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  • How would one build a relational database on a key-value store, a-la Berkeley DB's SQL interface?

    - by coleifer
    I've been checking out Berkeley DB and was impressed to find that it supported a SQL interface that is "nearly identical" to SQLite. http://docs.oracle.com/cd/E17076_02/html/bdb-sql/dbsqlbasics.html#identicalusage I'm very curious, at a high-level, how this kind of interface might have been architected. For instance: since values are "transparent", how do you efficiently query and sort by value how are limits and offsets performed efficiently on large result sets how would the keys be structured and serialized for good average-case performance

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  • mysql_tzinfo_to_sql missing on my system

    - by Sk1ppeR
    I ran into problem with timezones within MySQL. Long story short, my application is worldwide, and each database has it's own timezone set within the application (not the server) in the way of "Europe/Berlin", "Europe/Vienna", "America/Sao Paulo". Obviously this is unacceptable for MySQL at first per connection. I read that it handles data better if you use UTC offsets. Basically my goal is to log a field's alteration in another table using a trigger. For that I use UNIX_TIMESTAMP within the trigger. Although UNIX_TIMESTAMP() follows the global timezone for the server which obviously bothers me a lot :| So I went to search for a "per connection" solution to use inside the trigger and well I found that mysql_tzinfo_to_sql can actually import zone info (UTC offsets) from my linux's zoneinfo files. Although to my amuse, when I ran the commant I got the following: bash: mysql_tzinfo_to_sql: command not found So I'm looking for a solution to fix that. I don't want to "map" the timezone names into UTC offset just so I could use in the trigger. Is there an alternative tool? Or at least sources for this one in particular only? What kind of queries does this tool generates so I could do it manually then if there is no alternative tool. Thanks in advance on any help on the issue! P.S: The OS is Debian GNU/Linux 6.0 and the MySQL server is the one from aptitude with performance tweaks with my.cnf

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  • Vmware Workstation downloads as a txt file?

    - by George Mauer
    I just went to the vmware website because I want to try workstation over virtualbox. I signed up for a workstation trial and clicked download on the 64bit linux version. What downloaded is a 320 megabyte txt file VMware-Workstation-Full-8.0.2-591240.x86_64.txt What gives? Is anyone familiar with this pattern of delivering software? How do I run it? Here is the beginning of that file: #!/usr/bin/env bash # # VMware Installer Launcher # # This is the executable stub to check if the VMware Installer Service # is installed and if so, launch it. If it is not installed, the # attached payload is extracted, the VMIS is installed, and the VMIS # is launched to install the bundle as normal. # Architecture this bundle was built for (x86 or x64) ARCH=x64 if [ -z "$BASH" ]; then # $- expands to the current options so things like -x get passed through if [ ! -z "$-" ]; then opts="-$-" fi # dash flips out of $opts is quoted, so don't. exec /usr/bin/env bash $opts "$0" "$@" echo "Unable to restart with bash shell" exit 1 fi set -e ETCDIR=/etc/vmware-installer OLDETCDIR="/etc/vmware" ### Offsets ### # These are offsets that are later used relative to EOF. FOOTER_SIZE=52 # This won't work with non-GNU stat. FILE_SIZE=`stat --format "%s" "$0"` offset=$(($FILE_SIZE - 4)) MAGIC_OFFSET=$offset offset=$(($offset - 4)) CHECKSUM_OFFSET=$offset offset=$(($offset - 4)) VERSION_OFFSET=$offset offset=$(($offset - 4)) PREPAYLOAD_OFFSET=$offset

