86 lines
2.3 KiB
C
86 lines
2.3 KiB
C
#pragma once
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#include "foundation/types.h"
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#include "foundation/endian.h"
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/* this is separated out to processor-specific types for a few reasons
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1) Unaligned writes are fast/easy on x86, slow on some platforms (ARM, x64), very slow on a few (Itanium) and crash on others (PowerPC)
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2) ARM is very good at *ptr++, x86 is very good at ptr[offset]
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3) Endian issues
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*/
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typedef struct ByteWriter
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{
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uint8_t *data;
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size_t data_length;
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size_t offset;
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} ByteWriter, *nu_bytewriter_t;
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/* --------- Construction & Utility --------- */
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#define BYTEWRITER_INIT(data, length) { (uint8_t *)data, length, 0 }
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inline static uint32_t bw_bytes_written(nu_bytewriter_t bw)
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{
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return bw->offset;
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}
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/* --------- Little Endian writers --------- */
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inline static void bytewriter_fourcc_string(nu_bytewriter_t bw, const char *fourcc)
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{
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bw->data[bw->offset] = fourcc[0];
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bw->data[bw->offset+1] = fourcc[1];
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bw->data[bw->offset+2] = fourcc[2];
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bw->data[bw->offset+3] = fourcc[3];
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bw->offset += 4;
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}
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inline static void bytewriter_uint32_le(nu_bytewriter_t bw, uint32_t value)
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{
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*(uint32_t *)(&bw->data[bw->offset]) = value;
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bw->offset+=4;
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}
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inline static void bytewriter_uint16_le(nu_bytewriter_t bw, uint16_t value)
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{
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*(uint16_t *)(&bw->data[bw->offset]) = value;
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bw->offset+=2;
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}
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/* --------- Big Endian writers --------- */
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inline static void bytewriter_uint32_be(nu_bytewriter_t bw, uint32_t value)
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{
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*(uint32_t *)(&bw->data[bw->offset]) = _byteswap_ulong(value);
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bw->offset+=4;
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}
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inline static void bytewriter_uint24_be(nu_bytewriter_t bw, uint32_t value)
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{
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bw->data[bw->offset] = (uint8_t)(value >> 16) & 0xFF;
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bw->data[bw->offset+1] = (uint8_t)(value >> 8) & 0xFF;
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bw->data[bw->offset+2] = (uint8_t)value & 0xFF;
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bw->offset+=3;
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}
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inline static void bytewriter_uint16_le(nu_bytewriter_t bw, uint16_t value)
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{
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*(uint16_t *)(&bw->data[bw->offset]) = value;
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bw->offset+=2;
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}
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/* --------- Neutral Endian writers --------- */
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inline static void bytewriter_uint32_zero(nu_bytewriter_t bw)
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{
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*(uint32_t *)(&bw->data[bw->offset]) = 0;
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bw->offset+=4;
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}
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inline static void bytewriter_uint32_nzero(nu_bytewriter_t bw, uint32_t num_zeroes)
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{
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memset(bw->data, 0, num_zeroes*4);
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bw->offset+=num_zeroes*4;
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}
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inline static void bytewriter_uint8(nu_bytewriter_t bw, uint8_t value)
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{
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*(uint8_t *)&bw->data[bw->offset] = value;
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bw->offset++;
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}
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