[m-dev.] for review: Fix bug in io__read_file_as_string/4

[Tyson Dowd]

Hi,

This is for Peter Ross -- you break it, you review it ;-)

Your original (buggy) diff was:

@@ -1650,7 +1667,7 @@
        char *buffer = (Char *) Buffer0;
        int items_read;
 
-       items_read = fread(buffer + Pos0, sizeof(Char), Size - Pos0, f->file);
+       MR_READ(*f, buffer + Pos0, Size - Pos0);
        Buffer = (Word) buffer;
        Pos = Pos0 + items_read;

===================================================================


Estimated hours taken: 2

The xml parser wasn't working, because all the files read using
io__read_file_as_string/4 were empty.  It turns out this is a due to a
bug in the library.

library/io.m:
	Fix a bug that petdr introduced when changing the file stream
	structures.
	Make sure we use the return value of fread (or whatever is used
	to read the file) when reading into a buffer.

tests/general/Mmakefile:
tests/general/io_regression.exp:
tests/general/io_regression.inp:
tests/general/io_regression.m:
	Add a test case for this problem to the test suite.


Index: library/io.m
===================================================================
RCS file: /home/mercury1/repository/mercury/library/io.m,v
retrieving revision 1.201
diff -u -r1.201 io.m
--- library/io.m	2000/08/11 16:50:15	1.201
+++ library/io.m	2000/09/11 02:48:21
@@ -1667,7 +1667,7 @@
 	char *buffer = (Char *) Buffer0;
 	int items_read;
 
-	MR_READ(*f, buffer + Pos0, Size - Pos0);
+	items_read = MR_READ(*f, buffer + Pos0, Size - Pos0);
 
 	Buffer = (Word) buffer;
 	Pos = Pos0 + items_read;
Index: tests/general/Mmakefile
===================================================================
RCS file: /home/mercury1/repository/tests/general/Mmakefile,v
retrieving revision 1.30
diff -u -r1.30 Mmakefile
--- tests/general/Mmakefile	2000/08/10 10:36:38	1.30
+++ tests/general/Mmakefile	2000/09/11 03:12:57
@@ -37,6 +37,7 @@
 		higher_order \
 		intermod_type \
 		interpreter \
+		io_regression \
 		liveness \
 		liveness2 \
 		mode_inf \
Index: tests/general/io_regression.exp
===================================================================
RCS file: io_regression.exp
diff -N io_regression.exp
--- /dev/null	Tue May 16 14:50:59 2000
+++ io_regression.exp	Mon Sep 11 14:11:36 2000
@@ -0,0 +1,3 @@
+
+This is a test of the reading files using io__read_file_as_string.
+
Index: tests/general/io_regression.inp
===================================================================
RCS file: io_regression.inp
diff -N io_regression.inp
--- /dev/null	Tue May 16 14:50:59 2000
+++ io_regression.inp	Mon Sep 11 14:08:49 2000
@@ -0,0 +1,3 @@
+
+This is a test of the reading files using io__read_file_as_string.
+
Index: tests/general/io_regression.m
===================================================================
RCS file: io_regression.m
diff -N io_regression.m
--- /dev/null	Tue May 16 14:50:59 2000
+++ io_regression.m	Mon Sep 11 14:11:23 2000
@@ -0,0 +1,22 @@
+:- module io_regression.
+
+%
+% io__read_file_as_string stopped working one day, and it wasn't noticed
+% because it wasn't in any of the test cases.  So now it is.
+%
+
+:- interface.
+:- import_module io.
+
+:- pred main(io__state::di, io__state::uo) is det.
+
+:- implementation.
+
+main --> 
+	io__read_file_as_string(Res, Str),
+	( { Res = ok } ->
+		io__write_string(Str)
+	;
+		io__write_string("Error reading file.\n")
+	).
+


-- 
       Tyson Dowd           # 
                            #  Surreal humour isn't everyone's cup of fur.
     trd at cs.mu.oz.au        # 
http://www.cs.mu.oz.au/~trd #
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