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  • Tiff Analyzer

    - by Kevin
    I am writing a program to convert some data, mainly a bunch of Tiff images. Some of the Tiffs seems to have a minor problem with them. They show up fine in some viewers (Irfanview, client's old system) but not in others (Client's new system, Window's picture and fax viewer). I have manually looked at the binary data and all the tags seem ok. Can anyone recommend an app that can analyze it and tell me what, if anything, is wrong with it? Also, for clarity sake, I'm only converting the data about the images which is stored seperately in a database and copying the images, I'm not editting the images myself, so I'm pretty sure I'm not messing them up. UDPATE: For anyone interested, here are the tags from a good and bad file: BAD Tag Type Length Value 256 Image Width SHORT 1 1652 257 Image Length SHORT 1 704 258 Bits Per Sample SHORT 1 1 259 Compression SHORT 1 4 262 Photometric SHORT 1 0 266 Fill Order SHORT 1 1 273 Strip Offsets LONG 1 210 (d2 Hex) 274 Orientation SHORT 1 3 277 Samples Per Pixel SHORT 1 1 278 Rows Per Strip SHORT 1 450 279 Strip Byte Counts LONG 1 7264 (1c60 Hex) 282 X Resolution RATIONAL 1 <194 200 / 1 = 200.000 283 Y Resolution RATIONAL 1 <202 200 / 1 = 200.000 284 Planar Configuration SHORT 1 1 296 Resolution Unit SHORT 1 2 Good Tag Type Length Value 254 New Subfile Type LONG 1 0 (0 Hex) 256 Image Width SHORT 1 1193 257 Image Length SHORT 1 788 258 Bits Per Sample SHORT 1 1 259 Compression SHORT 1 4 262 Photometric SHORT 1 0 266 Fill Order SHORT 1 1 270 Image Description ASCII 45 256 273 Strip Offsets LONG 1 1118 (45e Hex) 274 Orientation SHORT 1 1 277 Samples Per Pixel SHORT 1 1 278 Rows Per Strip LONG 1 788 (314 Hex) 279 Strip Byte Counts LONG 1 496 (1f0 Hex) 280 Min Sample Value SHORT 1 0 281 Max Sample Value SHORT 1 1 282 X Resolution RATIONAL 1 <301 200 / 1 = 200.000 283 Y Resolution RATIONAL 1 <309 200 / 1 = 200.000 284 Planar Configuration SHORT 1 1 293 Group 4 Options LONG 1 0 (0 Hex) 296 Resolution Unit SHORT 1 2

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  • error when plotting log'd array in matplotlib/scipy/numpy

    - by user248237
    I have two arrays and I take their logs. When I do that and try to plot their scatter plot, I get this error: File "/Library/Python/2.6/site-packages/matplotlib-1.0.svn_r7892-py2.6-macosx-10.6-universal.egg/matplotlib/pyplot.py", line 2192, in scatter ret = ax.scatter(x, y, s, c, marker, cmap, norm, vmin, vmax, alpha, linewidths, faceted, verts, **kwargs) File "/Library/Python/2.6/site-packages/matplotlib-1.0.svn_r7892-py2.6-macosx-10.6-universal.egg/matplotlib/axes.py", line 5384, in scatter self.add_collection(collection) File "/Library/Python/2.6/site-packages/matplotlib-1.0.svn_r7892-py2.6-macosx-10.6-universal.egg/matplotlib/axes.py", line 1391, in add_collection self.update_datalim(collection.get_datalim(self.transData)) File "/Library/Python/2.6/site-packages/matplotlib-1.0.svn_r7892-py2.6-macosx-10.6-universal.egg/matplotlib/collections.py", line 153, in get_datalim offsets = transOffset.transform_non_affine(offsets) File "/Library/Python/2.6/site-packages/matplotlib-1.0.svn_r7892-py2.6-macosx-10.6-universal.egg/matplotlib/transforms.py", line 1924, in transform_non_affine self._a.transform(points)) File "/Library/Python/2.6/site-packages/matplotlib-1.0.svn_r7892-py2.6-macosx-10.6-universal.egg/matplotlib/transforms.py", line 1420, in transform return affine_transform(points, mtx) ValueError: Invalid vertices array. the code is simply: myarray_x = log(my_array[:, 0]) myarray_y = log(my_array[:, 1]) plt.scatter(myarray_x, myarray_y) any idea what could be causing this? thanks.

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  • Algorithm to match list of regular expressions

    - by DSII
    I have two algorithmic questions for a project I am working on. I have thought about these, and have some suspicions, but I would love to hear the community's input as well. Suppose I have a string, and a list of N regular expressions (actually they are wildcard patterns representing a subset of full regex functionality). I want to know whether the string matches at least one of the regular expressions in the list. Is there a data structure that can allow me to match the string against the list of regular expressions in sublinear (presumably logarithmic) time? This is an extension of the previous problem. Suppose I have the same situation: a string and a list of N regular expressions, only now each of the regular expressions is paired with an offset within the string at which the match must begin (or, if you prefer, each of the regular expressions must match a substring of the given string beginning at the given offset). To give an example, suppose I had the string: This is a test string and the regex patterns and offsets: (a) his.* at offset 0 (b) his.* at offset 1 The algorithm should return true. Although regex (a) does not match the string beginning at offset 0, regex (b) does match the substring beginning at offset 1 ("his is a test string"). Is there a data structure that can allow me to solve this problem in sublinear time? One possibly useful piece of information is that often, many of the offsets in the list of regular expressions are the same (i.e. often we are matching the substring at offset X many times). This may be useful to leverage the solution to problem #1 above. Thank you very much in advance for any suggestions you may have!

