Commit 79b0aae86c9ea97b4ad8eaf385dfc3b1b804656e
2021-09-22T11:42:10
The return value of SDL_snprintf is the number of characters that would have been written. Fixes https://github.com/libsdl-org/SDL/issues/4762
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diff --git a/src/stdlib/SDL_string.c b/src/stdlib/SDL_string.c
index ec43b1e..76005e2 100644
--- a/src/stdlib/SDL_string.c
+++ b/src/stdlib/SDL_string.c
@@ -1472,6 +1472,8 @@ int SDL_vsnprintf(SDL_OUT_Z_CAP(maxlen) char *text, size_t maxlen, const char *f
return vsnprintf(text, maxlen, fmt, ap);
}
#else
+#define TEXT_AND_LEN_ARGS (length < maxlen) ? &text[length] : NULL, (length < maxlen) ? (maxlen - length) : 0
+
/* FIXME: implement more of the format specifiers */
typedef enum
{
@@ -1514,25 +1516,27 @@ SDL_PrintString(char *text, size_t maxlen, SDL_FormatInfo *info, const char *str
filllen = SDL_min(width, maxlen);
SDL_memset(text, fill, filllen);
text += filllen;
- length += filllen;
maxlen -= filllen;
+ length += width;
}
- slen = SDL_strlcpy(text, string, maxlen);
- length += SDL_min(slen, maxlen);
+ SDL_strlcpy(text, string, maxlen);
+ length += sz;
if (info) {
if (info->precision >= 0 && (size_t)info->precision < sz) {
slen = (size_t)info->precision;
if (slen < maxlen) {
- text[slen] = 0;
- length -= (sz - slen);
+ text[slen] = '\0';
}
+ length -= (sz - slen);
}
- if (info->force_case == SDL_CASE_LOWER) {
- SDL_strlwr(text);
- } else if (info->force_case == SDL_CASE_UPPER) {
- SDL_strupr(text);
+ if (maxlen > 1) {
+ if (info->force_case == SDL_CASE_LOWER) {
+ SDL_strlwr(text);
+ } else if (info->force_case == SDL_CASE_UPPER) {
+ SDL_strupr(text);
+ }
}
}
return length;
@@ -1585,7 +1589,7 @@ SDL_PrintLong(char *text, size_t maxlen, SDL_FormatInfo *info, long value)
}
SDL_ltoa(value, p, info ? info->radix : 10);
- SDL_IntPrecisionAdjust(num, maxlen, info);
+ SDL_IntPrecisionAdjust(num, sizeof(num), info);
return SDL_PrintString(text, maxlen, info, num);
}
@@ -1595,7 +1599,7 @@ SDL_PrintUnsignedLong(char *text, size_t maxlen, SDL_FormatInfo *info, unsigned
char num[130];
SDL_ultoa(value, num, info ? info->radix : 10);
- SDL_IntPrecisionAdjust(num, maxlen, info);
+ SDL_IntPrecisionAdjust(num, sizeof(num), info);
return SDL_PrintString(text, maxlen, info, num);
}
@@ -1609,7 +1613,7 @@ SDL_PrintLongLong(char *text, size_t maxlen, SDL_FormatInfo *info, Sint64 value)
}
SDL_lltoa(value, p, info ? info->radix : 10);
- SDL_IntPrecisionAdjust(num, maxlen, info);
+ SDL_IntPrecisionAdjust(num, sizeof(num), info);
return SDL_PrintString(text, maxlen, info, num);
}
@@ -1619,126 +1623,92 @@ SDL_PrintUnsignedLongLong(char *text, size_t maxlen, SDL_FormatInfo *info, Uint6
char num[130];
SDL_ulltoa(value, num, info ? info->radix : 10);
- SDL_IntPrecisionAdjust(num, maxlen, info);
+ SDL_IntPrecisionAdjust(num, sizeof(num), info);
return SDL_PrintString(text, maxlen, info, num);
}
