From 9a210ca2d50e02bf045866bbb2f44a33a3c48cd9 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Tue, 1 Jul 2014 23:10:38 +0200
Subject: Audit and replace all ctype.h uses

Something like "char *s = ...; isdigit(s[0]);" triggers undefined
behavior, because char can be signed, and thus s[0] can be a negative
value. The is*() functions require unsigned char _or_ EOF. EOF is a
special value outside of unsigned char range, thus the argument to the
is*() functions can't be a char.

This undefined behavior can actually trigger crashes if the
implementation of these functions e.g. uses lookup tables, which are
then indexed with out-of-range values.

Replace all <ctype.h> uses with our own custom mp_is*() functions added
with misc/ctype.h. As a bonus, these functions are locale-independent.
(Although currently, we _require_ C locale for other reasons.)
---
 sub/find_subfiles.c |  6 +++---
 sub/sd_microdvd.c   |  1 -
 sub/sd_srt.c        | 12 ++++++------
 3 files changed, 9 insertions(+), 10 deletions(-)

(limited to 'sub')

diff --git a/sub/find_subfiles.c b/sub/find_subfiles.c
index 9313bf379d..ade267cfa6 100644
--- a/sub/find_subfiles.c
+++ b/sub/find_subfiles.c
@@ -1,16 +1,16 @@
 #include <dirent.h>
 #include <string.h>
 #include <stdlib.h>
-#include <ctype.h>
 #include <assert.h>
 
 #include "osdep/io.h"
 
+#include "common/common.h"
 #include "common/global.h"
 #include "common/msg.h"
+#include "misc/ctype.h"
 #include "options/options.h"
 #include "options/path.h"
-#include "common/common.h"
 #include "sub/find_subfiles.h"
 
 static const char *const sub_exts[] = {"utf", "utf8", "utf-8", "idx", "sub", "srt",
@@ -75,7 +75,7 @@ static struct bstr guess_lang_from_filename(struct bstr name)
 
     if (name.start[i] == ')' || name.start[i] == ']')
         i--;
-    while (i >= 0 && isalpha(name.start[i])) {
+    while (i >= 0 && mp_isalpha(name.start[i])) {
         n++;
         if (n > 3)
             return (struct bstr){NULL, 0};
diff --git a/sub/sd_microdvd.c b/sub/sd_microdvd.c
index 6e6a9c31a8..5de9a1814b 100644
--- a/sub/sd_microdvd.c
+++ b/sub/sd_microdvd.c
@@ -24,7 +24,6 @@
 #include <stdio.h>
 #include <stdarg.h>
 #include <stdbool.h>
-#include <ctype.h>
 #include <libavutil/common.h>
 
 #include "common/msg.h"
diff --git a/sub/sd_srt.c b/sub/sd_srt.c
index 733a27d0f4..0ca807f312 100644
--- a/sub/sd_srt.c
+++ b/sub/sd_srt.c
@@ -24,11 +24,11 @@
 #include <stdio.h>
 #include <stdarg.h>
 #include <stdbool.h>
-#include <ctype.h>
-#include <libavutil/common.h>
 
+#include "common/common.h"
 #include "common/msg.h"
 #include "bstr/bstr.h"
+#include "misc/ctype.h"
 #include "sd.h"
 
 struct line {
@@ -259,7 +259,7 @@ static int read_attr(char **s, struct bstr *attr, struct bstr *val)
     attr->start = *s;
     attr->len = eq - *s;
     for (int i = 0; i < attr->len; i++)
-        if (!isalnum(attr->start[i]))
+        if (!mp_isalnum(attr->start[i]))
             return -1;
     val->start = eq + 1;
     bool quoted = val->start[0] == '"';
@@ -290,7 +290,7 @@ static void convert_subrip(struct sd *sd, const char *orig,
     while (*line && new_line.len < new_line.bufsize - 1) {
         char *orig_line = line;
 
-        for (int i = 0; i < FF_ARRAY_ELEMS(subrip_basic_tags); i++) {
+        for (int i = 0; i < MP_ARRAY_SIZE(subrip_basic_tags); i++) {
             const struct tag_conv *tag = &subrip_basic_tags[i];
             int from_len = strlen(tag->from);
             if (strncmp(line, tag->from, from_len) == 0) {
@@ -331,7 +331,7 @@ static void convert_subrip(struct sd *sd, const char *orig,
                 }
             }
         } else if (strncmp(line, "<font ", 6) == 0
-                   && sp + 1 < FF_ARRAY_ELEMS(font_stack)) {
+                   && sp + 1 < MP_ARRAY_SIZE(font_stack)) {
             /* Opening font tag */
             char *potential_font_tag_start = line;
             int len_backup = new_line.len;
@@ -360,7 +360,7 @@ static void convert_subrip(struct sd *sd, const char *orig,
                     int found = 0;
 
                     // Try to lookup the string in standard web colors
-                    for (int i = 0; i < FF_ARRAY_ELEMS(subrip_web_colors); i++) {
+                    for (int i = 0; i < MP_ARRAY_SIZE(subrip_web_colors); i++) {
                         char *color = subrip_web_colors[i].s;
                         if (bstrcasecmp(val, bstr0(color)) == 0) {
                             uint32_t xcolor = subrip_web_colors[i].v;
-- 
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