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sf_code/esrgpcpj/shared/tclxtens/crchashextns.c revision 25 by dashley, Sat Oct 8 06:43:03 2016 UTC projs/trunk/shared_source/c_tclxtens_7_5/crchashextns.c revision 71 by dashley, Sat Nov 5 11:07:06 2016 UTC
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1  /* $Header: /cvsroot/esrg/sfesrg/esrgpcpj/shared/tclxtens/crchashextns.c,v 1.2 2001/07/26 23:18:07 dtashley Exp $ */  //$Header$
2    //-------------------------------------------------------------------------------------------------
3  //--------------------------------------------------------------------------------  //This file is part of "David T. Ashley's Shared Source Code", a set of shared components
4  //Copyright 2001 David T. Ashley  //integrated into many of David T. Ashley's projects.
5  //-------------------------------------------------------------------------------------------------  //-------------------------------------------------------------------------------------------------
6  //This source code and any program in which it is compiled/used is provided under the GNU GENERAL  //This source code and any program in which it is compiled/used is provided under the MIT License,
7  //PUBLIC LICENSE, Version 3, full license text below.  //reproduced below.
8  //-------------------------------------------------------------------------------------------------  //-------------------------------------------------------------------------------------------------
9  //                    GNU GENERAL PUBLIC LICENSE  //Permission is hereby granted, free of charge, to any person obtaining a copy of
10  //                       Version 3, 29 June 2007  //this software and associated documentation files(the "Software"), to deal in the
11  //  //Software without restriction, including without limitation the rights to use,
12  // Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>  //copy, modify, merge, publish, distribute, sublicense, and / or sell copies of the
13  // Everyone is permitted to copy and distribute verbatim copies  //Software, and to permit persons to whom the Software is furnished to do so,
14  // of this license document, but changing it is not allowed.  //subject to the following conditions :
15  //  //
16  //                            Preamble  //The above copyright notice and this permission notice shall be included in all
17  //  //copies or substantial portions of the Software.
18  //  The GNU General Public License is a free, copyleft license for  //
19  //software and other kinds of works.  //THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20  //  //IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21  //  The licenses for most software and other practical works are designed  //FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
22  //to take away your freedom to share and change the works.  By contrast,  //AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23  //the GNU General Public License is intended to guarantee your freedom to  //LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24  //share and change all versions of a program--to make sure it remains free  //OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
25  //software for all its users.  We, the Free Software Foundation, use the  //SOFTWARE.
26  //GNU General Public License for most of our software; it applies also to  //-------------------------------------------------------------------------------------------------
27  //any other work released this way by its authors.  You can apply it to  #define MODULE_CRCHASHEXTNS
28  //your programs, too.  
29  //  #include <string.h>
30  //  When we speak of free software, we are referring to freedom, not  
31  //price.  Our General Public Licenses are designed to make sure that you  #include "tcl.h"
32  //have the freedom to distribute copies of free software (and charge for  #include "tcldecls.h"
33  //them if you wish), that you receive source code or can get it if you  
34  //want it, that you can change the software or use pieces of it in new  #include "crchashextns.h"
35  //free programs, and that you know you can do these things.  #include "crchashfuncs.h"
36  //  
37  //  To protect your rights, we need to prevent others from denying you  #include "strfuncs.h"
38  //these rights or asking you to surrender the rights.  Therefore, you have  #include "tclalloc.h"
39  //certain responsibilities if you distribute copies of the software, or if  
40  //you modify it: responsibilities to respect the freedom of others.  
41  //  //Procedure called when the "crc32" command is encountered in a Tcl script.
42  //  For example, if you distribute copies of such a program, whether  //
43  //gratis or for a fee, you must pass on to the recipients the same  int CRCHASHEXTNS_Crc32extnCommand(ClientData dummy,
44  //freedoms that you received.  You must make sure that they, too, receive                                    Tcl_Interp *interp,
45  //or can get the source code.  And you must show them these terms so they                                    int objc,
46  //know their rights.                                    Tcl_Obj *objv[])
47  //     {
48  //  Developers that use the GNU GPL protect your rights with two steps:     Tcl_Obj *rv;
49  //(1) assert copyright on the software, and (2) offer you this License        //Value that will be returned.
50  //giving you legal permission to copy, distribute and/or modify it.     Tcl_Obj *block_obj;
51  //        //Used for file reads.
52  //  For the developers' and authors' protection, the GPL clearly explains     char buffer[11];
53  //that there is no warranty for this free software.  For both users' and        //Space for "0x" followed by 8 hex chars and terminator.
54  //authors' sake, the GPL requires that modified versions be marked as     struct CRCHASHFUNCS_Crc32StateStruct crc_state;
55  //changed, so that their problems will not be attributed erroneously to        //CRC state structure, internals nominally known and accessible to another
56  //authors of previous versions.        //another software module.
57  //     unsigned long crc;
58  //  Some devices are designed to deny users access to install or run        //Calculated CRC.
59  //modified versions of the software inside them, although the manufacturer     unsigned long bytearraysize;
60  //can do so.  This is fundamentally incompatible with the aim of        //Size of block allocated or portion used.
61  //protecting users' freedom to change the software.  The systematic     char *bytearrayptr;
62  //pattern of such abuse occurs in the area of products for individuals to        //Pointer to array of bytes.
63  //use, which is precisely where it is most unacceptable.  Therefore, we     char *fname;
64  //have designed this version of the GPL to prohibit the practice for those        //File name specified.
65  //products.  If such problems arise substantially in other domains, we     char *blockbuf;
66  //stand ready to extend this provision to those domains in future versions        //Pointer to array of bytes.
67  //of the GPL, as needed to protect the freedom of users.     Tcl_Channel chan;
68  //        //Channel opened using the Tcl libraries.
69  //  Finally, every program is threatened constantly by software patents.     int return_code, return_code_b;
