Stream Unicode C Reference Documentation
Stream
Current Version: 10.1.0
Provides a generic class for streaming from a source to a sink. Streams can be connected together where the sink of one feeds to the source of another.
Note: This class was added in Chilkat v9.5.0.56. Initially it will seem somewhat useless, but over time, streaming functionality will be added to existing Chilkat classes and will be prevalent in new Chilkat classes.
Create/Dispose
HCkStreamW instance = CkStreamW_Create(); // ... CkStreamW_Dispose(instance);
Creates an instance of the HCkStreamW object and returns a handle ("void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.
Objects created by calling CkStreamW_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function. Also, any handle returned by a Chilkat "C" function must also be freed by the application by calling the appropriate Dispose method, such as CkStreamW_Dispose.
Callback Functions
Provides the opportunity for a method call to be aborted. If TRUE is returned, the operation in progress is aborted. Return FALSE to allow the current method call to continue. This callback function is called periodically based on the value of the HeartbeatMs property. (If HeartbeatMs is 0, then no callbacks are made.) As an example, to make 5 AbortCheck callbacks per second, set the HeartbeatMs property equal to 200.
Provides the percentage completed for any method that involves network communications or time-consuming processing (assuming it is a method where a percentage completion can be measured). This callback is only called when it is possible to know a percentage completion, and when it makes sense to express the operation as a percentage completed. The pctDone argument will have a value from 1 to 100. For methods that complete very quickly, the number of PercentDone callbacks will vary, but the final callback should have a value of 100. For long running operations, no more than one callback per percentage point will occur (for example: 1, 2, 3, ... 98, 99, 100).
This callback counts as an AbortCheck callback, and takes the place of the AbortCheck event when it fires.
The return value indicates whether the method call should be aborted, or whether it should proceed. Return TRUE to abort, and FALSE to proceed.
This is a general callback that provides name/value information about what is happening at certain points during a method call. To see the information provided in ProgressInfo callbacks, if any, write code to handle this event and log the name/value pairs. Most are self-explanatory.
Called in the background thread when an asynchronous task completes. (Note: When an async method is running, all callbacks are in the background thread.)
Properties
AbortCurrent
void CkStreamW_putAbortCurrent(HCkStreamW cHandle, BOOL newVal);
When set to TRUE, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to FALSE when the next method is called. When the abort occurs, this property is reset to FALSE. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)
topCanRead
TRUE if the stream supports reading. Otherwise FALSE.
Note: A stream that supports reading, which has already reached the end-of-stream, will still have a CanRead value of TRUE. This property indicates the stream's inherent ability, and not whether or not the stream can be read at a particular moment in time.
topCanWrite
TRUE if the stream supports writing. Otherwise FALSE.
Note: A stream that supports writing, which has already been closed for write, will still have a CanWrite value of TRUE. This property indicates the stream's inherent ability, and not whether or not the stream can be written at a particular moment in time.
topDataAvailable
TRUE if it is known for sure that data is ready and waiting to be read. FALSE if it is not known for sure (it may be that data is immediately available, but reading the stream with a ReadTimeoutMs of 0, which is to poll the stream, is the way to find out).
topDebugLogFilePath
void CkStreamW_putDebugLogFilePath(HCkStreamW cHandle, const wchar_t *newVal);
const wchar_t *CkStreamW_debugLogFilePath(HCkStreamW cHandle);
If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.
This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:
- a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
- the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
- there is an internal problem (bug) in the Chilkat code that causes the hang.
DefaultChunkSize
void CkStreamW_putDefaultChunkSize(HCkStreamW cHandle, int newVal);
The default internal chunk size for reading or writing. The default value is 65536. If this property is set to 0, it will cause the default chunk size (65536) to be used. Note: The chunk size can have significant performance impact. If performance is an issue, be sure to experiment with different chunk sizes.
topEndOfStream
TRUE if the end-of-stream has already been reached. When the stream has already ended, all calls to Read* methods will return FALSE with the ReadFailReason set to 3 (already at end-of-stream).
topHeartbeatMs
void CkStreamW_putHeartbeatMs(HCkStreamW cHandle, int newVal);
The time interval, in milliseconds, between AbortCheck event callbacks. The heartbeat provides a means for an application to monitor a method call that has event callbacks, and to abort it while in progress.
topIsWriteClosed
TRUE if the stream is closed for writing. Once closed, no more data may be written to the stream.
topLastErrorHtml
const wchar_t *CkStreamW_lastErrorHtml(HCkStreamW cHandle);
Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.
topLastErrorText
const wchar_t *CkStreamW_lastErrorText(HCkStreamW cHandle);
Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.