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  • implementing a download manager that supports resuming

    - by Idan K
    hi, I intend on writing a small download manager in C++ that supports resuming (and multiple connections per download). From the info I gathered so far, when sending the http request I need to add a header field with a key of "Range" and the value "bytes=startoff-endoff". Then the server returns a http response with the data between those offsets. So roughly what I have in mind is to split the file to the number of allowed connections per file and send a http request per splitted part with the appropriate "Range". So if I have a 4mb file and 4 allowed connections, I'd split the file to 4 and have 4 http requests going, each with the appropriate "Range" field. Implementing the resume feature would involve remembering which offsets are already downloaded and simply not request those. Is this the right way to do this? What if the web server doesn't support resuming? (my guess is it will ignore the "Range" and just send the entire file) When sending the http requests, should I specify in the range the entire splitted size? Or maybe ask smaller pieces, say 1024k per request? When reading the data, should I write it immediately to the file or do some kind of buffering? I guess it could be wasteful to write small chunks. Should I use a memory mapped file? If I remember correctly, it's recommended for frequent reads rather than writes (I could be wrong). Is it memory wise? What if I have several downloads simultaneously? If I'm not using a memory mapped file, should I open the file per allowed connection? Or when needing to write to the file simply seek? (if I did use a memory mapped file this would be really easy, since I could simply have several pointers). Note: I'll probably be using Qt, but this is a general question so I left code out of it.

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  • Optimizing processing and management of large Java data arrays

    - by mikera
    I'm writing some pretty CPU-intensive, concurrent numerical code that will process large amounts of data stored in Java arrays (e.g. lots of double[100000]s). Some of the algorithms might run millions of times over several days so getting maximum steady-state performance is a high priority. In essence, each algorithm is a Java object that has an method API something like: public double[] runMyAlgorithm(double[] inputData); or alternatively a reference could be passed to the array to store the output data: public runMyAlgorithm(double[] inputData, double[] outputData); Given this requirement, I'm trying to determine the optimal strategy for allocating / managing array space. Frequently the algorithms will need large amounts of temporary storage space. They will also take large arrays as input and create large arrays as output. Among the options I am considering are: Always allocate new arrays as local variables whenever they are needed (e.g. new double[100000]). Probably the simplest approach, but will produce a lot of garbage. Pre-allocate temporary arrays and store them as final fields in the algorithm object - big downside would be that this would mean that only one thread could run the algorithm at any one time. Keep pre-allocated temporary arrays in ThreadLocal storage, so that a thread can use a fixed amount of temporary array space whenever it needs it. ThreadLocal would be required since multiple threads will be running the same algorithm simultaneously. Pass around lots of arrays as parameters (including the temporary arrays for the algorithm to use). Not good since it will make the algorithm API extremely ugly if the caller has to be responsible for providing temporary array space.... Allocate extremely large arrays (e.g. double[10000000]) but also provide the algorithm with offsets into the array so that different threads will use a different area of the array independently. Will obviously require some code to manage the offsets and allocation of the array ranges. Any thoughts on which approach would be best (and why)?

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  • How to implement escape Sequence in SDL

    - by Sa'me Smd
    Im trying to use the STL library inside the SDL. but it gives me the error "undeclared identifier" Is there any way i can use "\n"or even cout<<endl; Can the function SDL_WarpMousewhich places the mouse cursor on a desired location on screen help me with this. Because i want to put a tile on the next line sequence. I hope you get the Question. Its very vague and messed up question though (sorry for that). EDIT: void putMap(SDL_Surface* tile, SDL_Surface* screen) { for(int y = 0; y < 21; y++) { for(int x = 0; x < 60; x++) { if(maze[x][y] != '#') { apply_surface( x*10 , y*10 , tile, screen); } } cout<<endl; } } c:\documents and settings\administrator\my documents\visual studio 2008\projects\craptest\craptest\main.cpp(605) : error C2065: 'cout' : undeclared identifier c:\documents and settings\administrator\my documents\visual studio 2008\projects\craptest\craptest\main.cpp(605) : error C2065: 'endl' : undeclared identifier This is my apply_surface funtion. void apply_surface( int x, int y, SDL_Surface* source, SDL_Surface* destination ) { //Make a temporary rectangle to hold the offsets SDL_Rect offset; //Give the offsets to the rectangle offset.x = x; offset.y = y; //Blit the surface SDL_BlitSurface( source, NULL, destination, &offset ); }