70  //States should not allow patents to restrict development and use of        //Return codes from Tcl library functions.
71  //software on general-purpose computers, but in those that do, we wish to     int loop_exit_flag;
72  //avoid the special danger that patents applied to a free program could        //Looping exit flag.
73  //make it effectively proprietary.  To prevent this, the GPL assures that     int chars_read;
74  //patents cannot be used to render the program non-free.        //Number of characters read (i.e. for short read).
75  //     int block_obj_n;
76  //  The precise terms and conditions for copying, distribution and  
77  //modification follow.  
78  //     if (objc < 2 || objc > 3)
79  //                       TERMS AND CONDITIONS        {
80  //        Tcl_WrongNumArgs(interp,
81  //  0. Definitions.                         1,
82  //                         objv,
83  //  "This License" refers to version 3 of the GNU General Public License.                         "?-string? filename_or_string_value");
84  //  
85  //  "Copyright" also means copyright-like laws that apply to other kinds of        return TCL_ERROR;
86  //works, such as semiconductor masks.        }
87  //     else if (objc == 2)
88  //  "The Program" refers to any copyrightable work licensed under this        {
89  //License.  Each licensee is addressed as "you".  "Licensees" and        //Be sure that the internal crc table has been built.  This function
90  //"recipients" may be individuals or organizations.        //also returns a table correctness code.  Error out severely if the
91  //        //CRC module believes its internal data has been corrupted.
92  //  To "modify" a work means to copy from or adapt all or part of the work        if (!CRCHASHFUNCS_Crc32TableCheck())
93  //in a fashion requiring copyright permission, other than the making of an           {
94  //exact copy.  The resulting work is called a "modified version" of the           //Serious internal error.  Error out.
95  //earlier work or a work "based on" the earlier work.  
96  //           //Create the return object.
97  //  A "covered work" means either the unmodified Program or a work based           rv = Tcl_NewStringObj("CRCHASHEXTNS.C:  Serious internal error:  CRC-32 lookup table corrupted.", -1);
98  //on the Program.  
99  //           //Set the return value to be the error message.
100  //  To "propagate" a work means to do anything with it that, without           Tcl_SetObjResult(interp, rv);
101  //permission, would make you directly or secondarily liable for  
102  //infringement under applicable copyright law, except executing it on a           //Error return.
103  //computer or modifying a private copy.  Propagation includes copying,           return TCL_ERROR;
104  //distribution (with or without modification), making available to the           }
105  //public, and in some countries other activities as well.  
106  //        //We need to open a channel, run it through the CRC algorithm, and
107  //  To "convey" a work means any kind of propagation that enables other        //return results.
108  //parties to make or receive copies.  Mere interaction with a user through  
109  //a computer network, with no transfer of a copy, is not conveying.        //Get the string representation of the object.
110  //        fname = Tcl_GetString(objv[1]);
111  //  An interactive user interface displays "Appropriate Legal Notices"  
112  //to the extent that it includes a convenient and prominently visible        //Attempt to open a file channel.  The error information, if any,
113  //feature that (1) displays an appropriate copyright notice, and (2)        //will be placed in the interpreter's state.
114  //tells the user that there is no warranty for the work (except to the        chan = Tcl_OpenFileChannel(interp, fname, "r", 0);
115  //extent that warranties are provided), that licensees may convey the  
116  //work under this License, and how to view a copy of this License.  If        //There is the possibility that the channel could not be opened
117  //the interface presents a list of user commands or options, such as a        //successfully.  If there was an error, error out.
118  //menu, a prominent item in the list meets this criterion.        if (!chan)
119  //           {
120  //  1. Source Code.           //Create the return object.
121  //           rv = Tcl_NewStringObj("crc32: Tcl_OpenFileChannel() failure on file name: ", -1);
122  //  The "source code" for a work means the preferred form of the work  
123  //for making modifications to it.  "Object code" means any non-source           //Tack on the offensive argument.
124  //form of a work.           Tcl_AppendToObj(rv, fname, -1);
125  //  
126  //  A "Standard Interface" means an interface that either is an official           //Set the return value to be the error message.
127  //standard defined by a recognized standards body, or, in the case of           Tcl_SetObjResult(interp, rv);
128  //interfaces specified for a particular programming language, one that  
129  //is widely used among developers working in that language.           //Error return.
130  //           return TCL_ERROR;
131  //  The "System Libraries" of an executable work include anything, other           }
132  //than the work as a whole, that (a) is included in the normal form of  
133  //packaging a Major Component, but which is not part of that Major        //Try to set the channel encoding to binary and record the return code.
134  //Component, and (b) serves only to enable use of the work with that        return_code   = Tcl_SetChannelOption(interp, chan, "-encoding", "binary");
135  //Major Component, or to implement a Standard Interface for which an  
136  //implementation is available to the public in source code form.  A        //Try to set the channel translation mode to binary and record the return
137  //"Major Component", in this context, means a major essential component        //code.
138  //(kernel, window system, and so on) of the specific operating system        if (return_code == TCL_OK)
139  //(if any) on which the executable work runs, or a compiler used to           return_code_b = Tcl_SetChannelOption(interp, chan, "-translation", "binary");
140  //produce the work, or an object code interpreter used to run it.  
141  //        //If the attempt to set the channel encoding or translation
142  //  The "Corresponding Source" for a work in object code form means all        //didn't go well, error out.  Must also try to chose the channel because
143  //the source code needed to generate, install, and (for an executable        //it was successfully opened.
144  //work) run the object code and to modify the work, including scripts to        if ((return_code != TCL_OK) || (return_code_b != TCL_OK))
145  //control those activities.  However, it does not include the work's           {
146  //System Libraries, or general-purpose tools or generally available free           //Try to close the channel.  "interp" not supplied so as not
147  //programs which are used unmodified in performing those activities but           //to overwrite error info.
148  //which are not part of the work.  For example, Corresponding Source           Tcl_Close(NULL, chan);
149  //includes interface definition files associated with source files for  
150  //the work, and the source code for shared libraries and dynamically           //Create the return object.
