github.com/solo-io/cue@v0.4.7/internal/cuetest/chunker.go (about)

     1  // Copyright 2019 CUE Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package cuetest
    16  
    17  import (
    18  	"bytes"
    19  	"testing"
    20  )
    21  
    22  // A Chunker is used to find segments in text.
    23  type Chunker struct {
    24  	t *testing.T
    25  	b []byte
    26  	s []byte
    27  	p int
    28  }
    29  
    30  // NewChunker returns a new chunker.
    31  func NewChunker(t *testing.T, b []byte) *Chunker {
    32  	return &Chunker{t: t, b: b}
    33  }
    34  
    35  // Next finds the first occurrence from the current scan position of beg,
    36  // records the segment from that position until the first occurrence of end
    37  // and then updates the current position. It reports whether a segment enclosed
    38  // by beg and end can be found.
    39  func (c *Chunker) Next(beg, end string) bool {
    40  	if !c.Find(beg) {
    41  		return false
    42  	}
    43  	if !c.Find(end) {
    44  		c.t.Fatalf("quotes at position %d not terminated", c.p)
    45  	}
    46  	return true
    47  }
    48  
    49  // Text returns the text segment captured by the last call to Next or Find.
    50  func (c *Chunker) Text() string {
    51  	return string(c.s)
    52  }
    53  
    54  // Bytes returns the segment captured by the last call to Next or Find.
    55  func (c *Chunker) Bytes() []byte {
    56  	return c.s
    57  }
    58  
    59  // Find searches for key from the current position and sets the current segment
    60  // to the text from current position up till the key's position. If successful,
    61  // the position is updated to point directly after the occurrence of key.
    62  func (c *Chunker) Find(key string) bool {
    63  	p := bytes.Index(c.b, []byte(key))
    64  	if p == -1 {
    65  		c.s = c.b
    66  		return false
    67  	}
    68  	c.p += p + len(key)
    69  	b := c.b
    70  	c.s = b[:p]
    71  	c.b = b[p+len(key):]
    72  	return true
    73  }