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  • Vector deltas and moving in unknown areas

    - by dekz
    Hi All, I was in need of a little math help that I can't seem to find the answer to, any links to documentation would be greatly appreciated. Heres my situation, I have no idea where I am in this maze, but I need to move around and find my way back to the start. I was thinking of implementing a waypoint list of places i've been offset from my start at 0,0. This is a 2D cartesian plane. I've been given 2 properties, my translation speed from 0-1 and my rotation speed from -1 to 1. -1 is very left and +1 is very right. These are speed and not angles so thats where my problem lies. If I'm given 0 as a translation speed and 0.2 I will continually turn to my right at a slow speed. How do I figure out the offsets given these 2 variables? I can store it every time I take a 'step'. I just need to figure out the offsets in x and y terms given the translations and rotation speeds. And the rotation to get to those points. Any help is appreciated.

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  • Add two hexBinarys with XPATH 1.0

    - by fielding
    Hi, my xml document looks somewhat like that (Values are both xsl:hexBinary): <Offsets> <Offset> <Name>ErrorOffset</Name> <Value>DD</Value> </Offset> <Offset> <Name>OtherOffset</Name> <Value>FF</Value> </Offset> </Offsets> <Value> <Name>Error1</Name> <Code>01</Code> </Value> <Value> <Name>Error2</Name> <Code>02</Code> <Offset>ErrorOffset</Offset> </Value> now i want to transform this to a new xml file: <Value> <Name>Error1</Name> <Code>01</Code> </Value> <Value> <Name>Error2</Name> <Code>DF</Code> </Value> All that should happen is adding <Offset> to the basic <Value>. But plain + returns NaN and sum() expects only one parameter. XSLT and XPATH are quite nice, but it goes on my nerves that easy operations like adding two hex values just dont work as easy as it should.

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  • How to interpret the contents of /proc/bus/pci/devices ?

    - by vivekian2
    The first few fields of 'cat /proc/bus/pci/devices' are understandable. Field 1 - BusDevFunc Field 2 - Vendor Id + Device Id Field 3 - Interrupt Line Field 4 - BAR 0 and the rest of the BAR registers (0 - 5) after that. After the BAR registers are printed out, what are the other fields? Specifically, what PCI configuration space registers(offsets) are printed out?

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  • Can You Have "Empty" Abstract/Classes?

    - by ShrimpCrackers
    Of course you can, I'm just wondering if it's rational to design in such a way. I'm making a breakout clone and was doing some class design. I wanted to use inheritance, even though I don't have to, to apply what I've learned in C++. I was thinking about class design and came up with something like this: GameObject - base class (consists of data members like x and y offsets, and a vector of SDL_Surface* MovableObject : GameObject - abstract class + derived class of GameObject (one method void move() = 0; ) NonMovableObject : GameObject - empty class...no methods or data members other than constructor and destructor(at least for now?). Later I was planning to derive a class from NonMovableObject, like Tileset : NonMovableObject. I was just wondering if "empty" abstract classes or just empty classes are often used...I notice that the way I'm doing this, I'm just creating the class NonMovableObject just for sake of categorization. I know I'm overthinking things just to make a breakout clone, but my focus is less on the game and more on using inheritance and designing some sort of game framework.

