From e0c6872cf40896c7be36b11dcc744620f10adf1d Mon Sep 17 00:00:00 2001 From: Norbert Preining Date: Mon, 2 Sep 2019 13:46:59 +0900 Subject: Initial commit --- support/dktools/dk4rld.ctr | 274 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 274 insertions(+) create mode 100644 support/dktools/dk4rld.ctr (limited to 'support/dktools/dk4rld.ctr') diff --git a/support/dktools/dk4rld.ctr b/support/dktools/dk4rld.ctr new file mode 100644 index 0000000000..e981d30119 --- /dev/null +++ b/support/dktools/dk4rld.ctr @@ -0,0 +1,274 @@ +%% options + +copyright owner = Dirk Krause +copyright year = 2015-xxxx +license = bsd + + +%% header + +/** @file dk4rld.h Run-length decoder. + +Use dk4rld_init() to initialize the decoder before feeding data to it. + +Feed the encoded data into the decoder byte by byte, use the +dk4rld_add() function. +If the function returns DK4_EDSTM_ACCEPT, the input was successfully stored +into the internal data structures, not need for further action. +If the function returns DK4_EDSTM_FINISHED, an output secquence was +completed, either a run or a literal byte sequence. Use dk4rld_output() +to retrieve output data. +If the dk4rld_add function returns DK4_EDSTM_STOP, an end of data +(EOD) marker was found; do not feed further bytes into the decoder. + +After feeding all input bytes into the decoder, use dk4rld_finish() to check +syntax. If the function returns DK4_EDSTM_ERROR, the input data stream +was not properly run-length encoded. +*/ + +#include "dk4error.h" + +/** Run length decoder. +*/ +typedef struct { + unsigned char ob[128]; /**< Output buffer. */ + size_t oused; /**< Number of used bytes in ob. */ + size_t ll; /**< Number of expected bytes. */ + int st; /**< Current state. */ +} dk4_rl_dec_t; + + +#ifdef __cplusplus +extern "C" { +#endif + +/** Initialize decoder. + @param dec Decoder to initialize. + @param erp Error report, may be NULL. + + Error codes: + - DK4_E_INVALID_ARGUMENTS if enc is NULL. +*/ +void +dk4rld_init(dk4_rl_dec_t *dec, dk4_er_t *erp); + +/** Add one encoded byte to decoder. + @param dec Decoder. + @param inbyte Byte to process. + @param erp Error report, may be NULL. + @return Action to take, one from: + - DK4_EDSTM_ACCEPT
+ if the byte was successfully added + to the internal data structures, no further action necessary. + - DK4_EDSTM_FINISHED
+ if output is available, use dk4rld_output() to retrieve output. + - DK4_EDSTM_STOP
+ if an EOD marker was detected. Do not feed further bytes + to the decoder. + - DK4_EDSTM_ERROR
+ if an error occured. + + Error codes: + - DK4_E_INVALID_ARGUMENTS if enc is NULL. +*/ +int +dk4rld_add(dk4_rl_dec_t *dec, unsigned char inbyte, dk4_er_t *erp); + +/** Finish decoding. + @param dec Decoder. + @param erp Error report, may be NULL. + @return Action to take, one from: + - DK4_EDSTM_ACCEPT
+ if no remaining data is stored in the decoder, no further + action necessary. + - DK4_EDSTM_FINISHED
+ if output is available, use dk4rld_output() to retrieve output. + - DK4_EDSTM_ERROR
+ if an error occured. + + Error codes: + - DK4_E_INVALID_ARGUMENTS
+ if enc is NULL. + - DK4_E_SYNTAX
