 16) /* distance */
+ {
+ c->sub.copy.get = e & 15;
+ c->sub.copy.dist = t->base;
+ c->mode = DISTEXT;
+ break;
+ }
+ if ((e & 64) == 0) /* next table */
+ {
+ c->sub.code.need = e;
+ c->sub.code.tree = t + t->base;
+ break;
+ }
+ c->mode = BADCODE; /* invalid code */
+ z->msg = (char*)"invalid distance code";
+ r = Z_DATA_ERROR;
+ LEAVE
+ case DISTEXT: /* i: getting distance extra */
+ j = c->sub.copy.get;
+ NEEDBITS(j)
+ c->sub.copy.dist += (uInt)b & inflate_mask[j];
+ DUMPBITS(j)
+ Tracevv((stderr, "inflate: distance %u\n", c->sub.copy.dist));
+ c->mode = COPY;
+ case COPY: /* o: copying bytes in window, waiting for space */
+#ifndef __TURBOC__ /* Turbo C bug for following expression */
+ f = (uInt)(q - s->window) < c->sub.copy.dist ?
+ s->end - (c->sub.copy.dist - (q - s->window)) :
+ q - c->sub.copy.dist;
+#else
+ f = q - c->sub.copy.dist;
+ if ((uInt)(q - s->window) < c->sub.copy.dist)
+ f = s->end - (c->sub.copy.dist - (uInt)(q - s->window));
+#endif
+ while (c->len)
+ {
+ NEEDOUT
+ OUTBYTE(*f++)
+ if (f == s->end)
+ f = s->window;
+ c->len--;
+ }
+ c->mode = START;
+ break;
+ case LIT: /* o: got literal, waiting for output space */
+ NEEDOUT
+ OUTBYTE(c->sub.lit)
+ c->mode = START;
+ break;
+ case WASH: /* o: got eob, possibly more output */
+ if (k > 7) /* return unused byte, if any */
+ {
+ Assert(k < 16, "inflate_codes grabbed too many bytes")
+ k -= 8;
+ n++;
+ p--; /* can always return one */
+ }
+ FLUSH
+ if (s->read != s->write)
+ LEAVE
+ c->mode = END;
+ case END:
+ r = Z_STREAM_END;
+ LEAVE
+ case BADCODE: /* x: got error */
+ r = Z_DATA_ERROR;
+ LEAVE
+ default:
+ r = Z_STREAM_ERROR;
+ LEAVE
+ }
+#ifdef NEED_DUMMY_RETURN
+ return Z_STREAM_ERROR; /* Some dumb compilers complain without this */
+#endif
+}
+
+
+void inflate_codes_free(c, z)
+inflate_codes_statef *c;
+z_streamp z;
+{
+ ZFREE(z, c);
+ Tracev((stderr, "inflate: codes free\n"));
+}
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