ref: f5911b3cda06461a8f4fab259bb6f86d5453a0bb
dir: /jbig2_arith_iaid.c/
/* Annex A.3 */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include "os_types.h" #include <stddef.h> #include <string.h> /* memset() */ #ifdef VERBOSE #include <stdio.h> /* for debug printing only */ #endif #include "jbig2.h" #include "jbig2_priv.h" #include "jbig2_arith.h" #include "jbig2_arith_iaid.h" struct _Jbig2ArithIaidCtx { int SBSYMCODELEN; Jbig2ArithCx *IAIDx; }; Jbig2ArithIaidCtx * jbig2_arith_iaid_ctx_new(Jbig2Ctx *ctx, int SBSYMCODELEN) { Jbig2ArithIaidCtx *result = jbig2_new(ctx, Jbig2ArithIaidCtx, 1); int ctx_size = 1 << SBSYMCODELEN; result->SBSYMCODELEN = SBSYMCODELEN; result->IAIDx = jbig2_alloc(ctx->allocator, ctx_size); memset(result->IAIDx, 0, ctx_size); return result; } /* A.3 */ /* Return value: -1 on error, 0 on normal value */ int jbig2_arith_iaid_decode(Jbig2ArithIaidCtx *ctx, Jbig2ArithState *as, int32_t *p_result) { Jbig2ArithCx *IAIDx = ctx->IAIDx; int SBSYMCODELEN = ctx->SBSYMCODELEN; int PREV = 1; int D; int i; /* A.3 (2) */ for (i = 0; i < SBSYMCODELEN; i++) { D = jbig2_arith_decode(as, &IAIDx[PREV]); #ifdef VERBOSE fprintf(stderr, "IAID%x: D = %d\n", PREV, D); #endif PREV = (PREV << 1) | D; } /* A.3 (3) */ PREV -= 1 << SBSYMCODELEN; #ifdef VERBOSE fprintf(stderr, "IAID result: %d\n", PREV); #endif *p_result = PREV; return 0; } void jbig2_arith_iaid_ctx_free(Jbig2Ctx *ctx, Jbig2ArithIaidCtx *iax) { jbig2_free(ctx->allocator, iax->IAIDx); jbig2_free(ctx->allocator, iax); }