static size_t
SDL_PrintFloat(char *text, size_t maxlen, SDL_FormatInfo *info, double arg)
{
- int width;
- size_t len;
- size_t left = maxlen;
- char *textstart = text;
+ size_t length = 0;
if (arg) {
/* This isn't especially accurate, but hey, it's easy. :) */
unsigned long value;
if (arg < 0) {
- if (left > 1) {
- *text = '-';
- --left;
+ if (length < maxlen) {
+ text[length] = '-';
}
- ++text;
+ ++length;
arg = -arg;
} else if (info->force_sign) {
- if (left > 1) {
- *text = '+';
- --left;
+ if (length < maxlen) {
+ text[length] = '+';
}
- ++text;
+ ++length;
}
value = (unsigned long) arg;
- len = SDL_PrintUnsignedLong(text, left, NULL, value);
- if (len >= left) {
- text += (left > 1) ? left - 1 : 0;
- left = SDL_min(left, 1);
- } else {
- text += len;
- left -= len;
- }
+ length += SDL_PrintUnsignedLong(TEXT_AND_LEN_ARGS, NULL, value);
arg -= value;
if (info->precision < 0) {
info->precision = 6;
}
if (info->force_type || info->precision > 0) {
int mult = 10;
- if (left > 1) {
- *text = '.';
- --left;
+ if (length < maxlen) {
+ text[length] = '.';
}
- ++text;
+ ++length;
while (info->precision-- > 0) {
value = (unsigned long) (arg * mult);
- len = SDL_PrintUnsignedLong(text, left, NULL, value);
- if (len >= left) {
- text += (left > 1) ? left - 1 : 0;
- left = SDL_min(left, 1);
- } else {
- text += len;
- left -= len;
- }
+ length += SDL_PrintUnsignedLong(TEXT_AND_LEN_ARGS, NULL, value);
arg -= (double) value / mult;
mult *= 10;
}
}
} else {
- if (left > 1) {
- *text = '0';
- --left;
+ if (length < maxlen) {
+ text[length] = '0';
}
- ++text;
+ ++length;
if (info->force_type) {
- if (left > 1) {
- *text = '.';
- --left;
+ if (length < maxlen) {
+ text[length] = '.';
}
- ++text;
+ ++length;
}
}
- width = info->width - (int)(text - textstart);
- if (width > 0) {
+ if (info->width > 0 && (size_t)info->width > length) {
const char fill = info->pad_zeroes ? '0' : ' ';
- char *end = text+left-1;
- len = (text - textstart);
- for (len = (text - textstart); len--; ) {
- if ((textstart+len+width) < end) {
- *(textstart+len+width) = *(textstart+len);
- }
- }
- len = (size_t)width;
- if (len >= left) {
- text += (left > 1) ? left - 1 : 0;
- left = SDL_min(left, 1);
- } else {
- text += len;
- left -= len;
- }
+ size_t width = info->width - length;
+ size_t filllen, movelen;
- if (end != textstart) {
- const size_t filllen = SDL_min(len, ((size_t) (end - textstart)) - 1);
- SDL_memset(textstart, fill, filllen);
- }
+ filllen = SDL_min(width, maxlen);
+ movelen = SDL_min(length, (maxlen - filllen));
+ SDL_memmove(&text[filllen], text, movelen);
+ SDL_memset(text, fill, filllen);
+ length += width;
}
- return (text - textstart);
+ return length;
}
int
SDL_vsnprintf(SDL_OUT_Z_CAP(maxlen) char *text, size_t maxlen, const char *fmt, va_list ap)
{
- size_t left = maxlen;
- char *textstart = text;
+ size_t length = 0;
+ if (!text) {