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  • Anatomy of a .NET Assembly - CLR metadata 2

    - by Simon Cooper
    Before we look any further at the CLR metadata, we need a quick diversion to understand how the metadata is actually stored. Encoding table information As an example, we'll have a look at a row in the TypeDef table. According to the spec, each TypeDef consists of the following: Flags specifying various properties of the class, including visibility. The name of the type. The namespace of the type. What type this type extends. The field list of this type. The method list of this type. How is all this data actually represented? Offset & RID encoding Most assemblies don't need to use a 4 byte value to specify heap offsets and RIDs everywhere, however we can't hard-code every offset and RID to be 2 bytes long as there could conceivably be more than 65535 items in a heap or more than 65535 fields or types defined in an assembly. So heap offsets and RIDs are only represented in the full 4 bytes if it is required; in the header information at the top of the #~ stream are 3 bits indicating if the #Strings, #GUID, or #Blob heaps use 2 or 4 bytes (the #US stream is not accessed from metadata), and the rowcount of each table. If the rowcount for a particular table is greater than 65535 then all RIDs referencing that table throughout the metadata use 4 bytes, else only 2 bytes are used. Coded tokens Not every field in a table row references a single predefined table. For example, in the TypeDef extends field, a type can extend another TypeDef (a type in the same assembly), a TypeRef (a type in a different assembly), or a TypeSpec (an instantiation of a generic type). A token would have to be used to let us specify the table along with the RID. Tokens are always 4 bytes long; again, this is rather wasteful of space. Cutting the RID down to 2 bytes would make each token 3 bytes long, which isn't really an optimum size for computers to read from memory or disk. However, every use of a token in the metadata tables can only point to a limited subset of the metadata tables. For the extends field, we only need to be able to specify one of 3 tables, which we can do using 2 bits: 0x0: TypeDef 0x1: TypeRef 0x2: TypeSpec We could therefore compress the 4-byte token that would otherwise be needed into a coded token of type TypeDefOrRef. For each type of coded token, the least significant bits encode the table the token points to, and the rest of the bits encode the RID within that table. We can work out whether each type of coded token needs 2 or 4 bytes to represent it by working out whether the maximum RID of every table that the coded token type can point to will fit in the space available. The space available for the RID depends on the type of coded token; a TypeOrMethodDef coded token only needs 1 bit to specify the table, leaving 15 bits available for the RID before a 4-byte representation is needed, whereas a HasCustomAttribute coded token can point to one of 18 different tables, and so needs 5 bits to specify the table, only leaving 11 bits for the RID before 4 bytes are needed to represent that coded token type. For example, a 2-byte TypeDefOrRef coded token with the value 0x0321 has the following bit pattern: 0 3 2 1 0000 0011 0010 0001 The first two bits specify the table - TypeRef; the other bits specify the RID. Because we've used the first two bits, we've got to shift everything along two bits: 000000 1100 1000 This gives us a RID of 0xc8. If any one of the TypeDef, TypeRef or TypeSpec tables had more than 16383 rows (2^14 - 1), then 4 bytes would need to be used to represent all TypeDefOrRef coded tokens throughout the metadata tables. Lists The third representation we need to consider is 1-to-many references; each TypeDef refers to a list of FieldDef and MethodDef belonging to that type. If we were to specify every FieldDef and MethodDef individually then each TypeDef would be very large and a variable size, which isn't ideal. There is a way of specifying a list of references without explicitly specifying every item; if we order the MethodDef and FieldDef tables by the owning type, then the field list and method list in a TypeDef only have to be a single RID pointing at the first FieldDef or MethodDef belonging to that type; the end of the list can be inferred by the field list and method list RIDs of the next row in the TypeDef table. Going back to the TypeDef If we have a look back at the definition of a TypeDef, we end up with the following reprensentation for each row: Flags - always 4 bytes Name - a #Strings heap offset. Namespace - a #Strings heap offset. Extends - a TypeDefOrRef coded token. FieldList - a single RID to the FieldDef table. MethodList - a single RID to the MethodDef table. So, depending on the number of entries in the heaps and tables within the assembly, the rows in the TypeDef table can be as small as 14 bytes, or as large as 24 bytes. Now we've had a look at how information is encoded within the metadata tables, in the next post we can see how they are arranged on disk.

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  • Index independent character comparison within text blocks

    - by Michael IV
    I have the following task: developing a program where there is a block of sample text which should be typed by user. Any typos the user does during the test are registered. Basically, I can compare each typed char with the sample char based on caret index position of the input, but there is one significant flaw in such a "naive" approach. If the user typed mistakenly more letters than a whole string has, or inserted more white spaces between the string than should be, then the rest of the comparisons will be wrong because of the index offsets added by the additional wrong insertions. I have thought of designing some kind of parser where each string (or even a char ) is tokenized and the comparisons are made "char-wise" and not "index-wise," but that seems to me like an overkill for such a task. I would like to get a reference to possibly existing algorithms which can be helpful in solving this kind of problem.

