/* ========================================================================== File: def_code.c Compiler: Turbo C 2.0 Description: library for automatic identification encoding text (ALT, WIN, KOI). M_def_code function for the case of a text in memory function f_def_code when the text file. Description algorithm: http://ivr.webzone.ru/articles/defcod_2/ (c) Ivan Roshchin, Moscow, 2004. ========================================================================= */ #include /* Global */ static int len_; static unsigned char *p_; static FILE *f_; /* Table combinations */ static unsigned char table_2s[128]={0xFF,0xFF,0xFF,0xC7,0xFE,0xBE,0xF7,0xFB, 0xFD,0xBF,0xF7,0xF9,0xFC,0xBE,0xF1,0x80,0xFF,0xFF,0xF7,0xBB,0xFF,0xFF,0xFF, 0xCF,0xDE,0xBF,0xD1,0x08,0xFF,0xBF,0xF1,0xBF,0xFF,0xFF,0xFF,0xC7,0x1D,0x3F, 0x7F,0x81,0xA7,0xB6,0xF2,0x82,0xFF,0xFF,0x75,0xDB,0xFC,0xBF,0xD7,0x9D,0xFF, 0xAE,0xFB,0xDF,0xFF,0xFF,0xFF,0xC7,0x84,0xB7,0xF3,0x9F,0xFF,0xFF,0xFF,0xDB, 0xFF,0xBF,0xFF,0xFF,0xFD,0xBF,0xFF,0xFF,0xFF,0xFF,0xE7,0xC7,0x84,0x9E,0xF0, 0x12,0xBC,0xBF,0xF0,0x84,0xA4,0xBA,0x10,0x10,0xA4,0xBE,0xB8,0x88,0xAC,0xBF, 0xF7,0x0A,0x84,0x86,0x90,0x08,0x04,0x00,0x00,0x03,0x7F,0xFD,0xF7,0xC1,0x7D, 0xAE,0x6F,0xCB,0x15,0x3D,0xFC,0x00,0x7F,0x7D,0xE7,0xC2,0x7F,0xFD,0xF7,0xC3}; /* ========================================================================= Alt2num support functions. Admission: a Russian-code letters in the encoding ALT. Withdrawal: number of the letters (0-31). ========================================================================= */ static int alt2num (int a) { if (a>=0xE0) a-=0x30; return (a&31); } /* ========================================================================= Koi2num support functions. Admission: a Russian-code letters in the encoding KOI. Withdrawal: number of the letters (0-31). ========================================================================= */ static int koi2num (int a) { static unsigned char t[32]={30,0,1,22,4,5,20,3,21,8,9,10,11,12,13,14,15,31, 16,17,18,19,6,2,28,27,7,24,29,25,23,26}; return (t[a&31]); } /* ========================================================================= Auxiliary functions work_2s-processing combine the two. Admission: c1-number first letter (0-31) c2-number second letter (0-31) I must check-out, I found the combination of earlier (1 yes, 0 no) buf-addressed array of information encountered together. Withdrawal: 0-specified combination has been met before, 1-mix not met before and is a valid, 2-combination not met before and is unacceptable. ========================================================================= */ static int work_2s (int c1, int c2, int check, unsigned char buf[128]) { int i=(c1<<2)+(c2>>3); /* Number of bytes in the array. */ int mask=0x80>>(c2&7); /* mask, the number of bits in bytes.*/ /* If you check = 1, check: if the bit is 0 array buf, thus, this combination has already met earlier. Then go out functions returning 0. If the combination is not met, then mark that it met (obnulyaem a bit array buf). */ if (check==1) { if ((buf[i]&mask)==0) return (0); buf[i]&=~mask; } /* Checking, acceptable combination or not. */ if ((table_2s[i]&mask)!=0) return (1); /* Acceptable. */ return (2); /* unacceptable.*/ } /* ========================================================================= Auxiliary functions def_code-definition encoding text. Functions m_def_code f_def_code and only add to this feature. Admission: get_char-pointer to a function that should be called for another symbol of the text. The function should return or code symbol, or, when you reach the end of the text, -1. n is the number of different combinations of Russian letters (1-255), which enough for encoding. Withdrawal: 0-text encoding ALT-1 WIN, 2-KOI. ========================================================================= */ static int def_code (int (*get_char)(), int n) { /* The array buf_1 stores information about what combination of letters battle have met in alternative ALT, and the array buf_2-in option WIN.