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bh=CPPsWVR0U6xteWYRUrvPeNQcFUnYVMY8kJRb5ji6y3o=; b=H36qudFQX2sRXxem2ormkfuuVTRtQFY4zfhIzl/VjVqHFBOE8jbw/7pZug/m/2upGDSdEE fEb3tZa92bffBSIiu7m9p9K1xx4g3XEshhWc9KIUnqTpwiGVeD9BRFaEetq5GDb2+T+8pk F7/mdeovexS+EJKROFkjiDeLOla1+6k= X-MC-Unique: aw5m9S95NxiVF55VTZWwwA-1 From: Eric Blake To: qemu-devel@nongnu.org Cc: Hanna Czenczek Subject: [PULL 08/21] cutils: Document differences between parse_uint and qemu_strtou64 Date: Thu, 1 Jun 2023 17:02:52 -0500 Message-Id: <20230601220305.2130121-9-eblake@redhat.com> In-Reply-To: <20230601220305.2130121-1-eblake@redhat.com> References: <20230601220305.2130121-1-eblake@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.166, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1685657124290100003 Content-Type: text/plain; charset="utf-8" These two functions are subtly different, and not just because of swapped parameter order. It took me adding better unit tests to figure out why. Document the differences to make it more obvious to developers trying to pick which one to use, as well as to aid in upcoming semantic changes. While touching the documentation, adjust a mis-statement: parse_uint does not return -EINVAL on invalid base, but assert()s, like all the other qemu_strto* functions that take a base argument. Signed-off-by: Eric Blake Reviewed-by: Hanna Czenczek Message-Id: <20230522190441.64278-7-eblake@redhat.com> --- util/cutils.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/util/cutils.c b/util/cutils.c index 9b6ce9179c4..36c14b769fd 100644 --- a/util/cutils.c +++ b/util/cutils.c @@ -611,6 +611,8 @@ int qemu_strtoi64(const char *nptr, const char **endptr= , int base, * Convert string @nptr to an uint64_t. * * Works like qemu_strtoul(), except it stores UINT64_MAX on overflow. + * (If you want to prohibit negative numbers that wrap around to + * positive, use parse_uint()). */ int qemu_strtou64(const char *nptr, const char **endptr, int base, uint64_t *result) @@ -721,7 +723,8 @@ const char *qemu_strchrnul(const char *s, int c) * * @s: String to parse * @value: Destination for parsed integer value - * @endptr: Destination for pointer to first character not consumed + * @endptr: Destination for pointer to first character not consumed, must + * not be %NULL * @base: integer base, between 2 and 36 inclusive, or 0 * * Parse unsigned integer @@ -729,15 +732,16 @@ const char *qemu_strchrnul(const char *s, int c) * Parsed syntax is like strtoull()'s: arbitrary whitespace, a single opti= onal * '+' or '-', an optional "0x" if @base is 0 or 16, one or more digits. * - * If @s is null, or @base is invalid, or @s doesn't start with an - * integer in the syntax above, set *@value to 0, *@endptr to @s, and - * return -EINVAL. + * If @s is null, or @s doesn't start with an integer in the syntax + * above, set *@value to 0, *@endptr to @s, and return -EINVAL. * * Set *@endptr to point right beyond the parsed integer (even if the inte= ger * overflows or is negative, all digits will be parsed and *@endptr will * point right beyond them). * * If the integer is negative, set *@value to 0, and return -ERANGE. + * (If you want to allow negative numbers that wrap around within + * bounds, use qemu_strtou64()). * * If the integer overflows unsigned long long, set *@value to * ULLONG_MAX, and return -ERANGE. @@ -794,10 +798,10 @@ out: * * Parse unsigned integer from entire string * - * Have the same behavior of parse_uint(), but with an additional check - * for additional data after the parsed number. If extra characters are pr= esent - * after the parsed number, the function will return -EINVAL, and *@v will - * be set to 0. + * Have the same behavior of parse_uint(), but with an additional + * check for additional data after the parsed number. If extra + * characters are present after a non-overflowing parsed number, the + * function will return -EINVAL, and *@v will be set to 0. */ int parse_uint_full(const char *s, unsigned long long *value, int base) { --=20 2.40.1