44 lines
1011 B
C
44 lines
1011 B
C
/*
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* Bitstream encoder.
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*/
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#include "third_party/duktape/duk_internal.h"
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DUK_INTERNAL void duk_be_encode(duk_bitencoder_ctx *ctx, duk_uint32_t data, duk_small_int_t bits) {
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duk_uint8_t tmp;
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DUK_ASSERT(ctx != NULL);
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DUK_ASSERT(ctx->currbits < 8);
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/* This limitation would be fixable but adds unnecessary complexity. */
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DUK_ASSERT(bits >= 1 && bits <= 24);
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ctx->currval = (ctx->currval << bits) | data;
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ctx->currbits += bits;
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while (ctx->currbits >= 8) {
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if (ctx->offset < ctx->length) {
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tmp = (duk_uint8_t) ((ctx->currval >> (ctx->currbits - 8)) & 0xff);
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ctx->data[ctx->offset++] = tmp;
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} else {
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/* If buffer has been exhausted, truncate bitstream */
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ctx->truncated = 1;
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}
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ctx->currbits -= 8;
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}
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}
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DUK_INTERNAL void duk_be_finish(duk_bitencoder_ctx *ctx) {
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duk_small_int_t npad;
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DUK_ASSERT(ctx != NULL);
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DUK_ASSERT(ctx->currbits < 8);
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npad = (duk_small_int_t) (8 - ctx->currbits);
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if (npad > 0) {
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duk_be_encode(ctx, 0, npad);
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}
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DUK_ASSERT(ctx->currbits == 0);
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}
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