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| author | Ed Schonberg <schonberg@adacore.com> | 2019-07-08 08:13:25 +0000 |
|---|---|---|
| committer | Pierre-Marie de Rodat <pmderodat@gcc.gnu.org> | 2019-07-08 08:13:25 +0000 |
| commit | 4962dc441d317b6f28ab4ee3bf6b0d83f7c61837 (patch) | |
| tree | fdc72c0911cbbc2fbfd602d3fa11004cb5af1854 /gcc | |
| parent | 4a0e6ac18f731f41f7ddfa05c370186cd32bef52 (diff) | |
| download | gcc-4962dc441d317b6f28ab4ee3bf6b0d83f7c61837.zip gcc-4962dc441d317b6f28ab4ee3bf6b0d83f7c61837.tar.gz gcc-4962dc441d317b6f28ab4ee3bf6b0d83f7c61837.tar.bz2 | |
[Ada] Semantics of Delete for fixed strings
This patch corrects a bug in the implementation of Delete in an unusual
boundary case: the RM describes the semantics of Delete as equivalent to
that of Replace_String with a null argument. As a result, deleting a
null string that starts past the end of its argument is a noop and must
not raise Index_Error.
2019-07-08 Ed Schonberg <schonberg@adacore.com>
gcc/ada/
* libgnat/a-strfix.adb (Delete): The RM describes the semantics
of Delete as equivalent to that of Replace_String with a null
argument. As a result, deleting a null string that starts past
the end of its argument is a noop and must not raise
Index_Error.
gcc/testsuite/
* gnat.dg/fixed_delete.adb: New testcase.
From-SVN: r273205
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ada/ChangeLog | 8 | ||||
| -rw-r--r-- | gcc/ada/libgnat/a-strfix.adb | 10 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/testsuite/gnat.dg/fixed_delete.adb | 17 |
4 files changed, 38 insertions, 1 deletions
diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog index 969e933..2f97ab9 100644 --- a/gcc/ada/ChangeLog +++ b/gcc/ada/ChangeLog @@ -1,3 +1,11 @@ +2019-07-08 Ed Schonberg <schonberg@adacore.com> + + * libgnat/a-strfix.adb (Delete): The RM describes the semantics + of Delete as equivalent to that of Replace_String with a null + argument. As a result, deleting a null string that starts past + the end of its argument is a noop and must not raise + Index_Error. + 2019-07-08 Javier Miranda <miranda@adacore.com> * exp_disp.adb (Register_Primitive): When registering a diff --git a/gcc/ada/libgnat/a-strfix.adb b/gcc/ada/libgnat/a-strfix.adb index 6bf825b..b8b5f42 100644 --- a/gcc/ada/libgnat/a-strfix.adb +++ b/gcc/ada/libgnat/a-strfix.adb @@ -192,7 +192,15 @@ package body Ada.Strings.Fixed is elsif From not in Source'Range or else Through > Source'Last then - raise Index_Error; + -- In most cases this raises an exception, but the case of deleting + -- a null string at the end of the current one is a special-case, and + -- reflects the equivalence with Replace_String (RM A.4.3 (86/3)). + + if From = Source'Last + 1 and then From = Through then + return Source; + else + raise Index_Error; + end if; else declare diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 14d127f..a0b6bb4 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2019-07-08 Ed Schonberg <schonberg@adacore.com> + + * gnat.dg/fixed_delete.adb: New testcase. + 2019-07-08 Javier Miranda <miranda@adacore.com> * gnat.dg/interface9.adb, gnat.dg/interface9_root-child.ads, diff --git a/gcc/testsuite/gnat.dg/fixed_delete.adb b/gcc/testsuite/gnat.dg/fixed_delete.adb new file mode 100644 index 0000000..c13c71c --- /dev/null +++ b/gcc/testsuite/gnat.dg/fixed_delete.adb @@ -0,0 +1,17 @@ +-- { dg-do run } + +with Ada.Text_IO; use Ada.Text_IO; +with Ada.Strings.Fixed; use Ada.Strings.Fixed; + +procedure Fixed_Delete is + Str : String := "a"; + Str1 : String := Replace_Slice (Str, 2, 2, ""); + Str2 : String := Delete (Str, 2, 2); +begin + if Str1 /= "a" then + raise Program_Error; + end if; + if Str2 /= "a" then + raise Program_Error; + end if; +end Fixed_Delete; |