*/ unsigned char buf_1 [128]; unsigned char buf_2 [128]; int bad_1=0; int bad_2=0; int bad_3=0; int all_1=0; int all_3=0; /* all_2=all_3 */ int c1; int c2=0; /* Characters treated this combination. */ int i; /* Initialization buf_1 and buf_2. */ for (i=0;i<128;i++) buf_1[i]=0xFF; for (i=0;i<128;i++) buf_2[i]=0xFF; /* main loop-handling combinations for each of the three options. Cycle running until the earlier text, or in any of the options meet n combinations. */ while (((c1=c2,c2=(*get_char)())!=-1)&&(all_1=0x80)&&(c1<0xB0))||((c1>=0xE0)&&(c1<0xF0)))&& (((c2>=0x80)&&(c2<0xB0))||((c2>=0xE0)&&(c2<0xF0)))) { switch (work_2s(alt2num(c1),alt2num(c2),1,buf_1)) /* Obrabotali. */ { case 2: bad_1++; case 1: all_1++; } } /* Options WIN and KOI. First check whether the current characters combining codes Russians letters in the code (in both encoding ranges codes Russians letters match). */ if ((c1&c2)>=0xC0) /*Ekvivalentno conditions (c1> = 0xC0) & & (c2> = 0xC0). */ { switch (work_2s(c1&31,c2&31,1,buf_2)) /* Obrabotali. */ { case 0: continue; /* If the combination of letters already found in version WIN, it has already met with option KOI, so ignore processing option and turn KOI the next major iteration cycle. */ case 2: bad_2++; } /* If the combination of letters had not yet met to form WIN, it certainly not found in version KOI, so it is not specifically check must mean, as work_2s causing property check equal to 0. */ switch (work_2s(koi2num(c1),koi2num(c2),0,NULL)) /* Obrabotali. */ { case 2: bad_3++; case 1: all_3++; } } } /* Data collected. Now, if any of the options unacceptable the combination of no more than 1 / 32 of the total number, then think that they are not it was.. */ if (bad_1<=(all_1>>5)) bad_1=0; if (bad_2<=(all_3>>5)) bad_2=0; if (bad_3<=(all_3>>5)) bad_3=0; /* Obtain result. */ { unsigned int a=((255-bad_1)<<8)+all_1; unsigned int b=((255-bad_2)<<8)+all_3; unsigned int c=((255-bad_3)<<8)+all_3; if ((a>=b)&&(a>=c)) return (0); if (b>=c) return (1); else return (2); } } /* ========================================================================= Auxiliary functions m_get_char function is called from def_code when one result of m_def_code. Withdrawal: regular text character or -1 if it ended. ========================================================================= */ static int m_get_char() { if (len_==0) return (-1); len_--; return (*(p_++)); } /* ========================================================================= Feature m_def_code-definition encoding text is remembered. Admission: p-address text len-length text, n is the number of different combinations of Russian letters (1-255), which enough for encoding. Withdrawal: 0-text encoding ALT-1 WIN, 2-KOI. ========================================================================= */ int m_def_code (unsigned char *p, int len, int n) { /* values Prisvaivaem global variables len_ and p_ that will be available from m_get_char functions. */ len_=len; p_=p; /* Obtain result. */ return (def_code(&m_get_char,n)); } /* ========================================================================= Auxiliary functions f_get_char function is called from def_code when one result of f_def_code. Withdrawal: regular text character or -1 if it ended. ========================================================================= */ static int f_get_char() { int a=fgetc(f_); if (a==EOF) return (-1); return (a); } /* ========================================================================= Feature f_def_code-definition encoding text, located in the file. Admission: f-pointer to the structure associated with the file (the current directory entries in the file to indicate the beginning of the file) n is the number of different combinations of Russian letters (1-255), which enough for encoding. Withdrawal: 0-text encoding ALT-1 WIN, 2-KOI. ========================================================================= */ int f_def_code (FILE *f, int n) { /* Prisvaivaem important global variable states, which will be available f_get_char of functions. */ f_=f; /* Obtain result. */ return (def_code(&f_get_char,n)); }