LastErrorXml
const wchar_t *CkStreamW_lastErrorXml(HCkStreamW cHandle);
Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.
topLastMethodSuccess
void CkStreamW_putLastMethodSuccess(HCkStreamW cHandle, BOOL newVal);
Indicate whether the last method call succeeded or failed. A value of TRUE indicates success, a value of FALSE indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:
- Any method that returns a string.
- Any method returning a Chilkat object, binary bytes, or a date/time.
- Any method returning a standard boolean status value where success = TRUE and failure = FALSE.
- Any method returning an integer where failure is defined by a return value less than zero.
Note: Methods that do not fit the above requirements will always set this property equal to TRUE. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.
topLength
void CkStreamW_putLength(HCkStreamW cHandle, __int64 newVal);
The length (in bytes) of the stream's source. If unknown, then this property will have a value of -1. This property may be set by the application if it knows in advance the length of the stream.
topLength32
void CkStreamW_putLength32(HCkStreamW cHandle, int newVal);
The length (in bytes) of the stream's source. If unknown, then this property will have a value of -1. This property may be set by the application if it knows in advance the length of the stream.
Setting this property also sets the Length property (which is a 64-bit integer).
topNumReceived
The number of bytes received by the stream.
topNumSent
The number of bytes sent by the stream.
topReadFailReason
This property is automatically set when a Read* method is called. It indicates the reason for failure. Possible values are:
- No failure (success)
- Timeout, or no data is immediately available for a polling read.
- Aborted by an application callback.
- Already at end-of-stream.
- Fatal stream error.
- Out-of-memory error (this is very unlikely).
ReadTimeoutMs
void CkStreamW_putReadTimeoutMs(HCkStreamW cHandle, int newVal);
The maximum number of seconds to wait while reading. The default value is 30 seconds (i.e. 30000ms). A value of 0 indicates a poll. (A polling read is to return with a timeout if no data is immediately available.)
Important: For most Chilkat timeout related properties, a value of 0 indicates an infinite timeout. For this property, a value of 0 indicates a poll. If setting a timeout related property (or method argument) to zero, be sure to understand if 0 means "wait forever" or "poll".
The timeout value is not a total timeout. It is the maximum time to wait while no additional data is forthcoming.
topSinkFile
void CkStreamW_putSinkFile(HCkStreamW cHandle, const wchar_t *newVal);
const wchar_t *CkStreamW_sinkFile(HCkStreamW cHandle);
Sets the sink to the path of a file. The file does not need to exist at the time of setting this property. The sink file will be automatically opened on demand, when the stream is first written.
Note: This property takes priority over other potential sinks. Make sure this property is set to an empty string if the stream's sink is to be something else.
SinkFileAppend
void CkStreamW_putSinkFileAppend(HCkStreamW cHandle, BOOL newVal);
If TRUE, the stream appends to the SinkFile rather than truncating and re-writing the sink file. The default value is FALSE.
topSourceFile
void CkStreamW_putSourceFile(HCkStreamW cHandle, const wchar_t *newVal);
const wchar_t *CkStreamW_sourceFile(HCkStreamW cHandle);
Sets the source to the path of a file. The file does not need to exist at the time of setting this property. The source file will be automatically opened on demand, when the stream is first read.
Note: This property takes priority over other potential sources. Make sure this property is set to an empty string if the stream's source is to be something else.
SourceFilePart
void CkStreamW_putSourceFilePart(HCkStreamW cHandle, int newVal);
If the source is a file, then this property can be used to stream one part of the file. The SourceFilePartSize property defines the size (in bytes) of each part. The SourceFilePart and SourceFilePartSize have default values of 0, which means the entire SourceFile is streamed.