+ if data indicated by the run-length byte or literally-length + byte is missing. +*/ +int +dk4rld_finish(dk4_rl_dec_t *dec, dk4_er_t *erp); + +/** Retrieve decoder output. + @param dptr Address of pointer to set to decoder output, + should be initialized to NULL. + @param szptr Address of variable to receive buffer size, + should be initialized to 0. + @param dec Decoder. + @param erp Error report, may be NULL. + @return 1 if data is available, 0 otherwise. + + Error codes: + - DK4_E_INVALID_ARGUMENTS if enc is NULL. +*/ +int +dk4rld_output( + const unsigned char **dptr, size_t *szptr, dk4_rl_dec_t *dec, dk4_er_t *erp +); + +#ifdef __cplusplus +} +#endif + +%% module + +#include "dk4rld.h" +#include "dk4edstm.h" +#include "dk4mem.h" + + + +$!trace-include + + + +/** Decoder states. +*/ +enum { + /** Start state, exepect run length + or literal data length. + */ + RLD_ST_EXPECT_KEY_BYTE = 0, + + /** Expect byte value for run. + */ + RLD_ST_EXPECT_RUN_BYTE , + + /** Expect literal byte. + */ + RLD_ST_EXPECT_LITERAL_BYTE , + + /** No further input accepted as + EOD marker was found. + */ + RLD_ST_EOD_FOUND +}; + + + +void +dk4rld_init(dk4_rl_dec_t *dec, dk4_er_t *erp) +{ + $? "+ dk4rld_init" + if (NULL != dec) { + DK4_MEMRES(dec, sizeof(dk4_rl_dec_t)); + dec->oused = 0; + dec->ll = 0; + dec->st = RLD_ST_EXPECT_KEY_BYTE; + } else { + dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS); + } $? "- dk4rld_init" +} + + + +int +dk4rld_add(dk4_rl_dec_t *dec, unsigned char inbyte, dk4_er_t *erp) +{ + int back = DK4_EDSTM_ERROR; + $? "+ dk4rld_add" + if (NULL != dec) { + switch (dec->st) { + case RLD_ST_EXPECT_KEY_BYTE : { + if ((unsigned char)128 > inbyte) { + /* + Literal byte sequence + */ + dec->st = RLD_ST_EXPECT_LITERAL_BYTE; + dec->ll = (size_t)inbyte + 1; + back = DK4_EDSTM_ACCEPT; + } else { + if ((unsigned char)128 < inbyte) { + /* + Run of equal bytes + */ + dec->st = RLD_ST_EXPECT_RUN_BYTE; + dec->ll = (size_t)257 - (size_t)inbyte; + back = DK4_EDSTM_ACCEPT; + } else { + /* + EOD marker found + */ + dec->st = RLD_ST_EOD_FOUND; + back = DK4_EDSTM_STOP; + } + } + } break; + case RLD_ST_EXPECT_RUN_BYTE : { + dk4mem_set(&(dec->ob[0]), dec->ll, inbyte, NULL); + dec->oused = dec->ll; + dec->st = RLD_ST_EXPECT_KEY_BYTE; + back = DK4_EDSTM_FINISHED; + } break; + case RLD_ST_EXPECT_LITERAL_BYTE : { + dec->ob[0] = inbyte; + dec->oused = 1; + dec->ll -= 1; + if (0 == dec->ll) { + dec->st = RLD_ST_EXPECT_KEY_BYTE; + } + back = DK4_EDSTM_FINISHED; + } break; + default : { + dk4error_set_simple_error_code(erp, DK4_E_SYNTAX); + } break; + } + } else { + dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS); + } $? "- dk4rld_add %d", back + return back; +} + + + +int +dk4rld_finish(dk4_rl_dec_t *dec, dk4_er_t *erp) +{ + int back = DK4_EDSTM_ERROR; + $? "+ dk4rld_finish" + if (NULL != dec) { + switch (dec->st) { + case RLD_ST_EXPECT_KEY_BYTE : case RLD_ST_EOD_FOUND : { + back = DK4_EDSTM_ACCEPT; + } break; + default : { + dk4error_set_simple_error_code(erp, DK4_E_SYNTAX); + } break; + } + } else { + dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS); + } $? "- dk4rld_finish %d", back + return back; +} + + + +int +dk4rld_output( + const unsigned char **dptr, size_t *szptr, dk4_rl_dec_t *dec, dk4_er_t *erp +) +{ + int back = 0; + $? "+ dk4rld_output" + if (NULL != dec) { + if (0 < dec->oused) { + *dptr = &(dec->ob[0]); + *szptr = dec->oused; + back = 1; + } else { + *dptr = NULL; + *szptr = 0; + } + } else { + dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS); + } $? "- dk4rld_output %d", back + return back; +} + -- cgit v1.2.3