151  //linked subprograms that the work is specifically designed to require,           rv = Tcl_NewStringObj("crc32: Tcl_SetChannelOption() failure.", -1);
152  //such as by intimate data communication or control flow between those  
153  //subprograms and other parts of the work.           //Set the return value to be the error message.
154  //           Tcl_SetObjResult(interp, rv);
155  //  The Corresponding Source need not include anything that users  
156  //can regenerate automatically from other parts of the Corresponding           //Error return.
157  //Source.           return TCL_ERROR;
158  //           }
159  //  The Corresponding Source for a work in source code form is that  
160  //same work.        //Allocate the object to hold the block buffer.  I've examined the
161  //        //function, and cannot do it with with a NULL pointer.  Must instead
162  //  2. Basic Permissions.        //allocate SOMETHING, although it will be destroyed immediately on
163  //        //the first read.  This will have reference count zero.
164  //  All rights granted under this License are granted for the term of        block_obj = Tcl_NewByteArrayObj("Trash", 5);
165  //copyright on the Program, and are irrevocable provided the stated  
166  //conditions are met.  This License explicitly affirms your unlimited        //Calculate the CRC.  The essential process is to keep reading
167  //permission to run the unmodified Program.  The output from running a        //and adding to the CRC until end of file.
168  //covered work is covered by this License only if the output, given its        //Open and initialize the necessary structure.
169  //content, constitutes a covered work.  This License acknowledges your        CRCHASHFUNCS_Crc32StateStructOpen(&crc_state);
170  //rights of fair use or other equivalent, as provided by copyright law.  
171  //        loop_exit_flag = 0;
172  //  You may make, run and propagate covered works that you do not  
173  //convey, without conditions so long as your license otherwise remains        do
174  //in force.  You may convey covered works to others for the sole purpose           {
175  //of having them make modifications exclusively for you, or provide you           //Grab as many chars as possible, up to 65536 of them.
176  //with facilities for running those works, provided that you comply with           //65536 was chosen because this is large enough for great
177  //the terms of this License in conveying all material for which you do           //performance, but small enough that it won't make a significant
178  //not control copyright.  Those thus making or running the covered works           //virtual memory impact.
179  //for you must do so exclusively on your behalf, under your direction           chars_read = Tcl_ReadChars(chan, block_obj, 65536, 0);
180  //and control, on terms that prohibit them from making any copies of  
181  //your copyrighted material outside their relationship with you.           //If the characters read shows as <0, this is an error
182  //           //condition.  Trap.
183  //  Conveying under any other circumstances is permitted solely under           if (chars_read < 0)
184  //the conditions stated below.  Sublicensing is not allowed; section 10              {
185  //makes it unnecessary.               //Try to close the channel.  "interp" not supplied so as not
186  //              //to overwrite error info.
187  //  3. Protecting Users' Legal Rights From Anti-Circumvention Law.              Tcl_Close(NULL, chan);
188  //  
189  //  No covered work shall be deemed part of an effective technological              //Deallocate the buffer used to accept block file reads.  Because the
190  //measure under any applicable law fulfilling obligations under article              //creation process set the reference count to zero, a single
191  //11 of the WIPO copyright treaty adopted on 20 December 1996, or              //decrement will destroy the object.
192  //similar laws prohibiting or restricting circumvention of such              Tcl_DecrRefCount(block_obj);
193  //measures.  
194  //              //Create the return object.
195  //  When you convey a covered work, you waive any legal power to forbid              rv = Tcl_NewStringObj("crc32: Tcl_ReadChars() failure.", -1);
196  //circumvention of technological measures to the extent such circumvention  
197  //is effected by exercising rights under this License with respect to              //Set the return value to be the error message.
198  //the covered work, and you disclaim any intention to limit operation or              Tcl_SetObjResult(interp, rv);
199  //modification of the work as a means of enforcing, against the work's  
200  //users, your or third parties' legal rights to forbid circumvention of              //Error return.
201  //technological measures.              return TCL_ERROR;
202  //              }
203  //  4. Conveying Verbatim Copies.  
204  //           //Obtain a pointer to the binary block that was read.
205  //  You may convey verbatim copies of the Program's source code as you           blockbuf = Tcl_GetByteArrayFromObj(block_obj, &block_obj_n);
206  //receive it, in any medium, provided that you conspicuously and  
207  //appropriately publish on each copy an appropriate copyright notice;           //Add to the CRC for those chars read.  Skip the zero case.
208  //keep intact all notices stating that this License and any           if (block_obj_n > 0)
209  //non-permissive terms added in accord with section 7 apply to the code;              {
210  //keep intact all notices of the absence of any warranty; and give all              CRCHASHFUNCS_Crc32StateStructAddData(&crc_state,
211  //recipients a copy of this License along with the Program.                                                   blockbuf,
212  //                                                   block_obj_n);
213  //  You may charge any price or no price for each copy that you convey,              }
214  //and you may offer support or warranty protection for a fee.  
215  //           //We want to exit if EOF is true.  A short read would
216  //  5. Conveying Modified Source Versions.           //also be an indication, but short read should imply
217  //           //EOF, so should not test both.
218  //  You may convey a work based on the Program, or the modifications to           return_code = Tcl_Eof(chan);
219  //produce it from the Program, in the form of source code under the           loop_exit_flag = (return_code != 0);
220  //terms of section 4, provided that you also meet all of these conditions:           } while(!loop_exit_flag);
221  //  
222  //    a) The work must carry prominent notices stating that you modified        //Extract the CRC.
223  //    it, and giving a relevant date.        crc = CRCHASHFUNCS_Crc32Extract(&crc_state);
224  //  
225  //    b) The work must carry prominent notices stating that it is        //Postprocess the structure.
226  //    released under this License and any conditions added under section        CRCHASHFUNCS_Crc32StateStructClose(&crc_state);
227  //    7.  This requirement modifies the requirement in section 4 to  
228  //    "keep intact all notices".        //Close the channel.
229  //        return_code = Tcl_Close(interp, chan);
230  //    c) You must license the entire work, as a whole, under this  