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  • Version hash to solve Event Sourcing problems

    - by SystematicFrank
    The basic examples I have seen about Event Sourcing do not deal with out of order events, clock offsets in different systems and late events from system partitions. I am wondering if more polished Event Sourcing implementations rely on a version stamp of modified objects? For example, assuming that the system is rendering the entity Client with version id ABCD1234. If the user modifies the entity, the system will create an event with the modified fields AND the version id reference to which version it applies. Later the event responder would detect out of order events and merge them.

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  • How do I implement layers on a tile map?

    - by mitch
    I have a game where, based upon the visible tiles in the viewport, I need to retrieve data of items in the visible tiles. I am planning to use Javascript to AJAX request in a batch based upon the visible tiles which contain image tags like Google Maps. The layer will be in SVG or canvas. The item information will be in JSON format. What is the best approach, to fetch the data? I currently have complex class I wrote in Javascript which determines the visible columns/rows and offsets relative to the visible area shown. Each item is also user contributed and will be rendered in canvas or SVG layer.

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  • Need to produce an animated texture of Water where each image tiles in all directions

    - by ProfVersaggi
    I need to produce a 2D 'animated' texture of "water" for a game in which each image tiles in 'all' directions, much like those produced by the Caustics Generator, but with the power and flexibility of something the likes of Blender. The final result from Caustics Generator is 32 images that are actually animated such that when the full 32 images are played in a loop they will seamlessly loop forever. They will not only loop in time, but each image also tile in all directions. This is nice, but it comes in only one flavor so to speak. I'd like to accomplish the same thing with a Blender type tool, and I have actually gotten to the point where I generate the X number of images, but they do not tile in 'all' directions, nor are they slightly animated. I've tried Blender texture animations using offsets but with only limited success. Does anyone know of how to (or of a tool) which will animate textures such that they tile in all (4) directions? Many thanks in advance ....

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  • OpenGL VBOs are slower then glDrawArrays.

    - by Arelius
    So, this seems odd to me. I upload a large buffer of vertices, then every frame I call glBindbuffer and then the appropriate gl*Pointer functions with offsets into the buffer, then I use glDrawArrays to draw all of my triangles. I'm only drawing about 100K triangles, however I'm getting about 15FPS. This is where it gets weird, if I change it to not call glBindBuffer, then change the gl*Pointer calls to be actual pointers into the array I have in system memory, and then call glDrawArrays the same, my framerate jumps up to about 50FPS. Any idea what I weird thing I could be doing that would cause this? Did I maybe forget to call glEnable(GL_ALLOW_VBOS_TO_RUN_FAST) or something?

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  • Lots of questions about file I/O (reading/writing message strings)

    - by Nazgulled
    Hi, For this university project I'm doing (for which I've made a couple of posts in the past), which is some sort of social network, it's required the ability for the users to exchange messages. At first, I designed my data structures to hold ALL messages in a linked list, limiting the message size to 256 chars. However, I think my instructors will prefer if I save the messages on disk and read them only when I need them. Of course, they won't say what they prefer, I need to make a choice and justify the best I can why I went that route. One thing to keep in mind is that I only need to save the latest 20 messages from each user, no more. Right now I have an Hash Table that will act as inbox, this will be inside the user profile. This Hash Table will be indexed by name (the user that sent the message). The value for each element will be a data structure holding an array of size_t with 20 elements (20 messages like I said above). The idea is to keep track of the disk file offsets and bytes written. Then, when I need to read a message, I just need to use fseek() and read the necessary bytes. I think this could work nicely... I could use just one single file to hold all messages from all users in the network. I'm saying one single file because a colleague asked an instructor about saving the messages from each user independently which he replied that it might not be the best approach cause the file system has it's limits. That's why I'm thinking of going the single file route. However, this presents a problem... Since I only need to save the latest 20 messages, I need to discard the older ones when I reach this limit. I have no idea how to do this... All I know is about fread() and fwrite() to read/write bytes from/to files. How can I go to a file offset and say "hey, delete the following X bytes"? Even if I could do that, there's another problem... All offsets below that one will be completely different and I would have to process all users mailboxes to fix the problem. Which would be a pain... So, any suggestions to solve my problems? What do you suggest?

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  • JavaScript: Given an offset and substring length in an HTML string, what is the parent node?