This property is a 0-based index. For example, if the SourceFilePartSize is 1000, then part 0 is for bytes 0 to 999, part 1 is for bytes 1000 to 1999, etc.
SourceFilePartSize
void CkStreamW_putSourceFilePartSize(HCkStreamW cHandle, int newVal);
If the source is a file, then this property, in conjunction with the SourceFilePart property, can be used to stream a single part of the file. This property defines the size (in bytes) of each part. The SourceFilePart and SourceFilePartSize have default values of 0, which means that by default, the entire SourceFile is streamed.
StringBom
void CkStreamW_putStringBom(HCkStreamW cHandle, BOOL newVal);
If TRUE, then include the BOM when creating a string source via SetSourceString where the charset is utf-8, utf-16, etc. (The term "BOM" stands for Byte Order Mark, also known as the preamble.) Also, if TRUE, then include the BOM when writing a string via the WriteString method. The default value of this property is FALSE.
topStringCharset
void CkStreamW_putStringCharset(HCkStreamW cHandle, const wchar_t *newVal);
const wchar_t *CkStreamW_stringCharset(HCkStreamW cHandle);
Indicates the expected character encoding, such as utf-8, windows-1256, utf-16, etc. for methods that read text such as: ReadString, ReadToCRLF, ReadUntilMatch. Also controls the character encoding when writing strings with the WriteString method. The supported charsets are indicated at the link below.
The default value is "utf-8".
VerboseLogging
void CkStreamW_putVerboseLogging(HCkStreamW cHandle, BOOL newVal);
If set to TRUE, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is FALSE. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
topVersion
const wchar_t *CkStreamW_version(HCkStreamW cHandle);
WriteFailReason
This property is automatically set when a Write* method is called. It indicates the reason for failure. Possible values are:
- No failure (success)
- Timeout, or unable to immediately write when the WriteTimeoutMs is 0.
- Aborted by an application callback.
- The stream has already ended.
- Fatal stream error.
- Out-of-memory error (this is very unlikely).
WriteTimeoutMs
void CkStreamW_putWriteTimeoutMs(HCkStreamW cHandle, int newVal);
The maximum number of seconds to wait while writing. The default value is 30 seconds (i.e. 30000ms). A value of 0 indicates to return immediately if it is not possible to write to the sink immediately.
topMethods
LoadTaskCaller
ReadBd
Read as much data as is immediately available on the stream. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive. The incoming data is appended to binData.
Returns TRUE for success, FALSE for failure.
ReadBdAsync (1)
Creates an asynchronous task to call the ReadBd method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
ReadBytes
Read as much data as is immediately available on the stream. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive.
Returns TRUE for success, FALSE for failure.
topReadBytesAsync (1)
Creates an asynchronous task to call the ReadBytes method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topReadBytesENC
const wchar_t *CkStreamW_readBytesENC(HCkStreamW cHandle, const wchar_t *encoding);
The same as ReadBytes, except returns the received bytes in encoded string form. The encoding argument indicates the encoding, which can be "base64", "hex", or any of the multitude of encodings indicated in the link below.
Returns TRUE for success, FALSE for failure.
ReadBytesENCAsync (1)
Creates an asynchronous task to call the ReadBytesENC method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topReadNBytes
Reads exactly numBytes bytes from the stream. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive.
Returns TRUE for success, FALSE for failure.
topReadNBytesAsync (1)
Creates an asynchronous task to call the ReadNBytes method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topReadNBytesENC
const wchar_t *CkStreamW_readNBytesENC(HCkStreamW cHandle, int numBytes, const wchar_t *encoding);
The same as ReadNBytes, except returns the received bytes in encoded string form. The encoding argument indicates the encoding, which can be "base64", "hex", or any of the multitude of encodings indicated in the link below.
Returns TRUE for success, FALSE for failure.
ReadNBytesENCAsync (1)
Creates an asynchronous task to call the ReadNBytesENC method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topReadSb
Read as much data as is immediately available on the stream. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive. The data is appended to sb. The incoming bytes are interpreted according to the StringCharset property. For example, if utf-8 bytes are expected, then StringCharset should be set to "utf-8" prior to calling ReadSb.