231  //    License to anyone who comes into possession of a copy.  This        //If there was an error closing the channel, error out.
232  //    License will therefore apply, along with any applicable section 7        if (return_code != TCL_OK)
233  //    additional terms, to the whole of the work, and all its parts,           {
234  //    regardless of how they are packaged.  This License gives no           //Create the return object.
235  //    permission to license the work in any other way, but it does not           rv = Tcl_NewStringObj("crc32: Tcl_Close() failure.", -1);
236  //    invalidate such permission if you have separately received it.  
237  //           //Set the return value to be the error message.
238  //    d) If the work has interactive user interfaces, each must display           Tcl_SetObjResult(interp, rv);
239  //    Appropriate Legal Notices; however, if the Program has interactive  
240  //    interfaces that do not display Appropriate Legal Notices, your           //Error return.
241  //    work need not make them do so.           return TCL_ERROR;
242  //           }
243  //  A compilation of a covered work with other separate and independent  
244  //works, which are not by their nature extensions of the covered work,        //Deallocate the buffer used to accept block file reads.  Because the
245  //and which are not combined with it such as to form a larger program,        //creation process set the reference count to zero, a single
246  //in or on a volume of a storage or distribution medium, is called an        //decrement will destroy the object.
247  //"aggregate" if the compilation and its resulting copyright are not        Tcl_DecrRefCount(block_obj);
248  //used to limit the access or legal rights of the compilation's users  
249  //beyond what the individual works permit.  Inclusion of a covered work        //Return the CRC to the caller.  No detectable errors
250  //in an aggregate does not cause this License to apply to the other        //are possible at this point.
251  //parts of the aggregate.  
252  //        //Convert the long integer to a hexadecimal representation.
253  //  6. Conveying Non-Source Forms.        Strfuncs_UlToHexString(crc, buffer+2, 1);
254  //  
255  //  You may convey a covered work in object code form under the terms        //Stuff the leading characters of the hexadecimal representation.
256  //of sections 4 and 5, provided that you also convey the        buffer[0]  = '0';
257  //machine-readable Corresponding Source under the terms of this License,        buffer[1]  = 'x';
258  //in one of these ways:  
259  //        //Stuff the string terminator.
260  //    a) Convey the object code in, or embodied in, a physical product        buffer[10] =  0;
261  //    (including a physical distribution medium), accompanied by the  
262  //    Corresponding Source fixed on a durable physical medium        //Create the return object.
263  //    customarily used for software interchange.        rv = Tcl_NewStringObj(buffer, -1);
264  //  
265  //    b) Convey the object code in, or embodied in, a physical product        //Set the return value to be the hexadecimal representation of the
266  //    (including a physical distribution medium), accompanied by a        //CRC.
267  //    written offer, valid for at least three years and valid for as        Tcl_SetObjResult(interp, rv);
268  //    long as you offer spare parts or customer support for that product  
269  //    model, to give anyone who possesses the object code either (1) a        //Everything went well, return the OK code.
270  //    copy of the Corresponding Source for all the software in the        return TCL_OK;
271  //    product that is covered by this License, on a durable physical        }
272  //    medium customarily used for software interchange, for a price no     else /* if (objc == 3) */
273  //    more than your reasonable cost of physically performing this        {
274  //    conveying of source, or (2) access to copy the        //The second parameter positively must be "-string" or a substring
275  //    Corresponding Source from a network server at no charge.        //of that.  At present, there are no competing option flags, so
276  //        //a simple substring lookup will handle it.
277  //    c) Convey individual copies of the object code with a copy of the        //Yank the string pointer.
278  //    written offer to provide the Corresponding Source.  This        bytearrayptr = Tcl_GetString(objv[1]);
279  //    alternative is allowed only occasionally and noncommercially, and  
280  //    only if you received the object code with such an offer, in accord        //If not a substring, error out.
281  //    with subsection 6b.        if ((strlen(bytearrayptr)<2) || !Strfuncs_IsSubstring(bytearrayptr, "-string"))
282  //           {
283  //    d) Convey the object code by offering access from a designated           //Create the return object.
284  //    place (gratis or for a charge), and offer equivalent access to the           rv = Tcl_NewStringObj("crc32: Unrecognized switch: ", -1);
285  //    Corresponding Source in the same way through the same place at no  
286  //    further charge.  You need not require recipients to copy the           //Tack on the offensive argument.
287  //    Corresponding Source along with the object code.  If the place to           Tcl_AppendToObj(rv, bytearrayptr, -1);
288  //    copy the object code is a network server, the Corresponding Source  
289  //    may be on a different server (operated by you or a third party)           //Set the return value to be the error message.
290  //    that supports equivalent copying facilities, provided you maintain           Tcl_SetObjResult(interp, rv);
291  //    clear directions next to the object code saying where to find the  
292  //    Corresponding Source.  Regardless of what server hosts the           //Error return.
293  //    Corresponding Source, you remain obligated to ensure that it is           return TCL_ERROR;
294  //    available for as long as needed to satisfy these requirements.           }
295  //  
296  //    e) Convey the object code using peer-to-peer transmission, provided        //Convert the last parameter to its byte representation and get a
297  //    you inform other peers where the object code and Corresponding        //pointer to this representation and the length.  This was the
298  //    Source of the work are being offered to the general public at no        //library call that Ajuba recommended.
299  //    charge under subsection 6d.        bytearrayptr = Tcl_GetByteArrayFromObj(objv[2], &bytearraysize);
300  //  
301  //  A separable portion of the object code, whose source code is excluded        //Be sure that the internal crc table has been built.  This function
302  //from the Corresponding Source as a System Library, need not be        //also returns a table correctness code.  Error out severely if the
303  //included in conveying the object code work.        //CRC module believes its internal data has been corrupted.
304  //        if (!CRCHASHFUNCS_Crc32TableCheck())
305  //  A "User Product" is either (1) a "consumer product", which means any           {
306  //tangible personal property which is normally used for personal, family,           //Serious internal error.  Error out.
