READFILE$: Difference between revisions
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{{PageParameters}} | {{PageParameters}} | ||
* {{Parameter|contents$}} is the entire file contents returned as [[STRING]]. May return an empty string, if the specified file was empty, or if the program was continued from a file related [[ERROR Codes|ERROR]]. | * {{Parameter|contents$}} is the entire file contents returned as [[STRING]]. May return an empty string, if the specified file was empty, or if the program was continued from a file related [[ERROR Codes|ERROR]]. | ||
* {{Parameter|fileSpec$}} is the name of the file to read as literal or variable [[STRING]], if required inclusive a full or relative path. | |||
** To avoid errors you should use [[_FILEEXISTS]] before calling this function to make sure the file exists. | ** To avoid errors you should use [[_FILEEXISTS]] before calling this function to make sure the file exists. | ||
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* Sometimes it's required or at least useful to have the whole contents of a file in a single string for further processing, e.g. to pass it to hashing or compression functions which expect strings. | * Sometimes it's required or at least useful to have the whole contents of a file in a single string for further processing, e.g. to pass it to hashing or compression functions which expect strings. | ||
* In earlier versions of QB64(PE) you had to implement that loading process manually all the time or create a reusable custom [[FUNCTION]] for it. | * In earlier versions of QB64(PE) you had to implement that loading process manually all the time or create a reusable custom [[FUNCTION]] for it. | ||
* Now '''_READFILE$''' will simplify this, it's mainly a convenience function to wrap the following code sequence | * Now '''_READFILE$''' will simplify this, it's mainly a convenience function to wrap the following code sequence into one handy function: | ||
{{TextStart}} | {{TextStart}} | ||
fh = {{Cb|FREEFILE}} | fh = {{Cb|FREEFILE}} | ||
Revision as of 09:17, 17 February 2024
The _READFILE$ function returns the complete contents of a file in a single string, but without the usual overhead. It does OPEN, GET and CLOSE the file in one run.
Syntax
- contents$ = _READFILE$(fileSpec$)
Parameters
- contents$ is the entire file contents returned as STRING. May return an empty string, if the specified file was empty, or if the program was continued from a file related ERROR.
- fileSpec$ is the name of the file to read as literal or variable STRING, if required inclusive a full or relative path.
- To avoid errors you should use _FILEEXISTS before calling this function to make sure the file exists.
Description
- Sometimes it's required or at least useful to have the whole contents of a file in a single string for further processing, e.g. to pass it to hashing or compression functions which expect strings.
- In earlier versions of QB64(PE) you had to implement that loading process manually all the time or create a reusable custom FUNCTION for it.
- Now _READFILE$ will simplify this, it's mainly a convenience function to wrap the following code sequence into one handy function:
fh = FREEFILE OPEN fileSpec$ FOR BINARY AS #fh contents$ = SPACE$(LOF(fh)) GET #fh, , contents$ CLOSE #fh |
Availability
none
v3.12.0
yes
yes
yes
Examples
- Example 1
- Showing that this function's result is equal to the code sequence shown above.
$COLOR:0 fileSpec$ = "source\global\settings.bas" fh = FREEFILE OPEN fileSpec$ FOR BINARY AS #fh content$ = SPACE$(LOF(fh)) GET #fh, , content$ CLOSE #fh COLOR LightGreen PRINT "Using old manual load method..." COLOR White PRINT content$ COLOR LightGreen PRINT "Using new direct load method..." COLOR White PRINT _READFILE$(fileSpec$) END |
- Example 2
- Passing a whole file's contents to hashing functions.
$COLOR:0 fileSpec$ = "source\global\settings.bas" COLOR LightGreen PRINT "CRC32 of the file..." COLOR White PRINT RIGHT$("00000000" + HEX$(_CRC32(_READFILE$(fileSpec$))), 8) PRINT COLOR LightGreen PRINT "MD5 of the file..." COLOR White PRINT _MD5$(_READFILE$(fileSpec$)) END |
See also