%% options copyright owner = Dirk Krause copyright year = 2015-xxxx license = bsd %% header /** @file dk4ahd.h ASCIIHex decoder. First initialize the decoder using the dk4ahex_dec_init() function. Add text characters using the dk4ahex_dec_add() function. The function returns DK4_EDSTM_ACCEPT if the text character was successfully stored in the decoder without completing a byte. The DK4_EDSTM_FINISHED return code indicates that a byte was finished, use dk4ahex_output() to retrieve it. The DK4_EDSTM_STOP return code indicates that an end of data (EOD) marker was found. After feeding all text characters into the decoder use dk4ahex_finish() to check whether there is an unprocessed half-byte stored. If the function returns DK4_EDSTM_FINISHED, use dk4ahex_output() to retrieve the final byte. Note: The call to dk4ahex_finish() is also necessary after obtaining DK4_EDSTM_STOP from dk4ahex_dec_add(). */ #include "dk4conf.h" #include "dk4error.h" /** ASCII-Hex decoder. */ typedef struct { int cpos; /**< Current position. */ unsigned char obyte; /**< Output byte. */ } dk4_ahex_dec_t; #ifdef __cplusplus extern "C" { #endif /** Initialize decoder. @param dec Decoder to initialize. @param erp Error report, may be NULL. */ void dk4ahex_dec_init(dk4_ahex_dec_t *dec, dk4_er_t *erp); /** Add text character to decoder. @param dec Decoder. @param tc Text character to add. @param erp Error report, may be NULL. @return Action to take: - DK4_EDSTM_ACCEPT
if the text was saved in the decoder, no action necessary. - DK4_EDSTM_FINISHED
if a byte was completed, use dk4ahex_dec_output() to retrieve the byte. - DK4_EDSTM_STOP
if the end of data (EOD) marker was detected. Use dk4ahex_finish() to check whether there is still data in the decoder. - DK4_EDSTM_ERROR
if an error occured. */ int dk4ahex_dec_add(dk4_ahex_dec_t *dec, char tc, dk4_er_t *erp); /** Check for final byte. @param dec Decoder. @param erp Error report, may be NULL. @return Action to take, one from: - DK4_EDSTM_ACCEPT
if there is no action necessary. - DK4_EDSTM_FINISHED
if there is data available, use dk4ahex_dec_output() to retrieve the byte. - DK4_EDSTM_ERROR
if an error occured. */ int dk4ahex_finish(dk4_ahex_dec_t *dec, dk4_er_t *erp); /** Retrieve current decoder content. @param dec Decoder. @param erp Error report, may be NULL. @return The current byte stored in the decoder. */ unsigned char dk4ahex_output(dk4_ahex_dec_t *dec, dk4_er_t *erp); #ifdef __cplusplus } #endif %% module #include "dk4ahd.h" #include "dk4mem.h" #include "dk4edstm.h" $!trace-include void dk4ahex_dec_init(dk4_ahex_dec_t *dec, dk4_er_t *erp) { if (NULL != dec) { DK4_MEMRES(dec, sizeof(dk4_ahex_dec_t)); dec->cpos = 0; dec->obyte = 0x00; } else { dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS); } } int dk4ahex_dec_add(dk4_ahex_dec_t *dec, char tc, dk4_er_t *erp) { int back = DK4_EDSTM_ERROR; if (NULL != dec) { switch (tc) { case ' ' : case '\t' : case '\r' : case '\n' : case 0x00 : case 0x0C : { back = DK4_EDSTM_ACCEPT; } break; case '>' : { back = DK4_EDSTM_STOP; } break; case '0' : { if (0 != dec->cpos) { dec->cpos = 2; } else { dec->obyte = 0x00; dec->cpos = 1; } } break; case '1' : { if (0 != dec->cpos) { dec->obyte |= 0x01; dec->cpos = 2; } else { dec->obyte = 0x10; dec->cpos = 1; } } break; case '2' : { if (0 != dec->cpos) { dec->obyte |= 0x02; dec->cpos = 2; } else { dec->obyte = 0x20; dec->cpos = 1; } } break; case '3' : { if (0 != dec->cpos) { dec->obyte |= 0x03; dec->cpos = 2; } else { dec->obyte = 0x30; dec->cpos = 1; } } break; case '4' : { if (0 != dec->cpos) { dec->obyte |= 0x04; dec->cpos = 2; } else { dec->obyte = 0x40; dec->cpos = 1; } } break; case '5' : { if (0 != dec->cpos) { dec->obyte |= 0x05; dec->cpos = 2; } else { dec->obyte = 0x50; dec->cpos = 1; } } break; case '6' : { if (0 != dec->cpos) { dec->obyte |= 0x06; dec->cpos = 2; } else { dec->obyte = 0x60; dec->cpos = 1; } } break; case '7' : { if (0 != dec->cpos) { dec->obyte |= 0x07; dec->cpos = 2; } else { dec->obyte = 0x70; dec->cpos = 1; } } break; case '8' : { if (0 != dec->cpos) { dec->obyte |= 0x08; dec->cpos = 2; } else { dec->obyte = 0x80; dec->cpos = 1; } } break; case '9' : { if (0 != dec->cpos) { dec->obyte |= 0x09; dec->cpos = 2; } else { dec->obyte = 0x90; dec->cpos = 1; } } break; case 'a' : case 'A' : { if (0 != dec->cpos) { dec->obyte |= 0x0A; dec->cpos = 2; } else { dec->obyte = 0xA0; dec->cpos = 1; } } break; case 'b' : case 'B' : { if (0 != dec->cpos) { dec->obyte |= 0x0B; dec->cpos = 2; } else { dec->obyte = 0xB0; dec->cpos = 1; } } break; case 'c' : case 'C' : { if (0 != dec->cpos) { dec->obyte |= 0x0C; dec->cpos = 2; } else { dec->obyte = 0xC0; dec->cpos = 1; } } break; case 'd' : case 'D' : { if (0 != dec->cpos) { dec->obyte |= 0x0D; dec->cpos = 2; } else { dec->obyte = 0xD0; dec->cpos = 1; } } break; case 'e' : case 'E' : { if (0 != dec->cpos) { dec->obyte |= 0x0E; dec->cpos = 2; } else { dec->obyte = 0xE0; dec->cpos = 1; } } break; case 'f' : case 'F' : { if (0 != dec->cpos) { dec->obyte |= 0x0F; dec->cpos = 2; } else { dec->obyte = 0xF0; dec->cpos = 1; } } break; } if (2 == dec->cpos) { dec->cpos = 0; back = DK4_EDSTM_FINISHED; } } else { dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS); } return back; } int dk4ahex_finish(dk4_ahex_dec_t *dec, dk4_er_t *erp) { int back = DK4_EDSTM_ERROR; if (NULL != dec) { switch (dec->cpos) { case 1: { back = DK4_EDSTM_FINISHED; } break; default : { back = DK4_EDSTM_ACCEPT; } break; } } else { dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS); } return back; } unsigned char dk4ahex_output(dk4_ahex_dec_t *dec, dk4_er_t *erp) { unsigned char back = 0x00; if (NULL != dec) { back = dec->obyte; } else { dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS); } return back; }