307  //or household purposes, or (2) anything designed or sold for incorporation  
308  //into a dwelling.  In determining whether a product is a consumer product,           //Create the return object.
309  //doubtful cases shall be resolved in favor of coverage.  For a particular           rv = Tcl_NewStringObj("CRCHASHEXTNS.C:  Serious internal error:  CRC-32 lookup table corrupted.", -1);
310  //product received by a particular user, "normally used" refers to a  
311  //typical or common use of that class of product, regardless of the status           //Set the return value to be the error message.
312  //of the particular user or of the way in which the particular user           Tcl_SetObjResult(interp, rv);
313  //actually uses, or expects or is expected to use, the product.  A product  
314  //is a consumer product regardless of whether the product has substantial           //Error return.
315  //commercial, industrial or non-consumer uses, unless such uses represent           return TCL_ERROR;
316  //the only significant mode of use of the product.           }
317  //  
318  //  "Installation Information" for a User Product means any methods,        //Open and initialize the necessary structure.
319  //procedures, authorization keys, or other information required to install        CRCHASHFUNCS_Crc32StateStructOpen(&crc_state);
320  //and execute modified versions of a covered work in that User Product from  
321  //a modified version of its Corresponding Source.  The information must        //Process the string.
322  //suffice to ensure that the continued functioning of the modified object        CRCHASHFUNCS_Crc32StateStructAddData(&crc_state,
323  //code is in no case prevented or interfered with solely because                                            bytearrayptr,
324  //modification has been made.                                            bytearraysize);
325  //        //Extract the CRC.
326  //  If you convey an object code work under this section in, or with, or        crc = CRCHASHFUNCS_Crc32Extract(&crc_state);
327  //specifically for use in, a User Product, and the conveying occurs as  
328  //part of a transaction in which the right of possession and use of the        //Postprocess the structure.
329  //User Product is transferred to the recipient in perpetuity or for a        CRCHASHFUNCS_Crc32StateStructClose(&crc_state);
330  //fixed term (regardless of how the transaction is characterized), the  
331  //Corresponding Source conveyed under this section must be accompanied        //Convert the long integer to a hexadecimal representation.
332  //by the Installation Information.  But this requirement does not apply        Strfuncs_UlToHexString(crc, buffer+2, 1);
333  //if neither you nor any third party retains the ability to install  
334  //modified object code on the User Product (for example, the work has        //Stuff the leading characters of the hexadecimal representation.
335  //been installed in ROM).        buffer[0]  = '0';
336  //        buffer[1]  = 'x';
337  //  The requirement to provide Installation Information does not include a  
338  //requirement to continue to provide support service, warranty, or updates        //Stuff the string terminator.
339  //for a work that has been modified or installed by the recipient, or for        buffer[10] =  0;
340  //the User Product in which it has been modified or installed.  Access to a  
341  //network may be denied when the modification itself materially and        //Create the return object.
342  //adversely affects the operation of the network or violates the rules and        rv = Tcl_NewStringObj(buffer, -1);
343  //protocols for communication across the network.  
344  //        //Set the return value to be the hexadecimal representation of the
345  //  Corresponding Source conveyed, and Installation Information provided,        //CRC.
346  //in accord with this section must be in a format that is publicly        Tcl_SetObjResult(interp, rv);
347  //documented (and with an implementation available to the public in  
348  //source code form), and must require no special password or key for        //Everything went well, return the OK code.
349  //unpacking, reading or copying.        return TCL_OK;
350  //        }
351  //  7. Additional Terms.     }
352  //  
353  //  "Additional permissions" are terms that supplement the terms of this  
354  //License by making exceptions from one or more of its conditions.  //Performs initial registration to the hash table.
355  //Additional permissions that are applicable to the entire Program shall  //
356  //be treated as though they were included in this License, to the extent  void CRCHASHEXTNS_Crc32extnInit(Tcl_Interp *interp)
357  //that they are valid under applicable law.  If additional permissions     {
358  //apply only to part of the Program, that part may be used separately     //Register a command named "crc32".
359  //under those permissions, but the entire Program remains governed by     Tcl_CreateObjCommand(interp,
360  //this License without regard to the additional permissions.                          "crc32",
361  //                          (Tcl_ObjCmdProc *)CRCHASHEXTNS_Crc32extnCommand,
362  //  When you convey a copy of a covered work, you may at your option                          NULL,
363  //remove any additional permissions from that copy, or from any part of                          NULL);
364  //it.  (Additional permissions may be written to require their own     }
365  //removal in certain cases when you modify the work.)  You may place  
366  //additional permissions on material, added by you to a covered work,  
367  //for which you have or can give appropriate copyright permission.  //Returns version control string for file.
368  //  //
369  //  Notwithstanding any other provision of this License, for material you  const char *CRCHASHEXTNS_cvcinfo(void)
370  //add to a covered work, you may (if authorized by the copyright holders of  {  
371  //that material) supplement the terms of this License with terms:      return ("$Header$");
372  //  }
373  //    a) Disclaiming warranty or limiting liability differently from the  
374  //    terms of sections 15 and 16 of this License; or  
375  //  //Returns version control string for associated .H file.
376  //    b) Requiring preservation of specified reasonable legal notices or  //
377  //    author attributions in that material or in the Appropriate Legal  const char *CRCHASHEXTNS_hvcinfo(void)
378  //    Notices displayed by works containing it; or  {  
379  //      return (CRCHASHEXTNS_H_VERSION);
380  //    c) Prohibiting misrepresentation of the origin of that material, or  }
381  //    requiring that modified versions of such material be marked in  
382  //    reasonable ways as different from the original version; or  //End of crchashextns.c.
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 //may consider it more useful to permit linking proprietary applications with  
 //the library.  If this is what you want to do, use the GNU Lesser General  
 //Public License instead of this License.  But first, please read  
 //<http://www.gnu.org/philosophy/why-not-lgpl.html>.  
 //-------------------------------------------------------------------------------------------------  
 //--------------------------------------------------------------------------------  
 /* IJS_SM_FILE_PUBLIC */  
   