+ maxlen = 0;
+ }
if (!fmt) {
fmt = "";
}
- while (*fmt && left > 1) {
+ while (*fmt) {
if (*fmt == '%') {
SDL_bool done = SDL_FALSE;
- size_t len = 0;
SDL_bool check_flag;
SDL_FormatInfo info;
enum
@@ -1800,18 +1770,18 @@ SDL_vsnprintf(SDL_OUT_Z_CAP(maxlen) char *text, size_t maxlen, const char *fmt,
while (!done) {
switch (*fmt) {
case '%':
- if (left > 1) {
- *text = '%';
+ if (length < maxlen) {
+ text[length] = '%';
}
- len = 1;
+ ++length;
done = SDL_TRUE;
break;
case 'c':
/* char is promoted to int when passed through (...) */
- if (left > 1) {
- *text = (char) va_arg(ap, int);
+ if (length < maxlen) {
+ text[length] = (char) va_arg(ap, int);
}
- len = 1;
+ ++length;
done = SDL_TRUE;
break;
case 'h':
@@ -1835,15 +1805,15 @@ SDL_vsnprintf(SDL_OUT_Z_CAP(maxlen) char *text, size_t maxlen, const char *fmt,
}
switch (inttype) {
case DO_INT:
- len = SDL_PrintLong(text, left, &info,
+ length += SDL_PrintLong(TEXT_AND_LEN_ARGS, &info,
(long) va_arg(ap, int));
break;
case DO_LONG:
- len = SDL_PrintLong(text, left, &info,
+ length += SDL_PrintLong(TEXT_AND_LEN_ARGS, &info,
va_arg(ap, long));
break;
case DO_LONGLONG:
- len = SDL_PrintLongLong(text, left, &info,
+ length += SDL_PrintLongLong(TEXT_AND_LEN_ARGS, &info,
va_arg(ap, Sint64));
break;
}
@@ -1876,23 +1846,23 @@ SDL_vsnprintf(SDL_OUT_Z_CAP(maxlen) char *text, size_t maxlen, const char *fmt,
}
switch (inttype) {
case DO_INT:
- len = SDL_PrintUnsignedLong(text, left, &info,
+ length += SDL_PrintUnsignedLong(TEXT_AND_LEN_ARGS, &info,
(unsigned long)
va_arg(ap, unsigned int));
break;
case DO_LONG:
- len = SDL_PrintUnsignedLong(text, left, &info,
+ length += SDL_PrintUnsignedLong(TEXT_AND_LEN_ARGS, &info,
va_arg(ap, unsigned long));
break;
case DO_LONGLONG:
- len = SDL_PrintUnsignedLongLong(text, left, &info,
+ length += SDL_PrintUnsignedLongLong(TEXT_AND_LEN_ARGS, &info,
va_arg(ap, Uint64));
break;
}
done = SDL_TRUE;
break;
case 'f':
- len = SDL_PrintFloat(text, left, &info, va_arg(ap, double));
+ length += SDL_PrintFloat(TEXT_AND_LEN_ARGS, &info, va_arg(ap, double));
done = SDL_TRUE;
break;
case 'S':
@@ -1902,18 +1872,18 @@ SDL_vsnprintf(SDL_OUT_Z_CAP(maxlen) char *text, size_t maxlen, const char *fmt,
if (wide_arg) {
char *arg = SDL_iconv_string("UTF-8", "UTF-16LE", (char *)(wide_arg), (SDL_wcslen(wide_arg)+1)*sizeof(*wide_arg));
info.pad_zeroes = SDL_FALSE;
- len = SDL_PrintString(text, left, &info, arg);
+ length += SDL_PrintString(TEXT_AND_LEN_ARGS, &info, arg);
SDL_free(arg);
} else {
info.pad_zeroes = SDL_FALSE;
- len = SDL_PrintString(text, left, &info, NULL);
+ length += SDL_PrintString(TEXT_AND_LEN_ARGS, &info, NULL);
}
done = SDL_TRUE;
}
break;
case 's':
info.pad_zeroes = SDL_FALSE;
- len = SDL_PrintString(text, left, &info, va_arg(ap, char *));
+ length += SDL_PrintString(TEXT_AND_LEN_ARGS, &info, va_arg(ap, char *));
done = SDL_TRUE;
break;
default:
