X-Git-Url: https://iam.tj/gitweb/gitweb.cgi?p=firmware_extractor.git;a=blobdiff_plain;f=lzw_decode.c;fp=lzw_decode.c;h=e33156039ee40f65c6e184e12eafa8117551cea0;hp=0000000000000000000000000000000000000000;hb=1693f804f61fb9856114c39185ea3eb46e3f93e5;hpb=471193f5356782a85ea6378fd4355db97930d122

diff --git a/lzw_decode.c b/lzw_decode.c
new file mode 100644
index 0000000..e331560
--- /dev/null
+++ b/lzw_decode.c
@@ -0,0 +1,212 @@
+/*
+ * LZW decoder
+ * Copyright (c) 2003 Fabrice Bellard.
+ * Copyright (c) 2006 Konstantin Shishkov.
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+
+#ifdef COMPRESSED_CONFIG_FILE
+
+#include "cms_lzw.h"
+
+
+
+static const uint16_t mask[17] =
+{
+    0x0000, 0x0001, 0x0003, 0x0007,
+    0x000F, 0x001F, 0x003F, 0x007F,
+    0x00FF, 0x01FF, 0x03FF, 0x07FF,
+    0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF
+};
+
+
+enum FF_LZW_MODES{
+    FF_LZW_GIF,
+    FF_LZW_TIFF
+};
+
+
+/* get one code from stream */
+static int lzw_get_code(LZWDecoderState *s)
+{
+    int c;
+
+    /* always use TIFF mode */
+
+    while (s->bbits < s->cursize) {
+        s->bbuf = (s->bbuf << 8) | (*s->pbuf++);
+        s->bbits += 8;
+    }
+    //    printf("TIFF: bbuf=0x%08x bbits=%d cursize=%d\n", s->bbuf, s->bbits, s->cursize);
+    c = s->bbuf >> (s->bbits - s->cursize);
+
+    s->bbits -= s->cursize;
+
+    //    printf("bbits=%d c=0x%08x curmask=0x%08x\n", s->bbits, c, s->curmask);
+    return c & s->curmask;
+}
+
+
+void ff_lzw_decode_tail(LZWDecoderState *s)
+{
+    /* always use TIFF mode */
+    s->pbuf= s->ebuf;
+}
+
+
+CmsRet cmsLzw_initDecoder(LZWDecoderState **p, UINT8 *inbuf, UINT32 inbuf_size)
+{
+    LZWDecoderState *s;
+    int mode = FF_LZW_TIFF;  /* always use TIFF mode */
+    int csize = 8;  /* the encoder side has this hardcoded, so hardcode here too */
+
+    *p = (LZWDecoderState *) cmsMem_alloc(sizeof(LZWDecoderState), ALLOC_ZEROIZE);
+    if (*p == NULL)
+    {
+       cmsLog_error("could not allocate %d bytes for decoder state", sizeof(LZWDecoderState));
+       return CMSRET_RESOURCE_EXCEEDED;
+    }
+    else
+    {
+       cmsLog_debug("%d bytes allocated for decoder state", sizeof(LZWDecoderState));
+    }
+
+    s = *p;
+
+    /* read buffer */
+    s->pbuf = inbuf;
+    s->ebuf = s->pbuf + inbuf_size;
+    s->bbuf = 0;
+    s->bbits = 0;
+    s->bs = 0;
+
+    /* decoder */
+    s->codesize = csize;
+    s->cursize = s->codesize + 1;
+    s->curmask = mask[s->cursize];
+    s->top_slot = 1 << s->cursize;
+    s->clear_code = 1 << s->codesize;
+    s->end_code = s->clear_code + 1;
+    s->slot = s->newcodes = s->clear_code + 2;
+    s->oc = s->fc = -1;
+    s->sp = s->stack;
+
+    s->mode = mode;
+    s->extra_slot = (s->mode == FF_LZW_TIFF);
+
+    return CMSRET_SUCCESS;
+}
+
+
+SINT32 cmsLzw_decode(LZWDecoderState *s, UINT8 *outbuf, UINT32 outlen)
+{
+    UINT32 l;
+    int c, code, oc, fc;
+    uint8_t *sp;
+
+    if (s->end_code < 0)
+        return -1;
+
+    l = outlen;
+    sp = s->sp;
+    oc = s->oc;
+    fc = s->fc;
+
+    for (;;) {
+
+        while (sp > s->stack) {
+           //           printf("transfer stack to buf, sp=0x%02x buf=%p\n", *sp, outbuf);
+            *outbuf++ = *(--sp);
+            if ((--l) == 0)
+                goto the_end;
+        }
+
+        c = lzw_get_code(s);
+        if (c == s->end_code) {
+            cmsLog_debug("got end code %d", c);
+            break;
+        } else if (c == s->clear_code) {
+            cmsLog_debug("got clear code %d", c);
+            s->cursize = s->codesize + 1;
+            s->curmask = mask[s->cursize];
+            s->slot = s->newcodes;
+            s->top_slot = 1 << s->cursize;
+            fc= oc= -1;
+        } else {
+            code = c;
+            //            printf("got valid code %d (0x%02x)\n", c, c);
+
+            if (code == s->slot && fc>=0) {
+                *sp++ = fc;
+                code = oc;
+            }else if(code >= s->slot) {
+                cmsLog_error("code %d greater than slot %d", code, s->slot);
+                break;
+            }
+
+            while (code >= s->newcodes) {
+               //               printf("transfer suffix to to sp \n");
+                *sp++ = s->suffix[code];
+                code = s->prefix[code];
+            }
+
+            //            printf("sp=%p gets code %d\n", sp, code);
+            *sp++ = code;
+
+
+            if (s->slot < s->top_slot && oc>=0) {
+               //                printf("suffix[%d]=%d prefix[%d]=%d\n", s->slot, code, s->slot, oc);
+                s->suffix[s->slot] = code;
+                s->prefix[s->slot++] = oc;
+            }
+            fc = code;
+            oc = c;
+
+            if (s->slot >= s->top_slot - s->extra_slot) {
+                if (s->cursize < LZW_MAXBITS) {
+                    s->top_slot <<= 1;
+                    s->curmask = mask[++s->cursize];
+                    //                    printf("new top_slot=0x%x curmask=0x%x\n", s->top_slot, s->curmask);
+                }
+            }
+        }
+    }  // end of for loop
+
+
+    s->end_code = -1;
+  the_end:
+    s->sp = sp;
+    s->oc = oc;
+    s->fc = fc;
+
+    cmsLog_debug("about to return, outlen=%d l=%d\n", outlen, l);
+    return outlen - l;
+}
+
+
+
+void cmsLzw_cleanupDecoder(LZWDecoderState **s)
+{
+   cmsMem_free(*s);
+   *s = NULL;
+}
+
+
+
+#endif /* COMPRESSED_CONFIG_FILE */