 #define MODULE_CRCHASHEXTNS  
   
 #include <string.h>  
   
 #include "tcl.h"  
 #include "tcldecls.h"  
   
 #include "crchashextns.h"  
 #include "crchashfuncs.h"  
   
 #include "strfuncs.h"  
 #include "tclalloc.h"  
   
   
 //Procedure called when the "crc32" command is encountered in a Tcl script.  
 //  
 int CRCHASHEXTNS_Crc32extnCommand(ClientData dummy,  
                                   Tcl_Interp *interp,  
                                   int objc,  
                                   Tcl_Obj *objv[])  
    {  
    Tcl_Obj *rv;  
       //Value that will be returned.  
    Tcl_Obj *block_obj;  
       //Used for file reads.  
    char buffer[11];  
       //Space for "0x" followed by 8 hex chars and terminator.  
    struct CRCHASHFUNCS_Crc32StateStruct crc_state;  
       //CRC state structure, internals nominally known and accessible to another  
       //another software module.  
    unsigned long crc;  
       //Calculated CRC.  
    unsigned long bytearraysize;  
       //Size of block allocated or portion used.  
    char *bytearrayptr;  
       //Pointer to array of bytes.  
    char *fname;  
       //File name specified.  
    char *blockbuf;  
       //Pointer to array of bytes.  
    Tcl_Channel chan;  
       //Channel opened using the Tcl libraries.  
    int return_code, return_code_b;  
       //Return codes from Tcl library functions.  
    int loop_exit_flag;  
       //Looping exit flag.  
    int chars_read;  
       //Number of characters read (i.e. for short read).  
    int block_obj_n;  
   
   
    if (objc < 2 || objc > 3)  
       {  
       Tcl_WrongNumArgs(interp,  
                        1,  
                        objv,  
                        "?-string? filename_or_string_value");  
   
       return TCL_ERROR;  
       }  
    else if (objc == 2)  
       {  
       //Be sure that the internal crc table has been built.  This function  
       //also returns a table correctness code.  Error out severely if the  
       //CRC module believes its internal data has been corrupted.  
       if (!CRCHASHFUNCS_Crc32TableCheck())  
          {  
          //Serious internal error.  Error out.  
   
