On Thu, 2015-01-29 at 11:03 +0100, Rasmus Villemoes wrote: > When printf is given the format specifier %pE, it needs a way of > obtaining the total output size that would be generated if the buffer > was large enough, and string_escape_mem doesn't easily provide > that. This is a refactorization of string_escape_mem in preparation of > changing its external API to provide that information.
Few comments below. > > Signed-off-by: Rasmus Villemoes <[email protected]> > --- > lib/string_helpers.c | 182 > ++++++++++++++++++++------------------------------- > 1 file changed, 72 insertions(+), 110 deletions(-) > > diff --git a/lib/string_helpers.c b/lib/string_helpers.c > index 58b78ba57439..e14dd8555760 100644 > --- a/lib/string_helpers.c > +++ b/lib/string_helpers.c > @@ -243,29 +243,21 @@ int string_unescape(char *src, char *dst, size_t size, > unsigned int flags) > } > EXPORT_SYMBOL(string_unescape); > > -static int escape_passthrough(unsigned char c, char **dst, size_t *osz) > +static bool escape_passthrough(unsigned char c, char **dst, char *end) > { > char *out = *dst; > > - if (*osz < 1) > - return -ENOMEM; > - > - *out++ = c; > - > - *dst = out; > - *osz -= 1; > - > - return 1; > + if (out < end) > + *out = c; > + *dst = out + 1; > + return true; > } > > -static int escape_space(unsigned char c, char **dst, size_t *osz) > +static bool escape_space(unsigned char c, char **dst, char *end) > { > char *out = *dst; > unsigned char to; > > - if (*osz < 2) > - return -ENOMEM; > - > switch (c) { > case '\n': > to = 'n'; > @@ -283,26 +275,23 @@ static int escape_space(unsigned char c, char **dst, > size_t *osz) > to = 'f'; > break; > default: > - return 0; > + return false; > } > > - *out++ = '\\'; > - *out++ = to; > + if (out + 0 < end) > + out[0] = '\\'; > + if (out + 1 < end) > + out[1] = to; Could we do this in the same way like for hex_string, i.e. if (out < end) *out = '\\'; ++out; … *dst = out; return true; ? > > - *dst = out; > - *osz -= 2; > - > - return 1; > + *dst = out + 2; > + return true; > } > > -static int escape_special(unsigned char c, char **dst, size_t *osz) > +static bool escape_special(unsigned char c, char **dst, char *end) > { > char *out = *dst; > unsigned char to; > > - if (*osz < 2) > - return -ENOMEM; > - > switch (c) { > case '\\': > to = '\\'; > @@ -314,71 +303,66 @@ static int escape_special(unsigned char c, char **dst, > size_t *osz) > to = 'e'; > break; > default: > - return 0; > + return false; > } > > - *out++ = '\\'; > - *out++ = to; > + if (out + 0 < end) > + out[0] = '\\'; > + if (out + 1 < end) > + out[1] = to; Ditto. > > - *dst = out; > - *osz -= 2; > - > - return 1; > + *dst = out + 2; > + return true; > } > > -static int escape_null(unsigned char c, char **dst, size_t *osz) > +static bool escape_null(unsigned char c, char **dst, char *end) > { > char *out = *dst; > > - if (*osz < 2) > - return -ENOMEM; > - > if (c) > - return 0; > - > - *out++ = '\\'; > - *out++ = '0'; > + return false; > > - *dst = out; > - *osz -= 2; > + if (out + 0 < end) > + out[0] = '\\'; > + if (out + 1 < end) > + out[1] = '0'; Ditto. > > - return 1; > + *dst = out + 2; > + return true; > } > > -static int escape_octal(unsigned char c, char **dst, size_t *osz) > +static bool escape_octal(unsigned char