mirror of https://github.com/status-im/nimPNG.git
48 lines
1.4 KiB
Nim
48 lines
1.4 KiB
Nim
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import sequtils
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type
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Buffer*[T] = object ## Uses T as internal data buffer
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data*: T
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offset*: int
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SeqBuffer*[T] = Buffer[seq[T]] ## Uses seq[T] as internal data buffer
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template `[]`*[T](b: Buffer[T], i: int): auto = b.data[b.offset + i]
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template `[]=`*[S, T](b: var Buffer[S], i: int, v: T) = b.data[b.offset + i] = v
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proc init*[T](b: var Buffer[T], d: T) =
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shallowCopy(b.data, d)
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b.offset = 0
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proc initBuffer*[T](d: T): Buffer[T] =
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shallowCopy(result.data, d)
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proc subbuffer*[T](b: Buffer[T], offset: int): Buffer[T] =
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shallowCopy(result.data, b.data)
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result.offset = b.offset + offset
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template isNil*[T](b: Buffer[T]): bool = b.data.isNil
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template copyElements*[T](dst: var Buffer[T], src: Buffer[T], count: int) =
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when defined(js):
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for i in 0 ..< count: dst[i] = src[i]
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else:
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copyMem(addr dst[dst.offset], unsafeAddr src[src.offset], count * sizeof(dst[0]))
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template zeroMem*[T](dst: var Buffer[T]) =
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when defined(js):
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applyIt(dst.data, type(dst[0])(0))
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else:
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zeroMem(addr dst.data[dst.offset], sizeof(dst[0]) * (dst.data.len - dst.offset))
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when isMainModule:
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var buf: SeqBuffer[uint8]
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buf.init(newSeq[uint8](1024))
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buf[1] = 5
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buf.offset = 1
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echo buf[0].int
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var strBuf = initBuffer(newString(20))
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strBuf[1] = 'A'
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let subBuf = strBuf.subbuffer(1)
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echo subBuf[0] # Should print A
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