Returns TRUE for success, FALSE for failure.
topReadSbAsync (1)
Creates an asynchronous task to call the ReadSb method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
ReadString
const wchar_t *CkStreamW_readString(HCkStreamW cHandle);
Read as much data as is immediately available on the stream. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive. The data is returned as a string. The incoming bytes are interpreted according to the StringCharset property. For example, if utf-8 bytes are expected, then StringCharset should be set to "utf-8" prior to calling ReadString.
Returns TRUE for success, FALSE for failure.
topReadStringAsync (1)
Creates an asynchronous task to call the ReadString method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topReadToCRLF
const wchar_t *CkStreamW_readToCRLF(HCkStreamW cHandle);
Reads the stream until a CRLF is received. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive. The data is returned as a string. The incoming bytes are interpreted according to the StringCharset property. For example, if utf-8 bytes are expected, then StringCharset should be set to "utf-8" prior to calling ReadString.
Note: If the end-of-stream is reached prior to receiving the CRLF, then the remaining data is returned, and the ReadFailReason property will be set to 3 (to indicate end-of-file). This is the only case where as string would be returned that does not end with CRLF.
Returns TRUE for success, FALSE for failure.
topReadToCRLFAsync (1)
Creates an asynchronous task to call the ReadToCRLF method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topReadUntilMatch
const wchar_t *CkStreamW_readUntilMatch(HCkStreamW cHandle, const wchar_t *matchStr);
Reads the stream until the string indicated by matchStr is received. If no data is immediately available, it waits up to ReadTimeoutMs milliseconds for data to arrive. The data is returned as a string. The incoming bytes are interpreted according to the StringCharset property. For example, if utf-8 bytes are expected, then StringCharset should be set to "utf-8" prior to calling ReadString.
Note: If the end-of-stream is reached prior to receiving the match string, then the remaining data is returned, and the ReadFailReason property will be set to 3 (to indicate end-of-file). This is the only case where as string would be returned that does not end with the desired match string.
Returns TRUE for success, FALSE for failure.
ReadUntilMatchAsync (1)
Creates an asynchronous task to call the ReadUntilMatch method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topReset
Resets the stream. If a source or sink is open, then it is closed. Properties such as EndOfStream and IsWriteClose are reset to default values.
topSetSourceBytes
Sets the stream's source to the contents of sourceData.
Returns TRUE for success, FALSE for failure.
topSetSourceString
Sets the stream's source to the contents of srcStr. The charset indicates the character encoding to be used for the byte representation of the srcStr.
Returns TRUE for success, FALSE for failure.
topWriteBd
WriteBdAsync (1)
Creates an asynchronous task to call the WriteBd method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topWriteByte
Writes a single byte to the stream. The byteVal must have a value from 0 to 255.
Returns TRUE for success, FALSE for failure.
topWriteByteAsync (1)
Creates an asynchronous task to call the WriteByte method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topWriteBytes
WriteBytesAsync (1)
Creates an asynchronous task to call the WriteBytes method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topWriteBytes2
WriteBytesENC
Writes binary bytes to a stream. The byte data is passed in encoded string form, where the encoding can be "base64", "hex", or any of the supported binary encodings listed at the link below.
Returns TRUE for success, FALSE for failure.
WriteBytesENCAsync (1)
Creates an asynchronous task to call the WriteBytesENC method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topWriteClose
Indicates that no more data will be written to the stream.
Returns TRUE for success, FALSE for failure.
topWriteSb
Writes the contents of sb to the stream. The actual bytes written are the byte representation of the string as indicated by the StringCharset property. For example, to write utf-8 bytes, first set StringCharset equal to "utf-8" and then call WriteSb.
Returns TRUE for success, FALSE for failure.
topWriteSbAsync (1)
Creates an asynchronous task to call the WriteSb method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topWriteString
Writes a string to a stream. The actual bytes written are the byte representation of the string as indicated by the StringCharset property. For example, to write utf-8 bytes, first set StringCharset equal to "utf-8" and then call WriteString.
Returns TRUE for success, FALSE for failure.
topWriteStringAsync (1)
Creates an asynchronous task to call the WriteString method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
top