go-vise

split.go (4787B)

---

 package render
 
 import (
 	"fmt"
 	"log"
 	"strings"
 )
 
 
 func bookmark(values []string) []uint32 {
 	var c int
 	var bookmarks []uint32 = []uint32{0}
 
 	for _, v := range values {
 		c += len(v) + 1
 		bookmarks = append(bookmarks, uint32(c))
 	}
 	return bookmarks
 }
 //
 //func paginate(bookmarks []uint32, capacity uint32) ([][]uint32, error) {
 //	if len(bookmarks) == 0 {
 //		return nil, fmt.Errorf("empty bookmark array")
 //	}
 //	var c uint32
 //	var pages [][]uint32
 //	var prev uint32
 //	
 //	pages = append(pages, []uint32{})
 //	currentPage := 0
 //	lookAhead := bookmarks[1:]
 //
 //	for i, v := range lookAhead {
 //		lc := v - c
 //		if lc > capacity {
 //			c = prev
 //			if lc - c > capacity {
 //				return nil, fmt.Errorf("value at %v alone exceeds capacity", i)
 //			}
 //			currentPage += 1
 //			pages = append(pages, []uint32{})
 //		}
 //		pages[currentPage] = append(pages[currentPage], bookmarks[i])
 //		prev = v
 //	}
 //
 //	pages[currentPage] = append(pages[currentPage], bookmarks[len(bookmarks)-1])
 //	return pages, nil
 //}
 
 func isLast(cursor uint32, end uint32, capacity uint32) bool {
 	l := end - cursor
 	remaining := capacity
 	return l <= remaining
 }
 
 func paginate(bookmarks []uint32, capacity uint32, nextSize uint32, prevSize uint32) ([][]uint32, error) {
 	if len(bookmarks) == 0 {
 		return nil, fmt.Errorf("empty page array")
 	}
 
 	var pages [][]uint32
 	var c uint32
 	lastIndex := len(bookmarks) - 1
 	last := bookmarks[lastIndex]
 	var haveMore bool
 
 	if isLast(0, last, capacity) {
 		pages = append(pages, bookmarks)
 		return pages, nil
 	}
 
 	lookAhead := bookmarks[1:]
 	pages = append(pages, []uint32{})
 	var i int
 
 	haveMore = true
 	for haveMore {
 		remaining := int(capacity)
 		if i > 0 {
 			remaining -= int(prevSize)
 		}
 		if remaining < 0 {
 			return nil, fmt.Errorf("underrun in item %v:%v (%v) index %v prevsize %v remain %v cap %v", bookmarks[i], lookAhead[i], lookAhead[i] - bookmarks[i], i, prevSize, remaining, capacity)
 		}
 		if isLast(c, last, uint32(remaining)) {
 			haveMore = false
 		} else {
 			remaining -= int(nextSize)
 		}
 		if remaining < 0 {
 			return nil, fmt.Errorf("underrun in item %v:%v (%v) index %v prevsize %v nextsize %v remain %v cap %v", bookmarks[i], lookAhead[i], lookAhead[i] - bookmarks[i], i, prevSize, nextSize, remaining, capacity)
 		}
 
 		var z int
 		currentPage := len(pages) - 1
 		for i < lastIndex {
 			log.Printf("have item %v:%v (%v) index %v prevsize %v nextsize %v remain %v cap %v", bookmarks[i], lookAhead[i], lookAhead[i] - bookmarks[i], i, prevSize, nextSize, remaining, capacity)
 
 			v := lookAhead[i]
 			delta := int((v - c) + 1)
 			if z == 0 {
 				if delta > remaining {
 					return nil, fmt.Errorf("single value at %v exceeds capacity", i)
 				}
 			}
 			z += delta
 			if z > remaining {
 				break
 			}
 			pages[currentPage] = append(pages[currentPage], bookmarks[i])
 			c = v
 			i += 1
 		}
 		log.Printf("more %v remaining %v c %v last %v pages %v", haveMore, remaining, c, last, pages)
 
 		if haveMore {
 			pages = append(pages, []uint32{})
 		}
 	}
 
 	l := len(pages)-1
 	pages[l] = append(pages[l], last)
 	return pages, nil
 }
 
 func explode(values []string, pages [][]uint32) string {
 	s := strings.Join(values, "")
 	s += "\n"
 	sb := strings.Builder{}
 
 	var start uint32
 	var end uint32
 	var lastPage int
 	var z uint32
 	for i, page := range pages {
 		for _, c := range page {
 			if c == 0 {
 				continue
 			}
 			z += 1
 			if i != lastPage {
 				sb.WriteRune('\n')
 			} else if c > 0 {
 				sb.WriteByte(byte(0x00))
 			}
 			end = c - z
 			v := s[start:end]
 			log.Printf("page %v part %v %v %s", i, start, end, v)
 			v = s[start:end]
 			sb.WriteString(v)
 			start = end
 		}
 		lastPage = i
 	}
 	r := sb.String()
 	r = strings.TrimRight(r, "\n")
 	return r
 }
 
 //	if lastCursor <= capacity {
 //		return pages, nil
 //	}
 //
 //	var flatPages [][]uint32 
 //
 //	pages = append(pages, []uint32{})
 //	for _, v := range bookmarks {
 //		for _, vv := range v {
 //			pages[0] = append(pages[0], vv)
 //		}
 //	}
 //
 //	var c uint32
 //	var prev uint32
 //	currentPage := 0 
 //
 //	for i, page := range pages {
 //		var delta uint32
 //		if i == 0 {
 //			delta = nextSize
 //		} else if i == len(pages) - 1 {
 //			delta = prevSize
 //		} else {
 //			delta = nextSize + prevSize
 //		}
 //		remaining := capacity - delta
 //		log.Printf("processing page %v", page)
 //		lookAhead := page[1:]
 //
 //		for j, v := range lookAhead {
 //			lc := v - c
 //			log.Printf("currentpage j %v lc %v v %v remain %v", j, lc, v, remaining)
 //			if lc > remaining {
 //				c = prev
 //				if lc - c > remaining {
 //					return nil, fmt.Errorf("value at page %v idx %v alone exceeds capacity", i, v)
 //				}
 //				currentPage += 1
 //				page = append(page, []uint32{})
 //			}
 //			page[currentPage] = append(page[currentPage], page[j])
 //			prev = v
 //		}
 //	}
 //	return page, nil
 //}