diff options
Diffstat (limited to 'src/misc.c')
| -rw-r--r-- | src/misc.c | 144 |
1 files changed, 126 insertions, 18 deletions
@@ -93,6 +93,15 @@ static const ContentType_t MimeTypes[] = { { NULL, 0 } }; +typedef enum { + DT_OCTET_STREAM = 0, + DT_TEXT_HTML, + DT_TEXT_PLAIN, + DT_IMAGE_GIF, + DT_IMAGE_PNG, + DT_IMAGE_JPG, +} DetectedContentType; + /* * Detects 'Content-Type' from a data stream sample. * @@ -105,10 +114,10 @@ static const ContentType_t MimeTypes[] = { */ int a_Misc_get_content_type_from_data(void *Data, size_t Size, const char **PT) { - int st = 1; /* default to "doubt' */ - int Type = 0; /* default to "application/octet-stream" */ + size_t i, non_ascci, non_ascci_text, bin_chars; char *p = Data; - size_t i, non_ascci; + int st = 1; /* default to "doubt' */ + DetectedContentType Type = DT_OCTET_STREAM; /* default to binary */ /* HTML try */ for (i = 0; i < Size && isspace(p[i]); ++i); @@ -119,36 +128,50 @@ int a_Misc_get_content_type_from_data(void *Data, size_t Size, const char **PT) /* this line is workaround for FTP through the Squid proxy */ (Size - i >= 17 && !dStrncasecmp(p+i, "<!-- HTML listing", 17))) { - Type = 1; + Type = DT_TEXT_HTML; st = 0; /* Images */ } else if (Size >= 4 && !dStrncasecmp(p, "GIF8", 4)) { - Type = 3; + Type = DT_IMAGE_GIF; st = 0; } else if (Size >= 4 && !dStrncasecmp(p, "\x89PNG", 4)) { - Type = 4; + Type = DT_IMAGE_PNG; st = 0; } else if (Size >= 2 && !dStrncasecmp(p, "\xff\xd8", 2)) { /* JPEG has the first 2 bytes set to 0xffd8 in BigEndian - looking * at the character representation should be machine independent. */ - Type = 5; + Type = DT_IMAGE_JPG; st = 0; /* Text */ } else { - /* We'll assume "text/plain" if the set of chars above 127 is <= 10 - * in a 256-bytes sample. Better heuristics are welcomed! :-) */ - non_ascci = 0; + /* Heuristic for "text/plain" + * {ASCII, LATIN1, UTF8, KOI8-R, CP-1251} + * All in the above set regard [00-31] as control characters. + * LATIN1: [7F-9F] unused + * CP-1251 {7F,98} unused (two characters). + * + * We'll use [0-31] as indicators of non-text content. + * Better heuristics are welcomed! :-) */ + + non_ascci = non_ascci_text = bin_chars = 0; Size = MIN (Size, 256); - for (i = 0; i < Size; i++) - if ((uchar_t) p[i] > 127) + for (i = 0; i < Size; i++) { + int ch = (uchar_t) p[i]; + if (ch < 32 && !isspace(ch)) + ++bin_chars; + if (ch > 126) ++non_ascci; - if (Size == 256) { - Type = (non_ascci > 10) ? 0 : 2; - st = 0; - } else { - Type = (non_ascci > 0) ? 0 : 2; + if (ch > 190) + ++non_ascci_text; + } + if (bin_chars == 0) { + /* Let's say text: if "rare" chars are <= 10% */ + if ((non_ascci - non_ascci_text) <= Size/10) + Type = DT_TEXT_PLAIN; } + if (Size == 256) + st = 0; } *PT = MimeTypes[Type].str; @@ -156,6 +179,91 @@ int a_Misc_get_content_type_from_data(void *Data, size_t Size, const char **PT) } /* + * Parse Content-Type string, e.g., "text/html; charset=utf-8". + */ +void a_Misc_parse_content_type(const char *str, char **major, char **minor, + char **charset) +{ + const char *s; + + if (major) + *major = NULL; + if (minor) + *minor = NULL; + if (charset) + *charset = NULL; + if (!str) + return; + + for (s = str; isalnum(*s) || (*s == '-'); s++); + if (major) + *major = dStrndup(str, s - str); + + if (*s == '/') { + for (str = ++s; isalnum(*s) || (*s == '-'); s++); + if (minor) + *minor = dStrndup(str, s - str); + } + + if (charset && *s) { + const char terminators[] = " ;\t"; + const char key[] = "charset"; + + if ((s = dStristr(str, key)) && + (s == str || strchr(terminators, s[-1]))) { + s += sizeof(key) - 1; + for ( ; *s == ' ' || *s == '\t'; ++s); + if (*s == '=') { + size_t len; + for (++s; *s == ' ' || *s == '\t'; ++s); + if ((len = strcspn(s, terminators))) { + if (*s == '"' && s[len-1] == '"' && len > 1) { + /* quoted string */ + s++; + len -= 2; + } + *charset = dStrndup(s, len); + } + } + } + } +} + +/* + * Compare two Content-Type strings. + * Return 0 if they are equivalent, and 1 otherwise. + */ +int a_Misc_content_type_cmp(const char *ct1, const char *ct2) +{ + char *major1, *major2, *minor1, *minor2, *charset1, *charset2; + int ret; + + if ((!ct1 || !*ct1) && (!ct2 || !*ct2)) + return 0; + if ((!ct1 || !*ct1) || (!ct2 || !*ct2)) + return 1; + + a_Misc_parse_content_type(ct1, &major1, &minor1, &charset1); + a_Misc_parse_content_type(ct2, &major2, &minor2, &charset2); + + if (major1 && major2 && !dStrcasecmp(major1, major2) && + minor1 && minor2 && !dStrcasecmp(minor1, minor2) && + ((!charset1 && !charset2) || + (charset1 && charset2 && !dStrcasecmp(charset1, charset2)) || + (!charset1 && charset2 && !dStrcasecmp(charset2, "UTF-8")) || + (charset1 && !charset2 && !dStrcasecmp(charset1, "UTF-8")))) { + ret = 0; + } else { + ret = 1; + } + dFree(major1); dFree(major2); + dFree(minor1); dFree(minor2); + dFree(charset1); dFree(charset2); + + return ret; +} + +/* * Check the server-supplied 'Content-Type' against our detected type. * (some servers seem to default to "text/plain"). * @@ -177,7 +285,7 @@ int a_Misc_content_type_check(const char *EntryType, const char *DetectedType) int i; int st = -1; - _MSG("Type check: [Srv: %s Det: %s]\n", EntryType, DetectedType); + MSG("Type check: [Srv: %s Det: %s]\n", EntryType, DetectedType); if (!EntryType) return 0; /* there's no mismatch without server type */ |