          //Create the return object.  
          rv = Tcl_NewStringObj("CRCHASHEXTNS.C:  Serious internal error:  CRC-32 lookup table corrupted.", -1);  
   
          //Set the return value to be the error message.  
          Tcl_SetObjResult(interp, rv);  
   
          //Error return.  
          return TCL_ERROR;  
          }  
   
       //We need to open a channel, run it through the CRC algorithm, and  
       //return results.  
   
       //Get the string representation of the object.  
       fname = Tcl_GetString(objv[1]);  
   
       //Attempt to open a file channel.  The error information, if any,  
       //will be placed in the interpreter's state.  
       chan = Tcl_OpenFileChannel(interp, fname, "r", 0);  
   
       //There is the possibility that the channel could not be opened  
       //successfully.  If there was an error, error out.  
       if (!chan)  
          {  
          //Create the return object.  
          rv = Tcl_NewStringObj("crc32: Tcl_OpenFileChannel() failure on file name: ", -1);  
   
          //Tack on the offensive argument.  
          Tcl_AppendToObj(rv, fname, -1);  
   
          //Set the return value to be the error message.  
          Tcl_SetObjResult(interp, rv);  
   
          //Error return.  
          return TCL_ERROR;  
          }  
   
       //Try to set the channel encoding to binary and record the return code.  
       return_code   = Tcl_SetChannelOption(interp, chan, "-encoding", "binary");  
   
       //Try to set the channel translation mode to binary and record the return  
       //code.  
       if (return_code == TCL_OK)  
          return_code_b = Tcl_SetChannelOption(interp, chan, "-translation", "binary");  
   
       //If the attempt to set the channel encoding or translation  
       //didn't go well, error out.  Must also try to chose the channel because  
       //it was successfully opened.  
       if ((return_code != TCL_OK) || (return_code_b != TCL_OK))  
          {  
          //Try to close the channel.  "interp" not supplied so as not  
          //to overwrite error info.  
          Tcl_Close(NULL, chan);  
   
          //Create the return object.  
          rv = Tcl_NewStringObj("crc32: Tcl_SetChannelOption() failure.", -1);  
   
          //Set the return value to be the error message.  
          Tcl_SetObjResult(interp, rv);  
   
          //Error return.  
          return TCL_ERROR;  
          }  
   
       //Allocate the object to hold the block buffer.  I've examined the  
       //function, and cannot do it with with a NULL pointer.  Must instead  
       //allocate SOMETHING, although it will be destroyed immediately on  
       //the first read.  This will have reference count zero.  
       block_obj = Tcl_NewByteArrayObj("Trash", 5);  
   
       //Calculate the CRC.  The essential process is to keep reading  
       //and adding to the CRC until end of file.  
       //Open and initialize the necessary structure.  
       CRCHASHFUNCS_Crc32StateStructOpen(&crc_state);  
   
       loop_exit_flag = 0;  
   
       do  
          {  
          //Grab as many chars as possible, up to 65536 of them.  
          //65536 was chosen because this is large enough for great  
          //performance, but small enough that it won't make a significant  
          //virtual memory impact.  
          chars_read = Tcl_ReadChars(chan, block_obj, 65536, 0);  
   
          //If the characters read shows as <0, this is an error  
          //condition.  Trap.  
          if (chars_read < 0)  
             {  
              //Try to close the channel.  "interp" not supplied so as not  
             //to overwrite error info.  
             Tcl_Close(NULL, chan);  
   
             //Deallocate the buffer used to accept block file reads.  Because the  
             //creation process set the reference count to zero, a single  
             //decrement will destroy the object.  
             Tcl_DecrRefCount(block_obj);  
   
             //Create the return object.  
             rv = Tcl_NewStringObj("crc32: Tcl_ReadChars() failure.", -1);  
   
             //Set the return value to be the error message.  
             Tcl_SetObjResult(interp, rv);  
   
             //Error return.  
             return TCL_ERROR;  
             }  
   
          //Obtain a pointer to the binary block that was read.  
          blockbuf = Tcl_GetByteArrayFromObj(block_obj, &block_obj_n);  
   
          //Add to the CRC for those chars read.  Skip the zero case.  
          if (block_obj_n > 0)  
             {  
             CRCHASHFUNCS_Crc32StateStructAddData(&crc_state,  
                                                  blockbuf,  
                                                  block_obj_n);  
             }  
   
          //We want to exit if EOF is true.  A short read would  
          //also be an indication, but short read should imply  
          //EOF, so should not test both.  
          return_code = Tcl_Eof(chan);  
          loop_exit_flag = (return_code != 0);  
          } while(!loop_exit_flag);  
   
       //Extract the CRC.  
       crc = CRCHASHFUNCS_Crc32Extract(&crc_state);  
   
       //Postprocess the structure.  
       CRCHASHFUNCS_Crc32StateStructClose(&crc_state);  
   
       //Close the channel.  
       return_code = Tcl_Close(interp, chan);  
   
       //If there was an error closing the channel, error out.  
       if (return_code != TCL_OK)  
          {  
          //Create the return object.  
          rv = Tcl_NewStringObj("crc32: Tcl_Close() failure.", -1);  
   
          //Set the return value to be the error message.  
          Tcl_SetObjResult(interp, rv);  
   
          //Error return.  
          return TCL_ERROR;  
          }  
   
       //Deallocate the buffer used to accept block file reads.  Because the  
       //creation process set the reference count to zero, a single  
       //decrement will destroy the object.  
       Tcl_DecrRefCount(block_obj);  
   
       //Return the CRC to the caller.  No detectable errors  
       //are possible at this point.  
   
