READFILE$: Difference between revisions
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{{PageSyntax}} | {{PageSyntax}} | ||
: {{Parameter| | : {{Parameter|contents$}} = [[_READFILE$]]({{Parameter|fileSpec$}}) | ||
{{PageParameters}} | {{PageParameters}} | ||
* {{Parameter| | * {{Parameter|contents$}} is the entire file contents returned as [[STRING]]. May return an empty string, if the specified file was empty, or if the program was continued from a file related [[ERROR Codes|ERROR]]. | ||
** To avoid errors you should use [[_FILEEXISTS]] to make sure the file exists. | |||
* {{Parameter|fileSpec$}} is the name of the file to read as literal or variable [[STRING]], if required inclusive a full or relative path. | * {{Parameter|fileSpec$}} is the name of the file to read as literal or variable [[STRING]], if required inclusive a full or relative path. | ||
{{PageDescription}} | {{PageDescription}} | ||
* Sometimes it's required or at least useful to have the whole contents of a file in a single string for further processing, e.g. to pass it to | * Sometimes it's required or at least useful to have the whole contents of a file in a single string for further processing, e.g. to pass it to hashing or compression functions which expect strings. | ||
* In earlier versions of QB64(PE) you had to implement that loading process manually all the time or create a reusable custom [[FUNCTION]] for it. | * In earlier versions of QB64(PE) you had to implement that loading process manually all the time or create a reusable custom [[FUNCTION]] for it. | ||
* Now '''_READFILE''' will simplify this, it's mainly a convenience function to wrap the following code sequence in one handy function: | * Now '''_READFILE$''' will simplify this, it's mainly a convenience function to wrap the following code sequence in one handy function: | ||
{{TextStart}} | {{TextStart}} | ||
fh = {{Cb|FREEFILE}} | fh = {{Cb|FREEFILE}} | ||
{{Cb|OPEN}} fileSpec$ {{Cb|FOR}} {{Cb|BINARY}} {{Cb|AS}} #fh | {{Cb|OPEN}} fileSpec$ {{Cb|FOR}} {{Cb|BINARY}} {{Cb|AS}} #fh | ||
contents$ = {{Cb|SPACE$}}({{Cb|LOF}}(fh)) | |||
{{Cb|GET}} #fh, , | {{Cb|GET}} #fh, , contents$ | ||
{{Cb|CLOSE}} #fh | {{Cb|CLOSE}} #fh | ||
{{TextEnd}} | {{TextEnd}} | ||
| Line 64: | Line 65: | ||
---- | ---- | ||
;Example 2: Passing a | ;Example 2: Passing a whole file's contents to hashing functions. | ||
{{CodeStart}} | {{CodeStart}} | ||
{{Cm|$COLOR}}:{{Text|0|#F580B1}} | {{Cm|$COLOR}}:{{Text|0|#F580B1}} | ||
| Line 84: | Line 85: | ||
{{PageSeeAlso}} | {{PageSeeAlso}} | ||
* [[_WRITEFILE]] | |||
* [[_DEFLATE$]], [[_INFLATE$]] | * [[_DEFLATE$]], [[_INFLATE$]] | ||
* [[_ADLER32]], [[_MD5$]] | * [[_ADLER32]], [[_CRC32]], [[_MD5$]] | ||
{{PageNavigation}} | {{PageNavigation}} | ||
Revision as of 18:13, 15 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.
- To avoid errors you should use _FILEEXISTS to make sure the file exists.
- fileSpec$ is the name of the file to read as literal or variable STRING, if required inclusive a full or relative path.
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 in 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$(fileSpec$) |
- 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$)) |
See also