@@ -1922,23 +1892,23 @@ SDL_vsnprintf(SDL_OUT_Z_CAP(maxlen) char *text, size_t maxlen, const char *fmt,
}
++fmt;
}
- if (len >= left) {
- text += (left > 1) ? left - 1 : 0;
- left = SDL_min(left, 1);
- } else {
- text += len;
- left -= len;
- }
} else {
- *text++ = *fmt++;
- --left;
+ if (length < maxlen) {
+ text[length] = *fmt++;
+ }
+ ++length;
}
}
- if (left > 0) {
- *text = '\0';
+ if (length < maxlen) {
+ text[length] = '\0';
+ } else if (maxlen > 0) {
+ text[maxlen - 1] = '\0';
}
- return (int)(text - textstart);
+ return (int)length;
+
}
+
+#undef TEXT_AND_LEN_ARGS
#endif /* HAVE_VSNPRINTF */
/* vi: set ts=4 sw=4 expandtab: */
diff --git a/test/testautomation_stdlib.c b/test/testautomation_stdlib.c
index e741d54..9ea1964 100644
--- a/test/testautomation_stdlib.c
+++ b/test/testautomation_stdlib.c
@@ -44,6 +44,7 @@ int
stdlib_snprintf(void *arg)
{
int result;
+ int predicted;
char text[1024];
const char *expected;
@@ -60,55 +61,72 @@ stdlib_snprintf(void *arg)
SDLTest_AssertCheck(result == 3, "Check result value, expected: 3, got: %d", result);
result = SDL_snprintf(NULL, 0, "%s", "foo");
+ SDLTest_AssertPass("Call to SDL_snprintf(NULL, 0, \"%%s\", \"foo\")");
SDLTest_AssertCheck(result == 3, "Check result value, expected: 3, got: %d", result);
result = SDL_snprintf(text, sizeof(text), "%f", 1.0);
+ predicted = SDL_snprintf(NULL, 0, "%f", 1.0);
expected = "1.000000";
SDLTest_AssertPass("Call to SDL_snprintf(\"%%f\", 1.0)");
SDLTest_AssertCheck(SDL_strcmp(text, expected) == 0, "Check text, expected: %s, got: %s", expected, text);
SDLTest_AssertCheck(result == SDL_strlen(text), "Check result value, expected: %d, got: %d", (int) SDL_strlen(text), result);
+ SDLTest_AssertCheck(predicted == result, "Check predicted value, expected: %d, got: %d", result, predicted);
result = SDL_snprintf(text, sizeof(text), "%.f", 1.0);
+ predicted = SDL_snprintf(NULL, 0, "%.f", 1.0);
expected = "1";
SDLTest_AssertPass("Call to SDL_snprintf(\"%%.f\", 1.0)");
SDLTest_AssertCheck(SDL_strcmp(text, expected) == 0, "Check text, expected: %s, got: %s", expected, text);
SDLTest_AssertCheck(result == SDL_strlen(text), "Check result value, expected: %d, got: %d", (int) SDL_strlen(text), result);
+ SDLTest_AssertCheck(predicted == result, "Check predicted value, expected: %d, got: %d", result, predicted);
result = SDL_snprintf(text, sizeof(text), "%#.f", 1.0);
+ predicted = SDL_snprintf(NULL, 0, "%#.f", 1.0);
expected = "1.";
SDLTest_AssertPass("Call to SDL_snprintf(\"%%#.f\", 1.0)");
SDLTest_AssertCheck(SDL_strcmp(text, expected) == 0, "Check text, expected: %s, got: %s", expected, text);
SDLTest_AssertCheck(result == SDL_strlen(text), "Check result value, expected: %d, got: %d", (int) SDL_strlen(text), result);
+ SDLTest_AssertCheck(predicted == result, "Check predicted value, expected: %d, got: %d", result, predicted);
result = SDL_snprintf(text, sizeof(text), "%f", 1.0 + 1.0 / 3.0);