       //Convert the long integer to a hexadecimal representation.  
       Strfuncs_UlToHexString(crc, buffer+2, 1);  
   
       //Stuff the leading characters of the hexadecimal representation.  
       buffer[0]  = '0';  
       buffer[1]  = 'x';  
   
       //Stuff the string terminator.  
       buffer[10] =  0;  
   
       //Create the return object.  
       rv = Tcl_NewStringObj(buffer, -1);  
   
       //Set the return value to be the hexadecimal representation of the  
       //CRC.  
       Tcl_SetObjResult(interp, rv);  
   
       //Everything went well, return the OK code.  
       return TCL_OK;  
       }  
    else /* if (objc == 3) */  
       {  
       //The second parameter positively must be "-string" or a substring  
       //of that.  At present, there are no competing option flags, so  
       //a simple substring lookup will handle it.  
       //Yank the string pointer.  
       bytearrayptr = Tcl_GetString(objv[1]);  
   
       //If not a substring, error out.  
       if ((strlen(bytearrayptr)<2) || !Strfuncs_IsSubstring(bytearrayptr, "-string"))  
          {  
          //Create the return object.  
          rv = Tcl_NewStringObj("crc32: Unrecognized switch: ", -1);  
   
          //Tack on the offensive argument.  
          Tcl_AppendToObj(rv, bytearrayptr, -1);  
   
          //Set the return value to be the error message.  
          Tcl_SetObjResult(interp, rv);  
   
          //Error return.  
          return TCL_ERROR;  
          }  
   
       //Convert the last parameter to its byte representation and get a  
       //pointer to this representation and the length.  This was the  
       //library call that Ajuba recommended.  
       bytearrayptr = Tcl_GetByteArrayFromObj(objv[2], &bytearraysize);  
   
       //Be sure that the internal crc table has been built.  This function  
       //also returns a table correctness code.  Error out severely if the  
       //CRC module believes its internal data has been corrupted.  
       if (!CRCHASHFUNCS_Crc32TableCheck())  
          {  
          //Serious internal error.  Error out.  
   
          //Create the return object.  
          rv = Tcl_NewStringObj("CRCHASHEXTNS.C:  Serious internal error:  CRC-32 lookup table corrupted.", -1);  
   
          //Set the return value to be the error message.  
          Tcl_SetObjResult(interp, rv);  
   
          //Error return.  
          return TCL_ERROR;  
          }  
   
       //Open and initialize the necessary structure.  
       CRCHASHFUNCS_Crc32StateStructOpen(&crc_state);  
   
       //Process the string.  
       CRCHASHFUNCS_Crc32StateStructAddData(&crc_state,  
                                           bytearrayptr,  
                                           bytearraysize);  
       //Extract the CRC.  
       crc = CRCHASHFUNCS_Crc32Extract(&crc_state);  
   
       //Postprocess the structure.  
       CRCHASHFUNCS_Crc32StateStructClose(&crc_state);  
   
       //Convert the long integer to a hexadecimal representation.  
       Strfuncs_UlToHexString(crc, buffer+2, 1);  
   
       //Stuff the leading characters of the hexadecimal representation.  
       buffer[0]  = '0';  
       buffer[1]  = 'x';  
   
       //Stuff the string terminator.  
       buffer[10] =  0;  
   
       //Create the return object.  
       rv = Tcl_NewStringObj(buffer, -1);  
   
       //Set the return value to be the hexadecimal representation of the  
       //CRC.  
       Tcl_SetObjResult(interp, rv);  
   
       //Everything went well, return the OK code.  
       return TCL_OK;  
       }  
    }  
   
   
 //Performs initial registration to the hash table.  
 //  
 void CRCHASHEXTNS_Crc32extnInit(Tcl_Interp *interp)  
    {  
    //Register a command named "crc32".  
    Tcl_CreateObjCommand(interp,  
                         "crc32",  
                         (Tcl_ObjCmdProc *)CRCHASHEXTNS_Crc32extnCommand,  
                         NULL,  
                         NULL);  
    }  
   
   
 //Returns version control string for file.  
 //  
 const char *CRCHASHEXTNS_cvcinfo(void)  
 {    
     return ("$Header: /cvsroot/esrg/sfesrg/esrgpcpj/shared/tclxtens/crchashextns.c,v 1.2 2001/07/26 23:18:07 dtashley Exp $");  
 }  
   
   
 //Returns version control string for associated .H file.  
 //  
 const char *CRCHASHEXTNS_hvcinfo(void)  
 {    
     return (CRCHASHEXTNS_H_VERSION);  
 }  
   
   
 // $Log: crchashextns.c,v $  
 // Revision 1.2  2001/07/26 23:18:07  dtashley  
 // Swap out of CRC modules and extensions.  
 //  
 //End of CRCHASHEXTNS.C  

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