Messages in this thread Patch in this message | | | From | Rasmus Villemoes <> | Subject | [PATCH v2 2/3] lib/string_helpers.c: Refactor string_escape_mem | Date | Thu, 29 Jan 2015 11:03:19 +0100 |
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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.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> --- 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; - *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; - *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'; - 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'; - *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); - 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; + 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); + } + if (p > end) { + *dst = end; + return -ENOMEM; } + ret = p - *dst; *dst = p; - - if (ret < 0) - return ret; - - return p - out; + return ret; } EXPORT_SYMBOL(string_escape_mem); -- 2.1.3
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