+ predicted = SDL_snprintf(NULL, 0, "%f", 1.0 + 1.0 / 3.0);
expected = "1.333333";
SDLTest_AssertPass("Call to SDL_snprintf(\"%%f\", 1.0 + 1.0 / 3.0)");
SDLTest_AssertCheck(SDL_strcmp(text, expected) == 0, "Check text, expected: %s, got: %s", expected, text);
SDLTest_AssertCheck(result == SDL_strlen(text), "Check result value, expected: %d, got: %d", (int) SDL_strlen(text), result);
+ SDLTest_AssertCheck(predicted == result, "Check predicted value, expected: %d, got: %d", result, predicted);
result = SDL_snprintf(text, sizeof(text), "%+f", 1.0 + 1.0 / 3.0);
+ predicted = SDL_snprintf(NULL, 0, "%+f", 1.0 + 1.0 / 3.0);
expected = "+1.333333";
SDLTest_AssertPass("Call to SDL_snprintf(\"%%+f\", 1.0 + 1.0 / 3.0)");
SDLTest_AssertCheck(SDL_strcmp(text, expected) == 0, "Check text, expected: %s, got: %s", expected, text);
SDLTest_AssertCheck(result == SDL_strlen(text), "Check result value, expected: %d, got: %d", (int) SDL_strlen(text), result);
+ SDLTest_AssertCheck(predicted == result, "Check predicted value, expected: %d, got: %d", result, predicted);
result = SDL_snprintf(text, sizeof(text), "%.2f", 1.0 + 1.0 / 3.0);
+ predicted = SDL_snprintf(NULL, 0, "%.2f", 1.0 + 1.0 / 3.0);
expected = "1.33";
SDLTest_AssertPass("Call to SDL_snprintf(\"%%.2f\", 1.0 + 1.0 / 3.0)");
SDLTest_AssertCheck(SDL_strcmp(text, expected) == 0, "Check text, expected: %s, got: %s", expected, text);
SDLTest_AssertCheck(result == SDL_strlen(text), "Check result value, expected: %d, got: %d", (int) SDL_strlen(text), result);
+ SDLTest_AssertCheck(predicted == result, "Check predicted value, expected: %d, got: %d", result, predicted);
result = SDL_snprintf(text, sizeof(text), "%6.2f", 1.0 + 1.0 / 3.0);
+ predicted = SDL_snprintf(NULL, 0, "%6.2f", 1.0 + 1.0 / 3.0);
expected = " 1.33";
SDLTest_AssertPass("Call to SDL_snprintf(\"%%6.2f\", 1.0 + 1.0 / 3.0)");
SDLTest_AssertCheck(SDL_strcmp(text, expected) == 0, "Check text, expected: '%s', got: '%s'", expected, text);
SDLTest_AssertCheck(result == SDL_strlen(text), "Check result value, expected: %d, got: %d", (int) SDL_strlen(text), result);
+ SDLTest_AssertCheck(predicted == result, "Check predicted value, expected: %d, got: %d", result, predicted);
result = SDL_snprintf(text, sizeof(text), "%06.2f", 1.0 + 1.0 / 3.0);
+ predicted = SDL_snprintf(NULL, 0, "%06.2f", 1.0 + 1.0 / 3.0);
expected = "001.33";
SDLTest_AssertPass("Call to SDL_snprintf(\"%%06.2f\", 1.0 + 1.0 / 3.0)");
SDLTest_AssertCheck(SDL_strcmp(text, expected) == 0, "Check text, expected: '%s', got: '%s'", expected, text);
SDLTest_AssertCheck(result == SDL_strlen(text), "Check result value, expected: %d, got: %d", (int) SDL_strlen(text), result);
+ SDLTest_AssertCheck(predicted == result, "Check predicted value, expected: %d, got: %d", result, predicted);
result = SDL_snprintf(text, 5, "%06.2f", 1.0 + 1.0 / 3.0);
expected = "001.";