    - by Bungle
    My current project requires locating an array of strings within an element's text content, then wrapping those matching strings in <a> elements using JavaScript (requirements simplified here for clarity). I need to avoid jQuery if at all possible - at least including the full library. For example, given this block of HTML: <div> <p>This is a paragraph of text used as an example in this Stack Overflow question.</p> </div> and this array of strings to match: ['paragraph', 'example'] I would need to arrive at this: <div> <p>This is a <a href="http://www.example.com/">paragraph</a> of text used as an <a href="http://www.example.com/">example</a> in this Stack Overflow question.</p> </div> I've arrived at a solution to this by using the innerHTML() method and some string manipulation - basically using the offsets (via indexOf()) and lengths of the strings in the array to break the HTML string apart at the appropriate character offsets and insert <a href="http://www.example.com/"> and </a> tags where needed. However, an additional requirement has me stumped. I'm not allowed to wrap any matched strings in <a> elements if they're already in one, or if they're a descendant of a heading element (<h1> to <h6>). So, given the same array of strings above and this block of HTML (the term matching has to be case-insensitive, by the way): <div> <h1>Example</a> <p>This is a <a href="http://www.example.com/">paragraph of text</a> used as an example in this Stack Overflow question.</p> </div> I would need to disregard both the occurrence of "Example" in the <h1> element, and the "paragraph" in <a href="http://www.example.com/">paragraph of text</a>. This suggests to me that I have to determine which node each matched string is in, and then traverse its ancestors until I hit <body>, checking to see if I encounter a <a> or <h_> node along the way. Firstly, does this sound reasonable? Is there a simpler or more obvious approach that I've failed to consider? It doesn't seem like regular expressions or another string-based comparison to find bounding tags would be robust - I'm thinking of issues like self-closing elements, irregularly nested tags, etc. There's also this... Secondly, is this possible, and if so, how would I approach it?

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  • Elf: Dump symbol value in BSS, DATA or RODATA?

    - by noloader
    I have a ELF shared object with a symbol initialized to a value. I want to know what the value of a symbol is. I know objdump -T will give me the symbol's address and length but I need the value: $ arm-linux-androideabi-objdump -T libcrypto.so.1.0.0 | grep -i FIPS_signature 001a9668 g DO .bss 00000014 FIPS_signature However, hexdump knows nothing about ELF sections, offsets and virtual addresses, so I can't use the information: $ hexdump -v -x -n 0x14 -s 0x001a9668 libcrypto.so.1.0.0 $ How do I dump the value of the symbol? Jeff

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  • How to interpret the contents of /proc/bus/pci/devices ?

    - by vivekian2
    The first few fields of 'cat /proc/bus/pci/devices' are understandable. Field 1 - BusDevFunc Field 2 - Vendor Id + Device Id Field 3 - Interrupt Line Field 4 - BAR 0 and the rest of the BAR registers (0 - 5) after that. After the BAR registers are printed out, what are the other fields? Specifically, what PCI configuration space registers(offsets) are printed out?

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  • apply style to range of text with javascript in uiwebview

    - by drawnonward
    I am displaying some simple styled text as html in a UIWebView on iPhone. It is basically a series of paragraphs with the occasional strong or emphasized phrase. At runtime I need to apply styles to ranges of text. There are a few similar scenarios, one of which is highlighting search results. If the user has searched for "something" I would like to change the background color behind occurrences of the word, then later restore the original background. Is it possible to apply styles to ranges of text using javascript? A key part of this is also being able to unset the styles. There seem to be two likely paths to follow. One would be modifying some html in Objective-C and passing it through javascript as the new innerHTML of some container. The other would be to use javascript to directly manipulate DOM nodes. I could manipulate html, but that sounds tedious in Objective-C so I would rather manipulate the DOM if that is a reasonable approach. I am not that familiar with javascript and DOM so I do not know if it is a reasonable approach. I wrote some routines to translate between text ranges and node ranges with offsets. So if I start with text range 100-200 and that starts in one paragraph and ends in a third, I can get the text nodes and the offsets within the nodes that represent the given text range. I just need a way to split a text node at an offset in the text. Currently I just apply styles to the paragraphs containing the text range. A few notes: straight javascript please, no external frameworks like jquery. the changes never need to be written to disk. the changes should be undoable or at least removable. the styles to apply already exist in a css file. it needs to work in iPhone 3.0 and forward. all the source files are shipped with the app. please be verbose. Thanks for any suggestions.

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