c, char **dst, char *end) > { > char *out = *dst; > > - if (*osz < 4) > - return -ENOMEM; > - > - *out++ = '\\'; > - *out++ = ((c >> 6) & 0x07) + '0'; > - *out++ = ((c >> 3) & 0x07) + '0'; > - *out++ = ((c >> 0) & 0x07) + '0'; > + if (out + 0 < end) > + out[0] = '\\'; > + if (out + 1 < end) > + out[1] = ((c >> 6) & 0x07) + '0'; > + if (out + 2 < end) > + out[2] = ((c >> 3) & 0x07) + '0'; > + if (out + 3 < end) > + out[3] = ((c >> 0) & 0x07) + '0'; Ditto. > > - *dst = out; > - *osz -= 4; > - > - return 1; > + *dst = out + 4; > + return true; > } > > -static int escape_hex(unsigned char c, char **dst, size_t *osz) > +static bool escape_hex(unsigned char c, char **dst, char *end) > { > char *out = *dst; > > - if (*osz < 4) > - return -ENOMEM; > - > - *out++ = '\\'; > - *out++ = 'x'; > - *out++ = hex_asc_hi(c); > - *out++ = hex_asc_lo(c); > - > - *dst = out; > - *osz -= 4; > + if (out + 0 < end) > + out[0] = '\\'; > + if (out + 1 < end) > + out[1] = 'x'; > + if (out + 2 < end) > + out[2] = hex_asc_hi(c); > + if (out + 3 < end) > + out[3] = hex_asc_lo(c); Ditto. > > - return 1; > + *dst = out + 4; > + return true; > } > > /** > @@ -440,9 +424,10 @@ static int escape_hex(unsigned char c, char **dst, > size_t *osz) > int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz, > unsigned int flags, const char *esc) > { > - char *out = *dst, *p = out; > + char *p = *dst; Leave 'out' here and… > + char *end = p + osz; > bool is_dict = esc && *esc; > - int ret = 0; > + int ret; > > while (isz--) { > unsigned char c = *src++; > @@ -462,55 +447,32 @@ int string_escape_mem(const char *src, size_t isz, char > **dst, size_t osz, > (is_dict && !strchr(esc, c))) { > /* do nothing */ > } else { > - if (flags & ESCAPE_SPACE) { > - ret = escape_space(c, &p, &osz); > - if (ret < 0) > - break; > - if (ret > 0) > - continue; > - } > - > - if (flags & ESCAPE_SPECIAL) { > - ret = escape_special(c, &p, &osz); > - if (ret < 0) > - break; > - if (ret > 0) > - continue; > - } > - > - if (flags & ESCAPE_NULL) { > - ret = escape_null(c, &p, &osz); > - if (ret < 0) > - break; > - if (ret > 0) > - continue; > - } > + if (flags & ESCAPE_SPACE && escape_space(c, &p, end)) > + continue; > + > + if (flags & ESCAPE_SPECIAL && escape_special(c, &p, > end)) > + continue; > + > + if (flags & ESCAPE_NULL && escape_null(c, &p, end)) > + continue; > > /* ESCAPE_OCTAL and ESCAPE_HEX always go last */ > - if (flags & ESCAPE_OCTAL) { > - ret = escape_octal(c, &p, &osz); > - if (ret < 0) > - break; > + if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end)) > continue; > - } > - if (flags & ESCAPE_HEX) { > - ret = escape_hex(c, &p, &osz); > - if (ret < 0) > - break; > + > + if (flags & ESCAPE_HEX && escape_hex(c, &p, end)) > continue; > - } > } > > - ret = escape_passthrough(c, &p, &osz); > - if (ret < 0) > - break; > + escape_passthrough(c, &p, end); > + } + black line. > + if (p > end) { > + *dst = end; > + return -ENOMEM; > } > > + ret = p - *dst; > *dst = p; > - > - if (ret < 0) > - return ret; > - > - return p - out; …and do not change the logic right now. Just substitute if (ret < 0) by above if (p > end). > + return ret; > } > EXPORT_SYMBOL(string_escape_mem); -- Andy Shevchenko <[email protected]> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
